Edited by

Robert S. Neyland and Heather G. Brown

NAVAL HISTORY AND HERITAGE COMMAND

H. L. Hunley 

 Recovery Operations
H. L. Hunley

Recovery Operations

H. L. Hunley

Recovery Operations

Edited by:

Robert S. Neyland 

Heather G. Brown

Principal Investigator:

Robert S. Neyland, Ph.D.

Department of the Navy

Authors:

Robert S. Neyland

Claire Peachey

Shea McLean

Harry Pecorelli III

Heather G. Brown

M. Scott Harris

Maria Jacobsen

Paul Mardikian

Michael Scafuri

David L. Conlin

A Collaborative Project of:

Naval History and Heritage Command,

South Carolina Hunley Commission, 

and

Friends of the Hunley

Naval History and Heritage Command

Washington, D.C. 

2016
Library of Congress Cataloging-in-Publication Data

Names: Neyland, Robert S., editor, author. | Brown, Heather G. (Heather

 Gale), editor, author.

Title: H.L. Hunley recovery operations / edited by Robert S. Neyland, Heather

 G. Brown.

Description: Washington, D.C. : Naval History and Heritage Command, 2016. |

 Includes bibliographical references.

Identifiers: LCCN 2016028242| ISBN 9780945274902 (pbk.) | ISBN 9780945274919

 (pdf)

Subjects: LCSH: H.L. Hunley (Submarine) | Underwater archaeology--South

 Carolina--Charleston Harbor. | Excavations (Archaeology)--South

 Carolina--Charleston Harbor. | Submarines (Ships)--United

 States--History--19th century. | Charleston (S.C.)--History--Civil War,

 1861-1865--Naval operations--Submarine. | United States--History--Civil

 War, 1861-1865--Naval operations--Submarine. | Charleston Harbor

 (S.C.)--Antiquities.

Classification: LCC E599.H4 H13 2016 | DDC 975.7/915--dc23

LC record available at https://lccn.loc.gov/2016028242

Cover design by Heather G. Brown. Image composite of “Confederate Submarine H. L. Hunley (1863–1864)” by 

R. G. Skerrett, courtesy of the Navy Art Collection, NHHC, and photograph of H. L. Hunley by Cramer Gallimore, 

courtesy of the Friends of the Hunley. Book design by Heather G. Brown.

Satisfactory and important as have been the performances of the 

navy at this interesting period, they are scarcely more wonderful than 

the success of our mechanics and artisans in the production of war 

vessels which has created a new form of naval power.

-- Abraham Lincoln
v

Figures ................................................................... ix

Tables ................................................................... xiii

List of Abbreviations............................................ xv

Editor’s Note ...................................................... xvii

Foreword ............................................................ xix

Acknowledgments .............................................. xxi

1. INTRODUCTION 1

Robert S. Neyland

2. HISTORICAL BACKGROUND 5

Shea McLean

Early Submarine Development 5

Submarines and the American Civil War 7

Development of Pioneer, Pioneer II, and H. L. 

Hunley 10

Pioneer 11

Pioneer II 13

H. L. Hunley 16

Hunley’s Final Mission 31

3. ENVIRONMENTAL CONTEXT 37

M. Scott Harris and Robert S. Neyland

Regional Background 38

Physiography 38

Barrier Island Systems 39

Geologic Framework 40

Biologic Framework 41

Site-Specific Analysis 41

Conditions at the Time of Sinking 41

Physical Processes 42

Historical Bathymetric Analyses 45

Model of Site Formation 46

4. PREVIOUS INVESTIGATIONS 47

Harry Pecorelli III

Contemporary Salvage Attempts (1864) 47

Early Claim (1970) 47

First NUMA Search for H. L. Hunley (1980) 48

Second Search for H. L. Hunley (1981) 49

Third Search for H. L. Hunley (1994) 50

Discovery of H. L. Hunley (1995) 50

H. L. Hunley Site Assessment (1996) 51

USS Housatonic Site Assessment and 

Investigation (1999) 51

5. PROJECT HISTORY 53

Robert S. Neyland

Course to Recovery: Partners and 

Agreements 54

Friends of the Hunley 54

Hunley Oversight Committee 54

Laying the Groundwork: Studies and Plans 55

Option Study 55

Conservation Planning for H. L. Hunley 56

Conservation Symposium 57

Two Proposals 58

Oceaneering International Inc. 59

International Archaeological Lifts 60

Hunley Oversight Committee Review 61

Response to Reviewers’ Concerns 62

6. RECOVERY PLANNING 64

Robert S. Neyland

Recovery Mission 64

Recovery Operations Team 64

Project Leadership 64

HAT Personnel and Organization 65

Hunley Senior Project Manager/Recovery 

Operations Monitoring 67

Oceaneering Project Management 67

Senior Archaeologist 68

Senior Conservator 68

Logistics 68

Shore Support Facilities 68

Security 69

Media Plan 69

7. WARREN LASCH CONSERVATION CENTER 71

Robert S. Neyland, Maria Jacobsen, and Paul 

Mardikian

Wet Laboratory 72

Chilled Water Tank 72

Mezzanine 73

Dry Laboratory 73

Cathodic Protection System: Impressed 

Current 74

Electrolytic Reduction Control System 75

Treatment Solution 76

Treatment Tank 77

Chemical Disposal 77

Final Outfitting 77

Building Security 78

Conclusion 79

8. PRELIMINARY FIELDWORK 80

Claire Peachey and David L. Conlin

Sample Area 80

Contents
H . L . H U N L E Y R E C O V E R Y O P E R A T I O N S

vi

Rivets 82

Expansion Strake 82

Hull Thickness Measurements 82

Qualitative Hull Assessment 85

Sediment Samples 85

Conclusion 85

9. ENGINEERING 86

Heather G. Brown

Finite Element Analysis 87

Recovery Frame (Truss) 87

Suction Piles 89

Slings 91

Compliant Support System 91

Load Cells 92

Deflection Monitoring 93

Conclusion 93

10. EXCAVATION AND RECOVERY 94

Claire Peachey, Harry Pecorelli III, and Robert 

S. Neyland

Archaeological Objectives 94

Artifact Recovery 94

Loose Hull Components 95

Magnetic Anomalies 95

Site Plan 96

Hull Measurement and Drawings 96

Sampling 96

Hull Shape Monitoring 97

Equipment and Procedures 97

Dive Operations 97

Dredges 99

Documentation 100

Artifacts 100

Field Operations 101

Pre-disturbance Sampling 103

Anomaly Investigation 103

Corrosion Potential and Continuity 

Studies 103

Site Excavation 104

Spar excavation 105

Rudder and Other Artifacts Recovered 106

Lift Preparations 107

Million-Dollar Measurements 107

Operations Delayed 107

Resumption of Operations 108

Placing the Piles 109

Rigging the Slings 110

Raising the Hull 112

Conclusion 114

11. POST-RECOVERY SURVEYS 115

Harry Pecorelli III and Heather G. Brown

Background 115

Methods 115

Surface Survey 115

Diver Survey 118

Findings 119

2003 Site Visit 120

12. SITE DESCRIPTION 122

Heather G. Brown, Michael P. Scafuri, and 

Harry Pecorelli III

Hull 125

Main Body 125

Conning Towers 126

Bow and Stern Quarters 127

Bow Casting and Spar Assembly 127

Stern Casting, Propeller, and Steering 

Assembly 128

Other External Features 130

Condition 132

Holes in Hull 132

Other Damage 133

Surrounding Sediment Matrix 134

Wood 134

Coal and Slag 135

Concretions 135

Ceramics and Glass 136

Conclusion 137

13. SITE ANALYSIS 138

M. Scott Harris, Heather G. Brown, and Robert 

S. Neyland

Site Geology: Survey and Sampling 138

Data: Types and Sources 138

Sediment Sampling During Recovery 139

Results 142

Discussion 143

Faunal Samples 144

Microbial Analysis of Sediment from Cores 

and Hunley Interior 145

Site Formation Processes 146

Artifact Distribution 147

Coal and Slag 147

Hull Erosion 154

Scour and Burial 155

Discussion 158

14. HULL ANALYSIS 161

Heather G. Brown and Robert S. Neyland

Historical Sources 161

Archaeological Parallels 164

Analysis of Features 165

Hull Design 166

Conning Towers 170

Keel 171

Diving Planes 171

Bow and Stern Casting Holes 172

Propeller and Shroud 173

Rudder 174

Snorkel Box 175

Weapon System 176

Missing Features 180

Design Problems 181

Conclusion 181

15. ARTIFACT ASSEMBLAGE 182

Shea McLean, Heather G. Brown, Robert S. 

Neyland, and Ben Rennison

Metals 182
C O N T E N T S

vii

Tin Cans 193

Wood 196

Other Organics 198

Ceramics and Glass 200

16. CONCLUSIONS 205

Robert S. Neyland

Theories on the Loss of Hunley 207

Evidence from the Recovery 207

Analysis of Loss 208

Future Work 210

REFERENCES CITED 211

APPENDIX A: Hunley Conservation Symposium 

Summary of Proceedings 225

APPENDIX B: Recovery Operations Personnel 234

APPENDIX C: Companies Providing Essential 

Services to the Hunley Recovery 

Operation 237

APPENDIX D: Engineering Drawings 239

APPENDIX E: Summary of Environmental Data 

Collected at the Hunley Site over a Period of 

48 Hours 250

APPENDIX F: Analysis of Oxygen Reduction 

Potential of Hunley Iron Hull Plates In-Situ 

by Steve West 254

APPENDIX G: Catalog of Artifacts Recovered 

from the Seabed Surrounding the Submarine 

H. L. Hunley 257

APPENDIX H: Cumulative Frequency Diagrams 

of Sediment Cores taken at the H. L. Hunley 

Site 274

APPENDIX I: Trends for Mean Grain Size, 

Standard Deviation, and Skewness of 

Sediment Samples Taken at the H. L. Hunley 

Site 291

APPENDIX J: Benthic Infaunal Samples Identified 

from Cores Taken at the H. L. Hunley Site 298

APPENDIX K: Profiling of Iron-Reducing 

Microbial Populations Associated with 

the H. L. Hunley by Denaturing Gel 

Electrophoresis Analysis of Polymerase Chain 

Reaction-Amplified Genes Coding for 16S 

rDNA 301

APPENDIX L: Analytical Characterization of Coal 

Artifacts Recovered from H. L. Hunley and 

USS Housatonic by Rod Hatt 306

APPENDIX M: South Atlantic Blockading 

Squadron Ships Stationed off Charleston, 

South Carolina, 24 December 1861–1 July 

1865 310

APPENDIX N: Oral Account of H. L. Hunley 

by William G. Mazyck, Taken Down and 

Summarized by Robert Lunz (1957) 318

ix

Figure 2.1 An 1875 drawing of Bushnell’s Turtle by Francis M. Barber ................................................................ 6

Figure 2.2 Fulton’s Nautilus was unique in its design to function as a sailboat on the surface ............................ 7 

Figure 2.3 An unidentified submarine, once thought to be Pioneer .................................................................... 9

Figure 2.4 Photographs of James R. McClintock and Horace L. Hunley .............................................................. 11

Figure 2.5 Tracing of Pioneer enclosed in William H. Shock’s (1864) report ...................................................... 12

Figure 2.6 A drawing of the exterior of Pioneer made by Ensign Stauffer .......................................................... 13

Figure 2.7 Map of New Orleans showing where Pioneer was built .................................................................... 14

Figure 2.8 The second Seamen’s Bethel at its current location in Mobile .......................................................... 17

Figure 2.9 Detail from an 1863 map showing the positions of Charleston’s primary defenses ......................... 19

Figure 2.10 The interior of Fort Sumter photographed by George S. Cook on 8 September 1863 ...................... 20

Figure 2.11 A 1960s reconstruction of a Confederate torpedo boat designed like CSS David ............................. 23

Figure 2.12 Facial reconstruction of Lt. George Dixon .......................................................................................... 26

Figure 2.13 Facial reconstruction of Seaman Arnold Becker 26

Figure 2.14 Facial reconstruction of Quarter Gunner Lumpkin ............................................................................ 27

Figure 2.15 Facial reconstruction of Cpl. J. F. Carlsen ........................................................................................... 27

Figure 2.16 Facial reconstruction of Seaman Frank Collins .................................................................................. 27

Figure 2.17 Facial reconstruction of crewman Miller ........................................................................................... 28

Figure 2.18 Facial reconstruction of Quartermaster James Wicks 28

Figure 2.19 Facial reconstruction of Joseph Ridgaway ......................................................................................... 28

Figure 2.20 Map showing the route from Mount Pleasant to Battery Marshall and Breach Inlet ....................... 29

Figure 2.21 View from Fort Moultrie on Sullivan’s Island, looking east ................................................................ 30

Figure 2.22 Wash drawing of the United States Sloop-of-War Housatonic by R. G. Skerrett (1908) 32

Figure 3.1 The Hunley site was located approximately 4 nautical miles (7.4 km) from Charleston Harbor ....... 37

Figure 3.2 Regional physiography of the area surrounding Hunley 38

Figure 3.3 Charleston Bar in 1864 and in 1899 ................................................................................................... 39

Figure 3.4 A schematic representation of the stratigraphy beneath the site ..................................................... 40

Figure 3.5 A generalized stratigraphic column of the area immediately surrounding the site 40

Figure 3.6 The positions of the Hunley and Housatonic wreck sites are shown in relation to the directions 

of wind and current at the time of the sinking .................................................................................. 42

Figure 3.7 Number of hurricanes affecting the South Carolina area between 1864 and 2000 43

Figure 3.8 The fourth quarter ebb current flow in the vicinity of the Charleston Harbor entrance ................... 44

Figure 3.9 Sediment distribution at the mouth of the jetties in 1900 45

Figure 3.10 Two potential models of site formation 46

Figure 4.1 Map showing Charleston Harbor and 1980 NUMA search areas ...................................................... 48

Figure 4.2 Map showing Charleston Harbor and 1981 NUMA search areas ...................................................... 49

Figure 4.3 Screen capture from NUMA’s 1995 video footage of the site ........................................................... 51

Figure 4.4 Diver sketch of possible sunken buoy between USS Housatonic and Hunley sites ............................ 52

Figure 5.1 Friends of the Hunley board members, staff, and volunteers ........................................................... 53

Figure 5.2 Presenters at the Hunley Conservation Symposium .......................................................................... 58

Figure 5.3 Oceaneering created a digital animation of their proposed lift method ........................................... 59

Figure 6.1 The project consisted of personnel from multiple sources under a single project director 65

Figures
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

x

Figure 6.2 Assistant field manager Matt Russell briefs team members on the day’s dive objectives 66

Figure 6.3 Claire Peachey, assistant field manager for data collection, documents an artifact 66

Figure 6.4 Senior archaeologist Maria Jacobsen inspects progress at the conservation facility .........................68

Figure 6.5 U.S. Coast Guard Cutter Yellowfin providing an escort for the barge carrying Hunley ...................... 69

Figure 6.6 OII project manager Steve Wright gives an authorized interview ......................................................70

Figure 7.1 The bay area of the wet laboratory held a variety of custom treatment tanks 72

Figure 7.2 A view of the newly-constructed mezzanine looking down into the treatment tank .........................73

Figure 7.3 Senior conservator Paul Mardikian inspects the newly-installed digital x-ray unit ............................74

Figure 7.4 A negative cable for the impressed current system was attached to the bow 75

Figure 7.5 Design specifications for the piping system for treatment solution 76

Figure 8.1 Portside view showing thickness testing locations 1–6 and 9–10 ......................................................81

Figure 8.2 Dental putty mold of the seam between two hull plates and the expansion strake ..........................82

Figure 8.3 Graphs of the ultrasonic thickness readings from the port side of Hunley’s hull ...............................83

Figure 8.4 Ultrasonic thickness values from nine of the ten test areas on Hunley’s hull 84

Figure 9.1 Cross section of hull based on measurements taken at the site in 1996 86

Figure 9.2 Side view of the construction plan of the recovery frame with bearing seats attached ....................87

Figure 9.3 A view of the top of the frame in the chilled water tank 88

Figure 9.4 The soaker system designed to keep the hull wet during transport utilized ordinary sprinklers .......89

Figure 9.5 Three-dimensional cutaway view of caissons designed to support the recovery frame 89

Figure 9.6 Profile of suction pile as installed, with adjustable tower table for the bearing seat .........................90

Figure 9.7 Fully rigged suction pile being lowered into the water 90

Figure 9.8 Diagram showing proposed placement of secondary slings for added stability 91

Figure 9.9 Members of the engineering team practice fastening a vinyl bag to a sling in land-based trials 92

Figure 9.10 Turnbuckles in place on the frame with load cells rigged ...................................................................92

Figure 9.11 Display of weight distribution on the load cells supporting Hunley ...................................................93

Figure 9.12 Linear variable displacement transducers (LVDTs) for monitoring longitudinal displacement 93

Figure 10.1 Operating with decks awash was not uncommon during operations four miles out to sea ...............95

Figure 10.2 Magnetometer readings around the Hunley site 95

Figure 10.3 Site plan developed based on the 1996 investigation ........................................................................96

Figure 10.4 Senior project manager Leonard Whitlock tends to diver and field manager David Conlin 98

Figure 10.5 Hyperbaric chamber being readied for loading onto Marks Tide 98

Figure 10.6 Marks Tide moored over the site 98

Figure 10.7 Karlissa-B in place over the site along with supply the barge, which housed the dredge pumps ......99

Figure 10.8 Sluice boxes designed by OII for screening dredge outflow 100

Figure 10.9 Randy Burbage, Senator McConnell, and Robert Neyland examine profile taken by divers ............100

Figure 10.10 USCGC Madrona prepares to deploy the four mooring buoys used to secure Marks Tide .............101

Figure 10.11 Layout of the excavation boundaries and sample transects at the site 102

Figure 10.12 Steve West monitors instruments during corrosion potential studies .............................................104

Figure 10.13 The torpedo spar in its original position attached to Hunley’s bow 105

Figure 10.14 Mold of bolt and recovered bolt used to attach spar to main body of the hull ...............................105

Figure 10.15 Hunley’s torpedo spar was removed from the bow and raised separately 106

Figure 10.16 Measurements taken to determine the geometric centerline of the hull as it lay on the seabed ...107

Figure 10.17 Team members transferred from the crew boat to Karlissa-B via a crane-lifted Billy Pugh .............109

Figure 10.18 Diver working around the forward conning tower with truss beams directly overhead .................110

Figure 10.19 Bill Youmans, Michael Gatto Jr., and Mark van Emmerick demonstrate the foam 111

Figure 10.20 A patch was placed over the starboard stern hole to ensure no loss of interior contents ...............111

Figure 10.21 Aerial view of the raising of Hunley, showing disposition of vessels around Karlissa-B ..................112

Figure 10.22 The submarine H. L. Hunley breaks the surface for the first time in 136 years 113

Figure 10.23. The barge carrying Hunley was towed up the Cooper River to Pier Juliet in North Charleston .......113

Figure 10.24 H. L. Hunley on its final leg of the journey, carried by rail-based portal crane to the WLCC 114

Figure 11.1 Boundaries of 1996, 2000, and 2002 surveys ...................................................................................116

Figure 11.2 Magnetometer data from 1996 overlain on the post-recovery site plan .........................................117
xi

F I G U R E S

Figure 11.3 Area of hand-held magnetometer survey over original position of H. L. Hunley wreck ...................118

Figure 11.4 Illustration of the mushroom anchor and length of chain discovered near the site 120

Figure 12.1 Site plan 123

Figure 12.2 Plan and profile views of Hunley ..................................................................................................... 124

Figure 12.3 Diagram of the riveting style used on Hunley ...................................................................................125

Figure 12.4 Idealized view of the forward conning tower with cutwater and intact forward viewport ............. 126

Figure 12.5 Top of aft hatch cover after deconcretion 126

Figure 12.6 Portside view of the bow casting ..................................................................................................... 127

Figure 12.7 A substantial bolt laterally penetrates the bow casting ................................................................... 127

Figure 12.8 Spar attachment yoke based on measurements taken prior to deconcretion . ............................... 128

Figure 12.9 Outline of spar showing main sections and surviving hardware . .................................................... 128

Figure 12.10 Idealized port-side view of stern casting 129

Figure 12.11 Propeller as exposed by loss of the port side of the shroud ........................................................... 129

Figure 12.12 Idealized view of surviving elements of the rudder (HL-0686), port side ........................................ 130

Figure 12.13 Idealized plan view showing position of diving planes and their protective skegs .......................... 131

Figure 12.14 Layout of keel weights, based on 3D data collected prior to deconcretion ..................................... 131

Figure 12.15 The viewport on the starboard side of the forward conning tower was partially exposed ............. 132 

Figure 12.16 Horse oyster shells can be seen at the top of the port side of the bow casting .............................. 132

Figure 12.17 Hole in the forward conning tower encompassing the total loss of port viewport 133

Figure 12.18 Hole in bow, along boundary between wrought- and cast-iron components .................................. 133

Figure 12.19 The largest hole was at the stern near the top, exposing the steering rod ..................................... 133

Figure 12.20 Damage to the top starboard quarter of the propeller shroud . ...................................................... 134

Figure 12.21 The port side diving plane is in a slightly raised position 134

Figure 12.22 Sample of a wood lot collected from dredge outflow during the excavation 135

Figure 12.23 Typical collection of slag and coal collected from sediment surrounding Hunley 135

Figure 12.24 A radiograph of HL-0653, showing diagnostic seams of a tinned iron can 137

Figure 13.1 The Udden-Wentworth scale for clastic sedimentary materials 138

Figure 13.2 Drs. Pam Morris and Scott Harris prepare cores for sampling 139

Figure 13.3 Excavation profile measured from seafloor 143

Figure 13.4 Distribution of Mediomastus sp. and Spiophanes bombyx counts along Transects 1 and 2 145

Figure 13.5 Areas of sediment disturbed during the initial assessments of H. L. Hunley ................................... 146

Figure 13.6 Number of U.S. Navy vessels on station off Charleston, Stono Inlet, and Bull’s Bay 148

Figure 13.7 Distribution of coal around the Hunley site based on raw counts ................................................... 150

Figure 13.8 Distribution of slag around the Hunley site based on raw counts ................................................... 151

Figure 13.9 Positions of ceramic and glass artifacts recovered from the wreck site .......................................... 152

Figure 13.10 Positions of complete, partial, and fragmentary cans recovered from the wreck site .................... 153 

Figure 13.11 Site plan showing locations of the disarticulated components ....................................................... 154

Figure 13.12 Erosion is evident on the outer surface of the nut that connected the spar to the hull ................. 155

Figure 13.13 Generalized scour patterns for current striking a shiplike object .................................................... 156

Figure 13.14 Idealized projections of how the tidal current affected scour around Hunley ................................ 156

Figure 13.15 Hurricane activity affecting Charleston in the late 19th century 157

Figure 13.16 Idealized projections demonstrating asymmetrical, convergent scour pattern 160

Figure 14.1 Published drawings of H. L. Hunley based on sketches by William Alexander 161

Figure 14.2 Oil painting by Conrad Wise Chapman depicting H. L. Hunley in Charleston .................................. 163

Figure 14.3 A wash produced by R. G. Skerrett in 1902 based on Chapman’s painting 163

Figure 14.4 Intelligent Whale on display at the New York Navy Yard, 27 July 1915 .......................................... 164

Figure 14.5 The remains of Julius Kroehl’s Sub Marine Explorer on a beach in Panama .................................... 165

Figure 14.6 USS Skipjack (SSN-585) utilized a parabolic bow and gradually tapering body 166

Figure 14.7 Relative sizes and shapes of surviving American submarines built in the 1860s 167

Figure 14.8 This flue boiler provides an example of the number and position of rivets penetrating a typical

boiler plate, making reuse challenging ............................................................................................ 169

Figure 14.9 Two iron brackets likely correspond to bow hardware in Chapman’s painting ............................... 173 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

xii

Figure 14.10 Sketch by Conrad Wise Chapman showing Hunley with the forward hatch removed.......................175

Figure 14.11 Diameters of fire tubes from marine boilers compared to known spar diameters ......................... 178

Figure 14.12 A sketch by Francis Lee shows two rigging points close to the distal end of the spar ..................... 179

Figure 14.13 Drawing of a Civil War-era spar torpedo with multiple fuses .......................................................... 179

Figure 14.14 Sketch of Singer torpedo adapted for use on a spar ....................................................................... 180 

Figure 14.15 Detail from Chapman’s painting of Hunley showing a reel positioned aft of the snorkel box 181

Figure 15.1 Radiograph of HL-0428, the largest fragment of a heavily concreted curved iron rod .................... 182

Figure 15.2 Galvanized steel rod found near the submarine’s bow ................................................................... 183

Figure 15.3 Photograph of joint shows a band incidicating the position of a possible clamp or bracket ........... 184

Figure 15.4 Project staff hold bracket HL-0526 against its hypothesized position on the submarine’s bow ...... 184

Figure 15.5 Forward spar assembly bracket (HL-0526) 185

Figure 15.6 Starboard side of aft cutwater (HL-0555) ........................................................................................ 186

Figure 15.7 Aft spar assembly bracket (HL-0582) ............................................................................................... 187

Figure 15.8 Field drawing of snorkel tubes showing their heavily concreted state ............................................ 187

Figure 15.9 Paul Mardikian holds starboard shroud attachment bar (HL-0660) ................................................ 188

Figure 15.10 Cast of a wrought-iron bar (HL-0683) found near the rudder ......................................................... 188

Figure 15.11 Radiograph of concreted rivet (HL-0684) 189

Figure 15.12 Cast of a dome-headed spike or nail (HL-0685) found in a concretion near Hunley’s stern ............ 189

Figure 15.13 Port side of rudder (HL-0686) before and after conservation 190

Figure 15.14 Radiograph of concreted rivet head (HL-0705) 190

Figure 15.15 Five-tined grapnel anchor (HL-2917) and ring (HL-2918) after conservation 191

Figure 15.16 A grapnel, fire grapnel, and creeper as illustrated in Steel (1794) 192

Figure 15.17 A radiograph of HL-3667 shows a vented cap typical of late 19th century manufacture ................ 193

Figure 15.18 Comparison of known can sizes to those found at the Hunley site ................................................. 194

Figure 15.19 Metal can recovered from iron conglomerate HL-0582 196

Figure 15.20 Radiograph of metal can HL-3288, showing locations of specific manufacturing features ............. 196

Figure 15.21 Wooden plank (HL-0505) found close to starboard bow 196

Figure 15.22 Side view showing angled cut and cross section of HL-0505 ........................................................... 197

Figure 15.23 Wooden barrel cant recovered near the starboard side of the submarine ..................................... 197 

Figure 15.24 Sketch of wooden tool handle (HL-3289) showing socket for tool .................................................. 198

Figure 15.25 Worn wooden plank with pointed end (HL-0594) 198

Figure 15.26 Fragment of Z-twist rope (HL-0581) 199

Figure 15.27 Sample of rope fiber (HL-0585) examined under cross polarized light 199

Figure 15.28 Slip-banded American yellow ware bowl fragment (HL-0448) ........................................................ 200

Figure 15.29 Annular decorative bands on the outer surface of HL-0448 show some manufacturing flaws 201

Figure 15.30 White granite ceramic dish fragment (HL-0451), with maker’s mark on base of vessel 201

Figure 15.31 Reconstruction of fragmented U.S. Navy condiment bottle (HL-0506) ........................................... 202

Figure 15.32 Intact American-made Bristol-style glazed bottle (HL-0661) ........................................................... 203

Figure 15.33 Olive green bottle base fragments (HL-0662) 204

Figure 16.1 H. L. Hunley begins its journey up the Cooper River to the Warren Lasch Conservation Center .... 205

Figure 16.2 Members of the Hunley recovery team with the submarine in its tank .......................................... 206

Figure 16.3 What caused the hole in Hunley’s conning tower, and when, remain critical questions.................. 208
xiii

Tables

Table 8.1 Mean Thickness of Hull Plates ........................................................................................................... 84

Table 9.1 Gravity Load Data .............................................................................................................................. 88

Table 10.1 Archaeological Research Objectives .................................................................................................. 94

Table 11.1 Magnetometer Targets Investigated in 2002–2003 ......................................................................... 119

Table 12.1 Number of Artifact Lots Collected by Material Type ....................................................................... 122

Table 12.2 Iron and Lead Concretions Identified as Historic Cans .................................................................... 136

Table 13.1 Pound Cores Taken from around the H. L. Hunley in May 2000 ...................................................... 140

Table 13.2 Values and Description of the Standard Deviation (Sorting Parameter, 2nd moment) ................... 142

Table 13.3 Values and Description of the Skewness Parameter (3rd moment) ................................................ 142

Table 13.4 Benthic Infaunal Sample Analyses by Transect and Distance from Submarine ............................... 144

Table 14.1 Comparison of Early Submarine Propellers ..................................................................................... 174

Table 15.1 Dimensions of Cans from the Hunley Site ....................................................................................... 194

Table 15.2 Canned Goods from the Steamship Bertrand .................................................................................. 195

Table A1 Symposium Participants and Presentations ..................................................................................... 226

xv

List of Abbreviations

ACHP Advisory Council for Historic Preservation

AFM-DC Assistant Field Manager for Data Collection

AFM-L Assistant Field Manager for Logistics

CSN Confederate States Navy

DOD Department of Defense

FEA finite element analysis

FeRB iron reducing bacteria

FOTH The Friends of the Hunley, Inc.

GSA General Services Administration

HAT Hunley Archaeological Team

HOC Hunley Oversight Committee

HRC Hunley Research Center

IAL International Archaeological Lifts, L.L.C.

LIC level indicating controller

MSL mean sea level

NHC Naval Historical Center (processor organization to NHHC)

NHE normal hydrogen electrode

NHHC Naval History and Heritage Command

NOAA National Oceanographic and Atmospheric Administration

NPS National Park Service

NUMA National Underwater Marine Agency

OII Oceaneering International, Inc.

ORP oxygen reduction potential

PAL Public Affairs Liaison

RFP request for proposals

RO reverse osmosis

ROM rough order of magnitude

SCDAH South Carolina Department of Archives and History 

SCDNR South Carolina Department of Natural Resources

SCHC South Carolina Hunley Commision

SCIAA South Carolina Institute of Archaeology and Anthropology

SRC Submerged Resources Center (National Park Service)

SPAWAR Space and Naval Warfare Systems Command

SRC Submerged Resources Center

UAB Underwater Archaeology Branch (NHHC)

USCG United States Coast Guard

WLCC Warren Lasch Conservation Center

xvii

Editor’s Note

One of the more mundane challenges in documenting the Hunley recovery was reconciling the 

measurements. The global scientific standard is to use metric, while American engineers still use 

the U.S. customary units. The original engineering plans used feet and decimal inches, while many 

of the materials used were sold in fractions of inches. The hull and artifacts were predominately 

measured in in metric; however, since the submarine itself was built using the American system, 

occasional references to sizes or weights were recorded in that system. 

This has led to some interesting choices in order to make the data accessible to the widest 

possible audience while maintaining accuracy. As a result, the report lists all measurements in both 

systems, first in the standard of the original measurement as being the most accurate, followed by 

the converted value in parentheses. Due to the cumbersome nature of notating feet and inches, 

however, all such values have been converted to decimal feet. Fractions are used when less than 

an inch and represent a standard product gauge. Every effort was made to maintain consistency in 

the units being compared, as represented in the table below. 

 U.S. Metric

in. – inches cm – centimeters

ft. – feet m – meters

mi. – miles km – kilometers

lb. – pounds kg – kilograms

tn. – U.S. tons t – metric tons

p.s.f. – pounds per square foot k/m2

 – kilograms per square meter

p.s.i. – pounds per square inch bar – bar

xix

Foreword

In November 1999, I was privileged to be one of 

the 10 “authorities” gathered together for an international symposium in Charleston that was convened to 

consider a proposal to recover, conserve, enter, and 

excavate the famous and newly-found H. L. Hunley. 

Experienced and highly qualified corrosion specialists, expert experienced ship and object conservators, 

archaeologists, and museologists were there—their 

brief to present the lessons learned at CSS Alabama, 

USS Arizona, HM Monitor M33, USS Monitor, the British 

submarine Resurgam, SS Xantho, and elsewhere. There 

with my colleague Ian MacLeod, who would present 

what “we” (a close knit team of Australian and international archaeologists, conservators, volunteers, and 

technicians) had learned from the in-situ conservation, 

recovery, deconcretion, dismantling, subsequent conservation, and (at the time) imminent reassembly of 

Xantho’s former Royal Navy horizontal trunk engine, 

mine was to be an entirely different task. 

From the point of our first contact with the 

H. L. Hunley program, Ian and I both knew that the 

Charleston assembly were acutely aware of the decades 

of individual, collective, and institutional commitment, 

of public involvement, enormous sponsorship, and institutional backing that interpretation and exhibition facilities required—at Xantho for example, we are now only 

just completing our work after 30 years. 

As a result, I looked elsewhere for something to say 

and presented the notion that the submarine was a new 

class of archaeological site, one that remains unlike all 

other submerged historic vessels, an often still-sealed 

capsule broached not by the sea and its organisms as is 

the case at all other boats and ships lying on the world’s 

seabeds. Even when broached, submarines invariably 

have sealed compartments, entombing for centuries 

longer than will any other ship, their contents and in 

some cases even their unfortunate crew—theirs is 

then an unopened tomb. Enter it in full recognition of 

that fact and know full well that you are establishing a 

precedent, both archaeological and ethical, and if you 

proceed, know you are helping pioneer a new avenue of 

research and inquiry. The world will await your results. 

This was part of the message provided to those not 

already well aware of their onerous responsibilities 

should H. L. Hunley be raised.

Finally I expressed a belief, formed from what I had 

read of the H. L. Hunley project and from what I knew of 

its proponents and of those specialists already involved, 

that the project would “raise the bar” in maritime 

archaeology. This was for me a perception clearly reinforced by the presence of those speaking and those 

gathered to listen.

And so the bar has been raised.

Ample proof of that fact appears in this comprehensive work. It is one that ably brings to the world 

the complexity of such a multi-faceted project, its own 

history, including the search and finding, the engineering problems and solutions, the archaeology, conservation, historical research, public access, and future 

exhibition plans. Clearly evident is the fact that it has 

all required perseverance, dedication, and exceptional 

time management from not only the archaeologists, 

researchers, and conservators, but those who managed 

the funding and the enormous resources required to 

complete the project. What editors Robert Neyland and 

Heather Brown have brought together and presented 

in what follows is a fitting and lasting tribute to the 

project’s many and various constituents and, like H. 

L. Hunley itself, it is a monument to its builder and to 

its three brave crews, young men once lost and now 

known to all. 

— Dr. Michael McCarthy

Western Australia Museum

March 2016

xxi

Acknowledgments

A project of the magnitude of the H. L. Hunley 

recovery could not have been conducted without the 

dedication, generosity, and enthusiasm of many people. 

These included military and civilians, scientists and 

engineers, corporations, small business owners, financiers, and politicians. Recovery could not have been 

accomplished without the strong political support from 

federal, state, and local governments. The public-private 

partnership established between the South Carolina 

Hunley Commission (SCHC), Friends of the Hunley 

(FOTH), and Naval Historical Center (now Naval History 

and Heritage Command) made the project a success. 

Donations of services, manpower, equipment, and 

funds all contributed to the successful recovery of the 

Civil War submarine H. L. Hunley. A debt of gratitude is 

owed to everyone who participated in person or in spirit 

in this effort. A listing of project personnel is provided in 

Appendix B and the companies who provided essential 

services in Appendix C.

Major funding for the planning phase, $200K, as 

well as $2 million for the recovery was provided through 

the Department of Defense (DOD) Legacy Resources 

Management Program. This federal program was established in 1990 by Congress to assist the DOD and military 

services in preserving both natural and cultural heritage 

resources under DOD jurisdiction. The program also 

funded post-recovery conservation efforts to preserve 

the historic vessel, totaling $3 million over five years. 

The State of South Carolina provided $1 million to the 

recovery effort as well as $2 million for renovation of a 

former Navy warehouse at the former Charleston Naval 

Shipyard. Recovery would not have happened without 

having a dedicated conservation facility ready to receive 

the submarine. The Charleston Naval Complex Redevelopment Authority generously leased the building for a 

nominal $1 a year for eight years and later included a 

five-year extension of this agreement and the donation 

of a former base house that was used as temporary 

housing for students, interns, and visiting scientists to 

assist with the project, and in the case of the former, to 

obtain training and professional work experience.

The project could not have happened without the 

commitment of two key individuals, Warren Lasch, 

Chairman of the FOTH and the Honorable Glenn 

McConnell, South Carolina State Senator and Chairman 

of the SCHC and later Lt. Governor of South Carolina. 

Both men provided outstanding leadership and organizational skill, as well as committing large segments of 

their time. Chairman Lasch not only gave freely of his 

time but also assisted in financing the project through 

personal donations and a bank loan that ensured 

project expenses could be covered. Other Hunley Commission members during the time of recovery include 

Chris Sullivan (Vice-Chair), South Carolina state senators 

John Courson and Ernie Passailaigue, state representatives Rick Quinn, Harry Hallman Jr., and Chip Limehouse, 

businessman Randy Burbage, and Rear Admiral William 

Schachte, USN (Ret). 

Dr. William Dudley, director of the Naval Historical 

Center (1995–2004), assisted with the review of project 

objectives and methodology, and generously allowed 

Dr. Robert S. Neyland to go on loan to the State of 

South Carolina under the Intergovernmental Personnel 

Act from 1998 to 2004. The Navy also assisted with 

obtaining project funds through DOD Legacy Resources 

Management Program, loan of Navy equipment from 

Naval Sea Systems Command (NAVSEA) Emergency 

Ship Salvage Material (ESSM), and participation of 

NHC Underwater Archaeology Branch staff and diving 

assets. SPAWAR System Center Atlantic, Naval Weapons 

Station Charleston, and U.S. Coast Guard (USCG) Sector 

Charleston cooperated to provide site security. U.S. 

Navy Special Warfare Combatant Craft Special Boat 

Units 20 and 22 provided additional on-site security. 

The National Park Service (NPS) supported the 

project through the Submerged Resources Center 

(SRC), which provided on-site personnel, David L. 

Conlin, Matthew Russell, and Brett Seymour, as well 

as the expertise of its full staff. SRC Chief Dan Lenihan 

and Larry Murphy, although not on site, were available 

throughout the recovery to offer advice and support. 

NPS Fort Moultrie National Monument provided the 
H . L . H U N L E Y R E C O V E R Y O P E R A T I O N S

xxii

their documentary told the story of Hunley to millions 

of people around the world. NGS, through both the film 

and magazine divisions, contributed $200K in funds. Ira 

Block, an independent photographer and owner of Ira 

Block Photography working for the magazine National 

Geographic, produced exceptional still photographs 

of the recovery project. Cramer Gallimore, owner of 

Cramer Gallimore Photography, donated his time and 

photographic and pilot expertise to capture the only still 

aerial photographs of the site on the day of recovery. 

Mr. Gallimore would continue to donate his time during 

the excavation as a photographer.

The National Underwater and Marine Agency 

(NUMA) and founder Clive Cussler assisted in an 

advisory capacity and contributed to the recovery 

project in order for Mark Ragan to conduct archival 

research and create a project archive of historical 

documents related to Hunley, the builders, the crew, 

and other Civil War submarine attempts. These 

documents are archived at the Warren Lasch Conservation Center. He also followed this support up with 

funds that allowed Mr. Ragan to draft a report based 

on sponsored research on Civil War submarine development and, in particular, the efforts of the Confederate 

Singer torpedo group. Clive Cussler was on site during 

the recovery, watching the operation from the same 

boat used to locate the historic submarine in 1995, and 

has continued to stay interested in Hunley throughout 

its recovery, excavation, and preservation.

Oceaneering International, Inc. (OII) was the 

primary source of marine engineering during the 

planning phase, providing oversight for procurement of 

recovery-related materials, construction, dive support, 

and a variety of engineering services. Leonard Whitlock, 

OII Program Manager, assisted with making the initial 

connection between FOTH and Oceaneering, and, after 

leaving Oceaneering, worked directly with the recovery 

team as an independent contractor, providing invaluable planning and project monitoring assistance. Steve 

Wright, OII Project Director, worked directly with the 

archaeologists first in preparing the recovery options 

study, then the recovery engineering design, and finally 

overseeing all OII operations during the project. Perry 

Smith, OII Engineering, worked with archaeologists, 

architects, and engineers to design both the Hunley

truss system for the lift and the conservation tank in 

which Hunley would be placed. OII’s president, Jack 

Huff, took direct interest in the recovery operation and 

visited the project several times. 

The initial work platform was the offshore supply 

boat Marks Tide, provided by Tidewater Marine LLC of 

Amelia, Louisiana. It provided an excellent dive platform, 

and the company’s owners and personnel were very 

disappointed when they were unable to complete the 

lift due to conditions outside their control. On relatively 

short notice, Titan Maritime, LLC, agreed to provide the 

docking facilities for the daily crew transport, a site 

for a project office trailer, and a location for press 

conferences. Fort Moultrie also assisted the project 

through their mission of telling the history of the Fort 

and Hunley during the Civil War. The USCG Charleston 

District was instrumental to the protection of Hunley

following its discovery in 1995 until its recovery in 

2000. USCG Charleston established a Restricted Navigation Area (RNA) around the site that restricted 

anchoring, diving, dredging, and salvage. In preparation for recovery, they installed the mooring points for 

the large support vessel Marks Tide and the materials 

barge involved in the recovery. During the recovery, 

the USCG provided a security perimeter on site and, 

during Hunley’s transport on the day of recovery, 

assisted with a moving security zone around the vessels 

transporting the submarine. The United States Army 

Corps of Engineers (USACE) Savannah District took a 

variety of core samples for geologic analysis and USACE 

Charleston District consulted with the recovery team 

on preparing and submitting the EPA Environmental 

Assessment and consultation. 

Several South Carolina state agencies provided 

significant project support. The South Carolina Department of Archives and History (SCDAH) oversaw the 

Section 106 review under the NHPA and the resulting 

Programmatic Agreement between the federal agencies 

and South Carolina. It also served as the state partner 

with Navy in the Intergovernmental Personnel Act (IPA) 

agreement that permitted Neyland to be temporarily 

assigned to State of South Carolina. The South Carolina 

Institute of Archaeology and Anthropology (SCIAA) 

provided project technical review and other support, 

including archaeological diving and data collection, and 

project photo-documentation. South Carolina Department of Natural Resources (SCDNR) coordinated and 

maintained 24-hour security at the Hunley site during 

the recovery. SCDNR biologists collected and analyzed 

coral colonies and other macro-faunal samples from the 

submarine’s hull prior to recovery. Throughout the many 

surveys and projects SCDNR made their vessels available 

to the project. South Carolina Educational Television 

(SCETV) carried out complete video documentation of 

the recovery, aired statewide TV updates, conducted 

live scientist interviews with schools, and provided 

video footage to National Geographic and major media 

networks. Tom Posey, SCETV producer, was with the 

project throughout the recovery overseeing project 

video documentation for the State of South Carolina. 

National Geographic Society (NGS) filmed, 

produced and aired the National Geographic Explorer 

documentary Raising the Hunley, as well as producing 

a magazine article and several internet updates. They 

also made a cash contribution to the overall project. 

Producers John B. Bredar and Rakhi Varma were a 

pleasure to work with throughout the project and 
A C K N O W L E D G M E N T S

xxiii

heavy-lift crane, barge, and personnel necessary to raise 

Hunley from the bottom of the sea and transport it to 

the former Charleston Naval Base, using the jack-up 

barge Karlissa-B. Titan Maritime reflagged Karlissa-B to 

the United States in order to conduct the lift of Hunley.

The engineering analysis and science was supported 

by a donation of time and equipment from Dennis 

Donovan of Coastal Inspection Services, who provided 

seven days of non-destructive testing research and 

services at no cost. The equipment for this research was 

custom built by Krautkramer Branson especially for the 

ultrasonic testing of Hunley’s wrought iron hull. Mike 

Gatto, of NCS Supply Inc., selected the correct foam 

product manufactured by Froth-Pak to be injected into 

the recovery sling bags and was on site advising during 

the bag injection process. Engineer Kenny Johnson, 

of Soil Consultants Inc., analyzed the geological core 

samples and advised regarding the type and installation of piles to be used for the truss support. Mr. 

Johnson and his associates recommended driving piles 

that would reduce the vibration and potential impact 

to the submarine. Their concerns led to the selection 

of suction piles for the project. Rick Fielder, of YSI Inc., 

with help from local representative Johnston Inc.’s 

Roger Lymon and Rodney Edward, loaned a multiparameter probe used for taking environmental measurements around the hull under water.

Thompson Pump, Summerville, South Carolina 

branch, donated the large pumps to operate the 

OII dredges and provided on-site maintenance and 

expertise to keep them operational. The Hunley dive 

team was supported by donations from Body Glove 

International, represented by John Dailey, with wetsuits 

for the archaeological dive team, and Marketing Solutions’s Todd Beckett generously donated the silk 

screening of project logos for the dive suits. Divers 

Alert Network donated emergency training material, 

an oxygen supply kit, and provided dive insurance for 

archaeologists. The Wet Shop of North Charleston, South 

Carolina, owned by Ralph Wilbanks, one of the original 

discoverers of Hunley, discounted dive equipment, air 

fills, and provided the pool for training purposes.

Finally, this report could not have been written 

without the help of many people. Perry Smith and Steve 

Wright of Oceaneering provided the original reports 

used for drafting the engineering and commercial 

diving operations sections, along with feedback from 

Leonard Whitlock. National Park Service archaeologist David Conlin assisted with sections regarding the 

archaeological operations and his colleague Matthew 

Russell prepared the initial site plan. The staff and 

volunteers at the Warren Lasch Conservation Center, 

including Paul Mardikian, Maria Jacobsen, Michael 

Scafuri, Benjamin Rennison, Fred Tetor, and Steve 

Weise, as well as Kellen Correia of the Friends of the 

Hunley, provided essential information on a multitude 

of events, people, and research regarding Hunley’s 

logistics and recovery. Michael Scafuri was the lead 

archaeologist at Clemson University who assisted with 

resolving many research questions, patiently checked 

artifact and submarine measurements, and was always 

available to provide thoughtful input regarding Hunley

research. Dr. Stéphanie Cretté and Dr. Néstor GonzálezPereyra of the Clemson University Restoration Institute 

graciously allowed access to staff and records. Many 

others, both in Charleston and Washington, helped with 

editing or illustrating sections of this report, including 

James Hunter, Eugene Bialek, Mari Hagemeyer, and Ivor 

Mollema. Jeffrey Enright and Search, Inc. kindly assisted 

with several GIS maps. 

Many people, agencies, corporations, and not-forprofits supported Hunley’s recovery. It is possible that 

some have been overlooked. I extend my apologies in 

advance for any omissions and oversights. 

— Robert S. Neyland

Project Director

1

1. Introduction

R o b e r t S . N e y l a n d

On 3 May 1995, a team of maritime investigators 

under the direction of novelist Clive Cussler made a 

remarkable discovery four nautical miles (7.4 km) off 

the coast of Charleston, South Carolina: the wreck of 

the Confederate submarine H. L. Hunley, lost without a 

trace since the night of 17 February 1864, shortly after 

it exploded a torpedo filled with black powder underneath USS Housatonic, sending that ship to the bottom 

within minutes. This event marked the first time a 

submarine sank an enemy ship and at once exemplified 

both the promise and the risks of underwater warfare.

The discovery culminated many years of search 

by the team, and many others, over 130 years since 

Hunley’s loss (Chapter 4). News of the Civil War find was 

celebrated by many who had long wondered why the 

small underwater craft never made it home that fateful 

night, as well as by those who had a keen interest in 

the maritime history and technological developments 

of the 19th century. It was also a double-edged sword: 

by locating the site, opportunities for scholarship and 

public education were opened up, but so were avenues 

for illicit looting or well-intentioned but ill-planned 

recovery attempts that would destroy the site and 

possibly the boat itself.

With the site located outside of state waters, 

responsibility for its protection fell to the federal government, eventually resting with the U.S. Navy’s Naval 

Historical Center (now the Naval History and Heritage 

Command). The obligation to study and preserve this 

truly unique artifact of American history was clear, but 

the way forward for such an ambitious project was 

not as obvious. The recovery of a shipwreck requires 

a significant investment of time, money, and ingenuity. 

The logistical difficulties of rigging a multi-ton lift under 

water while ensuring that delicate, historic material 

is not damaged or lost is daunting in its own right. 

However, the long-term conservation work required 

after recovery is just as vital to the mission of preserving 

an invaluable piece of history for future generations, 

and must be fully in place before any attempt is made 

to raise it. Nevertheless, the threat to the site from 

potential looting was deemed significant enough that 

recovery was seen as the only way to guarantee preservation of the submarine (Chapter 5).

There were several precedents for intact shipwreck 

recoveries. Almost all were wooden-hulled ships, such 

as Sweden’s 17th century warship Vasa, lifted in 1961; 

the collection of five Viking ships from Skuldelev, near 

Roskilde, Denmark, recovered in 1962; the 14th century 

Bremen cog in Bremerhaven, Germany, discovered that 

same year; and finally, the widely-publicized remains 

of Henry VIII’s flagship Mary Rose, recovered off the 

coast of England in 1982. In addition, the Dutch had 

recovered a number of late and post-medieval vessels 

from land sites in the drained polders of the Netherlands. In the United States, the most well-known intact 

shipwreck recovery projects consisted of the Revolutionary War gunboat Philadelphia raised from Lake 

Champlain, Vermont, in 1935; the Civil War ironclad 

USS Cairo pulled from the Yazoo River, Vicksburg, Mississippi, in 1964; and the remains of French explorer 

LaSalle’s ship La Belle, excavated and recovered off the 

coast of Texas between 1996 and 1997. There were 

also the lesser known recoveries of the 18th century 

Brown’s Ferry vessel, War of 1812 veteran-ship USS 

Ticonderoga, several Confederate vessels—CSS Chattahoochee, Jackson, and Neuse—as well as the 1846-built 

topsail schooner Alvin Clark. Many of these American 

examples of recoveries were not successful templates 

for operations that resulted in preservation and exhibition. Perhaps the closest recovery of a vessel of similar 

complexity to that of Hunley was the recovery of the 

Holland 1 submarine that was salvaged in 1982 for the 

Royal Submarine Museum. At the time of planning 

for Hunley’s recovery, Holland 1 was in the process of 

being retreated, the corrosive salts removed, and, after 

more than a decade, properly conserved. Its conservation had been neglected when it was initially recovered 

and the submarine had suffered irreparable damage to 

its hull (Barker et al. 1997). Of smaller scale were the 

recoveries and subsequent conservation difficulties of 

the steam engines from the shipwrecks SS Xantho in 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

2

Rigging a sunken ship and raising it as a complete 

unit had been accomplished successfully with Philadelphia, Mary Rose, and Vasa, but it had also been 

attempted with disastrous results with USS Cairo in 

1964. Most of these vessels were raised using slings 

to support the vessel from underneath. At only 53 ft. 

(16 m) with a single deck, Philadelphia was closest to 

Hunley in size, but it was raised from relatively calm 

waters and was structurally robust, having been 

submerged in cold, fresh water. The flexibility of a 

wooden structure is also more conducive to a sling lift. 

Even the massive 47.5 m (156 ft.), four-decked Vasa

was lifted with steel cables slung through a series of six 

tunnels dredged beneath the hull (Hocker 2011:177). 

With such examples, it may have seemed like a 

straight-forward project to bring Hunley up. But the 

attempt to raise the 175 ft. (53 m) ironclad Cairo with 

cables slung beneath the hull resulted in the vessel 

being essentially cut apart at the sling points by the 

overwhelming weight of the vessel once it transitioned 

from water to air. Hunley was a much smaller prospect, 

but the weight of the iron hull completely filled with wet 

sediment would considerably exceed its original structural specifications. Also, since the internal structure 

of Hunley was hidden and the strength of the rivets 

uncertain, an insufficiently supported lift could rupture 

or, in effect, unzip the hull plates along the lines of 

rivets. The stiffness and brittleness of the wrought-iron 

structure also posed risks of cracking even if properly 

supported. In addition, in order to preserve as much 

evidence as possible that might help solve the mystery 

of why Hunley sank, it was vital to raise, transport, and 

excavate the vessel at the same 45° angle at which it 

was found. 

The overall condition and strength of Hunley’s hull 

was unknown, although preliminary investigations of 

the hull (Chapter 4) had revealed only minor damage 

(Hall 1995; Murphy 1998). The survival of the rivets, 

which held the wrought-iron plates of the hull, was the 

greatest worry. Conservation and corrosion experts 

agreed that the iron of the rivets would be sacrificial to 

the iron of the hull plating and could have completely 

corroded away or converted to a mineralized state. To 

better understand the key factors of hull integrity and 

rivet strength, additional hull testing and sampling was 

required before a plan could be finalized (Chapter 8). 

Ultimately, it was determined that hull thickness and 

rivet integrity were sufficient to allow a supported lift.

The engineering plan, including piles, truss, and 

conservation tank, would undergo many modifications from concept to final delivery. The project had 

to remain relatively flexible, all the while maintaining 

the guiding goal that it had to be done correctly and 

shortcuts should not be taken that would jeopardize 

the submarine or the recovery of archaeological information. While knowledge of past recoveries of historic 

Western Australia and Columbus in Maryland. There 

were, thus, far more grave examples of failures than 

successes in the spectrum of shipwreck recovery. The 

extensive damage to the iron structure of Holland 1 due 

to poor initial conservation was a particularly important 

lesson in the face of Hunley’s own iron structure. 

Hence, conservation was integral to Hunley’s recovery 

planning (Mardikian et al. 2009:82–83). The lack of 

success stories involving the recovery and conservation 

of large complex iron objects led to the gathering of 

world experts in submerged iron and composite artifact 

conservation in Charleston, South Carolina, in 1999 

(Chapter 5). Hence, from the beginning, Hunley conservation planning was integral to ensuring the recovery 

would result in a positive outcome that would raise the 

bar for shipwreck recoveries. Conservation would ultimately require the establishment of a professional laboratory located in North Charleston to handle a project 

of Hunley’s magnitude (Chapter 7).

Previous recovery projects and the conservation 

symposium provided lessons for how to proceed and 

how not to. Hunley posed a few unusual challenges, 

however. Factors that need to be considered when 

deciding how to raise a sunken ship safely include the 

depth and conditions of the site, the distance from 

shore, the structural integrity of the vessel, and cost. 

Certain of the above shipwreck recoveries involved disassembly in situ and recovery of the ships’ hull timbers, 

a feat accomplished more easily with a wooden vessel 

than an iron one. The disassembled examples lacked 

superstructure of one or more decks and did not have 

inaccessible spaces prohibiting access to artifacts and 

in-situ excavation. This would not have been practical 

for Hunley, which contained a wealth of archaeological data inside that would have been lost if it was 

disassembled, not to mention the impracticality of 

the process, which would have required the drastic 

measures of drilling rivets or the use of cutting torches 

or metal saws. 

La Belle provided an unusual precedent, as it was 

excavated inside of a cofferdam. The site was at a depth 

of only 12 ft. (3.66 m) within the relatively protected 

waters of Matagorda Bay on the Texas coast. The Texas 

Historical Commission was able to construct a doublewalled dam around the site, allowing them to drain 

all the water out and excavate as if it were a land site. 

Hunley, however, was 4.6 mi. (7.4 km) offshore in the 

Atlantic Ocean where a cofferdam could fail during a 

tropical storm or hurricane and would require a long 

period of costly offshore operations. Fortunately for the 

Hunley project planners, the relatively shallow depth 

and moderate currents at the site allowed for long 

dive windows, an invaluable asset when planning a full 

underwater recovery. The site could also be relatively 

quickly covered with sandbags should there be an evacuation due to storm or hurricane.
I N T R O D U C T I O N

3

wrecks, both successful and unsuccessful, informed 

the design of the Hunley recovery project, collaboration with experienced salvage engineers tempered with 

preservation principles was maintained throughout and 

ultimately resulted in a system designed solely to meet 

the specific needs of Hunley (Chapter 9).

The project elevated archaeological and conservation goals over logistical and financial aspects of 

the undertaking (Chapter 10). While a portion of the 

submarine had been exposed upon initial excavation, it was not known whether there were any hull 

breaches resulting in spillage of interior contents, or 

even if a crewmember had escaped the vessel and 

perished beside it. Thus the excavation was approached 

with meticulous care, always with the awareness that 

something unexpected could be encountered at any 

point. Artifacts or loose hull components associated 

with or contemporary with the wreck were to be documented in situ before being recovered, magnetic 

anomalies adjacent to Hunley had to be investigated, 

the submarine’s position in relation to associated loose 

vessel components and artifacts were to be mapped, 

in-situ hull drawings drafted, environmental samples 

collected, and a monitoring system for the hull improvised to ensure there would be no loss of integrity. 

Sediment samples from around the site would contribute significantly to our knowledge of the conditions 

in which Hunley lay for so long and to the reconstruction of the events of the sinking (Chapters 3 and 13). In 

order to be assured that all artifacts were recovered 

from the site, additional work was planned for after 

the removal of the submarine, when magnetometer 

readings would not be skewed by the presence of such 

a large iron mass in the area (Chapter 11). 

In keeping with archaeological ethical standards, all 

data recovered from the original site have been distilled 

and presented in this volume. All artifacts, both original 

to the site and intrusive, were collected and documented (Chapter 15). There is an overview of the submarine’s components and condition as observed prior 

to conservation (Chapter 12) and a preliminary analysis 

of the hull design in comparison to historical accounts 

and other submersibles from the period (Chapter 14). 

However, discussion of the interior workings has been 

left for a future work.

The history of Hunley and its recovery has been 

told in several popular works preceding this report. 

Charleston Post and Courier journalists Brian Hicks and 

Schuyler Kropf were close to the project throughout 

and witnessed the lift firsthand. Their account Raising 

the Hunley: The Remarkable History and Recovery of 

the Lost Confederate Submarine, published in 2002, 

recounted the history of the submarine, its discovery, 

and recovery, laying out the principal players and events 

leading up to the vessel’s installation in the Warren 

Lasch Conservation Center. Their book enlightened the 

general public on the historical importance of the wreck 

and the remarkable efforts, both technical and managerial, involved in recovering it safely.

A good many new primary and secondary sources 

had been unearthed since Hunley’s discovery, particularly by Mark Ragan under the auspices of the Friends 

of the Hunley. The documents he brought to light led 

to a much fuller understanding of the circumstances 

surrounding the submarine’s origins and the development of underwater warfare in general. Many of his 

initial findings were published in his 1995 work The 

Hunley: Submarines, Sacrifice, and Success in the Civil 

War. He updated this volume with new finds in 2006, 

and expanded his scope to cover a broader sphere in 

Submarine Warfare in the Civil War (2002). Tom Chaffin 

(2008) utilized much of the new historical and archaeological research in H. L. Hunley: The Secret Hope of the 

Confederacy, which focused more intensively on the 

historical background on the submarine and the forces 

leading up to its construction and final mission. There 

were also books on Hunley for the young reader with 

Sally Walker’s Secrets of a Civil War Submarine: Solving 

the Mysteries of the H. L. Hunley (2005) and Fran Hawk’s 

The Story of the H. L. Hunley and Queenie’s Coin (2004). 

More recently there is Brian Hicks’s Sea of Darkness: 

Unraveling the Mysteries of H. L. Hunley (2014) which 

seeks to cover more of the story of the recovery project 

and the recent research.

The aforementioned works cover the perceptions 

of popular writers. A certain amount of myth and historical inaccuracy has crept into the story of Hunley with 

each retelling. Writers of secondary source works frequently jump to conclusions and misinterpret archival 

sources. This report complements and corrects some of 

the previous works by restating the historical records 

as precisely and accurately as possible without making 

assumptions (Chapter 2). The authors’ goal is the documentation of the archaeological and logistical aspects 

of the recovery based the research of the project’s 

principal investigator and staff archaeologists. This 

report documents the archaeological findings specific 

to Hunley and provides a detailed example of what goes 

into responsibly planning and executing a successful 

shipwreck recovery. Every wreck recovery project has its 

own unique features that require customized methods 

and equipment. By providing an in-depth account of 

Hunley’s archaeological and logistical complexities, the 

authors establish a basis for further Hunley research 

as well as an example for future archaeological project 

planners to consider (Chapters 6 and 7).

The question of Hunley’s demise is still to be 

resolved. There is a range of possibilities with some 

seeming more likely than others (Chapter 16). It can 

be anticipated that the ongoing research will first 

eliminate several scenarios and, through this process, 

eventually lead to the most likely interpretation. There 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

4

have struck a balance between providing details from 

published research along with new data pertinent to 

the recovery operation, the submarine prior to the 

excavation of the interior, and surrounding artifacts, 

while leaving the monumental task of documenting the 

interior of the craft, analyzing the remains of the crew, 

and cataloging their personal effects for future work.

are many details about the vessel and crew that have 

been revealed in the years between Hunley’s recovery 

and this publication, and it is tempting to try to include 

them all here. Indeed, the finalization of this volume 

has been a challenge simply in deciding where to 

stop. The scope of the entire project, however, is too 

large for a single volume, and the authors in this work 
5

2. HISTORICAL BACKGROUND

S h e a M c C l e a n

Mariners have always marveled at, and often 

feared, the variety of denizens inhabiting the aquatic 

world. For centuries, a common fear among sailors was 

the possibility that they might be suddenly and violently 

attacked from beneath the waves. Classic works of literature such as Herman Melville’s Moby Dick or Jules 

Verne’s 20,000 Leagues under the Sea exemplify this 

fear. As a result, many nations originally considered the 

concept of underwater warfare reprehensible. In fact, 

many years passed and several conflicts were fought 

before submarines achieved a “respectable” status in 

naval warfare. Today, submarines are one of the world’s 

most advanced forms of human technology and are 

widely considered to be the best deterrent to nuclear 

war. Although submersible vehicles have been built for 

centuries, one historic event focused world attention on 

this specialized watercraft and its deadly potential. The 

sinking of USS Housatonic on 17 February 1864 proved 

that the best-prepared surface ship was completely vulnerable to attack from underwater. Consequently, naval 

warfare would be changed forever.

Early Submarine Development

As early as 400 b.c., ancient sponge divers operating 

in the Aegean Sea reportedly used inverted cauldrons to 

supply air while under water (Pseudo-Aristotle 960b). In 

300 b.c., Archimedes described the physical principles 

needed to achieve submersion from the surface. By 

the 12th century a.d., apocryphal tales had emerged 

of Alexander the Great venturing beneath the waves in 

a crude glass diving bell around 332 b.c. (Gaster 1897). 

All of the aforementioned reveal the deep infatuation 

with undersea travel that humans have harbored since 

ancient times. Interestingly, the impetus for these early 

submersibles or diving bells was somewhat benign. 

Ancient “submariners” were generally tasked with the 

collection of sponges or the salvage of sunken ships. 

However, being lowered into the sea via a surface tether 

(i.e., with a diving bell) and moving freely beneath the 

surface (via submarine) are two completely different 

concepts requiring two completely different types of 

submersible vehicle.

As time progressed, nations expanded their power 

at sea and developed more effective ways to wage war. 

Nations with large fleets soon found themselves in a 

position to affect international trade. Economic warfare 

was born. One form of maritime economic warfare was 

the interception and destruction of enemy merchant 

shipping. However, such an undertaking could prove 

time consuming and costly on the high seas. A more 

viable alternative was simply to deny access to the 

sea by blockading an adversary’s ports. Nations that 

lacked large numbers of warships were often unable 

to combat the naval blockade of a superior adversary. 

Smaller nations that lacked the variety and number of 

resources needed to build and maintain a large naval 

fleet eventually resorted to more non-traditional 

methods of defense. One of the most innovative and 

dangerous forms of asymmetrical naval warfare was the 

invention of non-tethered submersibles. 

Leonardo da Vinci, the renowned scientist, artist, 

and inventor, conceived one of the earliest designs for 

a non-tethered submersible. Da Vinci, who claimed to 

have developed a design for a “diving craft,” refused to 

publish his invention because of “the evil nature of men” 

that might “practice assassination at the bottom of the 

sea” (Harris 1997:1). However, da Vinci’s prophetic 

message did not deter others who would design and 

eventually build working submarines. 

In 1578, Englishman William Bourne described a 

ship that should be able to submerge completely under 

the water by contracting its size via leather-clad movable 

joints (Harris 1997:5–6). Subsequent speculation on 

how to interpret this idea led to various proposals for 

incorporating internal ballast tanks that allowed a ship 

to sink through the displacement of air with water. In 

1623, Cornelis Drebbel, a Dutch inventor and engineer, 

constructed the first true diving boat. The vessel was 

outfitted with oars that protruded through watertight 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

6

A diagram of his design was published in the December 

1747 issue of the Gentleman’s Magazine and Historical 

Chronicle and may have influenced future designers, 

including David Bushnell (Manstan and Frese 2010:37–

38). In 1773, an English wagon maker named J. Day 

converted a small fishing boat into a crude submarine 

and reportedly completed a successful dive to 30 ft. 

(9.14 m) (Fyfe 1907:160). According to one account, 

on 28 June 1774, Day and his submarine disappeared 

while attempting to remain submerged for 12 hours at 

a depth of 100 ft. (30.48 m) (Fyfe 1907:162).

On 6 September 1776, during the American Revolution, David Bushnell’s one-man wooden submarine 

Turtle became the first submersible to attack an enemy 

warship (Figure 2.1). Bushnell’s boat incorporated all of 

the successful innovations created by previous inventors. 

It had a 200 lb. (90.72 kg) keel weight, which could be 

dropped 40 to 50 ft. (12.19–15.24 m) below the vessel 

to provide instant buoyancy, a depth barometer, and 

pumps to adjust the vessel’s water ballast (Bushnell 

1799:303–305). Additionally, Bushnell incorporated a 

means to extend operation while submerged. The vessel 

was equipped with two air pipes, one for intake and one 

for exhaust, “so constructed, that they shut themselves 

whenever the water rose near their tops,” that allowed 

its pilot to replenish the submersible’s air supply during 

operation (Bushnell 1799:304). An oar “formed upon 

the principle of the screw” propelled the boat, and 

another at the top of the vessel was used to rise to 

the surface (Bushnell 1799:305). Turtle’s weaponry 

consisted of a wooden keg filled with 150 lb. (68.04 kg) 

of black powder that was to be was fastened to the 

hull of its intended victim via a small woodscrew and 

ignited by a mechanical time apparatus set to detonate 

after the submarine had reached a safe distance from 

its target (Bushnell 1799:307–308). Turtle attempted 

three attacks on the British fleet in the vicinity of New 

York City, but failed to sink an enemy ship.

Before his world-renowned invention of the 

steamboat, Robert Fulton launched a comparatively 

less famous 21 ft. (6.4 m) hand-cranked, copper-clad 

submersible in Paris on 24 July 1800 (Parsons 1922:25, 

33). The vessel, dubbed Nautilus, was fitted with a sail 

for added power on the surface, distinguishing it as the 

first vessel to be equipped with two separate methods 

of propulsion for travel above and below the water 

(Figure 2.2). Fulton traveled to France in 1797 to aid 

the French in their attempt to break England’s naval 

blockade during the War of the First Coalition. Fulton 

attempted to sell his submersible to Napoleon after 

an impressive demonstration in which a target vessel 

was sunk in the port of Brest. Fulton spent a considerable amount of time and money perfecting the vessel; 

however, Napoleon declined Fulton’s offer after the 

French naval hierarchy questioned the morality of using 

such an ignoble device. Undeterred, Fulton offered his 

seals, propelled by twelve oarsmen, and was apparently conned via a magnetic compass (Harris 1997:9). 

Although Drebbel’s ship reportedly could remain underwater for a few hours, it likely only submerged to a 

shallow depth (Harris 1997:8). The boat was apparently 

successful and was demonstrated in the Thames River 

for King James I (Harris 1997:9). An associate of Drebbel, 

Constantijn Huygens (1631), provided an insight into 

one of Drebbel’s motives for building such a boat.

[I]t is not hard to imagine what would be the 

usefulness of this bold invention in time of 

war, if in this manner (a thing which I have 

repeatedly heard Drebbel assert) enemy 

ships lying safely at anchor could be secretly 

attacked and sunk unexpectedly by means of 

a battering ram. (Harris 1997:11)

After Drebbel’s revolutionary demonstration in the 

Thames, several similar inventions appeared over the 

next two centuries. In 1652, French inventor De Son 

designed a 72 ft. (21.95 m) long submarine propelled 

by a paddle wheel and equipped with rams at both ends 

(Harris 1997:16). Although his invention was never successfully tested, De Son is noted as the first to develop 

a submersible for the sole purpose of sinking a surface 

ship. In the late 17th century, Denis Papin experimented 

with a one-man diving apparatus that may have been 

the first to incorporate detachable ballast, an internal 

barometer (depth gauge), and the use of pumps 

and valves to regulate water ballast (Harris 1997:17). 

Figure 2.1. This widely published 1875 drawing of Bushnell’s Turtle by Francis M. Barber is based only on written 

descriptions of the vessel, and likely contains many inaccuracies, particularly in the propellers, which were likely 

closer to standard screw propellers.
H I S T O R I C A L B A C K G R O U N D

7

invention to Napoleon’s archrival, Great Britain. Again, 

after considerable time and money were committed to 

the project and its abilities successfully demonstrated, 

the British Admiralty rejected the vessel. Regardless 

of its failed salability, Nautilus was a masterpiece of 

design and ingenuity. It was the first vessel to utilize 

compressed air and the first to actually sink a ship with 

an explosive device (Parsons 1922:42–43).

Wilhelm Bauer, a pioneering Prussian inventor, 

spent 25 years developing submarines on behalf of 

the governments of at least five different nations. He 

completed his first submersible Brandtaucher (“Incendiary Diver”) in 1850 to repel a blockading Danish fleet 

during the first Schleswig War (1848–1851). Seawater 

leaked into the vessel during a test dive in February 

1851, causing it to sink in Kiel Harbor to a depth of 50 ft. 

(15.24 m). During its unintentional descent, Brandtaucher’s sliding ballast weight slid too far forward, 

causing the vessel to plunge nose first into the harbor’s 

muddy bottom (Harris 1997:69). Over seven hours later, 

Bauer opened the submarine’s hatch when air pressure 

inside the hull, compressed by water leaking into the 

submarine, equalized with the water pressure outside. 

He and his crew swam to the surface to find their funeral 

services already in progress. After failed attempts 

to sell his invention to Austria and the United States, 

Bauer sold a prototype to the British Navy at the onset 

of the Crimean War. However, Bauer was dismissed 

from British service after producing another, considerably more lackluster prototype. Undaunted, Bauer 

approached England’s wartime nemesis, Russia, and 

built Le Diable-Marin (“The Sea Devil”)(Harris 1997:70). 

The 52 ft. (15.85 m) iron submarine accommodated 

a crew of 11 and was powered by a treadmill-driven 

screw propeller. Bauer’s newest design was extraordinarily successful. It completed as many as 134 test dives 

without incident. On the occasion of Czar Alexander II’s 

coronation in 1855, Bauer submerged with 16 observers 

(including several band members) at Kronstadt Naval 

Base and played the Russian national anthem while on 

the bottom. He experimented with various methods 

of chemical air purification and underwater communication. Bauer also took photographs through the submersible’s view ports; these are probably the first such 

images taken under water.

Submarines and the American Civil 

War

With the possible exception of Bauer’s contributions, no significant advancements in submarine technology were made between Fulton’s experiments in 

the early part of the 19th century and the American 

Civil War. However, submarine development assumed 

new urgency when, on 19 April 1861, Abraham Lincoln 

announced the blockade of all Southern ports during 

the first few days of the American Civil War: 

I, Abraham Lincoln, President of the United 

States . . . have further deemed it advisable to 

set on foot a blockade of the ports within the 

States aforesaid, [South Carolina, Georgia, 

Alabama, Florida, Mississippi, Louisiana, 

and Texas1

] in pursuance of the laws of the 

United States and of the law of nations 

in such case provided. For this purpose 

a competent force will be posted so as to 

prevent entrance and exit of vessels from 

the ports aforesaid. If, therefore, with a 

view to violate such blockade, a vessel shall 

approach or shall attempt to leave either of 

the said ports, she will be duly warned by the 

commander of one of the blockading vessels, 

who will endorse on her register the fact 

and date of such warning, and if the same 

vessel shall again attempt to enter or leave 

the blockaded port she will be captured, 

and sent to the nearest convenient port for 

such proceedings against her and her cargo 

as prize as may he deemed advisable. And 

I hereby proclaim and declare that if any 

person, under the pretended authority of 

the said states . . . shall molest a vessel of 

the United States . . . such person will be held 

amenable to the laws of the United States 

for the prevention and punishment of piracy. 

(ORN 1.4:156–157) 

By this time, Southerners considered themselves 

citizens of a new and independent nation and most 

deemed Lincoln’s action an infringement on their 

1 The blockade was extended to Virginia and North Carolina on 27 

April 1861.

Figure 2.2. Fulton’s Nautilus was unique in its design 

to function as a sailboat on the surface. (NHHC Photo 

Archives #NH 2057)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

8

after part of the boat. . . . A harpoon point, 

easily separated from the forward end of 

the boat after being driven into the enemy’s 

side, (some ten feet [3.05 m] under water,) 

carries the wire that holds the shell. . . . 

The air-pump, the inhalation tube, the eye 

glasses, are already used.—The new Aneroid 

Barometer, made for increased pressure will 

enable the adventurer easily to decide his 

exact distance below the surface. . . .

I am preparing a detailed Memoir on 

Submarine Warfare, discussing matters not 

proper to be spoken of here, illustrated with 

engravings. Copies of the pamphlet will be 

sent to the Mayor and municipal authorities 

of Southern maritime cities. (Smith 1861)

Smith’s article was later reprinted in several 

Southern newspapers throughout the Confederacy 

including the Mobile Advertiser and Register (26 June) 

and the Richmond Whig (2 July). The article apparently 

sparked the imagination of many people in the South 

and may have been the impetus for several submarine 

building programs. 

Smith’s article apparently caused some alarm in the 

Northern states. At least two letters were addressed to 

(United States) Secretary of the Navy Gideon Welles 

immediately after its publication:

My purpose in addressing you . . . on this 

subject is, that I am induced, by a vague hint 

in a New Orleans paper, to suspect that they 

now have in preparation on the Mississippi a 

plan . . . for running into and sinking some of 

the blockading vessels in the Gulf. 

I am of the opinion that it would be 

worth while to put our naval commanders 

there on their guard against that particular 

danger. 

—Charles Ellet, Civil Engineer, Georgetown, DC, 21 June 1861 (ORN 1.22:288)

Yesterday morning I met a lady belonging 

in the New England States, who has been 

engaged . . . in teaching school, a little north 

of New Orleans. . . . She tells me that the 

rebels in New Orleans are constructing 

an infernal submarine vessel to destroy 

the Brooklyn, or any vessel blockading the 

mouth of the Mississippi; from her description, she is to be used as a projectile with a 

sharp iron or steel pointed prow to perforate 

the bottom of the vessel and then explode. 

—E. P. Dorr, Buffalo, NY, 25 June 

1861 (ORN 1.22:288)

sovereign rights. Early in the war, the Confederate 

Congress passed a bill authorizing the government 

to issue letters of marque to individual citizens who 

wished to act as privateers. Independent commercial 

entities soon joined in and promised to pay bounties 

on any blockading ship destroyed by private means. 

In Charleston, South Carolina, the firm of John Fraser 

& Co. offered $100,000 to anyone who could destroy 

either of the two largest Union navy vessels blockading their harbor, New Ironsides or Wabash. Additionally, $50,000 was offered for the destruction of a 

Monitor-type ironclad. The production of an effective 

military submarine now appeared inevitable because 

the inventor of such a device stood to gain handsomely 

if just one blockader could be eliminated. Essentially, a 

combination of patriotism and profit motive became 

the incentive for Southern submarine development 

during the Civil War.

Franklin G. Smith, a chemist, inventor, and patriotic 

Southerner who may have been acquainted with the 

earlier exploits of Fulton and Bushnell, advocated the 

use of submersibles in a 10 June 1861 Columbia (TN) 

Herald article entitled “Submarine Warfare”: 

Excepting our Privateers, the Confederate 

States have not a ship at sea. We may safely 

originate plans for blowing up the vessels 

employed in blockading our ports, without 

danger of being ‘hoisted by our petard’ . . .

Throughout our Southern seaports, men 

of a mechanical turn and of the right spirit 

must go to work, maturing the best plans 

for the destruction or the capture of every 

blockading ship. 

All things invite the enterprise. From the 

Chesapeake to the mouth of the Rio Grande, 

our coast is better fitted for submarine 

warfare than any in the world. It has all been 

most minutely surveyed and mapped. It has 

almost no tides, it has uniform currents, 

and a bottom always sandy, seeming to 

invite adventurous feet to travel over it. It 

is probable ‘submarines’ are now traversing 

these sands, acquiring confidence in their 

new element and skill in the use of their 

terrible engines of destruction. . . .

But I would have every hostile keel 

chased from our coast by submarine propellers. The locomotive Diving Bell is well 

known. The new vessel must be cigar 

shaped for speed—made of plate-iron, 

joined without external rivet-heads, about 

30 feet [9.14 m] long, with a central section 

of about 4 by 2 feet [1.22 × 0.91 m]—driven 

by a spiral propeller, a fishtail sculler, or, (far 

better,) by a steam engine, occupying the 
H I S T O R I C A L B A C K G R O U N D

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In 1878, a diver on the dredge boat Valentine discovered a small submersible in Bayou St. John that 

resembled Dorr’s description (Kloeppel 1992:11). 

Although it is unclear who built the vessel, it was 

displayed at the Old Confederate Soldiers’ Home in 

New Orleans and for many years was believed to be the 

earliest predecessor of H. L. Hunley. The vessel, which 

was 20 ft. (6.1 m) in length, 6 ft. (1.83 m) deep, and 3 ft. 

(0.91 m) wide, was eventually moved to the Louisiana 

State Museum in New Orleans (Figure 2.3). 

On 21 October 1861, Charles P. Leavitt of Company 

K, 2nd Virginia Regiment, wrote a letter to the 

Secretary of War of the Confederacy, Judah P. Benjamin, 

requesting that he be allowed to go to Richmond to 

draft plans for an invention he called “a submarine 

gunboat.” He described the craft as:

A vessel . . . built of boiler iron of about fiftytons [45.36 t] burden, made of an oval form 

with the propeller behind. . . . Placed in the 

bow is a small mortar containing a selfexploding shell. As it strikes the enemy, the 

shell explodes, and blows in the ships [sic] 

side. (Smythe 1907:1) 

The 19 year old machinist’s letter also detailed the 

construction and operation of a submersible steam 

engine, as well as a method for producing breathable 

oxygen inside a submarine with carbonic acid and 

limewater. Leavitt’s ideas so impressed the Secretary 

that he was summoned to Richmond in December 1861. 

Between August 1861 and May 1862, at least two submersible boats were built at the Tredegar Iron Works 

in Richmond (Wills 2000:40). Acting Master William 

G. Cheeney, CSN, supervised the construction of these 

vessels. Although both vessels were tested successfully, 

and at least one made an attempted attack on a blockading vessel, neither was able to inflict any damage 

on the Union fleet. It is unclear whether Leavitt was 

recalled to Richmond to contribute to Cheeney’s work.

As the Union blockade gained momentum during 

the early months of the war, the U.S. Navy received 

reports that Confederate forces planned to break the 

blockade of the James River. The Confederate navy had 

raised the sunken warship Merrimac (scuttled as Federal 

forces abandoned the Gosport Navy Yard three days 

after Virginia’s secession) and was refitting the vessel 

with a thick armored casemate. Merrimac (renamed 

CSS Virginia) was intended to break the blockade and, 

perhaps, enter the Potomac River and bombard Washington, DC (Ragan 1999:22). The fact that the Union 

hurried construction of its own ironclad (USS Monitor) 

to thwart Confederate attempts on Washington is historically well documented. However, it is a little-known 

fact that the U.S. Navy attempted to build a submarine 

to achieve the same task. A French submarine builder, 

Brutus de Villeroi, was contracted to supervise construction of the U.S. Navy’s first combat submarine. De 

Figure 2.3. An unidentified submarine, once thought to be Pioneer, being moved to the Louisiana State 

Museum in New Orleans. The vessel is sometimes called Bayou St. John Confederate Submarine after 

the location where it was originally discovered. (Detail from NHHC Photo Archives #NH 42860)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

10

Villeroi began construction of the 46 ft. (14 m) long submersible (christened Alligator) at the Philadelphia Navy 

Yard on 1 November 1861, and launched it in April 1862 

at an estimated cost of $14,000 (Harris 1997:85). Once 

completed, Alligator was deemed too large and slow for 

operations in the James River. After being refitted with 

a hand-crank propulsion system and judged ready for 

service, Alligator was lost in a storm off Cape Hatteras 

on 2 April 1863, while being towed to Port Royal, South 

Carolina. 

There were many other attempts by many groups 

in many cities (both North and South) to build submersibles for the purpose of tipping the balance of naval 

power in favor of one side or the other. Unfortunately, 

much of the documentary evidence that detailed these 

pioneering efforts has been lost. Confederate records, 

in particular, suffered. Most of these documents were 

destroyed in the final chaotic days of the war as Confederate leaders attempted to deny the enemy details 

of their wartime progress. Many inventors feared they 

would be tried as pirates after the war if they could 

be linked to privateering vessels or the production 

of weapons of questionable morality. What can be 

deduced from fragmentary archival sources is this: each 

group that constructed submersibles during the Civil 

War borrowed from and built upon previous innovations. Bourne’s introduction of ballast tanks, Drebbel’s 

experiments in mobility, Bushnell’s use of screw propellers, Fulton’s use of auxiliary power, Papin’s incorporation of detachable ballast, internal barometers, and 

water ballast pumps, and Bauer’s experiments with 

various methods of chemical air purification were but 

a few of the seemingly endless progression of innovations that eventually culminated in the creation of the 

world’s first successful military submarine. 

Development of Pioneer, Pioneer II, 

and H. L. Hunley

Like many accounts that outline the development 

and production of Civil War submarines, the story of 

H. L. Hunley and its two predecessors is riddled with 

exaggerations and inconsistencies. Even primary 

archival sources, when compared, often contradict one 

another. Consequently, the following historical analysis 

is based on interpretation of the most credible of these 

conflicting sources. It attempts, as much as possible, to 

dispel many of the myths associated with the submarines, their crews, and their inventors.

Desperate times breed desperate measures, and 

desperate measures in turn can transform ordinary 

individuals into extraordinary historical figures. Such 

was the case when a group of young engineers, financiers, and Southern patriots combined their respective energy and expertise to produce the world’s first 

successful combat submarine. Prior to the Civil War, 

James R. McClintock and Baxter Watson manufactured 

steam gauges and parts for steam engines at a shop at 

31 Front Levee, located on the New Orleans waterfront. 

The team made its first contribution to the war effort by 

inventing a cold-press lead bullet mold for the Confederate army in the summer of 1861 (New Orleans Daily 

Delta 1861). McClintock was born in Cincinnati, Ohio, in 

1829 and was sometimes referred to as “the youngest 

steamboat captain on the river.” Little is known about 

Baxter Watson except that he—like McClintock—was 

an experienced machinist and practical marine engineer. 

The duo began construction of a two to three man submersible at nearby Leeds Foundry, located at the corner 

of Fourcher and DeLord Streets in mid-1861 (Kloeppel 

1992:6–7, Perry 1993:94).

This creative team was soon joined by a man with 

three important qualities: wealth, connections, and 

an unwavering belief in the potential of submarines. 

Horace Lawson Hunley was born on 9 December 1823 

in Sumner County, Tennessee. He and his younger sister 

Volumnia were the only children of John and Louisa 

(Lawson) Hunley. John Hunley left his Tennessee home 

and accompanied Andrew Jackson during the Indian 

Wars of 1812–1814 and fought at the Battle of New 

Orleans on 8 January 1815 (Duncan 1965:19). John 

Hunley’s experiences in New Orleans during the war 

may have prompted him to move his family from 

Tennessee to the port city. His name first appears in 

the New Orleans directory in 1830; the listing describes 

him as “a broker . . . engaged in the buying and selling of 

cotton” (Duncan 1965:19). After John Hunley’s untimely 

death in 1834, his young widow, Louisa, remarried. Her 

new husband, James R. Connor, was a cotton broker 

and plantation owner (Duncan 1965:20). Horace Hunley 

followed in his father’s and stepfather’s footsteps and 

became a wealthy cotton merchant and plantation 

owner. He was well educated and received a Bachelor of 

Law degree at the University of Louisiana (now Tulane 

University) in 1849. He later held the office of New 

Orleans Deputy Collector of Customs (Duncan 1965:53–

54). Hunley, like McClintock and Watson, was quick to 

contribute to the war effort. He traveled to Cuba in 

June 1861 to procure foreign arms and munitions for 

the Confederate military. It is not clear exactly when 

or how Hunley joined the McClintock-Watson team 

(Figure 2.4); however, historical sources indicate that he 

became acquainted with the duo during the construction of Pioneer in 1861 and continued to play an active 

role in the development of Confederate submersibles 

until his death in October 1863. It appears that Hunley 

had the political connections and the capital needed to 

transform McClintock and Watson’s engineering vision 

into reality. 
H I S T O R I C A L B A C K G R O U N D

11

Pioneer

This relatively small, cylindrical vessel (approximately 30 ft. [9.14 m] in length and 10 ft. [3.05 m] in 

circumference) was constructed of 1⁄4 in. (6.35 mm) iron 

plate wrapped around iron support frames. The forward 

and aft sections of the hull were fitted with conical 

ends, which gave the vessel a crude cigar-shaped 

appearance. Pioneer was propelled by a hand-cranked 

screw propeller and steered laterally with a rudder; the 

vertical attitude was controlled with “vanes” mounted 

to the submarine’s sides. The latter acted in a manner 

similar to the “pectoral fins of a fish” (Baird 1902:845). 

The explosive charge, or torpedo, was fitted with percussion fuses and towed behind Pioneer on a long 

tether. When Pioneer was completed, John K. Scott was 

selected as its commander. During trials, Scott found 

that the submarine responded sluggishly when maneuvered and was difficult to steer when submerged. He 

also discovered that Pioneer’s magnetic compass swung 

crazily when underwater, making it practically useless 

(Perry 1993:95). Scott learned that, with some practice, 

he could surface intermittently and visually reacquire 

his intended target with some degree of success. Eventually, the new captain felt confident that he and his 

crew were ready to attempt a simulated attack on a 

target vessel. In March 1862, Pioneer successfully sank 

a test barge in Lake Pontchartrain. 

Before their submarine could officially engage 

an enemy vessel, the Pioneer team required a letter 

of marque (privateering commission) from the Confederate government. This would grant legal permission for Pioneer to “cruise the high seas, bays, rivers, 

estuaries, etc., in the name of the Government, and 

aid said Government by the destruction or capture 

of any and all vessels opposed to or at war with said 

Confederate States, and to aid in repelling its enemies” 

(ORN 2.1:399). On 31 March 1862, the submarine’s 

crew received its commission. Details derived from the 

letter of marque and associated Customs House records 

provide most of the information concerning Pioneer, 

including its dimensions, crew, and the names of its 

owners/investors. The vessel was officially designated 

a “submarine propeller” with an overall length of 34 

ft. (10.36 m), maximum diameter of 4 ft. (1.22 m) and 

displacement of 4 tn. (3.63 t). The vessel was conically 

shaped at both ends and painted black. Pioneer’s 

armament was described as a “magazine of explosive 

matter” (this presumably was a reference to the submarine’s torpedo). 

The letter named Scott as the submarine’s skipper 

and referred to an additional crew consisting of one 

or two unnamed individuals. There is some indication that Horace Hunley’s influence may have determined Pioneer’s commander: Scott was an employee 

of the Customs House where Hunley served as Deputy 

Collector of Customs. The Register of Commissions 

kept at the Customs House Collector’s Office lists the 

vessel owners as James R. McClintock, Baxter Watson, 

Figure 2.4. Photographs of James R. McClintock (left) and Horace L. Hunley (right). There is no known 

photograph of Baxter Watson. (Left: NHHC Photo Archives #NH 95279; right: Horace Lawson Hunley 

ca. 1860, Gift of Mrs. Kathleen Grosclose, Courtesy of the Louisiana State Museum)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

12

and Robert R. Barrow. Barrow was a wealthy patron of 

the project who also happened to be Horace Hunley’s 

brother-in-law (Duncan 1965:64). Customs House 

records also indicate that the commission collected a 

surety bond of $5,000. The bond lists Hunley and an 

associate, Henry J. Leovy, as guarantors (ORN 2.1:401). 

Leovy was a prominent local attorney and, interestingly, editor of the New Orleans Picayune, and, as such, 

may have been familiar with Franklin Smith’s article 

“Submarine Warfare.”

Pioneer never had an opportunity to engage an 

actual enemy ship. On 28 April 1862, less than one 

month after the submarine’s owners received their 

letter of marque, New Orleans fell to Union land and 

naval forces. Hunley, McClintock, and their associates 

were forced to scuttle the submarine and flee the city. 

During the occupation of New Orleans, Pioneer was discovered by Federal troops. A U.S. naval engineer named 

Alfred Colin and his assistant, G. W. Baird, examined the 

vessel from late 1863 to early 1864. Baird, who met 

McClintock after the war, published an article with the 

following account of the boat: 

When a Third assistant on board the 

Pensacola during the Civil War, I had the 

pleasure of assisting Second Assistant 

Engineer Alfred Colin in the measurements 

and drawings of a submarine torpedo boat 

[Figure 2.5] which had been fished out of the 

canal near the “New Basin,” between New 

Orleans and Lake Pontchartrain. Mr. Colin’s 

drawing was sent by the Fleet Engineer (Mr. 

[William H.] Shock) to the Navy Department. 

The boat was built of iron cut from old 

boilers. . . . She was thirty feet [9.14 m] in 

length; the middle body was cylindrical, 

ten feet [3.05 m] long, and the ends were 

conical. She had a little conning tower with a 

manhole in the top and small, circular, glass 

windows in its sides.2

 She was propelled by 

a screw, which was operated by one man....

Mr. McClintock (whom I met after the Civil 

War had ended) informed me that he made 

several descents in his boat, in the lake, and 

succeeded in destroying a small schooner 

and several rafts. . . . His boat required but 

two men to operate it. . . .He frankly stated 

that the model of the boat was improper, in 

that the small displacement afforded by the 

sharp ends was insufficient to keep the boat 

on even keel if a man moved a few inches 

forward or aft, and that this was a serious 

objection. (Baird 1902:845–846)

2 This is contradicted by drawings (Figures 2.5 and 2.6), which show 

a separate hatch and pilot house.

Figure 2.5. Tracing of Pioneer enclosed in William H. Shock’s (1864) report to the Assistant Secretary of the Navy, presumably based on the work of Second Assistant Engineer Alfred Colin, showing the boat’s main functional features. 

(Image courtesy of NARA)
H I S T O R I C A L B A C K G R O U N D

13

While long confused with the vessel discovered at 

Bayou St. John (see Figure 2.3), the sketch provides clear 

evidence that Pioneer was a different boat altogether. 

Its ultimate fate is unknown. One possible explanation 

comes from the morning edition of the 15 February 

1868 New Orleans Picayune. The newspaper posted an 

auction ad for:

A torpedo boat, which was built in this city 

or hereabouts during the war, and which is 

now lying on the banks of the New Canal, 

near Claiborne Street, is to be sold at public 

auction to-day, by the United States authorities, at 12 o’clock. . . . The boat in question, 

which is built of iron and weighs about two 

tons, was sunk in the Canal about the time 

of the occupation of the city by the Federal 

forces, in 1862. 

A follow-up in the newspaper’s evening edition 

reports “[t]he torpedo boat, of which we made mention 

this morning, was sold at public auction, to day, at noon, 

for forty-three dollars. It cost, originally, twenty-six 

hundred” (Ragan 1995:21). That the article mentions 

that the submarine was found “lying on the banks of 

the New Canal” may hint at its identity. Historically, 

the New Canal connected Lake Pontchartrain to New 

Basin, which was also mentioned by Baird (1902:40) in 

reference to the boat he documented. An 1865 sketch 

by David M. Stauffer, then an ensign on USS Alexandria, 

depicts the same boat drawn by Colin and is labeled 

as coming “from the bottom of the New Basin, N.O.” 

(Figure 2.6). McClintock claimed that the submarine 

crew practiced operational procedures and conducted 

simulated attacks in Lake Pontchartrain. The area near 

Claiborne Street, where the submarine was discovered, 

is only eight blocks from the New Basin. The New Basin, 

incidentally, is only eight blocks from where Pioneer was 

built at the Leeds Foundry (located a 923 Tchoupitoulas 

Street). It is the closest water access to Lake Pontchartrain from the foundry (Figure 2.7).

Pioneer II 

After New Orleans fell to Union forces, McClintock 

and his associates regrouped in Mobile, Alabama. 

Mobile, like New Orleans, was a major Southern 

seaport on the Gulf Coast and possessed the resources 

and manufacturing facilities to produce another submersible. Upon their arrival in Mobile, the group discovered that the city’s military commander, Major 

Figure 2.6. A drawing of the exterior of Pioneer made by Ensign Stauffer showing the boat’s 

main functional features. (Original artwork by David Stauffer, David M. Stauffer, 1864. Courtesy 

of The Gilder Lehrman Institute of American History, GLC07713.01, p. 17.)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

14

General Dabney H. Maury, was a strong proponent of 

torpedo and submarine warfare. Several Southern cities, 

including Mobile, New Orleans, Savannah, Richmond, 

Galveston, and Norfolk, hosted a number of independent groups that were actively developing alternative 

weaponry. Franklin Smith, author of the 1861 article 

that endorsed the use of submarines by the Confederacy, had procured a patent and may have been 

building his own submersible in Mobile in January 1862 

(Ragan 1999:42). Maury welcomed McClintock’s team 

and supported its efforts by arranging an introduction 

between Pioneer’s owners/inventors and members of 

the firm Park and Lyons. Thomas W. Park and Thomas 

B. Lyons, like McClintock and Watson, were machinists 

and practical engineers. Before the war, both men were 

engaged in construction and repair of steam engines, 

and boilers. Park and Lyons were already heavily 

engaged in the production of artillery, steam engines, 

and machinery for the Confederate government when 

McClintock and his associates arrived, but were able to 

arrange an agreement under which the team’s second 

submarine would be produced (Perry 1993:96). Two 

young army officers assigned to the machine shop—

both of whom were experienced practical engineers 

and machinists—soon developed a keen interest in 

the project. These men were Lieutenants William A. 

Alexander and George E. Dixon. 

William Anthony Alexander was born in London 

on 21 December 1837 to Scottish parents. He immigrated to Mobile at the age of 22 and began business 

as a practical engineer and consulting machinist. In 

May 1861, Alexander enlisted in 

the Confederate army and served 

with Ketchum’s Battery, Company 

B, Alabama State Artillery, 21st 

Alabama Regiment (ADAH, n.d.). He 

was given command of fortification 

efforts at Fort Morgan, located on 

the eastern shore of the entrance 

to Mobile Bay. He remained at Fort 

Morgan until reassigned to Park and 

Lyons. 

George E. Dixon’s origins are 

more enigmatic. The details of his 

early life are unknown and the circumstances surrounding his arrival 

in Mobile are unclear at best. Dixon 

was likely born in Kentucky or Ohio, 

and was licensed as a steamboat 

second engineer in 1859 at St. Louis, 

Missouri (Mobile Daily Item 1910; 

BSI 1859:131). By 1861 he had 

made his way to Mobile, where his 

name appears in the city directory as 

“Dickson [sic], Geo, Engineer, steamer 

Flirt” (Mobile City Directory 1861:19; 

O’Brien, pers. comm.). While in Mobile, he joined the 

Mobile Greys, an auxiliary police force. Dixon’s senior 

officer in this organization, Major Palmer Pillans, stated 

in a local newspaper article that the Mobile Greys were 

established “to aid and strengthen the police force of 

the city, which, at that time, was totally inadequate to 

properly police the city” (Mobile Daily Register 1895). 

Apparently, Pillans thought highly of Dixon. The same 

article reports that “the ladies of Mobile” presented 

the commanding officer with a “handsome flag” that he 

gratefully received and later “turned . . . over to young 

Dixon, whom he had chosen as color bearer.” Pillans 

stated, “Lieutenant Dixon was . . . a splendid specimen of 

physical manhood, and . . . the Southern people should 

always revere and hold sacred the memory of this brave 

man.” 

At the beginning of the Civil War, the Mobile Greys 

were absorbed into the 21st Alabama Infantry Regiment. 

Captain John F. Cothran, Dixon’s Commanding Officer 

in that regiment, described Dixon as “very handsome, 

fair, nearly six feet tall, and of most attractive presence” 

(Hartwell 1900). Dixon, like many of his peers, enlisted 

as a private early in the war. However, he quickly rose 

through the ranks. By the beginning of 1862 he was 

appointed sergeant and departed with his unit for 

Corinth, Mississippi, that spring. It was later reported 

that:

On the day before the regiment left . . . 

Sergeant Geo E. Dixon . . . called on some 

ladies with whom he was familiarly 

Figure 2.7. Map of New Orleans showing discovery locations of (a) the 

Louisiana State Museum vessel, and (b) Pioneer, as well as (c) the Leeds 

Foundry where Pioneer was built. (Annotated detail from Abbot 1863)
H I S T O R I C A L B A C K G R O U N D

15

acquainted to bid them good bye. In the 

course of the visit some turn of the conversation induced him to take a $20 gold 

piece from his pocket, which one of the 

ladies told him he had better leave with 

her to remember him by. But he said no; he 

believed he would keep it; that it might save 

his life. (Memphis Daily Appeal 1862)

George Dixon, gold coin in hand, arrived with his 

regiment in March 1862, where they were integrated 

with a 45,000-strong force commanded by General 

Albert S. Johnston. On 6 April 1862, Johnston’s army 

engaged 47,700 Federal troops under the command 

of General Ulysses S. Grant at Shiloh, Tennessee. The 

Confederates were gaining ground by the end of the 

day, but reinforcements arrived overnight from Major 

General Don Carlos Buell’s Army of the Ohio, and the 

two-day battle ended with the Union army in possession of the field. Casualties were heavy on both sides. 

The final tally of dead or missing exceeded 13,000 

for Union forces and 10,500 for the Confederates. 

The 21st Alabama lost six successive color-bearers; 

approximately 200, or 31%, of the 650-man contingent deployed on the battlefield were either killed 

or wounded. George Dixon was among the casualties during the first day of the engagement. According 

to Dixon’s Company A commander, Captain James 

M. Williams, he (Dixon) was “shot in the hip, the ball 

striking a gold piece ranged upwards and came out of 

his side; will probably recover if he can be well cared 

for” (Folmar 1981:53). The event was remarkable 

enough to have been picked up by the press, reporting 

that his life was saved by a gold coin.

In the heat of the battle of Shiloh, Dixon felt 

a severe rap upon the part of his body near 

the hip where he carried his pocket book, 

and at the same moment was placed hors du 

combat by a severe wound. On examination 

it was found that a Yankee bullet had passed 

through one side of his pocket book, bending 

the $20 gold piece, and glancing, wounded 

him badly in the hip. Had the bullet not so 

glanced, it would have killed him. (Memphis 

Daily Appeal 1862)

Dixon was promoted to the rank of Second Lieutenant on 9 May 1862 while convalescing from his 

wound, and promoted again to First Lieutenant on 

30 August 1862. Although the wound Dixon received 

did not kill him, he reportedly “never recovered, and 

was sent to Mobile. Although he could not give his 

bodily powers, nevertheless his mind was still in good 

condition” (Mobile Daily Item 1910). Presumably, Dixon 

was reassigned to the Park and Lyons machine shop 

because of his debilitating condition. It was here that 

he developed an interest in submarines.

McClintock, Watson, and Hunley (with the aid of 

Alexander, Dixon, and the Park and Lyons staff) began 

construction on a second submarine by the summer 

of 1862. The five-man vessel, launched in late January 

1863, is commonly referred to as Pioneer II, since no 

historic reference that directly cites the name of the 

second submersible is currently known to exist (Ragan 

1999:93). In testimony from two Confederate deserters, 

Belton and Shipp, the name “American Diver” is used to 

identify the submarine practicing in Charleston, known 

to be the team’s third submarine (ORN 1.15:229, 231; 

discussed below). Many historians have attributed the 

name to the second vessel, based on Belton’s remark 

that he “worked near her in the same shop” while in 

Mobile (ORN 1.15:229). However, no historical evidence 

has emerged to clarify whether this name was applied 

to the second or third boat, both of which were built in 

Mobile. Since the name American Diver only appears in 

the above-mentioned depositions, which are clearly in 

relation to the Charleston craft, it has not been applied 

here to the second craft. If Belton was unaware of the 

loss of the second vessel, however, the name may 

indeed have been tied to the second craft.

For reasons that remain unclear, Hunley’s key 

financial supporters in New Orleans, Henry Leovy and 

Robert Barrow, did not provide monetary support to 

the project while it was based in Mobile. Consequently, 

Hunley assumed sole responsibility for the cost of the 

second submarine (Kloeppel 1992:23). According to 

McClintock (1872), Pioneer II, like Pioneer, was constructed of 1⁄4 in. (6.35 mm) thick rolled boilerplate but 

was larger, at 36 ft. (10.97 m) in overall length, 4 ft. (1.22 

m) high, and 3 ft. (0.91 m) wide. The submarine’s ends 

were reportedly “tapered like a wedge” (McClintock 

1872). Alexander recalled that “[t]he cross section 

was oblong, about 25 feet [7.62 m] long, tapering at 

each end, 5 feet [1.52 m] wide, and 6 feet [1.83 m] 

deep” (Alexander 1902b:165). Based on their respective 

accounts of Hunley, it is likely McClintock’s figures are 

more accurate. The stern was fitted with a propeller 30 

in. (0.76 m) in diameter that was initially powered by a 

steam engine. A prototype electromagnetic engine later 

replaced this propulsion system. The steam engine was 

a complete failure when the submarine was submerged, 

and the electromagnetic system proved to be about 

as reliable as the steam engine. Consequently, it, too, 

was abandoned. Despite their contradictory statements 

regarding the vessel’s dimensions, both McClintock and 

Alexander agreed that the experimental electromagnetic engine was useless. After the Civil War, McClintock 

addressed a letter to the British Admiralty in which he 

stated that “[t]here was much time and money lost in 

this endeavor . . . in its place, a hand crank was installed 

and operated by four men” (McClintock 1872). 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

16

A second hatch and coaming was added to facilitate entry and egress of two additional personnel, as 

well as to provide a means by which the submarine’s 

crew could examine the stern while underway. Like 

its predecessor, Pioneer II was armed with a torpedo 

that was towed behind the submarine on the water’s 

surface. To engage and sink an enemy vessel, Pioneer 

II would pass beneath its intended victim and drag the 

torpedo into its hull. Contact with the enemy hull at—

or slightly below—the waterline caused the torpedo 

to detonate. Pioneer II maneuvered better than its 

predecessor but several design flaws and operational 

problems associated with the latter soon developed. 

The air within the submarine quickly turned foul (due to 

constant cranking) and caused the crew to tire easily. In 

addition, its speed was limited and the helmsman had 

difficulty conning the vessel when it ran submerged for 

any length of time. In spite of these problems, Pioneer 

II underwent a quick series of tests and entered into 

service in February 1863. 

Alexander provided one of the few surviving 

accounts of the loss of Pioneer II, stating “It was 

towed off Fort Morgan, intending to man it there and 

attack the blockading fleet outside, but the weather 

was rough and with a heavy sea the boat became 

unmanageable, and finally sank, but no lives were lost” 

(Alexander 1902a). 

Although Mobile’s military commander, Major 

General Dabney H. Maury, was an enthusiastic 

proponent of submarine warfare, Mobile’s naval 

commander, Admiral Franklin Buchanan, was not. 

Buchanan had served in the U.S. Navy before the 

outbreak of war, but joined the Southern cause in 1861. 

He commanded the ironclad CSS Virginia (Merrimac) 

against the USS Monitor at the Battle of Hampton Roads 

on 8–9 March 1862. Although described as an openminded man, Buchanan had little faith in the submarine’s abilities. He stated his position clearly in a letter to 

Confederate Secretary of the Navy Stephen R. Mallory: 

I have witnessed the operations of the boat 

in the water when propelled by hand, the 

steam engine being a failure and had to be 

removed. 

On that occasion its speed was not more 

than two miles per hour [3.22 kph]. Since 

then other trials have been made all proving 

failures. The last trial was about a week since 

when the Boat was lost off this harbor and 

was sunk[,] the men came very near being 

lost. I never entertained but one opinion as 

to the result of this Boat, that it would prove 

a failure, and such has been the case. . . .

I considered the whole affair as impracticable from the Commencement. (Buchanan 

1863a) 

No attempt was ever made to raise the vessel. In 

fact, Buchanan’s letter seems to imply that he was 

happy to be rid of it. The submarine’s inability to achieve 

sustained speeds greater than two m.p.h. (3.22 kph), 

coupled with Buchanan’s overall lack of confidence in its 

operational abilities, essentially sealed the submarine’s 

fate. Pioneer II was abandoned where it sank. 

H. L. Hunley

The loss of Pioneer II was a tremendous setback 

for McClintock, Hunley, and Watson, who now found 

themselves without work and lacking funds to build 

another submarine. Hunley, who had bankrolled most 

of the construction and operational costs for Pioneer

and completely funded the Pioneer II project, could 

not afford to finance a third submarine on his own. 

Luckily for Hunley and his associates, a like-minded 

group of engineers and machinists were also developing “infernal” weapons for the Confederate government in Mobile. The Texas-based group was founded 

and directed by Edgar C. Singer and was commissioned 

to strengthen Mobile Bay’s defenses. Singer and his 

compatriots had developed a variety of naval contact 

mines—or torpedoes—and were in the process of 

placing the devices in upper and lower bay obstructions when they met McClintock, Hunley, and Watson. 

Singer and three associates, R. W. Dunn, J. D. Breaman, 

and B. A. Whitney, together with Hunley, invested the 

$15,000 needed to build a new submarine (Hill 1916; 

Duncan 1965:63–64; ORN 1.26:188). This third and final 

submarine would be the most practical, innovative, and 

effective. It would also be the most deadly. 

For years, historians have speculated where exactly 

in Mobile Pioneer II and H. L. Hunley were designed 

and assembled. Most archival sources agree that both 

submarines were manufactured at the Park and Lyons 

machine shop, located on the corner of Water and State 

Streets. However, post-war recollections from witnesses 

suggest that, while major components of both craft 

were manufactured in the Park and Lyons machine shop, 

their assembly actually took place in one of the two 

Seamen’s Bethels on Water Street in the 1860s. Bethels 

were non-denominational churches for seamen established in many American maritime communities in the 

19th century. The first bethel in Mobile was located 

between Theatre and Monroe streets, but was sold to 

Michael Hines in 1860 after a larger plot was acquired 

one block over, on the corner of Water and Church 

streets (O’Brien 2005:37). One witness, Benjamin Cox, 

claimed that as a child he and his friends used to go 

to “the old Bethel” on “the west side of Water Street 

second north of Monroe” to watch “the construction 

and play about the boat” (O’Brien 2005:33). However, 

an older, therefore possibly more reliable, witness, 
H I S T O R I C A L B A C K G R O U N D

17

Major Pillans, recalled that the new Seamen’s Bethel 

on Church Street was used:

The boat was built in the Seamen’s Bethel 

on Church Street, the floor being taken up 

for the purpose. When the boat was finished 

it was found that she was too wide to take 

through the exit of the Bethel, so that pieces 

had to be cut out of each of the columns to 

get her out. (Mobile Daily Register 1895) 

Pillans’s son, Harry, claimed to have accompanied 

his father in his youth and published a similar article 

in 1924:

The vessel was built in or at least completed 

in the old Bethel, on Water Street, behind 

the old soldiers’ home at the corner of 

Church Street. There shortly before its 

launching, the writer saw and went over it 

within and without. (Pillans 1924) 

Given the relative youth of Cox when he witnessed 

the boat and the number of other errors in his account, 

it is likely Pillans and his son are more reliable sources 

(O’Brien 2005:37). 

After the war ended, the bethel at 75 Church Street 

remained largely abandoned due to the economic 

strife that characterized the post-war South. However, 

religious services eventually resumed in 1879. In 1901, 

the church’s steeple and columns were removed in 

an attempt at modernizing the building. It was sold in 

1923 to The Little Theatre of Mobile, who had been 

renting it as a performing arts venue the previous two 

seasons (Mobile Register 1923). In the mid-1930s it 

was then sold to J. W. Hooge, who used the upper floor 

for storage and rented out the first floor for meetings 

(O’Brien 2005:37). It was acquired by the state of 

Alabama in the 1960s and moved from its original 

location to avoid demolition (Figure 2.8). 

Since both the bethel and the machine shop were 

located on the same street and separated by only a 

few blocks, transporting newly-constructed submarine 

components from one locale to the other would have 

been a relatively simple matter. Once the various parts 

were transported to the church, they could have been 

assembled without attracting too much attention to 

the project. By contrast, assembling the submarine in 

a busy machine shop frequented by clientele and the 

general public would have removed all elements of 

secrecy from its construction. 

Although it is unclear exactly what role Lieutenants 

Dixon and Alexander played in Hunley’s construction, 

Alexander provided a revealing description of the submarine’s basic features and method of construction:

We . . . took a cylinder boiler which we had on 

hand, 48 inches [1.22 m] in diameter and 25 

feet [7.62 m] long (all dimensions are from 

memory).3

 We cut this boiler in two, longitudinally, and inserted two 12-inch [30.48 cm] 

boiler-iron strips in her sides; lengthened 

her by one tapering course fore and aft, to 

which were attached bow and stern castings, 

making the boat about 30 feet [9.14 m] long, 

4 feet [1.22 m] wide and 5 feet [1.52 m] deep. 

A longitudinal strip 12 inches [30.48 cm] 

wide was riveted the full length on top. At 

each end a bulkhead was riveted across 

to form water ballast tanks (unfortunately 

these were left open on top); they were used 

in raising and sinking the boat. In addition 

to these water tanks the boat was ballasted 

by flat castings, made to fit the outside 

bottom of the shell and fastened thereto by 

‘Tee’ headed bolts passing through stuffing 

boxes inside the boat, the inside end of bolt 

squared to fit a wrench, that the bolts might 

be turned and the ballast dropped, should 

the necessity arise. 

In connection with each of the water 

tanks there was a sea-cock open to the sea 

to supply the tank for sinking; also a force 

pump to eject the water from the tanks into 

the sea for raising the boat to the surface. 

There was also a bilge connection to the 

pump. A mercury gauge, open to the sea, 

was attached to the shell near the forward 

3 Many of Alexander’s dimensions have proved incorrect upon 

examination of the recovered vessel; however, his overall description of the components and how they worked is generally reliable. 

See Chapter 12 for archaeological findings.

Figure 2.8. The second Seamen’s Bethel at its current 

location on the University of South Alabama campus in 

Mobile. (Photo by Shea McLean)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

18

tank, to indicate the depth of the boat below 

the surface. A one and a quarter shaft passed 

through stuffing boxes on each side of the 

boat, just forward of the end of the propeller 

shaft. On each end of this shaft, outside of 

the boat, castings, or lateral fins, five feet 

long [1.52 m] and eight inches [20.32 cm] 

wide, were secured. This shaft was operated 

by a lever amidships, and by raising or 

lowering the ends of these fins, operated as 

the fins of a fish, changing the depth of the 

boat below the surface at will, without disturbing the water in the ballast tanks. 

The rudder was operated by . . . levers 

connected to rods passing through stuffing 

boxes in the stern castings, and operated by 

the captain or pilot forward. An adjusted 

compass was placed in front of the forward 

tank. The boat was operated by manual 

power, with an ordinary propeller. On the 

propeller shaft there were formed eight 

cranks at different angles; the shaft was 

supported by brackets on the starboard side, 

the men sitting on the port side turning the 

cranks. The propeller shaft and cranks took 

up so much room that it was very difficult to 

pass fore and aft, and when the men were 

in their places this was next to impossible. . . . 

The propeller revolved in a wrought iron ring 

or band, to guard against a line being thrown 

in to foul it. There were two hatchways—one 

fore and one aft—16 inches by 12 [40.64 

× 30.48 cm] with a combing 8 inches high 

[20.32 cm]. These hatches had hinged covers 

with rubber gasket, and were bolted from 

the inside. In the sides and ends of these 

combings glasses were inserted to sight 

from. There was an opening made in the top 

of the boat for an air box, a casting with a 

close top 12 by 18 by 4 inches [30.48 × 45.72 

× 10.16 cm], made to carry a hollow shaft. 

This shaft passed through stuffing boxes. On 

each end was an elbow with a 4-foot [1.22 

m] length of 1 1⁄2 inch [3.81 cm] pipe, and 

keyed to the hollow shaft; on the inside was 

a lever with a stop-cock to admit air. 

The torpedo was a copper cylinder holding 

a charge of ninety pounds [40.82 kg] of 

explosive, with percussion and friction primer 

mechanism, set off by flaring triggers. It was 

originally intended to float the torpedo on the 

surface of the water, the boat to dive under 

the vessel to be attacked, towing the torpedo 

with a line 200 feet [60.96 m] long after her, 

one of the triggers to touch the vessel and 

explode the torpedo. (Alexander 1902a)

Alexander’s description indicates that the design 

of the third submarine was based on both successful 

and unsuccessful attributes of its predecessors. For 

example, the overall hull form of Pioneer II was retained, 

but its length was extended to accommodate additional crewmen. Because the mechanical engine was 

discarded from the submarine’s design altogether, 

more crewmen were needed to propel the vessel for 

extended periods of time and at greater speeds. The 

“air box” was likely added as a measure to prevent (or at 

least curb) the amount of foul air created in the hull by 

the introduction of additional crewmen. It was probably 

only used while the vessel cruised on the surface.

On 31 July 1863, the team successfully demonstrated the submarine’s abilities in the Mobile River. 

Mobile’s naval commander, Franklin Buchanan, was 

impressed with its performance and expressed his 

opinion in a letter to Charleston Naval Squadron 

Commander John R. Tucker:

I yesterday witnessed the destruction of 

a lighter or coal flat in Mobile River by a 

torpedo which was placed under it by a submarine iron boat, the invention of Messrs 

Whitney and McClintock; Messrs Watson 

and Whitney visits [sic] Charleston for the 

purpose of consulting Genl Beauregard and 

yourself to ascertain whether you will try it, 

they will explain all the advantages, and if it 

can operate in smooth water where 

the current is not strong as was the 

case yesterday, I can recommend it to your 

favorable consideration; it can be propelled 

about four knots per hour, to judge from the 

experiment of yesterday. I am fully satisfied 

it can be used successfully in blowing up one 

or more of the enemy’s Iron Clads in your 

harbor. 

Do me the favor to show this to Genl 

Beauregard with my regards. (Buchanan 

1863b)

Service in Charleston

By mid-1863, the siege of Charleston, South 

Carolina, by Federal forces had attained a new level 

of intensity. Charleston was regarded as the “cradle of 

secession” and its capture was one of the Federal government’s highest priorities. Union advances into Hilton 

Head, Folly Island, and Morris Island threatened the 

city’s southern approaches. Additionally, a long-range 

cannon nicknamed “Swamp Angel” was used to indiscriminately shell parts of downtown Charleston from a 

position on Morris Island. For two years, the Union navy 

had implemented a naval blockade of Charleston Harbor, 

adding to the misery of the city’s inhabitants (Figure 
H I S T O R I C A L B A C K G R O U N D

19

2.9). The increase in Union vessels not only reduced 

the number of successful blockade-running attempts 

into and out of the port, but also served as a supply 

line for the Federal troops advancing toward the city 

from the south. On 7 August 1863, Charleston’s military 

commander, General Pierre Gustave Toutant Beauregard, telegraphed “Quartermasters and Railroad agents 

on Lines from Charleston, S.C., to Mobile, Alabama” and 

ordered them to “[p]lease expedite transportation of 

Whitney’s submarine boat from Mobile here. It is much 

needed” (ORA 1.28(2):265). Beauregard hoped that 

Hunley could be successfully employed to break the 

Union blockade of Charleston.

Interestingly, Beauregard refers to the vessel at this 

point as “Whitney’s submarine.” This is a curious discrepancy, but understandable, given the following facts: 

although McClintock usually accompanied Hunley to 

instruct others in its operation, B. A. “Gus” Whitney (a 

part owner and representative of the Singer Group) was 

responsible for its transportation to Charleston. Further, 

he was the individual who managed all financial matters 

pertaining to the submarine while it remained in South 

Carolina. There is no historical evidence to indicate that 

the third submarine was named for Horace Hunley prior 

to its arrival in Charleston. The submarine is referred to 

as “the Hunley” for the first time in official Confederate 

correspondence in a letter from Hunley himself to Beauregard dated 19 September 1863 (discussed below). 

Although the vessel is referred to as Hunley in several 

wartime documents after this point, so far no sources 

calling it by this name have been found that predate 

Hunley’s letter to Beauregard. Based on the testimony 

of Belton discussed above, the third submersible may 

have originally been called American Diver and was later 

renamed H. L. Hunley after it arrived in Charleston. 

The boat was secretly loaded onto two flatbed 

rail cars within two days of Beauregard’s telegram 

and arrived in Charleston shortly thereafter. Historical sources indicate that Whitney was chosen as the 

Singer Group’s representative and was responsible 

for collecting any bounties that might result from the 

destruction of any enemy ships. Shortly after the team’s 

arrival in Charleston, Whitney received the following 

message from General Beauregard’s chief of staff, 

General Thomas Jordan:

I am authorized to say that John Fraser & Co. 

will pay over to any parties who shall destroy 

the U.S. steam iron-clad Ironsides the sum of 

$100,000, a similar sum for the destruction 

of the wooden frigate Wabash, and the sum 

of $50,000 for every monitor sunk. 

I have reason to believe that other men 

of wealth will unite and give with equal 

munificence toward the same end. (ORA 

1.28(2):285)

Figure 2.9. Detail from an 1863 map showing the positions of Charleston’s primary defenses as well as the distribution 

of Union bockading forces. (Detail from Tomlinson 1863)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

20

 Horace Hunley, who served as a captain in the Confederate army, was called to duty and spent much of 

the summer of 1863 performing various governmental 

tasks in Mississippi and Georgia. Although Hunley could 

not accompany the submarine and crew to Charleston, 

he maintained a keen interest in their mission. This is 

understandable, since he was one-third owner of the 

vessel and had invested a considerable amount of time, 

money, and energy in its conception and construction. 

Hunley wrote a letter on 15 August 1863 from an army 

camp near Enterprise, Mississippi, and expressed his 

views to McClintock and crew soon after their arrival 

in Charleston:

I have been extremely anxious about your 

experiment at Charleston. It is not at all on 

the question whether you will succeed in 

blowing up a vessel of the enemy for I think 

that more than probable and of itself only a

small matter. It is whether your success will 

be made available in effecting a real solid 

benefit to the Confederacy and conferring 

glory on its originators. I am anxious first

and above all for a dead silence on our part 

that the enemy may be lost in uncertainty 

and mystery which is more dreadful than 

any understood evil even of the greatest 

magnitude. Secondly. While in a panic if 

you succeed the enemy if properly pressed 

before he can make preparations to resist 

the consequences of your success might 

be possibly driven entirely from Morris 

Island. . . . Therefore as I can not join you I 

would be glad to have you in a conversation 

with Genl Beauregard if this reaches you 

before your experiment to ask him (by way 

of suggestion) if you should be so fortunate 

as to succeed, and if that success should 

create a panic and consequent retreat, if a 

rapid descent by vessels and men could not 

drive the enemy from the island . . .and then 

by at least one spare torpedo, for a second 

attempt make a heroic attempt to produce 

this panic. Remind your crew of Manassas 

& Shiloh and the consequences of faltering 

in the hour of success and make one grand 

effort & you may have cause to rejoice as 

long as you live. . . . Read this to Whitney. 

(Hunley 1863a; Duncan 1965:65–66)

Archival evidence suggests that Lieutenant 

Dixon may have accompanied the submarine 

from Mobile. James M. Williams, a good friend 

and fellow officer in the 21st Alabama Infantry, 

added the following statement in a letter to his 

wife dated 9 August 1863: 

I have heard that the Sub-marine is off for 

Charleston, I suppose that Dixon went with 

it.— with favorable circumstances it will 

succeed, and I hope to hear a report of its 

success before this month is out; still there 

are so many things which may ruin the enterprise that I am not so sanguine of its triumph 

as Dixon. (Folmar 1981:118) 

If Dixon did accompany the submarine to 

Charleston, it is likely that he returned to Mobile soon 

thereafter, as McClintock, Whitney, and Hunley never 

mention his presence in their correspondence.

The submarine and its crew could not have arrived 

in Charleston at a more desperate time. Battery Wagner, 

a Confederate fortification that guarded the entrance to 

Charleston Harbor, had survived two Union assaults in 

July but was not anticipated to repulse another attack. 

On 17 August, only five days after Hunley’s arrival, 

Union forces began the first major bombardment of 

Fort Sumter. Although the fortification withstood the 

assault, its 5 ft. (1.52 m) thick outer walls were reduced 

to rubble within seven days (Figure 2.10). To compound 

Confederate woes, the dreaded Swamp Angel began 

firing 200 lb. (90.72 kg) shells directly into the heart 

of Charleston on 22 August. McClintock had relatively 

little time between the crew’s arrival and their first 

attempted assault to drill them in the waters around 

Charleston. Nevertheless, he and his crew set out on 

their first nighttime excursion on 23 August. 

The same day, a letter from Brigadier General T. L. 

Clingman, Commander of Confederate forces on Sullivan’s Island, arrived at the office of General Beauregard’s Adjutant in Charleston. It stated simply, “[t]he 

torpedo boat started out at sunset, but returned, as they 

state, because of an accident. Whitney says that though 

Figure 2.10. The interior of Fort Sumter photographed 

by George S. Cook on 8 September 1863. (Courtesy of 

Library of Congress, LC-DIG-ppmsca-35434)
H I S T O R I C A L B A C K G R O U N D

21

McClintock is timid, yet it shall go to-night unless the 

weather is bad” (ORA 1.28(1):670). General Clingman 

submitted an even less complimentary dispatch separately: “The torpedo-boat has not gone out. I do not 

think it will render any service under its present management” (ORA 1.28(1):670). Beauregard quickly lost 

patience with Hunley’s crew and, by 24 August 1863 

(less than two weeks after the submarine’s arrival), the 

boat had been confiscated and placed under military 

jurisdiction (ORA 1.28(2):376). Following this event, 

McClintock completely disappears from all official Confederate correspondence. It is unclear whether he and 

the rest of the crew remained in Charleston or returned 

to Mobile. Whitney also disappears from official records 

after this point.

First Sinking

The “fish-boat” (as the submarine was now referred 

to around Charleston) did not remain idle for long. A 

crew of volunteers under the command of Naval Lieutenant John A. Payne took possession of the boat after 

the Confederate military confiscated it. Payne, a native 

Alabamian and executive officer aboard the ironclad 

CSS Chicora, was given very little time to train the new 

crew and fully familiarize himself with the submarine’s 

operation. Nevertheless, Beauregard ordered the 

boat into active service within a week of its confiscation. Beauregard’s haste would have tragic results. On 

29 August 1863, while undergoing final preparations for 

a mission, the submarine sank in waters immediately 

adjacent to the southern shore of Charleston Harbor, 

near Fort Johnson dock. Colonel Charles H. Olmstead, 

the fort’s commanding officer, submitted a report of 

the incident to Beauregard’s office the following day:

An unfortunate accident occurred at the 

wharf yesterday, by which 5 seamen of the 

Chicora were drowned. The submarine torpedo-boat became entangled in some way 

with ropes, was drawn on its side, filled, and 

went down. The bodies have not yet been 

recovered. (ORA 1.28(1):551) 

In a post-war publication, Beauregard also 

described the submarine’s loss:

While tied to the wharf at Fort Johnson, 

whence it was to start under cover of night to 

make the attack, a steamer passing [Etowah] 

close by capsized and sunk it. Lieut. Payne, 

who at the time was standing in one of the 

man-holes, jumped out into the water, which, 

rushing into the two openings, drowned 

two men then within the body of the boat. 

(Beauregard 1878:153)

A Charleston Daily Courier (1863) article published 

two days after the accident corroborates Olmstead’s 

letter and reports the loss of five seamen—as opposed 

to only two casualties reported by Beauregard:

Unfortunate Accident – On Saturday last, 

while Lieutenants PAYNE and HASKER, of 

the Confederate Navy, were about experimenting with a boat in this harbor, she 

parted from her moorings and became 

suddenly submerged, carrying down with 

her five seamen, who were drowned. The 

boat and bodies had not been recovered up 

to a late hour on Sunday. Four of the men 

belonged to the gunboat Chicora, and were 

named FRANK DOYLE, JOHN KELLY, MICHAEL 

CANE and NICHOLAS DAVIS. The fifth man, 

whose name we did not learn, was attached 

to the Palmetto State. 

The fifth crewman, from CSS Palmetto State, was 

Absolum Williams. His name appears in the vessel’s 

pay receipts ledger with the footnote “Drowned in the 

submarine battery on 29th August, 1863.” The survivors 

of the incident included Lt. Payne; William Robinson, 

an Australian who enlisted in the Confederate navy at 

New Orleans, and was described as “a giant in size and 

strength”: Charles Sprague, listed on pay records as a 

“torpedo boatman” and probably assigned to Hunley to 

maintain and rig the torpedo; and Lieutenant Charles 

Hasker (Ragan 1995:74–75). Hasker, who joined the 

submarine’s roster as a last-minute replacement for 

another crewman, provided a vivid account of the 

sinking: 

‘We were lying astern of the steamer Etowah, 

near Fort Johnson, in Charleston harbor. Lieutenant Payne, who had charge, got fouled in 

the manhole by the hawser and in trying to 

clear himself got his foot on the lever which 

controlled the fins. He had just previously 

given the order to go ahead. The boat made 

a dive while the manholes were open and 

filled rapidly. Payne got out of the forward 

hole and two others out of the aft hole. Six 

of us went down with the boat. I had to get 

over the bar which connected the fins and 

through the manhole. This I did by forcing 

myself through the column of water which 

was rapidly filling the boat. The manhole 

plate came down on my back; but I worked 

my way out until my left leg was caught 

by the plate, pressing the calf of my leg in 

two. Held in this manner, I was carried to 

the bottom in forty-two feet of water. When 

the boat touched bottom, I felt the pressure 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

22

relax. Stooping down, I took hold of the 

manhole plate, drew out my wounded limb, 

and swam to the surface.’ (Fort 1918:459) 

When Hasker reached the surface, Daniel M. Lee, 

a young midshipman, quickly removed his tunic and 

dove into the water to assist the exhausted survivor. Significantly, Hasker’s rescuer was the nephew of General 

Robert E. Lee, Commander of the Army of Northern 

Virginia (Metzger, n.d.). 

By the beginning of September 1863, the defenders 

of Charleston were experiencing the full impact of the 

war. The Swamp Angel was hurling shells into the city 

on a daily basis; on 6 September beleaguered forces 

at Battery Wagner abandoned their post and the 

remainder of Morris Island. Left with little time and 

no money to build another submarine, the Confederates opted to raise the one now lying at the bottom of 

Charleston Harbor. The task of recovering the vessel was 

granted to two civilian salvage divers, Angus Smith and 

David Broadfoot. Hard-hat diving was still in its infancy 

during the Civil War and the duo (both of whom were 

Scottish-born immigrants) held a virtual monopoly on 

underwater salvage in Charleston Harbor. Prior to the 

submarine’s loss, Smith and Broadfoot had performed 

various tasks for the Confederate government, 

including installation of submerged obstructions and 

placement of underwater contact mines (torpedoes). 

On 14 September, Smith and Broadfoot raised the 

submarine, removed the corpses of all five crewmen, 

and towed the vessel to the Charleston railroad wharf. 

As soon as it arrived at the wharf, Lieutenant Payne 

once again assumed command of the submarine. All 

five men who perished aboard the vessel were buried 

in a mariner’s cemetery on the outskirts of Charleston.

Upon hearing of the disaster that befell the 

submarine and its crew, Horace Hunley petitioned 

General Beauregard for command of the vessel: 

I am a part owner of the torpedo Boat the 

Hunley. I have been interested in building 

this description of boat since the beginning 

of the war, and furnished the means 

entirely of building the predecessor of this 

boat which was lost in an attempt to blow 

up a Federal vessel off fort Morgan Mobile 

Harbor. I feel therefore a deep interest in its 

success. I propose if you will place the boat 

in my hands to furnish a crew (in whole or in 

part) from Mobile who are well acquainted 

with its management & make the attempt 

to destroy a vessel of the enemy as early as 

practicable. (Hunley 1863b)

Within a week, Lieutenant Payne was relieved of 

command and operational control of the submarine 

was granted to Horace Hunley. William Alexander 

chronicled the event with the following passage: 

General Beauregard then turned the boat 

over to a volunteer crew from Mobile known 

as the ‘Hunley and Parks [sic] crew.’ Captain 

Hunley and Thos. Parks [sic] (one of the 

best men), of the firm Parks [sic] & Lyons, in 

whose shop the boat had been built, were in 

charge, with Messrs. Brockbank, Patterson, 

McHugh, Marshall, White, Beard, and 

another as the crew. . . . Nearly all the men 

had had some experience in the boat before 

leaving Mobile, and were well qualified to 

operate her. (Alexander 1902a) 

These may have been the same men who crewed 

the boat with McClintock before the submarine was 

seized by the Confederate government in August 1863. 

Although little is known about this group, some of its 

members were known to have associated with Thomas 

Park’s partner, Thomas B. Lyons. Lyons was the foreman 

of Mobile’s Washington Fire Company No. 8 between 

1860 and 1861. The list of volunteer firemen serving 

with Lyons during that period includes three of the 

names in Alexander’s list (Taylor 1972: 34–35). Although 

Alexander does not identify the last member of the 

crew by name, some evidence suggests that this individual may have been Lieutenant George Dixon. Dixon’s 

service record reveals that he was detached from the 

21st Alabama on 1 October 1863. General Beauregard 

provides additional evidence that Dixon left Mobile 

for Charleston, stating that “[a]fter the recovery of the 

sunken boat Mr. Hunley came from Mobile, bringing 

with him Lieutenant Dixon, of the Alabama volunteers, 

who had successfully experimented with the boat in 

the harbor of Mobile, and under him another naval 

crew volunteered to work it” (Beauregard 1878:153). 

Based on Beauregard’s statement, it appears that 

George Dixon, rather than Horace Hunley, piloted 

the submarine during operations in the waters off 

Charleston.

H. L. Hunley was not the only torpedo boat 

operating in Charleston Harbor during this period. On 

5 October 1863, a steam powered, semi-submersible 

vessel called CSS David attacked the formidable Union 

warship USS New Ironsides (Figure 2.11). The vessel was 

the invention of Theodore D. Stoney and Dr. St. Julian 

Ravenel. It was named after the biblical hero David 

who, though much smaller, confronted and slew his 

seemingly invincible adversary, the mighty giant Goliath. 

David was cigar-shaped and armed with a retractable, 

bow-mounted percussion spar torpedo loaded with 

65 lb. (29.48 kg) of black powder (Tomb, 1914:168). 

David was rendered temporarily inoperable when the 

explosion from the torpedo filled the boat with water, 
H I S T O R I C A L B A C K G R O U N D

23

extinguished the boiler, and nearly sank the vessel. 

Consequently, David’s commander, naval Lieutenant 

W. T. Glassel, ordered the vessel abandoned. As the 

stricken craft drifted away from New Ironsides, David’s 

chief engineer, James Tomb, managed to swim back to 

his vessel, where he discovered another crewmember 

(who could not swim) clinging to the hull. Together, 

both men boarded David, relit the boiler, and steered 

the vessel back to friendly waters. New Ironsides was 

damaged in the attack, and eventually had to be sent 

to Philadelphia to effect proper repairs. The Union 

fleet learned a valuable lesson from the ordeal; in the 

coming weeks, preparations were made throughout the 

blockading fleet for future submarine encounters. 

At the same time, Dixon, Hunley, Park, and the rest 

of the submarine’s crew were busy conducting practice 

runs with their vessel in Charleston Harbor. It is unclear 

what reaction, if any, the submarine’s crew might have 

had to news of the David-New Ironsides encounter. 

They may have been heartened by the near success of 

David’s attack; alternatively, considerable concern may 

have existed among the crew in regards to the Federal 

fleet’s heightened state of preparedness. 

Second Sinking

On 15 October 1863, the submarine suffered its 

worst catastrophe up to that point. According to Beauregard (1878:153), while Dixon usually piloted the 

vessel, “one day when he was absent from the city 

Mr. Hunley, unfortunately, wishing to handle the boat 

himself, made the attempt. It was readily submerged, 

but did not rise again to the surface, and all on board 

perished from asphyxiation.”

Captain Horace Lawson Hunley and a seven-man 

crew died while performing a routine diving exercise 

under the Confederate receiving ship CSS Indian Chief

(then moored at the mouth of the Cooper River). 

According to the Journal of Operations kept at Confederate headquarters in Charleston, the morning of 

15 October was rainy and “too hazy to get report of 

the fleet” (ORN 1.15:692). The submarine departed 

the wharf at 9:25 a.m. and submerged at 9:35 a.m.

(ORN 1.15:692). Shortly thereafter, observers on a 

nearby dock noticed a stream of bubbles emanating 

from the point where the vessel slipped beneath the 

water. According to eyewitnesses aboard Indian Chief, 

the submarine submerged a short distance from the 

port side of their vessel, after which “All on board went 

to the starboard side of the ship to see her rise to the 

surface after diving under us, but she did not come to 

the surface. Then all went to the side she went down 

and saw a great quantity of bubbles rising from the 

river” (Museum of the Confederacy, n.d.). 

Some observers postulated that one of the hatches 

may not have been properly closed, but did not consider 

this a serious discrepancy at the time. However, after 

several hours it became apparent that Hunley and his 

crew were lost. No immediate attempts at rescue were 

made due to the depth of water (nearly nine fathoms, 

or approximately 54 ft. [16.46 m]) in the channel where 

the submarine sank (ORN 1.15:692). George Dixon was 

not aboard the submarine that fateful day, but he did 

reportedly witness the event. James H. Tomb, First 

Assistant Engineer on CSS Chicora and Chief Engineer, 

and later Commander, aboard CSS David, recounted, 

“Lieutenant Dixon, James A. Eason, and myself stood 

on the wharf as she passed out and saw her dive, but 

she did not rise again” (ORN 1.15:335).

The following day, Dixon received orders to return 

to Mobile. While there, he spent time with his friend 

William Alexander. When the submarine was transported to Charleston three months before, Alexander 

remained in Mobile and worked at the Park and Lyons 

machine shop to develop a breech-loading gun for 

the Confederate Army. Since McClintock had been 

dismissed from the project, and Hunley, Park, and most 

of the Mobile crew were dead, few people remained 

who were familiar with the vessel’s operation. 

Following its second fatal accident in as many 

months, General Beauregard was hesitant to allow the 

submarine’s continued operation. Beauregard (1863) 

telegraphed Dixon in Mobile on 5 November 1863 and 

stated the following: “Lieutenant Dixon: I can have 

Figure 2.11. A 1960s reconstruction of a Confederate torpedo boat designed like CSS David, with spar torpedo 

deployed. (NHHC Photo Archives #NH 95242)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

24

nothing more to do with that submarine boat. It’s 

more dangerous to those who use it than the enemy.” 

Dixon and Alexander were either already en route to 

Charleston when the telegraph arrived, or elected afterwards to meet Beauregard in person to persuade him 

to change his mind. Regardless of the situation(s) surrounding their return, both men arrived in Charleston 

prior to the submarine’s recovery and presumably 

witnessed the opening of its hatches. Although the 

vessel had been located only three days after it sank, 

it was not raised until 7 November (Kloeppel 1992:43). 

After 23 days on the bottom of Charleston Harbor, the 

sights and smells within the submarine must have 

been unspeakably grotesque. General Beauregard was 

present as the hatches were opened, and described 

what greeted the first men to peer inside: “When the 

boat was discovered, raised and opened, the spectacle 

was indescribably ghastly; the unfortunate men 

were contorted into all kinds of horrible attitudes; 

some clutching candles, evidently endeavoring to 

force open the man-holes; others lying in the bottom 

tightly grappled together, and the blackened faces 

of all presented the expression of their despair and 

agony” (Beauregard 1878:153). Alexander’s account 

of the scene is somewhat more restrained but equally 

affecting:

The boat, when found, was lying on the 

bottom at an angle of about 35 degrees, the 

bow deep in the mud. The holding-down 

bolts of each cover had been removed. 

When the hatch covers were lifted considerable air and gas escaped. Captain Hunley’s 

body was forward, with his head in the 

forward hatchway, his right hand on top 

of his head (he had been trying, it would 

seem, to raise the hatch cover). In his left 

hand was a candle that had never been 

lighted, the sea-cock on the forward end, 

or Hunley’s ballast tank, was wide open, 

the cock-wrench not on the plug, but lying 

on the bottom of the boat. Mr. Parks’ [sic] 

body was found with his head in the after 

hatchway, his right hand above his head. He 

also had been trying to raise his hatch cover, 

but the pressure was too great. The seacock 

to his tank was properly closed, and the tank 

was nearly empty. The other bodies were 

floating in the water. Hunley and Parks [sic] 

were undoubtedly asphyxiated, the others 

drowned. The bolts that held the iron keel 

ballast had been partly turned, but not sufficient to release it. (Alexander 1902c:85–6) 

Historians have debated the cause of the calamity 

for years. Rumors spread widely almost immediately 

after the incident. A letter from General Henry A. Wise 

(1863) to his wife stated “a bottle was found tied with 

a strong cord to her wing which had so wound around 

& clogged the machine it could’nt work—evidently a 

secret enemy did it.” The most likely culprit, however, 

is pilot error. In the following passage, Alexander 

describes the standard operating procedure for diving 

and surfacing the vessel: 

All hands aboard and ready, they would 

fasten the hatch covers down tight, light a 

candle, then let the water in from the sea 

into the ballast tanks until the top of the shell 

was about three inches under water. This 

could be seen by the water level showing 

through the glasses in the hatch combings. 

The seacocks were then closed and the boat 

put under way. The captain would then lower 

the lever and depress the forward end of 

the fins very slightly, noting on the mercury 

gauge the depth of the boat beneath the 

surface; then bring the fins to a level; the 

boat would remain and travel at that depth. 

To rise to a higher level in the water he would 

raise the lever and elevate the forward end 

of the fins, and the boat would rise to its 

original position in the water. (Alexander 

1902b:167) 

Tomb reported simply that “Dixon said that they 

failed to close the after valve” (ORN 1.15:335). However, 

Alexander’s reconstruction of the chain of events, 

based on his own experience, the evidence from the 

submarine, and position of the bodies, suggests the 

problem was at the bow: 

Captain Hunley’s practice with the boat 

had made him quite familiar and expert in 

handling her, and this familiarity produced 

at this time forgetfulness. It was found in 

practice to be easier on the crew to come to 

the surface by giving the pumps a few strokes 

and ejecting some of the water ballast, than 

by the momentum of the boat operating 

on the elevated fins. At this time the boat 

was under way, lighted through the deadlights in the hatchways. He partly turned 

the fins to go down, but thought, no doubt, 

that he needed more ballast and opened 

his sea cock. Immediately the boat was in 

total darkness. He then undertook to light 

the candle. While trying to do this the tank 

quietly flooded, and under great pressure 

the boat sank very fast and soon overflowed, 

and the first intimation they would have of 

anything being wrong was the water rising 
H I S T O R I C A L B A C K G R O U N D

25

system were attested by Tomb, who was detailed on 

several occasions to take Hunley in tow from David: 

The last night the ‘David’ towed him down 

the harbor his torpedo got foul of us and 

came near blowing up both boats before 

we got it clear of the bottom, where it had 

drifted. I let him go after passing Fort Sumter, 

and on my making report of this, Flag-Officer 

Tucker refused to have the ‘David’ tow him 

again. (ORN 1.15: 334–5) 

Tomb strongly recommended using a spar like David

and the other torpedo boats being used in Charleston. 

With this method, the weapon was fixed to a long iron 

spar at the bow with a single hinged joint so that its 

position could be adjusted as needed. This allowed for 

the torpedo to be lowered into the water to a depth 

calculated to inflict the most damage to an enemy 

vessel’s hull beneath the waterline, while the attacking 

boat remained at the surface. General Beauregard 

(1878:174) agreed with this assessment and, mindful 

of the many men lost already in failed dives, ordered 

Hunley to operate as a semi-submersible with a sparmounted torpedo. 

Finding another group of men willing to risk 

their lives in such an untried vessel was Dixon’s next 

challenge. According to Alexander, both men:

reported to General Jordan, chief of staff, 

that the boat was again ready for service, 

and asked for a crew. After many refusals, 

and much dissuasion, General Beauregard 

finally assented to our going aboard the 

C.S.N. receiving ship Indian Chief, then lying 

in the river, and secure volunteers for a crew, 

strictly enjoining upon us, however, that a . . . 

full explanation of the hazardous nature of 

the service required of them, was to be given 

to each man. (Alexander 1902a) 

Only one piece of wartime correspondence 

that lists the new recruits by name is known to exist. 

Captain M. M. Gray, a Confederate army officer “in [c]

harge of [t]orpedoes,” provides the following roster of 

names in a letter to Major-General Maury of Mobile 

dated 29 April 1864: “I am informed that he [Dixon] 

requested Commodore Tucker to furnish him some men, 

which he did. Their names are as follows, viz: Arnold 

Becker, C. Simkins, James A. Wicks, F. Collins, and ——— 

Ridgeway, all of the Navy, and Corporal C. F. Carlsen, 

of Captain Wagener’s company of artillery” (ORN 

1.15:337–8). The recovery of the remains of the crew in 

2001 and the ensuing forensic research by Dr. Douglas 

Owsley and genealogy conducted by Linda Abrams 

has resulted in a better identification of the crew and 

fast, but noiselessly, about their feet in the 

bottom of the boat. They tried to release the 

iron keel ballast, but did not turn the keys 

quite far enough, therefore failed. The water 

soon forced the air to the top of the boat and 

into the hatchways, where Captains Hunley 

and Parks were found. Parks had pumped 

his ballast tank dry, and no doubt Captain 

Hunley had exhausted himself on his pump, 

but he had forgotten that he had not closed 

his sea cock. (Alexander 1902a) 

Alexander suggests that Hunley was careless due 

to over-familiarity with the submarine’s operation; 

however, he was not in Charleston prior to the sinking on 

15 October, and General Beauregard asserts that it was 

Dixon, not Hunley, who piloted the submarine during 

that time. Therefore, it may have been Hunley’s unfamiliarity with the boat that doomed him and his crew. 

We may never know how experienced Hunley was 

with operations, but his mistakes may have been compounded by Park, who, in an attempt to surface and 

unaware the forward sea cock was open, pumped the 

rear ballast tank dry. As the stern’s buoyancy increased, 

so too did the attitude at which the submarine 

descended. The vessel’s crew were probably further 

disoriented when its bow impacted with the riverbed. 

While the crew struggled to assess the situation, water 

continued to enter the forward ballast tank and silently 

spill over the forward bulkhead. Rising water within the 

hull eventually drowned the crew and forced Hunley 

and Park into their respective conning towers. Since the 

water pressure was too great for either man to open 

his hatch, Hunley and Park appear to have succumbed 

to asphyxiation within their coamings. Alexander’s 

description of the open forward seacock, the dislodged 

seacock handle, and the unlit candle provide damning 

evidence that pilot error contributed to the loss of the 

submarine. 

Hunley and the rest of the second crew were buried 

with full military honors at Charleston’s Magnolia 

Cemetery on 8 November 1863. The men interred 

were Horace L. Hunley, Robert Brookbank (according 

to Alexander, the correct spelling for this individual’s 

last name was “Brockbank”), Joseph Patterson, Thomas 

W. Park, Charles McHugh, Henry Beard (who has since 

been identified as Henry Baird), John Marshall, and 

Charles L. Sprague. 

Dixon Takes Charge

Following the funeral, Dixon and Alexander wasted 

no time refitting the submarine and petitioning Beauregard for a new crew. One of the main changes to the 

boat as part of the refit was to change the method of 

deploying the torpedo. The difficulties of the towed 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

26

understanding their personal histories than was previously known. We now know the crew (listed in order of 

their physical position in the submarine) consisted of 

Lieutenant George E. Dixon, CSN Captain’s Cook Arnold 

Becker, CSN Quartermaster Lumpkin, CSA Corporal J. F. 

Carlsen, Seaman Frank G. Collins, an unidentified man 

named Miller, CSN Boatswain James A. Wicks, and CSN 

Quartermaster Joseph F. Ridgaway (Jacobsen 2004). 

While research is on-going, an overview of the findings 

to date provides a fascinating picture of the men who 

volunteered for such hazardous duty.

First Lieutenant George E. Dixon

While accounts of Dixon’s 

wartime service have been 

presented above, the research 

brought new details to light about 

this charismatic leader. His age 

based on forensic analysis was 24 

to 28 years, with a height of 5 ft. 

9 in. (175 cm) (Figure 2.12). General 

health issues included a deviated 

nasal septum that would have 

restricted airflow through the right 

half of his nasal chamber and teeth 

with cavities and abscesses. Six of 

his lower jaw teeth had a total of 

eight cavities, some of which had 

been filled, five with gold fillings 

and one with a silver amalgam; the 

ones near abscesses had been extracted (Olds 2004). His 

teeth were also stained from tobacco, but were without 

the wear marks associated with pipe use, suggesting 

use of cigars or chewing tobacco. The most dramatic 

injury was that of the gunshot wound to the upper left 

thigh, which, while it did not break the bone due to 

the fortuitous placement of his 20 dollar gold coin, still 

produced significant soft tissue damage that was manifested in a bone spur as well as tiny metallic particles 

embedded in the femur (FOTH 2004a:4). 

Reports of Dixon’s midwestern origins are 

supported by forensic research, which uses the ratio 

of carbon isotopes 12 and 13 in tooth enamel to characterize grains ingested during childhood (Olds 2004; 

Neyland 2009:377). Archival research revealed that 

in 1860 he was a steamboat engineer on the Mississippi River route between St. Louis and Cincinnati, but 

the beginning of the Civil War found him in Mobile, 

Alabama, where he was a member of the Masonic Lodge 

and the Mobile Grays. His official enlistment in the 

21st Alabama infantry began in October, 1861. He rose 

from private to lieutenant quickly and was educated, as 

evidenced by the letters he wrote. His personal effects 

attested to a measure of personal wealth: besides the 

gold-filled teeth and coin, he carried a gold watch with a 

Mobile Masonic Lodge fob, a diamond ring, and brooch. 

However, there is no evidence of land ownership or a 

bank account that would indicate status and position. 

Instead his wealth was portable, carried on his person 

or stored in a trunk with his landlord in Mobile (Willey 

1866). That he cared for his men and his mission is 

evident from his correspondence to his friend Henry 

Willey of Mobile, in which he describes his men as 

“a splendid crew of men the best I think I ever seen” 

(Dixon 1864). 

Seaman Arnold Becker

The individual stationed aft of 

Lt. Dixon was the youngest member 

of the crew, a European immigrant 

named Arnold Becker (Figure 

2.13). His age was determined by 

Owsley to be 19 to 22 years and 

his height was 5 ft. 5 in. (165 cm), 

which made him the shortest of 

the crew. Although short of stature, 

his skeletal remains suggested an 

occupation requiring strength and 

hard labor to an extent that his 

vertebrae had deteriorated at the 

joint surfaces. It is speculation, but 

a small medicine bottle located 

on the bench near his seat might 

have dispensed pain relief for his 

back. Becker was not only born in Europe, but was 

a recent immigrant, as shown by the ratio of carbon 

12 and 13 isotopes. He had also suffered childhood 

illness and/or malnutrition, which was indicated by 

disruption in the linear tooth growth. Although the 

specifics of his childhood are unknown, his health and 

young adult occupation as a seaman suggests a poor 

or working class upbringing. Tobacco staining on the 

teeth indicated that, like Dixon, he might have smoked 

cigars or chewed tobacco, but did not incise his teeth 

from clenching the stem of a pipe (Olds 2004).

Becker, although a relatively recent arrival, was in 

the United States when the war began, working on the 

Mississippi riverboat Ed Howard or Howard, which was 

purchased by the Confederate government. Becker 

enlisted in the Confederate navy in New Orleans on 

19 October 1861 and was assigned to his former vessel, 

since converted to a timberclad and renamed CSSGeneral 

Polk (Raegan Quinn 2006:4). He was presumably on board 

when it was scuttled and burned in the Yazoo River on 

26 June 1862 to prevent capture after the fall of New 

Orleans to Union forces. Four months later, in October 

1862, records show Becker was in Charleston, assigned 

to the gunboat CSS Chicora. There he was promoted to 

the rank of Captain’s Cook and on the ship’s pay roster 

until September 1863 (NARA n.d. a, n.d. b). He was then 

assigned to CSS Indian Chief and was one of four volunteers from that ship recruited by Dixon (ORN 1.15:337).

Figure 2.12. 

Facial reconstruction of Lt. George 

Dixon. (Photo by 

Chip Clark, courtesy 

of FOTH)

Figure 2.13. Facial 

reconstruction of 

Seaman Arnold 

Becker. (Photo by 

Chip Clark, courtesy 

of FOTH)
H I S T O R I C A L B A C K G R O U N D

27

Quarter Gunner C. Lumpkin

The third person 

aft in the submarine is 

primarily known by the 

last name of Lumpkin 

(Figure 2.14). His name 

was mistakenly identified as Simkins or 

Simpkins when transcribing original handwritten documents 

(ORN 1.15:337), but 

genealogist Linda 

Abrams was able to 

determine his correct name was Lumpkin. The CSS Indian 

Chief pay roster from October 1863 clearly lists him as 

“C. Lumpkins” and a note written by William Alexander 

(1898) mentions “Lumpkin” as being on the submarine. 

Lumpkin, like Becker, was European born; however, 

isotope analysis revealed he had been in North 

America for some time. Owsley interpreted that, of the 

Europeans on Hunley, he had been away the longest. He 

was also one of the oldest men on board, between 37 

and 44 years, but probably in his early forties. He was 

a relatively large man, standing 5 ft. 10 in. (178 cm). He 

had had a strenuous life, perhaps as a sailor, and had a 

series of injuries that resulted in a broken nose, cheek, 

and foot. The breaks had all healed prior to his service on 

Hunley, but still he suffered from arthritis in his back and 

might have walked with a slouch. Adding to his health 

problems were the deeply worn notches in his teeth from 

pipe use and tobacco staining. His pipe was with him 

when he died, as was a sewing kit and pocketknife. 

The date and location of Lumpkin’s enlistment in 

the Confederate navy is unknown. He appears in the 

Charleston Naval Squadron’s regular payroll roster, from 

which he was stricken on 31 October 1863, coinciding 

with the time Dixon was assembling his new crew for 

Hunley (NARA, n.d. a, n.d. b). His position as Quarter 

Gunner indicates that he had experience handling 

explosives and suggests that he may have been responsible for arming the submarine’s torpedo.

Corporal J. F. Carlsen

The fourth Hunley crewman was J. F. Carlsen, another 

European-born volunteer, possibly from Scandinavia 

(Figure 2.15). Owsley’s forensic analysis determined 

he was 20 to 23 years old and 5 ft. 10 in. (178 cm) tall. 

Abrams’s genealogical research found he had enlisted 

in Company A, Light Artillery South Carolina Volunteers, 

which was also called the German Artillery.

Abrams found that, prior to his enlistment, he was 

helmsman on the privateer Jefferson Davis when it 

sailed from Charleston on 28 June 1861. On its privateering voyage, Jefferson Davis captured seven merchant 

ships and their crews. This success led to complications 

that eventually resulted in a trial of 

mutiny for some of the captured 

crewmen. Having placed prize 

crews on all the captured ships, 

Jefferson Davis found its complement much reduced and outnumbered by the merchant crewmen 

imprisoned onboard, who took 

advantage of this weakness and 

attempted to take over the ship. 

The ensuing fight caused Jefferson 

Davis to wreck off the coast of 

St. Augustine, Florida, in August 

1861. While in Charleston to sign 

witness statements for the trial in 

September 1861, Carlsen enlisted 

in the German Artillery, which was 

bivouacked nearby (CSN 1861). He was with them at the 

Battle of Fort Walker in November 1861 and was cited 

for his bravery (FOTH 2004b:5). 

In early 1864, Carlsen volunteered for service on 

Hunley (ORN 1.15:337), as one of two men Dixon reportedly recruited from the German Artillery after William 

Alexander was ordered back to Mobile (Alexander 

1902b:173). The German Artillery muster roll states that 

Carlsen was “lost in the Submarine Torpedo Boat on the 

16th, [17th], of Feb 1864 while in the act of sinking the 

U.S. Steamer Housatonic” (FOTH 2004b:5). 

Seaman Frank Collins

The fifth person stationed aft 

in Hunley was Frank Collins (Figure 

2.16). He was the largest crewmember at 6 ft. 1 in. (185 cm) in 

height, and it is perhaps because 

of his size and strength that he 

was positioned to turn the crank 

in the middle of the submarine. 

Collins and his brother John were 

orphaned and raised by their 

grandparents in Fredericksburg, 

Virginia. The 1860 census records 

him as a day laborer. It is possible 

he had trained as a cobbler, for 

both his grandfather and uncle 

were cobblers. This theory is 

supported by the “tailor notches” 

caused by holding needles or pins between his front 

teeth that were identified by Owsley (FOTH 2004b:4). 

Collins enlisted in the Confederate States Navy 

on 25 April 1863 in Richmond, Virginia. His rating as 

a seaman, rather than landsman, might indicate he 

had some prior seafaring experience. He served on 

CSS Indian Chief in Charleston, and also disappears from 

the Charleston Naval Squadron’s regular payroll roster 

after 31 October 1863, when he became one of four of 

Figure 2.14. Facial reconstruction of Quarter Gunner 

Lumpkin. (Photo by Chip Clark, 

courtesy of FOTH)

Figure 2.15. Facial 

reconstruction of 

Cpl. J. F. Carlsen. 

(Photo by Chip 

Clark, courtesy of 

FOTH)

Figure 2.16. Facial 

reconstruction 

of Seaman Frank 

Collins. (Photo 

by Chip Clark, 

courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

28

the volunteers chosen by Dixon (NARA n.d. a, n.d. b). 

Due to his size and position in the center of the vessel, 

it would have been difficult for him to escape from the 

submarine in any emergency (FOTH 2004b:5).

Miller

The sixth position in the 

submarine was filled by a crewman 

by the name of Miller (Figure 

2.17). Little has yet been learned 

of him, not even his first name. At 

first, it appeared that he may have 

been the second man from the 

German Artillery reportedly added 

to the crew after the departure of 

Alexander (1902b:173); however, 

Alexander (1898) mentioned in 

a letter that he knew Miller, suggesting the man had been recruited 

before Alexander left the team. 

Carbon isotope analysis indicates 

Miller was a relatively recent 

immigrant from Europe. Forensic 

analysis also concluded he was 

between 40 and 45 years of age 

and stood 5 ft. 8 in. (173 cm) in height (Jacobsen 2004). 

Owsley noted he was a heavy smoker and carried his 

wooden pipe with him inside the submarine (FOTH 

2005a:4). He had had a hard life, as evidenced by healed 

fractures to his ribs, leg, and skull. Not surprisingly, he 

showed early stages of arthritis (FOTH 2005a:4). 

Quartermaster James A. Wicks 

The seventh position in the 

submarine was filled by an experienced seaman, James A. Wicks 

(Figure 2.18). Wicks was a native 

Southerner, born in North Carolina 

circa 1819. In 1850, he enlisted 

in the United States Navy at the 

Brooklyn Navy Yard, New York. 

He also married that same year 

and by 1861 had fathered four 

daughters. He served in the U.S. 

Navy more than a decade, first as 

a seaman and later as a quartermaster (FOTH 2005b:4).

When the war began, his wife 

and daughters were living in Fernandina, Florida, deep in the heart 

of the Confederacy. Wicks served 

in the North Atlantic Blockading Squadron, first on USS 

Braziliera, then USS Congress. He was aboard this vessel 

on 8 March 1862, when it was attacked and sunk by CSS 

Virginia at the Battle of Hampton Roads. Wicks took 

this opportunity to head south and on 7 April 1862, 

in Richmond, he enlisted in the Confederate navy as 

a seaman. His first assignment was CSS Indian Chief, 

where he was eventually promoted to Boatswain’s Mate, 

before volunteering for Dixon’s new crew in October 

1863. He apparently took a break from his service on 

Hunley, as he is recorded as volunteering for a raid 

outside of New Bern, North Carolina, that destroyed 

the Union ship USS Underwriter on 3 February 1864 

(FOTH 2005b:5). He returned to his Charleston duties 

two days later, less than two weeks before Hunley’s 

final mission. 

Owsley’s analysis revealed that Wicks was a large 

man, standing 5 ft. 10 in. (178 cm) tall, and, like Lumpkin 

and Miller, was a heavy tobacco user (Jacobsen 2004). 

Abrams’s research of records found that he had light 

brown hair, blue eyes, and a florid complexion (FOTH 

2005b:5). His duties in the submarine included manning 

the hand crank and also releasing the keel ballast 

mechanism that was at his feet. 

Joseph F. Ridgaway

The eighth and last man in the 

submarine was Joseph Ridgaway 

of Talbot County, Maryland (Figure 

2.19). He was born in late 1833 

to James and Elizabeth Ridgaway 

(FOTH 2005c:6). James was a sea 

captain and owner of merchant 

vessels. Joseph earned his Seaman’s 

Protection Certificate and the rating 

of seaman at age 16. Like many 

from his home state, Ridgaway 

appears to have had Confederate 

sympathies and enlisted in the Confederate States Navy in Richmond 

on 29 August 1862. He first appears 

on the Charleston Naval Squadron’s payroll roster in October 1862 

and is later removed from regular pay records after 31 

October 1863, along with his fellow volunteers from CSS 

Indian Chief (ORN 2.1:317; NARA n.d. a, n.d. b).

Owsley’s analysis indicated Ridgaway was 5 ft. 10 in. 

(178 cm) tall and robust for his height (FOTH 2005c:6–7). 

He had suffered a broken nose and injured his shoulder, 

perhaps a result of his occupation. He also used tobacco 

and his wooden pipe was found nearby with his slouch 

hat, pencil, and an apparent war souvenir. The last 

was a copper alloy token or tag with the name Ezra 

Chamberlin, Company K, 7th Regiment Connecticut 

volunteers, who entered service on 6 September 1861. 

Chamberlin was killed at the Battle of Morris Island, 

South Carolina, in 1863. Abrams noted that since 

seamen from Indian Chief were assigned to picket 

duty off Morris Island, Ridgaway might have picked it 

up there or obtained it from someone who was there 

(FOTH 2005c:6). 

Figure 2.17. Facial 

reconstruction of 

crewman Miller. 

His first name is 

not yet known. 

(Photo by Chip 

Clark, courtesy of 

FOTH)

Figure 2.18. Facial 

reconstruction of 

Quartermaster 

James Wicks. 

(Photo by Chip 

Clark, courtesy of 

FOTH)

Figure 2.19. Facial 

reconstruction of 

Joseph Ridgaway. 

(Photo by Chip 

Clark, courtesy of 

FOTH)
H I S T O R I C A L B A C K G R O U N D

29

Ridgaway took over Alexander’s position on Hunley

when the engineer was recalled to Mobile (see below). 

This was a key position of responsibility, in which he 

would have been accountable for the securing the aft 

hatch, as well as operation of the seventh crank position, 

aft pump, and seacock valve. It is likely his extensive 

seafaring background made him an excellent candidate 

to take over these duties.

Ridgaway’s story does not end with his loss in 

Hunley, for he had a fellow shipmate from Indian Chief, 

James Joiner, who took news of Ridgaway’s death to the 

Ridgaway family in Maryland. Joiner became a member 

of his friend’s family, when he married one of Ridgaway’s four sisters (FOTH 2005c:7).

Training the Crew

Dixon and the new crew of submariners were 

garrisoned in the town of Mount Pleasant, a small 

fishing community located along the north shore of 

Charleston Harbor near the mouth of the Cooper River. 

Initially, practice runs were conducted in the Cooper 

River; however, the submarine’s base of operations was 

eventually moved to Back Bay, a small lagoon located 

behind Battery Marshall and along the northeast tip of 

Sullivan’s Island (Figure 2.20). Although Sullivan’s Island 

often received sporadic cannon fire from the blockade 

fleet, it was not in immediate danger of invasion (as 

was the case with Morris Island). Further, it provided a 

safe anchorage out of sight of the enemy, and access to 

the sea via a narrow channel known as Breach Inlet. In 

theory, the crew could conduct operational exercises in 

the Back Bay during the day, and (weather permitting) 

covertly slip into the ocean at night via the inlet. 

Alexander described the crew’s daily trek to Sullivan’s Island: “We would leave Mount Pleasant about 

one o’clock p.m., walk seven miles [11.27 km] back to 

Battery Marshall along the beach—this exposed us to 

the enemy’s fire, but it was the best walking—take 

the boat out, and practice the crew for two hours in 

the Back Bay” (Alexander 1903:748) (Figure 2.21). On 

nights when seas were calm, Hunley was piloted into 

the open ocean, where the crew practiced submerging 

and surfacing their vessel. According to Alexander, he 

and “Dixon . . . would . . . lie down on the beach with the 

compass between [them], and get the bearings of the 

nearest Federal vessel as she took her position for the 

night. [They] would ship up the torpedo on the boom, 

and, when dark, go out, steering for the ship [they] had 

marked” (Alexander 1903:748). The crew soon discovered that it was necessary to leave the island during 

the ebb tide and time their return for peak flood tide. 

On several occasions, the submarine came so close to 

U.S. Navy patrol boats operating in the area that they 

could hear the picket boat crews “talking and singing” 

(Alexander 1903:748). Occasionally, the tiny vessel 

and its exhausted crew would not return to Sullivan’s 

Island until sunrise. During a typical cruise, the submariners “would proceed until the condition of the men, 

the sea, the tide, the moon, the wind, or the approach 

of daylight compelled [their] return to the dock. Then 

[they] would unship the torpedo, put it under guard 

at Battery Marshall, walk back to quarters at Mount 

Pleasant, and cook breakfast” (Alexander 1903:748).

Dixon and Alexander were very concerned that the 

submarine and its crew might be caught at sea during 

the daylight return to Breach Inlet. Consequently, both 

men arranged a somewhat unorthodox (and dangerous) 

Figure 2.20. Map showing the route from Mount Pleasant (upper left) to Battery 

Marshall and Breach Inlet (right). (Detail from USCS 1865)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

30

experiment. Under controlled conditions in Back Bay, 

the crew would submerge Hunley and determine the 

length of time it could remain under water before their 

air supply was depleted: 

It was agreed to by all hands to sink 

and let the boat rest on the bottom, in the 

Back bay, off Battery Marshall, each man to 

make equal physical exertion in turning the 

propeller. It was also agreed that if anyone 

in the boat felt that he must come to the 

surface for air, and he gave the word ‘up,’ we 

would at once bring the boat to the surface.

. . . Dixon and myself and several of the 

crew compared watches, noted the time and 

sank for the test. In twenty-five minutes after 

I had closed the after manhead and excluded 

the outer air the candle would not burn. . . . 

Each man had determined that he would not 

be the first to say ‘up!’ Not a word was said, 

except the occasional, ‘How is it,’ between 

Dixon and myself, until it was as the voice 

of one man, the word ‘up’ came from all. . . . 

We started the pumps. Dixon’s worked all 

right, but I soon realized that my pump was 

not throwing. From experience I guessed the 

cause of the failure, took off the cap of the 

pump, lifted the valve, and drew out some 

seaweed that had choked it. 

During the time to do this, the boat was 

considerably by the stern. Thick darkness 

prevailed. All hands had already endured what 

they thought was the utmost limit. Some of 

the crew almost lost control of themselves. It 

was a terrible few minutes, ‘better imagined 

than described.’ We soon had 

the boat to the surface and the 

manhead opened. Fresh air! 

What an experience! (Alexander 

1902a) 

Dixon drilled the new crew 

throughout November; by mid-December 

he received orders to engage the enemy 

as soon as practicable. By the beginning 

of 1864, the intrepid submariners were 

conducting missions an average of four 

nights per week, and covering a distance 

between six and seven miles (9.66–11.27 

km) per excursion (Alexander 1902a). 

However, strong winds and high seas 

prevented the boat from venturing far 

from shore throughout January. Consequently, no Federal vessels were engaged 

during this time. Dixon’s feelings of frustration about not being able to effect an 

attack during this period were expressed in a letter to 

Henry Willey:

I suppose that you think strange that I have 

not done any thing here yet, but if I could 

tell you all of the circumstances that have 

occurred since I came here you would not 

think strange of my not having done any 

execution as yet. But it would take considerable paper and time to relate them to you 

at present so I will postpone relating them 

until I see you. But there is one thing very 

evident and that is to catch the Atlantic Ocean 

smooth during the winter months is considerable of an undertaking and one that I never 

wish to undertake again. Especially when 

all parties interested at sitting at home and 

wondering and criticizing all of my actions 

and saying why don’t he do something. if I 

have not done any thing “God Knows” it is 

not because I have not worked hard enough 

to do some thing. And I shall keep trying until 

I do some thing. I have been out-side several 

times but for various reasons I have not yet 

met with success. I am out-side every night 

in a small boat so that there is not a possible 

for any good night to pass with out my being 

able to take advantage of it. I have my boat 

lying between Sullivan’s and Long Islands and 

think that when the night does come that I 

will surprise the Yankees completely. The Fleet 

offshore have drawings of the sub-marine and 

of course they have taken all precautions that 

it is possible for Yankee ingenuity to invent, 

but I hope to Flank them yet. (Dixon 1864)

Figure 2.21. View from Fort Moultrie on Sullivan’s Island, looking east. 

Dixon and his men would have passed by here on the way to take Hunley

out to sea. (Courtesy of NARA, RG 94, Quincy Adams Gillmore papers)
H I S T O R I C A L B A C K G R O U N D

31

The tight-knit crew’s morale was shaken on 

5 February 1864, when William Alexander received 

orders to return to Mobile and construct a breechloading cannon for the Confederate army. According 

to Alexander, “This was a terrible blow, both to Dixon 

and myself, after we had gone through so much 

together. General Jordon told Dixon he would get 

two men to take my place from the German Artillery, 

but that I was wanted in Mobile” (Alexander 1902a). 

Alexander departed for Mobile the same day. To date, 

only Corporal Carlsen has been identified as a volunteer 

from this unit.

While Lieutenant Dixon introduced and integrated 

Alexander’s replacement(s) and waited for January’s 

foul weather to abate, the Federal fleet was gathering 

information about Confederate submersibles and 

preparing for an imminent attack. As mentioned above, 

the depositions of the Confederate deserters—George L. 

Shipp (ORN 1.15:229–33) and another individual identified only by the surname “Belton” (ORN 1.15:227)—

were recorded aboard the Flag Steamer Philadelphia on 

7 January 1864. According to Belton’s testimony, he had 

worked in the machine shop in Mobile where the boat 

“American Diver” was built and saw it “in all stages of 

construction” (ORN 1.15:229). He was later conscripted 

into the Confederate navy and assigned to a vessel in 

Charleston. He claimed to have been stationed aboard 

the receiving ship CSS Indian Chief, where he interacted 

with several of the submarine’s crewmen and personally witnessed practice dives under Indian Chief and CSS 

Charleston on a number of occasions. In his statement, 

George Shipp also claimed that he observed “American 

Diver” make several practice dives under ships in 

Charleston Harbor, and recounted the removal of the 

bodies of Horace Hunley and the second crew from the 

submarine in October 1863 (ORN 1.15:231). 

On 7 January 1864, Rear Admiral John A. Dahlgren, 

Commander of the South Atlantic Blockading Squadron, 

received a transcription of Belton and Shipp’s testimony 

from their interrogation officer. The same day, he issued 

the following orders to the blockade fleet:

I have reliable information that the rebels 

have two torpedo boats ready for service, 

which may be expected on the first 

night when the water is suitable for their 

movement. One of these is the ‘David,’ 

which attacked the Ironsides in October. . . .

There is also one of another kind, which 

is nearly submerged and can be entirely so. 

It is intended to go under the bottoms of 

vessels and there operate. 

This is believed by my informant to be sure 

of well working, though from bad management it has hitherto met with accidents, and 

was lying off Mount Pleasant two nights since. 

There being every reason to expect a 

visit from some or all of these torpedoes, the 

greatest vigilance will be needed to guard 

against them.

The ironclads must have their fenders 

rigged out and their own boats in motion 

about them. 

A netting must also be dropped 

overboard from the ends of the fenders, kept 

down with shot, and extending along the 

whole length of the sides; howitzers loaded 

with canister on the decks and a calcium 

for each monitor. The tugs and picket boats 

must be incessantly upon the lookout, when 

the water is not rough, whether the weather 

is clear or rainy. (ORN 1.15:226–227)

Hunley’s Final Mission

Toward the middle of February 1864, the weather 

began to moderate. Shortly thereafter, Dixon and the 

submarine crew initiated a new series of nighttime 

sorties from Breach Inlet. Just before sundown on 

Wednesday, 17 February 1864, Dixon presumably 

obtained bearings for nearby blockaders (as he had with 

William Alexander) and selected the nearest target. The 

logbook of the nearby USS Canandaigua captured the 

relative positions the blockading ships moored off Sullivan’s Island that evening: “February 17, 1864—Bearings 

of vessels at sundown: Wabash, S. 3⁄4 E.; Mary Sanford, 

N.N.E.; Housatonic, N.N.E. 3⁄4 E.; Paul Jones, N.N.E.” 

(ORN 1.15:332). Although it is difficult to ascertain 

exactly where each vessel in the fleet was positioned, 

the bearings provide an approximation of their overall 

formation. The squadron formed an “L,” with Canandaigua comprising the apex of the right angle. Housatonic, Mary Sanford and Paul Jones were positioned in 

a line to the northeast of Canandaigua; Wabash was to 

the southeast and located farther out to sea. 

As the sun set at 6:07 p.m., the moon emerged high 

in the evening sky. The moon was waxing and approximately 79% of its visible surface was illuminated (USNO, 

n.d.). Winds were reportedly out of the northwest at 

7 to 16 knots, the sea was calm, and the sky clear. At 

sunset the air temperature was 44°F (6.67°C); the 

tide was ebbing to the southwest at approximately 

1 to 3 knots (DON 1863–64, 1864a). Dixon probably 

would have preferred to attack on a moonless night, 

but realized that the propitious weather might not last 

long enough for another attempt. As the submarine 

was propelled toward the nearest blockade vessel, its 

crew may have contemplated which vessel they were 

attacking, and whether this mission, like so many before 

it, would end before they could carry out a successful 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

32

engagement. On that particular night, however, the 

crew of Hunley managed to avoid federal picket boats 

and propel their tiny craft within striking distance of the 

nearest blockader, USS Housatonic (Figure 2.22).

The steam sloop-of-war Housatonic was launched 

at the Charlestown Navy Yard on 20 November 1861. It 

had an overall length of 207 ft. (63.09 m), a depth of 

hold of 16 ft. 10 in. (5.13 m), and a maximum beam of 38 

ft. (11.58 m). Its maximum displacement was 1,240 tn. 

(1,126 t). When fully loaded, Housatonic drew 7 ft. 

7 in. (2.31 m) at the bow and 9 ft. 7 in. (2.92 m) at the 

stern. The warship’s single four-bladed propeller was 

powered by two horizontal 42 in. (1.07 m) Isherwood 

direct-acting steam engines. It was armed with a single 

100-pounder Parrott rifle, three 30-pounder Parrott 

rifles, one XI-inch Dahlgren smoothbore cannon, two 

32-pounder smoothbores, two 24-pounder Howitzers, 

one 12-pounder Howitzer and one 12-pounder rifle. 

Two additional 32-pounder smoothbores were added 

to its complement of armament in 1863 (ORN 2.1:104). 

The Commander of Housatonic, Captain Charles 

Whipple Pickering, was born in Portsmouth, New 

Hampshire, on 23 December 1815. He was appointed 

midshipman on 1 May 1822, when he was only six 

years old (Marvel 1996:12). He was promoted to lieutenant and attached to the U.S. Navy’s Pacific Squadron 

on 8 December 1838. He served as executive officer 

of USS Cyane and was present at the bombardment 

of Greytown, Nicaragua, in 1854. On 14 September 

1855, he was promoted to commander, and from 

1859 to 1861 was stationed near Key West, Florida. He 

advanced to the rank of captain on 15 July 1862, and 

commanded the warship USS Kearsarge in the Mediterranean and West Indies. While under Pickering’s 

command, Kearsarge failed to engage a single Confederate warship. His inability to intercept enemy ships on 

the high seas prompted Secretary Welles to transfer 

him to the South Atlantic Blockading Squadron. It was 

during this assignment—in spring 1863—that he was 

given command of Housatonic. 

Aside from periodic instances when the fleet would 

fire on enemy coastal fortifications or give chase to 

blockade-runners, blockade duty for Union sailors was 

largely uneventful. Dahlgren’s message warning the fleet 

of an imminent attack by one or more enemy torpedo 

boats changed the attitude of most blockader crews 

from malaise to one of excitement and/or anxiety. Some 

individuals serving aboard Union vessels prepared for 

the worst. Acting Master Joseph W. Congdon recounted:

As our information concerning their plans 

was very reliable, we naturally expected to 

go skyward sooner or later. With that in view, 

we concluded that if it were a possible thing, 

we would take our valuables with us on the 

journey. So before turning in each night, 

each one of us officers would attach a line 

to our valuables and lead the line up through 

the hatch on deck, making it fast and handy 

so that when the time did come for us to 

leave, we could clutch our lines, haul up our 

valuables and take them along with us just as 

easily as rolling off a log. (Historic Nantucket

1980:28–29) 

Pickering obeyed Dahlgren’s instructions to the 

letter and took extra precautions to protect his ship 

against a potential submarine attack. As night fell, 

Pickering ordered hammock netting to be deployed 

around Housatonic’s hull below the waterline as a 

measure to foil subsurface attacks. He also ensured 

that the vessel could quickly slip its moorings and 

Figure 2.22. Wash drawing of the United States Sloop-of-War Housatonic by R. G. 

Skerrett (1908). (NHHC Photo Archives #NH 53573)
H I S T O R I C A L B A C K G R O U N D

33

initiate evasive maneuvers in the event of an enemy 

assault. A small detachment of sailors was placed 

near the shackle holding the anchor chain. The anchor 

shackle was fitted with a wooden pin so it could be 

easily discarded, and the ship’s engines were set in 

reverse. Additionally, the stokers in the boiler room 

maintained a steady head of 25 lb.4

 (11.34 kg) of steam 

in the boilers between 6 a.m. and 6 p.m. so that the 

engines could be started immediately. Pickering also 

ordered Housatonic’s crew to maintain a vigilant watch 

at all times. 

The night of 17 February was clear and frigid. “It 

was a cold night, just making ice,” according to Congdon 

(Historic Nantucket 1980:30). That evening, six armed 

lookouts were positioned around the perimeter of the 

ship. Four men were assigned to slip the anchor chain 

on the forecastle and an additional man was positioned near the alarm gong in the stern of the ship. The 

forward watch consisted of two armed sentries (one at 

each cathead) and the four men assigned to the anchor 

chain. Acting Master’s Mate Louis A. Cornthwait supervised this group. The stern watch was commanded by 

Quartermaster James Timmons and consisted of a pair 

of sentries posted on the quarterdeck. The third pair of 

armed guards was posted on the gangway amidships 

and was supervised by the watch commander or Officer 

of the Deck. The Officer of the Deck, Acting Master John 

Keyes Crosby, was positioned on the bridge. Housatonic’s bridge was an elevated catwalk just forward of the 

vessel’s smokestack. From this elevated position, Crosby 

could maintain contact with the fore and aft watches as 

well as the two lookouts on the gangway. Each lookout 

was armed with a rifled musket and all were prepared 

to fire on any unfriendly vessel that approached the 

ship. Additional personnel were assigned to the ship’s 

battery (guns). On the night that Housatonic was 

attacked, Crosby recalls that “[t]he battery was all cast 

loose . . . with side tackles hooked in the fighting bolts . . ..

[and] the balance of the watch [number unknown] were 

at the guns armed as at quarters” (DON 1864a:0499). 

The sole task of the man stationed at the ship’s gong 

was to sound the alarm and fire rockets should the 

order be given.

Crosby began his watch at 8:00 p.m. The sea was 

calm, the sky was clear, and a light cold breeze blew 

from the northwest. He recounts that “the weather 

was clear, very bright moonlight” (DON 1864a:0501). 

Archival sources indicate that the first person to spot the 

approaching submarine was a young African American 

landsman named Robert F. Flemming. Flemming was 

posted on the starboard bow and recalled seeing 

something unusual just prior to the attack: 

4 This measurement is not the same as pounds per square inch; 

steam is measured in pounds of water used to make the equivalent 

amount of steam, hence a pound of steam is equal to a pound of 

water.

I saw something approaching the ship broad 

off the starboard bow, about two ship’s 

lengths off, and reported it to the Officer 

of the forecastle. He told me it was a log. 

I then told him this was not floating with the 

tide as a log would, but moving across the 

tide. He still thought it was a log so I called 

the lookout from the Port side [Landsman 

C. P. Slade] to see what it was. When the 

Officer of the fore-castle saw this other 

lookout coming over he looked at the object 

through his glasses and then ran aft. (DON 

1864a:0544–0545)

The officer that Flemming refers to, Acting Master’s 

Mate Lewis A. Cornthwait, reported:

[At] about 8:45 p.m. the lookout on the 

starboard cathead reported something 

adrift on the water, about two points on 

the starboard bow, and 100 yards [91.44 m] 

distant. I then made it out with my glasses 

and it looked to me like a log with two lumps 

as large as XV inch shell boxes on it, about 

ten feet apart. There was a break of the 

water forward, and aft and between these 

two lumps. As soon as I saw it, I ran aft and 

reported it to the Officer of the Deck, who 

was on the bridge, and his glass turned in the 

direction of this object. (DON 1864a:0524)

At almost the same moment, Crosby raised his 

glass and reported seeing “something on the water, 

which at first looked to me like a porpoise, coming up 

to the surface to blow. It was about 75 to 100 yards 

[68.58–91.44 m] from us on our starboard beam, 

the ship heading N.W. by W. 1⁄2 W. at the time” (DON 

1864a:0491–0492). Uncertain of the object’s identity, 

Crosby summoned Timmons to the stern and asked if he 

could see it. Timmons looked in the direction indicated 

by Crosby but claimed that all he could see was a tide 

ripple on the water. Moments later, Hunley turned 

toward Housatonic and increased speed. Crosby raised 

his glass a second time and noticed that the submarine 

“was coming towards the ship very fast. I gave orders to 

beat to Quarters, slip the chain and back the engine” 

(DON 1864a:0493). Within moments, the ship’s gong 

was sounded and the anchor chain was slipped. 

Housatonic’s cooper, George Kelly, was on the 

forecastle as Hunley approached the warship: “I saw 

something on the water looking like a capsized boat . . . 

about three points on the starboard bow, about 

75 yards [68.58 m] distant, moving astern nearly parallel 

with the keel” (DON 1864a:0558). As Quarters were 

sounded, Kelly moved aft toward his assigned position 

at the aft pivot gun. When Kelly arrived at his station at 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

34

the forward end of the gun’s starboard port, he “saw 

this object again, about fifteen yards [13.72 m] from 

the ship, making a sort of circle towards the starboard 

quarter” (DON 1864a:0559). Immediately after the 

alarm was sounded, Housatonic’s Executive Officer, 

Lieutenant L. J. Higginson, arrived on the bridge and 

questioned Crosby. Pickering soon followed Higginson 

to the bridge and repeated the order to slip the chain 

and back the engine. He also gave the order to open 

fire on the object. 

With the captain on the bridge, Crosby departed 

and went forward to make sure Housatonic’s anchor 

chain had been slipped. Higginson moved aft to the 

sentry positioned on the starboard quarter. He later 

recounted, “I . . . saw something resembling a plank 

moving towards the ship at a rate of 3 or 4 knots; it 

came close alongside, a little forward of the mizzen 

mast on the starboard side. It then stopped, and 

appeared to move off slowly” (DON 1864a:0530). The 

sentry, Landsman John Saunders, had tried to shoot 

at the submarine twice but his rifle had misfired both 

times. Higginson grabbed Saunders’ musket, took his 

place on the horseblock, quickly re-primed the weapon, 

and fired as the submarine started to move away. He 

was not the only person firing at Hunley with small arms 

during the attack. As the submarine moved away from 

Housatonic, Congdon claimed: “I discovered this Wild 

Cat and immediately opened fire from my revolver, but 

did not have the opportunity of using all the chambers” 

(Historic Nantucket 1980:30). 

As members of Housatonic’s crew discharged small 

arms at the submarine, Pickering made his way from 

the bridge towards the stern; en route, he procured his 

double-barreled shotgun from the ship’s clerk, Charles O. 

Muzzey. Pickering quickly assumed Higginson’s position 

on the horseblock along the starboard quarter rail and 

fired his weapon. He then stepped down and moved to 

the port side of the mizzenmast, where he issued additional commands to the engine room (DON 1864a:0580).

Seconds later, Hunley’s torpedo exploded. The 

effect of the black powder charge on Housatonic’s hull 

and crew was immediate and catastrophic. According 

to Congdon: 

The explosion was terrific, tearing a hole in 

the side of the ship large enough to drive a 

horse and cart through. I was raised several 

feet skyward but came down unharmed and 

somewhat bewildered, expecting of course 

that our magazine, containing some 5 ton 

[4.54 t] of powder would explode and that 

would end the affair. Fortunately for us, it did 

not. (Historic Nantucket 1980:29) 

Crosby later recounted, “The explosion started me 

off my feet, as if the ship had struck hard on the bottom. 

I saw fragments of wreck going up into the air. I saw no 

column of water thrown up, no smoke and no flame” 

(DON 1864a:0501). 

When the torpedo detonated, Housatonic’s engine 

was engaged but had not yet established enough 

momentum to move the vessel away from its mooring. 

According to Third Assistant Engineer James W. Holihan, 

the explosion disabled the engine: 

I heard the gong beat for Quarters, and 

gave orders to have everything ready for 

starting the engine. Immediately three 

bells were struck, and I gave orders to 

open the stop valves and back the engine. 

The engine had made about ten or twelve 

revolutions, at the rate of about thirty 

per minute, before I heard the crashing of 

timbers.... I was standing by the throttle 

valve and was staggered by the shock, and 

the engine commenced turning so rapidly 

I closed the throttle valve, supposing some 

part of the machinery had given way. (DON 

1864a:0549–0550)

Housatonic’s gun crews were also unable to respond 

effectively during the attack. Although all of the ship’s 

cannon were armed and ready to fire when the attack 

occurred, the gun crews could not bring their weapons 

to bear on a target so close to the ship. Ensign Charles H. 

Craven was below decks when the alarm was sounded. 

Craven commanded the ship’s starboard battery of four 

32-pounder guns. He immediately made his way topside 

when he heard the call to quarters. As he rushed to his 

post he spotted the submarine approaching Housatonic

from a distance of approximately 30 ft. [9.14 m]. Craven 

fired three shots from his revolver before he reached 

his post. Craven later testified that he:

Tried, with the Captain of No. 6 gun to train 

it on this object...; I had nearly succeeded, 

and was about to pull the lock string when 

the explosion took place. I was jarred and 

thrown back on the topsail sheet bitts, 

which caused me to pull the lock string and 

the hammer fell on the primer but without 

sufficient force to explode it. I replaced the 

primer and was trying to catch sight of the 

object in order to train the gun again upon 

it, when I found the water was ankle deep 

on deck by the main mast. I then went and 

assisted in clearing away the 2nd Launch. 

(DON 1864a:0505–0506) 

Nearly every man aboard was thrown to the deck 

by the force of the explosion. However, those on the 

quarterdeck fared much worse. Muzzey, and four others 
H I S T O R I C A L B A C K G R O U N D

35

were killed in the explosion. Pickering himself was badly 

injured: “I...was blown into the air the next instant from 

where I stood on the Port side abreast of the mizzen 

mast. I found myself in the water, about where I stood 

previous to the explosion, amongst broken timbers, 

the debris of panel work, and planking. I succeeded 

in getting into the mizzen rigging, very much bruised” 

(DON 1864a:0581).

Most of the remaining crew followed their captain’s 

example and scrambled into the ship’s rigging as the 

vessel sank. One minute after the explosion, Housatonic’s stern touched bottom. The crew frantically 

attempted to free the vessel’s remaining lifeboats as 

its bow slipped beneath the water. As Housatonic sank, 

it listed hard to port, swamping two of the lifeboats 

before they could be freed from their davits and sending 

several crewmen into the icy water. Because the ship 

sank in only 28 ft. (8.53 m) of water, “the sheepholes of 

the lower rigging at the waters edge” were accessible to 

crewmembers—a fortunate circumstance that probably 

saved several lives (Historic Nantucket 1980:30). 

Congdon describes the turmoil that ensued as Housatonic sank: “When the water reached the furnace fires, 

it made a roar even worse than the explosion, so that 

nearly everyone was overboard for a while . . .. Some of 

the crew in the excitement had divested themselves of 

their wearing apparel and started to swim somewhere. 

When they discovered that our masts offered a place 

of refuge, they swam back to the rigging and posed 

as Living Pictures in their primitive state.... (Historic 

Nantucket 1980:30).

Two of Housatonic’s launches were successfully 

deployed before the vessel sank. The first of these 

headed for USS Canandaigua, which was the nearest 

friendly ship and clearly visible from Housatonic. The 

second launch, commanded by Crosby, remained 

behind to assist men who had gone into the water. Once 

this task was completed, Crosby rescued Pickering from 

the mizzen rigging and then made for Canandaigua. 

That ship’s logbook records the events that followed: 

At 9:20 p.m. discovered a boat pulling 

toward us. Hailed her and found her to 

be from the Housatonic. She reported the 

Housatonic sunk by a torpedo. Immediately 

slipped our chain and started for the scene 

of danger, with the Housatonic’s boat in tow. 

At the same time sent up three rockets.... At 

9:30 p.m. picked up another boat from the 

Housatonic, with Captain Pickering on board.

At 9:35 arrived at the Housatonic and found 

her sunk. (ORN 1.15:332) 

Meanwhile, the survivors of Housatonic’s sinking 

waited anxiously in the rigging for Canandaigua to 

rescue them. Flemming, the young seaman who initially 

spotted Hunley, later claimed to have observed a flash 

of light just as Canandaigua arrived: “When the ‘Canandaigua’ got astern, and lying athwart of the ‘Housatonic’, 

about four ship’s lengths off, while I was in the forerigging, I saw a blue light on the water just ahead of 

the ‘Canandaigua’, and on the starboard quarter of the 

‘Housatonic’” (DON 1864a:0546–0547).5

Captain Joseph F. Green, commander of Canandaigua, dispatched his ship’s launches and ordered 

the removal of Housatonic’s surviving crew from the 

rigging. The following excerpt from Canandaigua’s 

logbook describes the rescue effort and its results: “at 

9:35, discovered her sunk with her hammock nettings 

underwater; dispatched all boats and rescued from 

the wreck 21 officers and 129 men. There are missing, 

and supposed to be drowned, the following-named 

officers and men: Ensign Edward C. Hazeltine, Captain’s 

Clerk Charles O. Muzzey, Quartermaster John Williams, 

Second-Class Fireman John Walsh, Landsman Theodore 

Parker” (ORN 1.15:328).

In the aftermath of its engagement with Housatonic, Hunley earned distinction as the first submarine 

to sink an enemy ship in combat. However, its victory 

was short-lived. Dixon and his crew failed to return 

to Sullivan’s Island. Federal forces were enraged by 

the loss of Housatonic, as evidenced by the average 

rate of artillery fire into Charleston, which increased 

five-fold within 24 hours of the attack. Colonel 

Laurence M. Keitt, Commanding Officer of Sullivan’s 

Island, recorded the number and frequency of Federal 

ordnance directed at the city between 10 February 

and 20 February 1864: 

Feb. 10, “nothing”

Feb. 11, “15 shots fired at City”

Feb. 12, “4 shell thrown in City by Enemy”

Feb. 13, no federal activity listed

Feb. 14, “3 at City by Enemy”

Feb. 15, “2 shells fired at Sull. Isl.”

Feb. 16, “Nothing”

Feb. 17, “13 shell fired at City”

Feb. 18, “86 shot fired at City by Enemy”

Feb. 19, “94 shots fired by enemy at the City”

Feb. 20, “106 shots fired at City”

(Keitt 1864)

The blockade fleet was shocked by the sudden 

turn of events. Dahlgren sent the following dispatch to 

5 While blue, red, green, and white lanterns were a standard part 

of night signaling, they were distinct from “blue lights,” which were 

bright, chemically-produced signals, generally burning in a wooden 

cup with a handle, used by both Union and Confederate forces in this 

period (Jenkins 1861:159–60). It is impossible to know if Flemming 

was referring to a blue light type signal or a fainter light with a blue 

tint, as he would have used the same phrasing in each case.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

36

Secretary Welles two days after the attack: “The Department will readily perceive the consequences likely to 

result from this event; the whole line of blockade will 

be infested with these cheap, convenient, and formidable defenses, and we must guard every point” (ORN 

1.15:329). He went on to suggest that Welles supply 

the blockade fleet with its own fleet of submersibles: 

“I am inclined to the belief that in addition to the various 

devices for keeping the torpedoes from the vessels, an 

effectual preventive may be found in the use of similar 

contrivances. I would therefore request that a number 

of torpedo boats be made and sent here with dispatch” 

(ORN 1.15:329). Dahlgren’s desire to learn more about 

Confederate submersibles is apparent in the closing 

sentence of his letter to Welles: “I desire to suggest to 

the Department the policy of offering a large reward of 

prize money for the capture or destruction of a ‘David;’ 

I should say not less than $20,000 or $30,000 for each. 

They are worth more than that to us” (ORN 1.15:330).

The Confederate garrison at Breach Inlet reported 

witnessing a signal from Hunley the night of the attack. 

It is possible that these men saw the same blue light 

reportedly observed by Flemming from Housatonic’s rigging, or perhaps the rockets fired from Canandaigua. Convinced that the light was a signal from 

the submarine, they answered it and awaited the 

tiny vessel’s return. Two days later, there was still no 

sign of Dixon and his crew. Battery Marshall’s garrison 

commander, Lieutenant Colonel O. M. Dantzler, thinking 

that the submarine might have drifted north, waited 

until 19 February before filing the following report: 

LIEUTENANT: I have the honor to report 

that the torpedo boat stationed at this post 

went out on the night of the 17th instant 

(Wednesday) and has not yet returned. The 

signals agreed upon to be given in case the 

boat wished a light to be exposed at this post 

as a guide for its return were observed and 

answered. (ORN 1.15:335) 

Confederate authorities in Charleston anxiously 

awaited news of the missing submarine and its crew. 

However, after another week passed, hope diminished 

for the vessel’s safe return. It was unclear whether 

Hunley had been captured or lost at sea. It was difficult 

to even verify whether the submarine had successfully accomplished its mission. News of the attack 

finally reached Charleston on 27 February. The crew 

of a Federal picket boat captured the previous evening 

related the story of the destruction of Housatonic to 

their captors. On 29 February 1864, an article in the 

Charleston Mercury described the loss of the Union 

blockade ship:

An official dispatch was received from 

Colonel ELLIOT at Fort Sumter, on Saturday, 

conveying the gratifying news that one of 

our picket boats, commanded by boatswain 

SMITH, had captured a Yankee picket boat 

containing one officer and five men. The 

prisoners have arrived in the city. Their 

accounts of the success of the pioneer of our 

fleet torpedo boats are really exhilarating. 

They state that the vessel sunk off the harbor 

on the night of the 16th, and reported lost 

in a gale, was the U.S. steamer Housatonic, 

carrying 12 guns and three hundred men, and 

that she was blown up by our torpedo boat.

. . . As a practical and important result 

of this splendid achievement, the prisoners 

state that all the wooden vessels of the 

blockading squadron now go far out to sea 

every night, being afraid of the risk of riding 

at anchor in any portion of the outer harbor. 

An article printed in the Charleston Daily Courier 

the same day added: “This glorious success of our little 

torpedo boat, under the command of Lieut. Dixon, of 

Mobile, has raised the hopes of our people, and the 

most sanguine expectations are now entertained of our 

being able to raise the siege in a way little dreamed of 

by the enemy.” 

Eventually, the Confederates learned that, in 

addition to destroying Housatonic, the crew of Hunley

avoided capture after the attack. Despite these good 

tidings, Dixon and the other members of the submarine’s crew never returned to tell their tale. Ultimately, 

the optimism expressed by the Charleston Daily Courier 

was short-lived, as Federal forces advanced throughout 

the South during 1864 and ultimately defeated the 

Confederacy. After Housatonic’s loss, the blockade 

fleet stationed off Charleston was never successfully 

challenged by rebel torpedo boats again. The siege of 

Charleston was never lifted, the blockade was never 

broken, and on 17 February 1865, precisely one year 

after Hunley’s successful attack, General Beauregard 

abandoned the city (ORN 1.16:369). 

The fate of the submarine and its crew of pioneering submariners was the subject of debate and 

conjecture for years after the vessel’s disappearance. 

Theories abounded: some speculated that it was 

mortally damaged by the attack and perished with 

Housatonic; others hypothesized that the vessel and 

its crew were swept out to sea during a gale that arose 

shortly after the engagement. Although many individuals and institutions searched for the tiny pioneering 

vessel, H. L. Hunley’s final resting place would not be 

discovered for 131 years. 
37

3. Environmental Context

M . S c o t t H a r r i s a n d R o b e r t S . N e y l a n d

The marine environment encompassing the H. L. 

Hunley site underwent several transformations over the 

course of 14 decades as a result of the interactions of 

geological, physical, chemical, and biological processes. 

While the wreck eventually stabilized after its burial 

beneath the seafloor, reconstructing how that came 

about provides important information for archaeological interpretation and conservation planning. To completely understand Hunley’s overall context, including 

artifact distribution and level of preservation, it is 

critical to interpret the complexities of site formation 

processes and their variability through time. The site 

developed over five critical phases: 1) the span of time 

prior to the submarine’s deposition on the seafloor; 2) a 

period of complete exposure of the sunken hull within 

the water column; 3) the burial process; 4) complete 

encapsulation of the submarine within the seabed; and 

5) excavation and recovery.

Data acquired during the H. L. Hunley and USS 

Housatonic surveys in 1996, 1998, and 2000 have all 

contributed to the environmental analysis (Murphy 

1998; Hansen et al. 2000; Conlin 2005). Research also 

included analysis of archival data for tides and currents, 

historic charts, geophysical remote sensing, and 

sediment coring, as well as visual observations made 

by project staff. Natural and anthropogenic alterations 

to the coastal zone—and the nearly infinite number of 

variables associated with them—played an important World Ocean Basemap from Esri, DeLorme, GEBCO, NOAA NGDC et al.

Figure 3.1. The Hunley site was located approximately 4 nautical miles (7.4 km) from the entrance 

to Charleston Harbor. Barrier islands are a significant feature of this part of the North American 

Atlantic coast. (Basemap from Esri et al., annotated by H. G. Brown, NHHC.)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

38

regional drainage systems. These larger systems are 

associated with rivers that originate in the Sand Hills, 

Piedmont, Blue Ridge, or Appalachian mountain chains. 

Rivers that empty into Charleston Harbor and its associated estuaries drain only the lower and middle coastal 

plains; consequently, freshwater discharge to the upper 

reaches of the estuaries is limited and seaward-reaching 

river delta formation is effectively eliminated. A small 

amount of freshwater discharge originates through 

aquifers, and surface recharge is likely on the barrier 

islands and along nearshore sections of the inner continental shelf. Currently, the Cooper River discharges into 

Charleston Harbor 151 m3

/s (Hughes 1994); by contrast, 

the Santee River to the north of Charleston Harbor and 

North Edisto River to the south have annual river discharges of 323 m3

/s and 74 m3/s, respectively.

Major regional physiographic features within the 

immediate vicinity of the Hunley site include active 

barrier islands, wide estuaries, Charleston Harbor, and 

a series of small inshore inlets (Figure 3.2). Moderate 

wave energy and mesotidal tide range (approximately 

2 m [6.56 ft.]) around Charleston Harbor has, over time, 

influenced the development of an abundance of deep 

inlets and a large, protected harbor within the barrier 

island system.

role in the development of site conditions prior to, 

during, and after the submarine sank. Analysis of these 

alterations provides insight into the physical site and the 

assemblage of materials and artifacts associated with it.

The Hunley wreck site was discovered approximately 4 nautical miles (7.4 km) ESE of the entrance 

to Charleston Harbor at a depth of 8–10 m (26.25–

32.81 ft.), depending on the tide, and buried beneath 

roughly 1 m (3.28 ft.) of sediment (Figure 3.1). The 

geology in the area is composed of a shallow, heterogeneous substrate resulting from a complex heritage. 

It was influenced by the availability and distribution of 

sediments within the marine system, long- and shortterm sedimentary evolutions of the area, and the deposition and burial of the submarine itself. Building on 

an understanding of the site context for both Hunley

and Housatonic provided by prior studies, a preliminary 

model of site formation was developed by considering 

the regional physiography, including the local barrier 

island systems, geological framework, and the impact 

of biological processes and human alterations to the 

environment. 

Regional Background

Physiography

The modern coastline in and around 

the Charleston area separates two distinct 

physiographic provinces: the lower coastal 

plain and inner continental shelf. The lower 

coastal plain, known locally as South Carolina’s Lowcountry, is a low and terraced 

region that originates 20 km (12.43 mi.) 

inland and drops in elevation from approximately 9 m (29.53 ft.) above mean sea 

level (MSL) to sea level at the coast. The 

emergent marine and estuarine terraces 

that characterize this zone were formed 

in response to successively lowered sea 

levels and repeated transgressions tied to 

glacial and interglacial periods throughout 

the Pleistocene Epoch (ca. 2.6 million 

to 11,700 BP). Due to ancient drainage 

patterns along the South Carolina lower 

coastal plain, the presence of terraces and 

poor drainage associated with this region, 

and the number of local sea-level changes, 

rivers are restricted almost entirely to 

Coastal Plain areas and are characterized by low annual discharge. This form 

of drainage reduces average annual river 

discharge to amounts significantly less 

than that commonly associated with larger 

Figure 3.2. Regional physiography of the area surrounding Hunley. 

The lower coastal plain and modern coastal environments are being 

submerged as the inner continental shelf expands to the northwest 

during sea level rise. The ancient deposits extending beneath the 

shoreline are exposed in the areas around the site (denoted with 

orange dot). (M. Scott Harris)
E N V I R O N M E N T A L C O N T E X T

39

Five km (3.11 mi.) offshore, the active shoreface 

gently dips to a depth of approximately 8 m (26.25 ft.) 

below sea level; between 6 and 8 km (3.79–4.97 mi.) 

from shore, the seabed steps down again to approximately 10 m (32.81 ft.) below sea level. Seabed ridges 

attached to the shoreface are common to the north 

and south of the site, particularly off Folly Island and 

Isle of Palms. Along the approximate 8 m (26.25 ft.) 

water depth contour, shoreface-attached ridges are 

not present and major seafloor features are largely 

oriented parallel to shore. Channel throats extend from 

the barrier islands straddling the shoreface inlets for 

a distance of approximately 1 to 2 km (0.62–1.24 mi.). 

Associated ebb-tidal deltas extend offshore for a 

distance of 1 to 5 km (0.6–3.11 mi.); these features 

create large masses of sediment that accumulate along 

the continental shelf. 

Harbor Entrance Changes

Prior to the 1880s, Charleston Harbor’s entrance 

was a difficult and circuitous path for ships to negotiate 

when entering or leaving port. At the time, the harbor’s 

large ebb-tidal shoals and delta extended approximately 

3 km (1.86 mi.) offshore, at which point they were 

forced south due to predominant longshore currents. 

Thus the primary entrance to the harbor developed well 

south of Morris Island (Figure 3.3). To improve navigation into the harbor, a pair of stone jetties was constructed between 1877 and 1895 (Moore 1981:32–36). 

The harbor entrance was thereby confined to 

a channel that extended directly offshore from the 

deepest portions of the harbor, resulting in a channel 

that extends to the southeast roughly 3 mi. (4.83 km) 

to an offshore water depth of approximately 14 m 

(45.93 ft.). As current and wave patterns shifted around 

this new obstruction, the harbor’s sediment discharge 

and accumulation shifted north to a zone directly 

offshore from the harbor entrance. 

Barrier Island Systems

The present day coastline is dissected by a series 

of inlets that separate classic mesotidally-dominated 

barrier islands (Hayes 1979). Moderate tidal range and 

moderate to low wave energy has created a series of 

classic drumstick-shaped barrier island complexes in 

this region. Backed by expansive salt marsh and tidal 

creeks, these barrier islands are separated by deep to 

shallow tidal inlets that, although locked in general 

position, have active ebb tidal channels that migrate 

frequently (Harris et al. 2005). The closest inlets to 

the Hunley site are Lighthouse Inlet to the south and 

Breach Inlet to the north, separated by the entrance 

to Charleston Harbor (see Figure 3.1). These inlets 

tend to be relatively shallow when compared to the 

Stono Inlet and Dewees Inlet systems, both of which 

are the dominant sandy sediment masses in the region. 

Marsh systems and shallow lagoons are responsible for 

retaining and releasing fine-grained sediments to the 

coastal ocean. Infrequent large-scale discharges from 

the inland rivers are the only means by which finegrained sediment is discharged onto the continental 

shelf. These sediment dynamics influence the outer 

reaches of the ebb tidal deltas and their associated 

shorelines. Shoreline changes associated with barrier 

islands and inlet positions also provide a means by 

Figure 3.3. Charleston Bar in 1864 (left) and in 1899 (right). The primary route to access the main 

shipping channel is indicated with a blue arrow. (Details from USCS 1864 and USCGS 1899)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

40

tocene, and Holocene materials, underlie the shallow 

nearshore continental shelf off Charleston. The older 

Tertiary strata consist of dense marls, foraminiferal sands 

and partially consolidated siltstones. These deposits 

crop out of the seafloor along a zone east of the 10 m 

(32.81 ft.) isobath. Younger Pleistocene-aged materials 

overlie the Tertiary deposits in an unconformable layer, 

and generally crop out of the seafloor between the 3 m 

(9.84 ft.) isobath (contour located inshore of the site in 

Figure 3.2) and the 10 m (32.81 ft.) isobaths (contour just 

east of the site). These Pleistocene deposits consist of 

unconsolidated sands, shelly sands, and muds created 

during former transgressive events.

Most of the localized stratigraphic exposures on 

the seafloor are composed of Cooper Marl (Tertiary), 

undifferentiated Tertiary shelf deposits, estuarine and 

marine Pleistocene units, and the modern Holocene 

sheet and wedge. These exposures are dependent on 

geologic heritage and modern sediment erosion-deposition patterns. Human intervention on the coastal system 

caused by construction of the jetties contributed to the 

creation of a sedimentary mass outside the outlet of 

the channel. 

In the modern Holocene system, sediments 

generally consist of fine to very fine sands interspersed 

which sediments are supplied or removed from the 

barrier islands and coastal systems. 

Geologic Framework

The Hunley site is situated on the inner continental 

shelf, along the western margin of the North Atlantic 

basin and is underlain by a thick wedge of predominantly marine, fluvial, and paralic (coastal) sediment 

deposits, which have accumulated since the Jurassic 

period. Near to the surface, three dominant geologic 

units underlie this region, all of which are internally 

heterogeneous and known to crop out in the vicinity 

of the site (Weems and Lewis 2002; Harris et al. 2005)

(Figure 3.4). The seafloor comprises a modern Holocene 

wedge inshore and exposed Pleistocene mud and sand 

just offshore. Partially indurated (cemented or lithified) 

deposits characterize the seabed in depths greater 

than 12 m (39.37 ft.). Older Tertiary units tend to be 

composed of semi-consolidated, phosphatic and foraminiferal sands and siltstones that form ledges and 

expansive hard grounds in water depths greater than 

9 m (29.52 ft.) below MSL. Pleistocene units deposited 

during one of several of the last interglacial periods are 

often composed of dense sticky mud (often misstated 

as marl or clay) and sand-filled fluvial and tidal channels. 

This dense estuarine mud crops out in water depths 

between approximately 4 to 10 m (13.12–32.81 ft.) 

below MSL and create a gentle platform or step that 

extends from beneath the modern offshore barrier island 

system. The third dominant geologic system is a Holocene 

sediment wedge that includes modern estuaries, barrier 

islands, ebb tidal deltas, linear rippled scour depressions, 

and offshore sand waves (Harris et al. 2005).

Within the immediate vicinity of the site, the 

dominant geologic strata at or near the seafloor range 

in age from the Tertiary period to modern (Figure 3.5). 

Cenozoic deposits, primarily comprising Tertiary, PleisFigure 3.4. A schematic representation of the 

stratigraphy beneath the site. The near surface 

units consist of three major depositional units or 

systems, each being quite heterogeneous in its sedimentological nature. Older Tertiary and Pleisotcene deposits commonly crop out at the seafloor in 

this area, and shell material at the seafloor may be 

modern or ancient reworked material. (Diagram 

by M. Scott Harris)

Figure 3.5. A generalized 

stratigraphic column of the 

area immediately surrounding 

the site. The Holocene 

sediments range from nonexistent on the shelf to very thick 

in ancient paleochannels. 

(Diagram by M. Scott Harris)
E N V I R O N M E N T A L C O N T E X T

41

with mud and shells, but frequently accumulate in 

un-conforming sediment combinations in response 

to varying environmental conditions. Materials at the 

seafloor, although recently deposited, may contain 

fossil shell and microfaunal constituents which behave 

as sediment particles in the modern system, creating 

a mix of both modern and ancient grains in the same 

sediment. One study of shell in beach sediment along 

the Atlantic coast of the United States found that 

approximately 60% of shell in beach sediment date 

from the Pleistocene (Wehmiller et al. 1995:326).

Biologic Framework

Biological processes can cause physical and 

chemical alterations to the environment that can either 

preserve or destroy cultural materials. Organisms can 

attach to or encrust the surfaces of artifacts, consume 

wood and other organics, burrow through and disturb 

soft overlying sediment, and remove oxygen creating 

an anaerobic environment. The type of potential biological activity relies on the sediments present, subsurface water flow, the local climate regime, and physical 

oceanographic processes acting in the area. This biogeochemical system created through the interaction 

of biological constituents on a system can potentially 

influence the acidity of a site and the oxygen content of 

the surrounding materials and hence the state of preservation of cultural materials on the sea floor. 

Site-Specific Analysis

Ultimately the state in which the submarine was 

recovered is related directly to the materials encasing it, 

the mechanisms that emplaced those materials, and the 

environmental variables in temperature and chemistry 

imposed on it through time. In general, elements of the 

marine environment that have influenced the preservation 

potential of the hull and its associated artifacts include 

a variety of physical, chemical, and biological processes. 

These processes, in conjunction with natural and anthropogenic materials within the marine realm, comprise a 

series of complex interactions that acted to preserve 

materials and their respective archaeological contexts. 

Conditions at the Time of Sinking

Understanding conditions on the night of the sinking 

provides an important basis for the interpretation of 

Hunley’s resting position and the subsequent processes 

affecting the site. Wind and tidal current information 

for the night of 17 February 1864 is difficult to obtain. 

Newspapers, during that time, did not publish regular 

weather reports or tidal information. The best information regarding environmental conditions at the time of 

the attack comes from USS Housatonic crewmembers’ 

accounts and entries made in USS Canandaigua’s log. 

During the court of inquiry concerning the attack, 

a number of crewmembers testified as to the weather 

and sea state. While there are some minor discrepancies in the details, the overall picture is one of a clear, 

cold night with moderate winds.

Acting Master John K. Crosby stated: “The wind was 

about NW by N; force 3. The tide was setting to N.E., 

about one knot per hour; the weather was clear, very 

bright moonlight” (DON 1864a:0501). Similarly, Ensign 

C. H. Craven recalled: “The sky was clear, with few 

clouds; little or no sea on; the weather good and the 

moon and stars shone clearly; a moderate wind from 

Northward and Westward” (DON 1864a:0512). Acting 

Master J. W. Congdon testified that “[t]he weather 

was fine, clear and bright moonlight; the sea was quite 

smooth; the wind was light and I think it was about 

N.N.W.” (DON 1864a:0521). 

General estimates for depth of water at the time of 

sinking range from 25 to 28 ft. (7.62–8.53 m). Congdon 

testified about the depth of water at Housatonic’s 

anchorage, that “[t]here was about twenty-five feet [7.62 

m] at low water, and she sank at about half flood” (DON 

1864a:0518). According to Lieutenant F. J. Higginson, “the 

sea was smooth; wind about N.W. force 2; it was about low 

water, and there was about 28 feet [8.53m] of water at her 

anchorage at low water” (DON 1864a:0537). Captain 

C. W. Pickering recalled the anchorage to be “26 or 27 

feet [7.29 or 8.23 m] at low water; it was a pleasant, 

moonlight night, with a fresh breeze and very cold; 

about half ebb tide, and 28 or 29 [8.53 or 8.84 m] feet 

of water” (DON 1864a:0584).

On 7 March 1864, at the conclusion of the inquiry, 

the court acknowledged the following facts: 

That the U.S. Steamer ‘Housatonic’ was 

blown up and sunk . . . at about 9 o’clock p.m., 

while lying at an anchor in 27 feet [8.23 m] 

of water off Charleston S.C. . . . The weather 

at the time of the occurrence was clear, the 

night bright and moonlight, wind moderate 

from the Northward and Westward, sea 

smooth and tide half ebb, the ship’s head 

about W. N. W. (DON 1864a:0588)

A 9:00 p.m. entry in Canandaigua ’s log for the 

evening of 17 February 1864 states the wind was from 

the NW at force 4 (DON 1863–4). The air temperature 

was recorded to be 44° Fahrenheit (6.7°C) at 6:00 p.m. 

The wind speed designation “force” refers to the 

Beaufort Wind Scale developed by Admiral Sir Francis 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

42

Beaufort in the early 19th century. The original scale 

was a qualitative estimate based on the effects of wind 

acting on the sails, with no quantitative measurement 

of wind speed. Wind of force 1 was designated as light 

air with just enough force to give a “well-conditioned 

man-of-war” steerage. By the Civil War, the Beaufort 

Wind Scale had been modified to reflect wind speed, 

with force 1 a wind speed of 1 to 3 knots, force 2 a 

wind speed of 4 to 6 knots, force 3 a wind speed of 7 

to 10 knots, and force 4 a wind speed of 11 to 16 knots.

Housatonic crewmembers reported the wind at 

the time of the attack as force 2 and force 3. Onboard 

Canandaigua, the six o’clock wind speed entry was force 

3 and the nine o’clock entry was force 4. With Canandaigua slightly over a mile away from Housatonic, one 

would not expect a significant difference in the wind 

speed. It appears that the wind speed was building as 

the evening progressed. Crewmembers onboard Housatonic may recall the calmer wind speed of the early 

evening, before the attack. Given the differing accounts, 

Canandaigua’s entry was probably more accurate.

Housatonic crewmember Crosby recalled that the 

tide was falling to the northeast at about one knot per 

hour. Additional crewmembers’ accounts place the 

tide somewhere between half ebb and low water. Tide 

or tidal current data for the precise time of the attack 

does not survive; however, an 1856 U.S. Coastal Survey 

chart contains a current rose from a position roughly 

one mile (1.6 km) west of the site, which shows the first 

quarter ebb flowing northeast, but the second and third 

quarter ebb currents turning southeast, the direction 

of Hunley’s orientation on the seabed (Figure 3.6). It is 

possible that Crosby was mistaken and was recalling the 

tide from earlier in the evening, prior to the attack. If 

it was running northeast at the time of the explosion, 

Hunley may have initially drifted in that direction, then 

been pushed southeast as the current shifted, provided 

they managed to stay afloat for some time afterward. 

The final position of Hunley almost directly east of Housatonic may support this interpretation. 

Once on the seabed, the submarine became part 

of a complex system of physical processes that would 

both alter it and protect it over the next 14 decades.

Physical Processes 

Coastal and estuarine processes influenced by 

climate are the dominant regional forces that acted on 

the Hunley site. These include coastline tidal exchanges, 

wave action and movement across the continental shelf, 

general wind fields, storm history, and sea level rise. 

Archival sources that record these attributes exist for 

much of the latter half of the 20th century; however, far 

fewer data are currently available for the years spanning 

1864 to 1940. Consequently, modern analysis and interpretation of the physical geological record recovered 

from the site complemented or, in some cases, acted 

as a proxy for data from historical records. 

Climate: Temperature and Precipitation

Hunley came to rest in waters located within the 

humid subtropical region of the western North Atlantic 

basin. Precipitation and temperature data have been 

collected for this area (identified as South Carolina Region 7 

by NOAA) since 1895 (NOAA 

2004). Between 1895 and 

2000, the average recorded 

temperature in this region 

was 18°C (65°F). Average high 

and low temperatures ranged 

from 27°C (81°F) in July to 9°C 

(48°F) in January. Precipitation 

amounts averaged 122 cm 

(48 in.) annually, generally in 

the form of rainfall. Single-year 

precipitation amounts ranged 

between a minimum and 

maximum of 70 cm (27.56 in.) 

and 180 cm (70.87 in.), respectively. The Charleston area 

receives more precipitation 

during the summer months 

due to thunderstorms and 

tropical events (tropical 

Figure 3.6. The positions of the Hunley and Housatonic wreck sites are shown in 

relation to the directions of wind and current at the time of the sinking. (Diagram 

by Alicia Massey and H. G. Brown; contains detail from USCS 1856)
E N V I R O N M E N T A L C O N T E X T

43

Figure 3.7. Number of hurricanes affecting the South Carolina area 

between 1864 and 2000. Positional data from NOAA compiled into a 

trackline density map for the region at 0.5-degree blocks. (Basemap 

by Esri et al., processed by M. Scott Harris) 

depressions, tropical storms, and hurricanes). Monthly rainfall amounts peak in 

March due to the passage of spring fronts. 

Precipitation affects stream and river 

flow and hence outgoing tides, sediment 

transport, and channel erosion. Offshore 

sedimentation is in part due to increased 

sediment transport. Changes in channels, 

either incision or filling, can result in 

movement of areas where sediment had 

previously accumulated. 

Temperature influences sedimentation 

through its effects on vegetation growth, as 

vegetation affects water run-off, river flow, 

and sediment transport. The dense vegetation of marshes and forests of coastal 

South Carolina is the product of the warm 

temperatures and humid climate. Much of 

the region’s rainfall is absorbed prior to it 

entering the river system. Flood events can 

result in excessive amounts of sediment 

transport and offshore deposition.

Winds, Storms & Hurricanes 

The Appalachian Mountains have a 

strong influence on the prevailing surface 

wind direction. The prevailing winds tend to 

be either from the northeast or southwest 

with average surface wind speeds between 

6 and 10 m.p.h. (9.66–16.09 kph). Cyclones 

occurring during the winter months usually 

pass to the south of the mountains and the 

winds are generally from the southwest 

but shifting to the northeast as they move out into 

the Atlantic. In summer, winds are from the south or 

southwest from the Gulf of Mexico. Autumn winds are 

from the northeast due to the effect of the mountains 

in forming the southern edge of the predominant continental high pressure pattern. This weather system 

moves southward along the eastern seaboard, fostering 

northeast winds circulating in a clockwise fashion. The 

Bermuda High can also contribute to air stagnation, 

usually during the summer. It is the semi-permanent 

subtropical high pressure area in the North Atlantic 

that moves east and west with varying central pressure. 

Displaced westward during the Northern Hemispheric 

summer and fall, the center is located in the western 

North Atlantic, near Bermuda. 

Tropical weather systems, including hurricanes, 

frequently pass over the region. A density plot of 

tropical storms and hurricanes reveals that approximately thirty-five recorded systems struck the region 

between 1864 and 2000 (Figure 3.7). Of these, two—an 

unnamed storm in 1893 and Hurricane Hugo in 1989—

had the strongest recorded winds and inflicted the 

most damage. Nor’easters, strong low pressure storm 

cells that develop off the East Coast, are typically not 

as powerful and frequent in the southeastern United 

States (especially when compared to those that strike 

the northeastern coast); however, their effect can be 

destructive, especially if a storm contains high winds 

for an extended period of time. One example of a 

Nor’easter that detrimentally impacted the Charleston 

area is the 1962 Ash Wednesday storm, which devastated the entire eastern seaboard.

Other severe weather systems, including shortlived thunderstorms, fast-moving tropical storms and 

hurricanes, and extratropical cyclones, are frequent 

along the South Carolina coastline during the spring, 

summer, and fall months. The most important influence 

on this coastline from storms is the interaction of the 

wave base on the seafloor, increased current flow along 

the coastline, and erosion of the near shore environment. It is possible these events increased sedimentation over the site, as evidence indicates sediment accumulation there with no periods of site erosion (Marot 

and Holmes 2005). 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

44

Coastal Processes: Tides, Currents, and Waves 

Dominant coastal processes that act upon the area 

surrounding the Hunley site are sea level rise, tides and 

tidal currents, and waves. These processes all interact 

to move the sediment from various sources and sinks. 

The Charleston area experiences a mixed semidiurnal 

tidal range. This includes a spring tide range and tidal 

extreme measuring approximately 1.7 m (5.58 ft.) and 

2.4 m (7.87 ft.), respectively (NOAA 1993). Offshore 

waters near Charleston typically exhibit slightly smaller 

tidal fluctuations; however, these fluctuations can 

undergo a rapid increase (or decrease) due to heavy 

winds, changes in barometric pressure, or surges associated with approaching storms. Because the tidal bulge 

passes through the waters off Charleston twice a day, 

local currents reverse on a daily basis. This creates two 

current surges for each tide, or four changes per day. 

Historic charts combined with records of shipboard 

observations provide an understanding of the tides as 

they existed in the harbor in the late 1850s (Figure 3.8). 

Slight variations in the ebb tidal shoals surrounding the 

natural harbor entrance would affect local tidal flows, 

but the overall patterns, prior to the jetty installation, 

should have been fairly consistent. The tidal wave—and 

subsequent tidal currents generated by it—responded 

to seafloor conditions present around a large ebb delta. 

Detailed bathymetry was conducted at several points 

along the harbor’s multiple entrance channels (USCS 

1858). Unfortunately, offshore observations, when 

available, were not comprehensive enough to complement the bathymetric data recovered inshore.

Installation of the jetties drastically changed the 

overall configuration of Charleston Harbor. As a consequence, tidal currents in the region have also changed, 

modifying the sediment dynamics. Over time, the 

alterations in these local tidal currents influenced the 

erosion and deposition of sediments in offshore zones, 

shifting the overall ebb tidal shield to the north and east 

over the Hunley site. By the end of the 19th century, the 

system reached a state of quasi-equilibrium with new 

hydrodynamic forces that were imposed on the existing 

environment. Likewise, dominant ebb and flood tides 

and tidal currents responded to the modified system. 

Sediment accumulations that normally would have 

been deposited at the mouth of the harbor and trending 

southward were now transported farther offshore, with 

some being forced to the north, 

within reach of the site, and 

some distributed south of the 

harbor entrance, influenced by 

the dominant wave climate and 

longshore currents (Figure 3.9).

Currents are integral to 

offshore sediment transport and 

the higher the current speed, 

the more sediment will be transported. This is particularly true for 

the larger and heavier sand grains 

and coarse shell. Current-transported sediment is influenced 

by the upward and/or settling 

velocities of the current flow. Individual particles of sediment vary 

in suspension within the flow, 

based upon size and weight and 

the force of the upward velocity 

on grains versus the force of the 

settling velocity. Currents offshore 

of Charleston under normal conditions are 10 to 26 cm/sec (.019–

0.51 knots) during flood and 36 

to 102 cm/sec (0.70–1.98 knots) 

during ebb currents. Flood usually 

occurs in a southerly direction 

and the ebb in a northeastwardly 

direction (NOAA 2005).

Compared to other regions in 

the United States, average wave 

size in the waters off Charleston 

Figure 3.8. The fourth quarter ebb current flow in the vicinity of the Charleston 

Harbor entrance depicted on 1870 Coast Survey chart (USCS 1870), with currents 

extracted from 1856 Coast Survey chart (USCS 1856). (Map annotations by M. 

Scott Harris). 
E N V I R O N M E N T A L C O N T E X T

45

are relatively small. This is largely attributable to the considerable length, width, and shallow depth of the continental shelf located to the east of the Hunley site. Significant wave heights recorded off Charleston between May 

1980 and December 1993 measured 1.3 m (4.27 ft.) (with 

a 5-second period) on average (NOAA 1998). Seafloor 

shears, when combined with significant wave heights and 

the relatively shallow depth of the wreck, results in fine 

sediment transport along the seafloor when wave height 

surpasses approximately 0.5 m (1.64 ft.). 

Sea Level Rise

When available, tidal gauge records are the best 

measure of sea level change for a particular region. 

Charleston, a large port city, has maintained a water 

level recorder in its harbor since approximately 1900. 

However, discrepancies exist in these data, including variations caused by potential dampening and sharpening of 

tidal measurements during storms and increased freshwater runoff conditions. Offshore tidal records, when 

compared to those of Charleston Harbor, reveal a strong 

correlation between the two data sets. In addition, a 

comparison of data collected from the Charleston 

Harbor and Isle of Palms tidal gauges indicates very little 

variation between inshore and offshore sites. Consequently, the Charleston Harbor tidal record can be used 

as a proxy for offshore measurements.

Sea levels around Charleston have risen approximately 0.3 m (1 ft.) since 1900 (Hicks 1978; Hicks et 

al. 1983). Using the trend back from 2000 to 1900, an 

extrapolated rise of slightly more than 0.4 m (1.3 ft.) is 

calculated. There is a record of strong sea level variation 

for the area, related to decadal changes in average 

barometric pressures and shifts in storm frequency. 

Many of these alterations relate directly to large-scale 

climatological changes that have occurred in the North 

Atlantic during the past 136 years. Sea level rise can 

cause long-term changes in coastal accretion and 

erosion patterns (Kana et al. 1984). 

Sediment Load

In addition to the jetties, another case of human 

alteration of the environment, specifically to the river 

drainage systems, may have increased the sediment 

load at the site. The diversion of the Santee River into 

the Cooper River for the generation of hydroelectric 

power in the late 1930s (completed in 1941) resulted in 

the unintended increase of current flow, sedimentation, 

and shoaling in Charleston Harbor (Kjefvre and Greer 

1978). This led to intensified offshore sedimentation as 

well as more frequent dredging in Charleston Harbor. 

To mitigate these periodic dredging requirements, a 

rediversion canal was implemented and completed in 

1985, sending most of the water flow back through the 

original Santee riverbed (Bradley et al. 1990:374–75). 

Historical Bathymetric Analyses

Bathymetric charts that depicted pre- and postjetty conditions were georectified to modern landmarks 

in the geographic information system ArcGIS 8.2. The 

georectification process required adjustments in 

longitude and latitude. Longitude exhibited the largest 

ordinate shift. Landmarks on the older charts shifted 

westward approximately 250 m (820 ft.). By contrast, 

adjustments in latitude rarely exceeded a few tens of 

meters. All of the landmarks’ locations shifted north. A 

systematic analysis of depth soundings depicted on the 

georectified charts identified the general bathymetric 

changes surrounding the Hunley site. According to an 

1864 chart (1863–5 bathymetry), water depth varied 

from 7.0 to 8.5 m (23–28 ft.) within 500 m (1,640 ft.) 

of the site. Recent (1997) charts depict much the same 

in terms of water depth, but since local sea levels have 

risen over 1 ft. (0.30 m) since 1864, it appears that at 

least an additional foot of sediment accumulated on 

the seabed around the submarine between 1900 and 

1997. Based on basic depositional trends, it appears 

that approximately 1.0–1.5 m ±1 m (3.28–4.29ft. 

±3.28 ft.) of sediment accumulated in this area from 

1864 to 1997.

Figure 3.9. Sediment distribution at the mouth 

of the jetties in 1900, showing build-up of 

delta-like conditions extending east toward 

the Hunley site. (Detail from USCGS 1900)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

46

Model of Site Formation

Hunley sank to the seafloor well north and east 

of the natural, pre-jetty ebb-tidal shield of Charleston 

Harbor. Analysis of sedimentological and geological 

data recovered during the initial phase of the submarine’s recovery, combined with information gleaned 

from historic and modern hydrographic charts, depth 

measurements, 210Pb analyses, and loci of encrusting 

organisms on the hull’s exterior, has enabled the 

development of two possible burial sequences. It is 

important to note that—in theory, at least—the thin 

Holocene sediment cover that characterizes the continental shelf surrounding the site should have prevented 

the submarine’s complete burial. Under normal conditions, the hull would have settled only 0.5 to 1.0 m 

(1.64–3.28 ft.) into the natural sand sheet; consequently, 

a sizable portion of the upper half of the submarine 

would have been exposed to the water column during 

the past century and a half. However, data derived 

from marine macrofauna (encrusting corals) on the 

hull, taken in conjunction with sediment accumulation 

rates at the site prior to excavation, suggest that the 

submarine remained buried from the end of the 19th 

century until its discovery in 1995. These findings are 

consistent with sediment transport that resulted from 

the creation and completion of jetties after the Civil War. 

There are two possible burial sequences (Figure 

3.10). Scenario 1 relies heavily on the presence of a 

scoured seafloor, with very little to no Holocene sedimentation at the site, and the submarine coming to 

rest directly on the dense Pleistocene mud bottom. 

Areas of exposed dense mud are not uncommon on the 

seafloor off the Charleston coast today, and charts from 

before the jetty installation show many readings of hard 

bottom rather than shell in the vicinity of the sinking 

site (USCS 1864). In this scenario, the submarine was 

gradually buried by accumulating sediment, primarily 

due to increased sediment load from the jetties. 

Scenario 2 is the most likely and is supported by bathymetric analysis and chart data, combined with existing 

sea level data. In this scenario Hunley came to rest on a 

thin Holocene sand layer, and was subsequently buried 

by a combination of the submarine’s natural tendency 

to settle into the sand, as it was scoured by currents 

and tidal action, and the gradual shift in the Charleston 

Harbor ebb-tidal delta. These events likely occurred 

simultaneously; the settling of the hull into the seabed 

was probably complete by the time the ebb-tidal shield 

had completely shifted northwards. It is interesting to 

note that had Hunley settled on the seabed approximately 50 m (164 ft.) farther to the southeast, it may 

have been buried 2–5 m (6.56–16.40 ft.) deeper in 

bottom sediment. This is because it would have come to 

rest in the sands of an ancient paleochannel rather than 

the dense Pleistocene mud layer common to the region. 

Figure 3.10. Two potential models of site formation. (Image by M. Scott Harris)
47

4. Previous Investigations

H a r r y P e c o r e l l i I I I

Contemporary Salvage Attempts 

(1864)

After the sinking of USS Housatonic and subsequent disappearance of H. L. Hunley, a marine diver 

in service with the U.S. Navy, William Churchill, led a 

search for the submarine. He convinced his superior, 

Lt. Commander A. W. Johnson, to request permission 

from Rear Admiral Dahlgren to salvage Housatonic

and uncover the torpedo boat (Quinn-Smith 2009:9). 

Having heard rumors about the submersible, Churchill 

was eager to see if he could find it. Dahlgren wanted to 

find Hunley to further the Navy’s submersible program 

and gave permission for Churchill to carry out his search 

in May 1864. 

Churchill filed a final report on 27 November 1864 

claiming that weather conditions had prevented him 

from fully salvaging Housatonic. His report went on 

to explain that “I have also caused the bottom to be 

dragged for an area of 500 yards [457.20 m] around the 

wreck, finding nothing of the torpedo boat. On the 24th 

the drag ropes caught something heavy (as I reported)” 

(ORN 1.15:334). He sent a diver down to examine it, but 

discovered it was only some rubbish on the seabed. In 

2002, archaeologists discovered a grapnel anchor dating 

from the 19th century in the same Pleistocene mud 

on which Hunley rested and only 5 m (16.40 ft.) from 

the hull (see Chapter 11). While no lost grapnel was 

specifically mentioned by Churchill, it may have been 

connected with his search efforts. It is also possible the 

object was simply lost from one of the many other ships 

active in the vicinity during or after the war. 

An article in the 1870 Charleston Daily Republican claims that Hunley had been discovered within 

the wreck of Housatonic. The boat was supposedly 

found with the remains of all if its occupants still 

inside. This false report likely originated from diving 

activities related to the demolition of Civil War-era 

wrecks around Charleston harbor; however, no further 

work was carried out to confirm the alleged discovery 

(Chaffin 2008:209). The matter seems to have been put 

to rest when work was done between 1908 and 1909 to 

lower the profile of the wreck, which was considered a 

hazard to navigation. Newspaper reports on the project, 

as well as the final report from the U.S. Army Chief of 

Engineers, included no indication that Hunley had sunk 

there (Conlin 2005:43–44). 

Early Claim (1970)

In November 1970, Edward Lee Spence (1995:37) 

found a “cylindrical object which formed an unnatural 

shelf or ledge in the sand” with “raised marks of hand 

hammered rivets.” He requested permission from 

the General Service Administration (GSA) in 1974 to 

salvage the wreck, but was denied due to historic preservation laws: “In view of the legal questions involved 

concerning the Antiquities Act and the formulation of 

the guidelines previously mentioned, we are holding 

in abeyance the issuance of any contracts covering the 

raising of sunken vessels” (Herman 1974).

The Navy was also notified of his discovery during 

this process. Believing he had discovered Hunley, Spence 

filed papers on 7 July 1981 with the U.S. District Court 

for the District of South Carolina Charleston Division 

to claim Hunley (Civil Action #80-1303-8). However, 

the find was never authenticated by any government 

agency or independent archaeologist on site. During the 

interceding decade, Spence published several articles 

advertising his claim to the public. Several proposals 

were made for expeditions to confirm the identity of 

this wreck, including one that was to be led by National 

Geographic.

It is possible that Spence’s target was actually a 

sunken navigation buoy that once might have marked 

the wreck of Housatonic and was documented in 1999 

when magnetic anomalies surrounding the sunken ship 

were investigated (discussed below). The iron buoy was 

partially exposed, with a curved side rising a few inches 

above the sea floor, and was of riveted construction. 

Hunley was constructed with rivets flush to the outside 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

48

Carolina. The search began with an extensive investigation of archival sources. These records helped Cussler’s 

group establish two high probability search areas 

(Figure 4.1). Operating on the assumption that the 

submarine made it back to shore, NUMA developed one 

search area in shallow waters just offshore of Breach 

Inlet. The second search area was established on the 

assumption that the submarine suffered damage during 

the attack on 17 February 1864, and was located in the 

vicinity of the wreck of Housatonic. 

NUMA deployed a proton-precession magnetometer (in conjunction with a Loran positioning system) 

from a rubber zodiac boat and surveyed a 1 mi. 

(1.61 km) wide by 3 mi. (4.83 km) long zone parallel 

to the beach at Breach Inlet. The search area near the 

wreck of Housatonic measured 2 mi. (3.22 km) wide 

by 2.5 mi. (4.02 km) in length. All survey operations 

associated with the latter survey zone were conducted 

aboard NUMA’s research vessel. A total of four 

anomalies were detected during investigation of both 

survey areas. One anomaly, discovered in the Breach 

Inlet survey area, was disregarded because it lacked the 

magnetic intensity expected of a large iron object like 

surface, while Spence described feeling raised rivets, a 

feature present on the buoy. In addition, lead isotope 

analysis of sediment samples around Hunley’s hull 

shows that once it was buried it had not been uncovered 

after its initial burial until the 1995 discovery (Moore 

1998:160–61). While Spence’s coordinates, published 

on his website, are known to be within several hundred 

meters of Hunley’s actual location, both the buoy and 

Housatonic lie within this radius as well. This combination of factors makes it likely that Spence discovered 

the buoy, and not Hunley, in 1970.

First NUMA Search for H. L. Hunley

(1980)

Author Clive Cussler founded the organization 

National Underwater Marine Agency (NUMA) in 1978 

for the sole purpose of locating America’s historic shipwrecks. In 1980, NUMA initiated a comprehensive 

search for Hunley in the waters off Charleston, South 

Figure 4.1. Map showing Charleston Harbor and 1980 NUMA search areas. (NOAA Chart 11521, 

annotated by Alicia Massey, NHHC)
P R E V I O U S I N V E S T I G A T I O N S

49

Hunley. The remaining anomalies were detected in the 

offshore survey area. These were later determined to 

be scattered ferrous objects associated with Housatonic

(Browning and West 1982).

Second Search for H. L. Hunley 

(1981)

NUMA researchers returned to Charleston in June 

of 1981 to continue the search for Hunley. The new 

survey was conducted in conjunction with the South 

Carolina Institute of Archaeology and Anthropology 

(SCIAA), and expanded to encompass a rectangle 3 mi. 

(4.83 km) wide by 5 mi. (8.05 km) long (Figure 4.2). 

The new area extended from Breach Inlet to an area 

immediately southeast of the wreck of Housatonic. Due 

to time restrictions, NUMA was forced to reduce the 

original 15 sq. mi. (38.85 km2

) search area to 8 sq. mi. 

(20.72 km2

). The 1981 survey employed the use of two 

separate teams; one was solely responsible for remotesensing operations, while the other consisted of divers 

that attempted to identify the targets acquired by the 

remote-sensing team. 

The NUMA/SCIAA team surveyed the search area 

by establishing multiple transect lines parallel to the 

beach spaced at 30 m (98.43 ft.) intervals. The survey 

team positioned all transects and anomalies with 

a Motorola Mini-Ranger III line-of-sight pulse radar 

tracking system. The Mini-Ranger system incorporated 

the use of two onshore transmitters—each placed at a 

known location—and a receiver station on the survey 

vessel. The Mini-Ranger console, located at the crew’s 

headquarters, computed the position of the survey 

vessel as it operated offshore. Course corrections 

were radioed to the survey vessel by CB radio, which 

increased the accuracy with which each survey lane was 

executed.

Ferrous targets were detected using an Elsec proton 

magnetometer. The magnetometer sensor was towed 

50 ft. (15.24 m) behind the survey vessel. As magnetic 

anomalies were detected, the verbal message “target” 

was radioed to the Mini-Ranger operators onshore. 

The operators in turn assigned and plotted coordinate 

Figure 4.2. Map showing Charleston Harbor and 1981 NUMA search areas. (NOAA Chart 11521, annotated 

by Alicia Massey, NHHC)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

50

garded as potential Hunley candidates because probing 

gave the appearance that they were much larger than 

they actually were. However, SCIAA staff did partially 

excavate and expose one of the targets and determined 

that it was the remains of a wooden vessel (Hall 1995:8). 

Discovery of H. L. Hunley (1995)

Throughout the spring of 1995, Clive Cussler 

employed Ralph Wilbanks and Wes Hall to continue 

searching for Hunley. When not working on other 

contract obligations, Wilbanks and Hall surveyed an 

ever-expanding portion of Charleston Harbor. During 

one magnetometer survey, they detected a sizable 

target. The magnetic signature produced by the 

anomaly was similar to what Wilbanks expected from 

Hunley. Wilbanks and Hall enlisted the aid of Harry 

Pecorelli III to investigate the target. On 3 May, Wilbanks 

anchored his survey vessel Diversity over the target 

locale. As the junior member of the team, Pecorelli was 

first in the water. The object that produced the large 

magnetic signature was an early 20th century ship’s 

windlass covered with anchor chain. Wilbanks, Hall, 

and Pecorelli, after identifying this anomaly, reviewed 

notes from the 1994 survey and decided that they 

should properly identify the targets located during the 

1980 and 1981 field seasons, rather than expanding the 

search area. 

Wilbanks and Hall selected the target with the most 

likely magnetic signature. Wilbanks approached the 

target from three different directions and marked the 

strongest magnetic intensity with a buoyed concrete 

cinder block. Once Diversity was anchored over the 

anomaly, Pecorelli went down to locate and identify it. 

Pecorelli was attached to one of the marker buoys by a 

search line and began probing toward the other marker 

buoys. He pushed a 1⁄4 in. (0.64 cm) diameter stainless 

steel probe 3 ft. (0.91 m) into the sand, where a dense 

layer of shell stopped it. Working the probe through the 

shell layer, Pecorelli detected a metallic surface. Next, 

he probed side-to-side and front-to-back to determine 

the orientation of the object. It was cylindrical, with an 

approximate width of 4 ft. (1.22 m) and length of 35 ft. 

(10.67 m). 

Water visibility on site ranged from zero to 1 ft. 

(0.30 m) and a moderate current was present. Pecorelli 

located a portion of the object that was the least deeply 

buried and stuck the probe in the sand next to it to 

mark it. After securing the search line to the probe, 

he followed the search line back to the marker buoy 

and up to the boat. Returning to the site with a water 

induction dredge, he excavated a conically-shaped test 

unit, and exposed a 1 ft. (0.30 m) diameter portion 

of the surface of the object before the need arose to 

data for each locality. A total of 19 magnetic anomalies 

were recorded using this system. Of these, seven 

exhibited the magnetic intensity expected for Hunley

(Hall 1995:6).

The dive team employed a combination of the MiniRanger system and a Schonstedt Instruments gradiometer 

to position the dive vessel in the vicinity of each target. 

Initially, divers would investigate a target to determine 

whether portions of it were exposed above the seabed. 

In instances where the target was completely buried, 

divers probed the bottom with 6 ft. (1.83 m) steel rods 

to determine its shape, size, and material type. If an 

anomaly exhibited characteristics consistent with those 

anticipated for Hunley, the sand overburden covering 

it was removed with an airlift. Of seven targets exhibiting the expected magnetic intensity, four were investigated. The four targets were individually identified as: 

1) the remains of Housatonic; 2) a 20th-century wooden 

vessel; 3) a buried wooden vessel of undetermined 

date; and 4) a torpedo-shaped iron cylinder. Divers were 

not able to identify the iron cylinder but determined 

that it was not Hunley. During the target investigation 

phase of the survey, the dive team conducted 57 dives, 

totaling 39 hours and 25 minutes. 

Third Search for H. L. Hunley (1994)

NUMA teamed up with SCIAA for a second time and 

returned to Charleston in 1994. The primary focus of 

this survey was to further investigate the seven targets 

located during the 1981 survey. NUMA relocated six 

of the seven targets; a shrimp trawler had moved the 

seventh from the area during the intervening period 

(Hall 1995:7). The shrimpers that reportedly snagged 

this object were unable to identify it. 

As soon as the six targets were relocated, NUMA 

resumed remote-sensing operations. Equipment used 

during this phase of the search included a Geometrics 

866 proton-precession marine magnetometer and a 

531-T 500 kHz Klein side-scan sonar. A NavStar Differential Global Positioning System, used in conjunction with 

Coastal Oceanographics HYPACK survey software was 

used to position targets and acquire data. The HYPACK 

system enabled NUMA to establish pre-planned parallel 

survey lines using 100 ft. (30.48 m) lane spacing, significantly expanding the 1981 survey area.

SCIAA underwater archaeologists were responsible 

for identifying the six targets located during the 1981 

survey. All targets were deeply buried in the seabed 

and required extensive probing. A thick shell lens 

buried approximately 3 feet (0.91 m) below the bottom 

hampered the probing process. Initially, SCIAA archaeologists thought that the shell lens represented a solid 

object; consequently, many of the targets were disre-
P R E V I O U S I N V E S T I G A T I O N S

51

resurface and change 

scuba cylinders. On 

the next dive, Hall 

expanded the hole 

to an approximate 

diameter of 3 ft. 

(0.91 m). Enlargement of the excavation area exposed 

the forward hatch, 

snorkel box, and a 

portion of the port 

diving plane. Identification of these 

features confirmed 

that the anomaly represented the remains 

of Hunley. Fortunately, the initial 

test excavation was 

placed immediately 

adjacent to the most 

diagnostic features 

on the submarine’s hull. The unit was quickly backfilled 

and the team returned to shore.

On 7 May 1995, Wilbanks, Hall, and Pecorelli 

returned to the site to document their discovery on 

videotape. Wilbanks had contacted Clive Cussler the 

previous evening, and Cussler requested that the find 

be substantiated on film. The team re-excavated the 

test unit and videotaped the forward hatch, snorkel 

box, and the port diving plane (Figure 4.3). The video 

evidence was presented two weeks later at a press conference held at the Charleston Museum.

H. L. Hunley Site Assessment (1996)

In May 1996, the National Park Service’s Submerged 

Cultural Resources Unit, now the Submerged Resources 

Center (SRC), Naval Historical Center (NHC), and SCIAA 

conducted a site assessment of the USS Housatonic/H. L. 

Hunley engagement site (Murphy 1998). This assessment served two purposes: 1) to confirm NUMA’s 1995 

discovery of Hunley and; 2) determine its state of preservation and gather information to assist those responsible for planning its management and possible recovery.

The assessment began with a comprehensive 

remote-sensing survey that encompassed the area comprising both the Housatonic and Hunley sites. The survey 

utilized a variety of equipment, including a Geometrics 

G-876 proton-precession magnetometer, Marine Sonic 

Technology side-scan sonar with a 600 kHz towfish, differentially corrected Trimble Navigation Accutime II GPS, 

and an EdgeTech X-Star digital sub-bottom profiler. 

T h e re m o te 

s e n s i n g s u r vey 

located the remains 

of the two vessels 

as well as a number 

of smaller, nearby 

ferrous objects 

(Murphy 1998:60). 

Although these 

latter targets were 

not investigated at 

the time, their close 

proximity suggested 

a possible association with one or 

both wreck sites, 

and were slated 

for further investigation (discussed 

below). Immediately 

following the conclusion of the remote 

sensing sur vey, 

underwater archaeologists from SRC, SCIAA and NHC 

excavated and exposed the entire upper surface of the 

submarine in order to confirm the vessel’s identity as 

well as collect data on its physical condition and surrounding environment. Additionally, project archaeologists wished to acquire preliminary data that addressed 

Hunley’s site formation processes. 

USS Housatonic Site Assessment and 

Investigation (1999)

In the summer of 1999, archaeologists from NHC, 

SRC, SCIAA, and the U.S. Geological Survey conducted a 

limited investigation of the buried remains of USS Housatonic. The project commenced with a series of 

3 in. (7.62 cm) diameter vibracore sediment samples 

collected from the seabed in the immediate vicinity of 

Housatonic and Hunley. Following the sampling phase of 

the project, the multi-agency team conducted a remote 

sensing survey to complement the results of the 1996 

survey. The new survey focused primarily on recording 

site-specific seismic and sonar data. Using an Applied 

Acoustic AA200 sub-bottom profiler system, Edge Tech 

Geo-Star FSSB CHIRP system, and Edge Tech 272 TD 

side-scan sonar, data was collected from a variety of 

points throughout the entire engagement site. 

Ground-truthing operations located the remains 

of Housatonic beneath approximately 6 ft. (1.83 m) of 

sediment (Conlin 2005:66–67). Archaeologists using 

water jet probes delineated the wreck site. In addition, 

Figure 4.3. Screen capture from NUMA’s 1995 video footage of the 

site. Distinguishing features such as the snorkel box helped build 

confidence that the vessel was indeed Hunley. (Courtesy of NUMA)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

52

three test trenches were excavated at specific points 

on the wreck where significant structural remains and 

archaeological features were anticipated to be present. 

Numerous diagnostic artifacts were recovered during 

excavation of these trenches. 

In addition to work at the Housatonic site, the team 

investigated the two nearby magnetic targets located 

in 1996. The first target, dubbed “Anomaly #3,” was 

situated midway between the two wrecks, and appears 

to be the remains of an old navigation buoy (Figure 4.4). 

This object was partially exposed above the seafloor 

and a preliminary excavation revealed it to be a large, 

roughly cylindrical, riveted iron object, approximately 

7 ft. (2.13 m) in length with a maximum diameter of 

8.58 ft. (2.62 m) (Conlin 2005:78–80). A dive weight 

and cable were found wrapped around the narrower 

portion of the object, buried just under the mud-line, 

an indication of previous activity by divers on the site. 

While historic charts indicate the Housatonic wreck was 

marked by a nun buoy beginning in 1901 (USCGS 1900, 

1901), followed by a bell buoy between 1906 and ca. 

1912 (USCGS 1906, 1912, 1914), the anomaly does not 

conform to either of those buoy types. U.S. Coast Guard 

Historian Dr. Robert Browning reviewed the data and 

found the object most resembled the remains of a gas 

or gas-and-whistle buoy from the 1920s or early 1930s. 

Due to the site’s proximity to the shipping channel, it 

is likely the buoy was struck by a vessel, and drifted 

toward the Hunley-Housatonic site as it sank (Browning, 

pers. comm.). It is possible this is the same cylindrical 

object identified as Hunley by Lee Spence, described 

above. The second target, documented as Anomaly #4, 

was identified as a small Admiralty-type ship’s anchor 

with open-link chain (Conlin 2005:80–81). 

Figure 4.4. Diver sketch of possible sunken navigation buoy between USS 

Housatonic and Hunley sites. (Murphy 1998:78)
53

5. Project History

R o b e r t S . N e y l a n d

After its discovery, there was almost immediate 

interest in recovering Hunley. State authorities and 

maritime archaeologists were concerned over the wreck 

site being looted. The Navy and the recently-formed 

South Carolina Hunley Commission (SCHC) agreed to 

keep the coordinates secure and confidential. Shortly 

after the discovery and at the request of Senator Ernest 

Hollings (D-SC), a Regulated Navigation Area (RNA) 

was created around the site. This prohibited anchoring, 

salvaging, dredging, and diving. A commitment was made 

by the General Counsel of the Navy Steven S. Honigman 

to Senator Strom Thurmond (R-SC), then Chairman of the 

Senate Armed Services Committee, to protect the site 

from unauthorized visitation (Neyland and Amer 1998:7).

In order to honor this commitment, the Navy’s 

Space and Naval Warfare Systems Command (SPAWAR) 

Atlantic placed security video and infrared cameras on 

Sullivan’s Island Lighthouse. These were monitored by 

base security at Naval Weapons Station Charleston. If a 

violation was observed, the base security would alert 

the U.S. Coast Guard (USCG) Sector Charleston, who 

then would send out a USCG boat to investigate 

(Neyland 1998). 

These procedures were successful in keeping 

interlopers off the site. However, that was not a viable 

long-term solution for managing the site. With rumors 

spreading of high cash rewards being offered for parts 

of the submarine, increased concern over looting 

prompted the Navy to investigate options for safely 

recovering the vessel, which represented a unique and 

significant milestone in naval history (Dudley 1998). 

Determining what happened to the submarine and 

the crew and returning the remains to Charleston also 

influenced the decision to recover the submarine. The 

story of the submarine and its crew is closely tied to 

South Carolina’s history. Hunley had become part of the 

City of Charleston’s identity and a Civil War icon, which 

stimulated the drive for its recovery. 

Figure 5.1. Friends of the Hunley board members, staff, and volunteers at the Warren Lasch Conservation 

Center in North Charleston. (Courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

54

Friends of the Hunley

 The Friends of the Hunley, Inc. (FOTH) was created 

in 1997 as a 501(c)(3) corporation by the SCHC, which 

also appointed all board members (Figure 5.1). That 

same year, Warren Lasch agreed to be chairman at the 

encouragement of South Carolina state senator Glenn 

McConnell, SCHC Chairman, and Rear Admiral William L. 

Schachte Jr. USN (ret), a governor-appointed member of 

the commission. FOTH’s mission as stated in their director’s handbook was to procure charitable donations for 

the raising, restoration, and preservation of the Hunley

submarine, manage and expend procured funds as 

needed to advance the raising, restoration, and preservation of Hunley and related artifacts, and to perform 

all necessary or desirable actions, incident to the abovestated purposes. 

The board consisted of both voting directors and 

non-voting ex officio members. The initial board of 

directors totaled eight and included Chairman Lasch; 

George Bell of Bultman & Bell Insurance; Clive Cussler 

of NUMA; Robert Evans of the law firm of Sterne, Agee 

& Leach, Inc.; the Honorable Harry Hallman, Mayor of 

Mount Pleasant; Dr. Charlie Peery, Charleston obstetrician and owner of a rare Confederate naval collection; City of Charleston Mayor Kenneth Riley; and 

Greenville businessman James D. Cockman. Ex officio 

members included Senator Thurmond; Representative 

Floyd Spence (D-SC-2); and Ted Turner, President and 

CEO Time Warner, Inc. (Tapp 1999:i–3). Lasch, with the 

help of Schachte and Thurmond, recruited Dr. Robert S. 

Neyland, Head of Underwater Archaeology at the NHC, 

in 1998. The Navy agreed to allow Neyland to work on 

the project through the South Carolina Department 

of Archives and History (SCDAH) on loan under the 

Intergovernmental Personnel Act. As Project Manager, 

Neyland assisted SCHC and FOTH in project planning 

and personnel recruitment.

Ultimately, FOTH would be integral to the recovery 

and preservation of Hunley, particularly through its 

ability to manage and expend money and negotiate 

contracts. Lasch brought considerable business acumen 

to the organization. His leadership was essential to 

keeping both the recovery operation and the renovation of the building that would become the conservation laboratory on schedule. 

Hunley Oversight Committee 

The Hunley Oversight Committee (HOC) was 

developed from a working group formed by the Navy in 

1995, shortly after the discovery of Hunley, in response 

to a number of recovery proposals that very quickly 

began to circulate after the news was announced. The 

body was primarily intended to assist in peer review of 

these documents. 

Course to Recovery: Partners and 

Agreements

The state and federal jurisdiction over Hunley

was resolved and a Programmatic Agreement (PA) 

was signed in August 1996 (Neyland and Amer 1998). 

The PA stipulated the roles of the principal state and 

federal agencies involved in the Hunley recovery and 

provided the administrative way forward. The parties 

to the agreement were the SCHC, which was created 

by the South Carolina State Legislature with members 

appointed by both the legislature and the governor, and 

the South Carolina State Historic Preservation Office 

(SHPO), which was under South Carolina Archives and 

History Division. Parties on the federal side included 

General Services Administration (GSA), Department of 

the Navy represented by Naval Historical Center (NHC, 

now Naval History and Heritage Command), and the 

Advisory Council for Historic Preservation (ACHP). In 

summary, the PA provided agreement between the consulting parties and the framework for undertaking the 

recovery of Hunley while providing the highest standard 

of protection under the National Historic Preservation 

Act (16 U.S.C. 1470). 

The agreement required anyone wishing to investigate or raise Hunley to submit detailed and adequate 

plans for the endeavor. The personnel involved in any 

such effort had to be qualified underwater archaeologists and conservators. Hull and artifact stabilization 

and conservation had to be provided for before any 

recovery effort could commence. The human remains 

would be treated with dignity, respect, and honor. The 

SCHC would be given the lead on preparing a plan for 

burial of the crew. All proposals would be reviewed 

by those party to the PA and by a committee, designated the Hunley Oversight Committee (HOC), made 

up of professionals and experts in the fields of underwater archaeology and conservation, including representatives from the Department of the Interior, GSA, 

the National Oceanic and Atmospheric Administration 

(NOAA), the Smithsonian Institution, and ACHP.

The submarine and associated artifacts would 

remain federal property and the Navy as the federal 

property manager would oversee their disposition to 

the appropriate institution via loan agreement. In turn, 

the federal agencies agreed that the artifacts could 

remain in South Carolina on indefinite loan as long 

as they were professionally curated and preserved in 

compliance with federal standards (36 CFR 79). SCHC 

would manage the intellectual property to defray the 

cost of recovery and preservation. The Navy was not 

obligated to any funding by the agreement, although 

the federal government would eventually contribute 

a significant level of funding through the DOD Legacy 

Resource Management Program for both the recovery 

and conservation. 
P R O J E C T H I S T O R Y

55

The first working group meeting was held on 

22 August 1995 to discuss the draft programmatic 

agreement and methods of public and state involvement, which at that time included both the states of 

South Carolina and Alabama. The group also reviewed 

the two proposals for recovery described below. Both 

were lacking in sufficient details and were submitted 

prior to the conclusion of negotiations regarding 

ownership and management. Present at the meeting 

were Navy representatives Dr. William S. Dudley, CDR 

Joseph Thomas, Robert R. Rossi, CAPT James K (Otto) 

Orzech, and Neyland. The National Park Service (NPS) 

was represented by E. C. Bearss and Kevin Foster. ACHP 

representatives included Valeria DeCallo, Druscilla Null, 

and Ralston Cox. The federal owner of the property, 

GSA, was represented by Property Division personnel 

Bill Tesh and Dona Gamble. Other federal officials were 

Dr. Paul F. Johnston, Smithsonian Institution; Ole Varmer, 

NOAA; and Caroline M. Zander, Department of Justice. 

In addition, peer reviewers included Bruce Terrell, NOAA 

Sanctuaries and Reserves Division; Dr. John Broadwater, NOAA USS Monitor National Marine Sanctuary; 

Colin Wagner, GSA Federal Preservation Office; Dan 

Lenihan, NPS-Southwest Regional Office; and Dr. Donny 

L. Hamilton, Nautical Archaeology Program Texas A&M 

University. These agencies and many of the same individuals would also participate in the review of the final 

Hunley recovery and conservation plans. 

Two proposals were submitted in 1995 hard on 

the heels of Hunley’s discovery, both of which were 

reviewed by the working group. The first was submitted 

by the SCIAA, which pointed out it was the state’s regulatory authority for underwater antiquities and, as 

such, its role required it to ascertain the location and 

manage sites within state waters (Leader 1995). Subsequent review of the coordinates, however, proved the 

site lay in federal, not state, waters. This proposal was 

still in the preliminary phase, as the recovery method 

was not outlined in detail, and reviewers had concerns 

about the chosen conservation methods and that no 

secure sources of funding had been established. No 

revised document was submitted by the organization. 

The second proposal was submitted by the Rescue 

Company of Rescue, Virginia, in September 1995. The 

plan included specialists in maritime archaeology, conservation, corrosion engineering, salvage, forensic 

anthropology, and history. Although relatively brief, it 

was a multifaceted approach that included all aspects 

of the project as well as fundraising and exhibition. 

Nevertheless, it lacked the level of detail required to 

fully approve the project. In addition, with the PA still 

in preparation, the authorizing parties were not yet in 

a position to commit to a way forward. 

When the PA was finalized, the working group 

became known as the Hunley Oversight Committee, 

though it remained an informal advisory body of federal 

subject matter experts directed “to provide guidance on 

the management of the Hunley” (DON 1996). From its 

very outset, the committee provided valuable expertise 

and insight in reviewing further proposals received by 

the Navy, and it continued to help shape the recovery 

plans with their advice, questions, and concerns. 

Laying the Groundwork: Studies 

and Plans

Originally it was thought that the way to proceed 

would be to generate a Request for Proposals (RFP) 

and publish the RFP in the federal register to entice 

contractors and appease competing groups. However, 

there was no precedent for the recovery of a Civil War 

submarine and many unknowns were evident regarding 

its state of preservation and the safest method for 

lifting it, as well as what to do in regards to conservation and excavation of the submarine’s interior once it 

was brought to shore. It was also apparent that even 

if proposals were submitted, it would be difficult to 

evaluate them without some basis for understanding 

what options were realistic. What was needed was a 

feasibility study that would determine the parameters 

for a recovery system. 

Option Study

The Navy’s Supervisor of Salvage (SUPSALV) had an 

indefinite delivery contract with Oceaneering Advanced 

Technologies, a division of Oceaneering International, 

Inc. (OII) for maintenance and development of the 

Navy’s deep-water remotely operated vehicles and 

advanced engineering services. Neyland worked with 

SUPSALV and Leonard Whitlock, OII’s program manager 

on this contract, to facilitate the Hunley recovery 

option design study, which was supported by DOD 

Legacy Resource Management funding. Steve Wright 

of OII was assigned to the study. Initial discussions concerning design options were conducted with NHC UAB 

personnel and NPS archaeologists Dan Lenihan and 

Larry Murphy.

OII’s “Preliminary Study for the Recovery of the H. 

L. Hunley,” submitted in August 1999, was fundamental 

to the mission. It provided a systematic evaluation of all 

potential lift methods with a recommended best option, 

as well as an important cost analysis to the rough order 

of magnitude (ROM). It was not intended to be a final 

plan but to provide a guide as to the best option for 

recovery and the basis for initiating an RFP. OII eventually was requested to fully develop this plan in order to 

meet a 2000 recovery goal set by the SCHC and FOTH, 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

56

Parcs Canada in Montreal, Jefferson Patterson Park and 

Museum, Maryland, and Texas A&M University Conservation Research Laboratory, College Station, Texas. 

The information gathered from touring these facilities 

and talking with the conservators was beneficial to the 

design team.

With a solid understanding of laboratory requirements in place, the search for an appropriate location 

for Hunley’s conservation was narrowed down to two 

possibilities—a new wing at the Charleston Museum, 

which would require design and construction, or 

Building 255 at the former Charleston Naval Shipyard 

in North Charleston, which had been built as a Navy 

warehouse but never occupied, due to closure of the 

shipyard by the Base Realignment and Closure Commission in 1996. As discussions progressed between SCHC 

and Charleston city and county officials, it was determined that Building 255 would be the best location 

for a conservation laboratory, since the structure was 

already built, it was located in an industrial area with 

access to the Cooper River, and had the requisite floor 

load capacity for supporting the conservation operation. 

It was apparent that an expansion of the Charleston 

Museum, which was adjacent to a historic residential 

area in downtown Charleston, would require public 

hearings and new construction would likely not be 

completed in time for the targeted 2000 recovery date. 

SCHC Chairman Senator McConnell noted that by renovating the warehouse building, it could also serve as 

a permanent conservation facility with a longer term 

benefit to the State of South Carolina. This decision 

would allow each building to be more effectively 

designed in accordance with its function and location. 

The renovation of an existing building would allow 

recovery and conservation to proceed at an efficient 

pace. Being in an industrial park would also be more 

suitable for the conservation process and make it easier 

to estimate the conservation cost. The location also 

reduced the transport and handling requirements for 

the submarine, since it was accessible to nearby piers, 

and the shipyard cranes, which were on railways, could 

be used to transfer Hunley directly from the barge to 

the building. The Charleston Museum was still considered as the final repository for exhibit and could then 

focus on building an exhibit wing dedicated to Hunley. 

Laboratory design and modification of Building 

255 was accomplished through the help of several 

conservators: Dr. Hamilton, who was contracted with 

for an overall conservation methodology study and 

report with ROM cost (Hamilton 2000); Betty Seifert 

of Maryland Archaeological Conservation Laboratory, 

who was contracted to prepare a cost analysis for the 

initial laboratory set up; Claire Peachey of NHC via NPS; 

and Dr. Jonathan Leader of SCIAA. Building renovation and laboratory outfitting were estimated to be $2 

million and were scheduled to be completed to receive 

but at the option study stage was not pre-selected as 

the final contractor. 

The study made some basic assumptions: 1) 

the wreck was intact; 2) the site was limited to the 

immediate area such that extensive archaeological 

excavation would not be required; 3) the submarine’s 

hull would be self-supporting during the lift; and 4) 

there would be a sufficient weather window to conduct 

the operation safely. A variety of standard recovery 

methods was considered. The site was shallow enough 

for a cofferdam, but this was ruled out due in part to the 

expense, but also the risk of drying out well-preserved 

organic artifacts and the vulnerability of the exposed 

site to potential hurricanes. Capturing and lifting the 

submarine within its surrounding sediments was considered infeasible due to the risk of soil fluidization, 

based on the analysis of sediment cores taken around 

the site. There were additional concerns about the total 

weight of such a load. Raising the vessel using flotation 

devices would be difficult to control given the active 

surface conditions at the site. The study ultimately recommended that a rigid space frame structure be built 

to contain Hunley. The frame and submarine would be 

lifted directly off the ocean floor by a crane deployed 

from a derrick barge or heavy lift boat. Hunley would 

then be transported by barge to Charleston for offloading and transfer to the conservation facility. 

ROM costs were estimated to be $2,270,200 for 

66 days at sea, which would comprise the excavation, 

rigging, and lift of the submarine. The study had several 

follow-on recommendations to aid in further planning: 

the preparation of a 3D model of the wreck for preengineering the lift system, obtaining an accurate wall 

thickness for the submarine, and preparing a more 

detailed recovery operations plan (OII 1999a:ii–18). 

Under the direction of Neyland, hull thickness data was 

collected in early November 1999 (see Chapter 8), and 

OII used this data to conduct a finite element analysis 

(FEA) to help predict potential stresses and critical 

failure points on the hull (see Chapter 9).

Conservation Planning for H. L. Hunley

In conjunction with planning the recovery itself, the 

project team had to secure an appropriate venue for 

the conservation and display of the submarine. With 

no ready-made facility available in the Charleston area, 

a state-of-the-art conservation laboratory had to be 

built and outfitted in time to receive Hunley as soon 

as it was raised. To assist with laboratory design, FOTH 

contracted with the firm of Davis & Floyd Engineering, 

Inc. of North Charleston, South Carolina, who would 

manage the design bid of the laboratory. With the 

assistance of Neyland and conservator Paul Mardikian, 

Davis & Floyd staff visited conservation laboratories at 
P R O J E C T H I S T O R Y

57

Hunley by April 2000. Detailed costing for transforming 

the empty warehouse into a conservation facility was 

estimated at $1,036,300, and the initial outfitting of 

the laboratory at $843,154. In comparison, the preliminary cost of recovery was estimated to be $2,405,250. 

Thus the project was heavily front-end loaded, with 

the costs totaling $4,284,704. The long-term conservation, curation, and public interpretation of Hunley and 

its associated artifacts were estimated to cost an additional $5 to $10 million over the following ten years 

(Neyland 1999). Davis & Floyd was selected to design 

and oversee the renovations. The facility, completed 

in time for the recovery, was dedicated as the Warren 

Lasch Conservation Center (WLCC) in August 2000, in 

honor of the FOTH chairman, who was the principal 

force behind overall project funding. 

Hunley’s interior excavation posed a dilemma. 

Hunley was sealed with both hatches closed, which 

were presumed to be fastened from the inside. It was 

determined during the 1996 survey and the 1999 

testing that the submarine was completely filled with 

sediment. The submarine’s interior dimensions were 

confined, with a height of only 4.5 ft. (1.37 m) and a 

width of 4 ft. (1.22 m), and the interior space was taken 

up with the hand crank, benches, ballast tanks, pumps, 

and other machinery. This would further restrict the 

archaeologists’ ability to excavate efficiently. How to get 

into the submarine was as yet an unresolved problem 

and, once in, excavating would be a complicated and 

slow process. 

Since excavation protocols were still in development, plans had to be made to keep the submarine 

and its contents stable until they were ready to begin 

work. In addition, there was concern that fragile organic 

materials could deteriorate due to bacterial and fungal 

activity or dry out during the course of the excavation, 

which was expected to take place over six to twelve 

months. To prevent the degradation, several options 

were considered, including total submersion in water, 

pumping out and refilling the tank daily; refrigeration 

of the entire submarine and its contents; or use of an 

inert gas. In the end, it was decided to utilize a large 

tank of water chilled to a temperature slightly above 

freezing, to better preserve organic materials and slow 

the corrosion rate of the iron. The chilled water would 

be used during archaeological excavation and afterward 

as a storage medium, until chemical or electrolytic 

treatment commenced. Recovery and delivery into the 

chilled water tank had to be a seamless, single process, 

one in which the lifting frame and the tank worked as 

two parts of a whole. OII was requested to prepare 

the design for the tank and plan Hunley’s delivery and 

installation therein. 

In addition to the tank, the laboratory was 

equipped with extensive space for small artifact conservation, an x-ray unit, a chilled room for storing organics 

and human remains, and a photography area (see also 

Chapter 7). There was also a darkroom, but the advent 

of digital photography ultimately limited its utility. The 

facility was designed to be one of the best-equipped 

conservation laboratories in North America.

Conservation Symposium

In November 1999, a symposium was held in 

Charleston to consider the recovery, excavation, and 

conservation of Hunley. The meeting brought together 

an international group of authorities experienced in 

the conservation and handling of large iron and steel 

artifacts from underwater archaeological sites around 

the world. Ten experts were invited to present papers 

on their research, participate in discussions regarding 

Hunley, and critique the methods proposed for raising 

and treating it (Appendix A). These included Drs. 

Michael McCarthy and Ian MacLeod of the Western 

Australia Maritime Museum, presenting work with 

sunken submarines as well as the recovery and conservation of the steam engine from SS Xantho; Martin 

Dean of the University of St. Andrews, on the submarine 

Resurgam; Dr. Donny Hamilton of Texas A&M University, on the conservation of large iron artifacts; Peter 

Lawton of Treadgold Industrial Heritage Museum, on 

the conservation of HM Monitor M33; Paul Mardikian, 

senior conservator of the Hunley project, on conserving 

the Blakely cannon from CSS Alabama; Curtiss Peterson 

of the Rescue Corporation, on the conservation of USS 

Monitor; and Drs. Donald Johnson and William Weins 

of the University of Nebraska, on corrosion and metallurgical research on USS Arizona (Figure 5.2). In addition, 

three papers were presented to update the participants on the previous work conducted on Hunley from 

Neyland, Murphy, and Leader. OII also presented their 

recovery plan, including the results of the FEA they commissioned, and received important critical feedback.

The main areas of concern participants raised about 

OII’s plan were:

• Maintaining sufficient water for the interior and 

exterior of the hull during transport, so no damage 

would be incurred through drying;

• Preparing for the possibility of a significant breach 

in the hull in the areas that had yet to be exposed, 

both in terms of hull structure and preventing loss 

of interior contents;

• Keeping the concretion encasing the hull intact and 

free of cracks during recovery and transport;

• Ensuring that the additional stress of the lift would 

not cause the submarine to collapse under its own 

weight, particularly if rivet strength was significantly compromised.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

58

Water loss during transport was found to be related 

to the condition of the concretion. If cracks in the concretion could be minimized, this would limit the loss 

of interior fluids and silts. Some time was spent discussing methods to prevent cracking through elaborate 

techniques such as consolidation under water, a plastic 

sheath filled with argon gas, or even a coating of waterretaining gel with sodium carbonate like that used 

during transport of the Xantho engine. It was agreed, 

however, that it was best not to introduce chemicals 

into the hull at this stage and that, without any of these 

measures, 12 hours out of the water would likely only 

result in some minor cracking, which would be better 

for the wreck than leaving it in situ indefinitely. OII also 

discussed its plans for patching any hull breaches, if 

encountered. 

There was a question about whether the submarine 

would experience increased rates of corrosion during 

the excavation, and should cathodic protection be 

employed in situ until it could be raised. However, this 

process posed a risk of altering the microenvironment 

inside the hull and would result in more loss of concretion by drilling into the hull plates to attach anodes. 

Concerns regarding structural integrity centered on 

ensuring proper support for the entire submarine, the 

potential for rivet failure, and the risk of deflection of 

the hull under the strain of the water and sediment 

trapped inside. Some were concerned about the reliability of the ultrasonic tests conducted on corroded 

and concreted wrought iron. 

Conservation-related topics were also discussed at 

length, including proposed methods for gaining access 

to the interior without damaging it, issues related to 

handling human remains, and potential treatments for 

the hull once excavation was complete. The reviewers 

were able to shed light on gasses that had developed in 

the interior, which were encountered during the ultrasonic thickness tests. These were identified as hydrogen, 

methane, and nitrogen, a common result of reduction 

and corrosion processes in an anaerobic environment. 

It was important to be aware the excavation team 

might encounter more and that it should be sampled 

for future conservation planning.

These discussions reflected the participants’ considerable experience with large iron artifacts and contributed to the improvement of the overall recovery 

plan. OII implemented several changes to their plan 

(discussed below), while another company represented 

at the event, International Archaeological Lifts (IAL), 

developed an alternate plan based on the ideas and 

concerns raised at the symposium. 

Two Proposals

The two proposals in contention for the recovery 

contract came from OII and IAL. One centered around a 

direct lift, while the other favored lifting Hunley within 

its surrounding sediment matrix. Both ideas had been 

considered from the beginning, and expert opinion 

varied on the potential success of each method and 

the likely effects on the submarine. Both submissions 

were thoroughly reviewed by the HOC.

Figure 5.2. Presenters at the Hunley Conservation Symposium, from left to right, Donny Hamilton, Peter Lawton, 

Donald Johnson, William Weins, Robert Neyland, Ian MacLeod, Larry Murphy, Paul Mardikian, Martin Dean, 

Michael McCarthy, and Curtiss Peterson. (Courtesy of FOTH)
P R O J E C T H I S T O R Y

59

Oceaneering International Inc. 

As the firm that had conducted the preliminary 

study for the recovery of Hunley, Oceaneering had 

detailed knowledge of the project and its unique difficulties and was therefore asked by FOTH and the SCHC 

to prepare a proposal. Their method relied on proven 

salvage methods, calling for 

the use of “an all welded 

steel tube box truss with 

bolt on bearing seats and 

a removable sling support 

system incorporated with 

load cells for data acquisition” (OII 2000a:2). This 

large metal structure would 

be custom built to accommodate the known dimensions of the hull. The truss 

would be lowered to the 

seabed, above the wreck, 

where it would be supported 

by two rigid cylindrical piles. 

With the truss anchored in 

place, divers would excavate 

around and underneath 

the submarine to allow the 

placement of a series of 

slings suspending the vessel 

from the truss (Figure 5.3). 

This method would maintain 

the same orientation of the 

hull at which it had been 

resting since its deposition, 

protecting it and its contents 

from sudden shifts, which 

could result in damage 

or loss of archaeological 

context. A crane would then 

lift the truss and submarine 

from the seabed and onto 

a barge for transportation 

back to shore, whereupon 

it would be immediately 

installed at the WLCC. The 

recovery was scheduled for 

May, June, and July based 

on historical weather data, 

which pointed to optimum 

conditions of calm seas and 

less chance of storms in that 

period.

OII provided a very 

detailed account of equipment 

needed, personnel involved, 

and time table. Diving operations would be mounted from a vessel secured at the 

site with a permanent four-point mooring system. This 

vessel would be mobilized at the Port of Charleston 

with operations personnel loading diving and excavation equipment, and lifting structures. All stationary 

equipment such as pumps, dive trailers, and decompression chamber would be welded to the deck of the 

diving platform. An archaeological dive team would 

coordinate with OII divers 

to excavate around the 

hull, document and recover 

artifacts, and rig the truss. 

The time table was based on 

a 24-hour operation for both 

dive teams, to maximize 

effort and reduce time at sea. 

The proposed excavation 

would encompass an area 

approximately 40 ft. (12.19m) 

wide by 130 ft. (39.62 m) long 

by 4 ft. (1.22 m) deep. Such a 

broad area allowed for slope 

stabilization, diver safety as 

excavation depth increased, 

and placement of the suction 

piles. The goal was to expose 

one third of Hunley, leaving 

the remaining sediment in 

place for support until the 

truss was positioned. All 

sediment excavated from 

around the hull would be 

screened using a custombuilt series of sluice boxes 

mounted on the deck of the 

dive platform. The hull would 

be documented by archaeologists before rigging the slings.

Foundation support for 

the truss and Hunley would 

be provided by suction piles. 

This type of pile, designed 

for mooring oil rigs in deep 

water, requires less penetration than those driven 

into the seafloor and can 

be placed accurately. They 

could be installed with 

limited vibration and other 

disturbances to the archaeological site and removed 

with relative ease. Complete 

removal of the piles would 

facilitate a magnetometer 

survey for small iron artifacts 

associated with the site after Hunley was removed. 

Figure 5.3. Oceaneering created a digital animation 

of their proposed lift method, demonstrating how 

Hunley would be rigged in slings beneath a custombuilt truss and raised by crane. (Courtesy of OII)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

60

The slinging of the submarine would begin at the 

bow, removing just enough sediment to place and 

tension one sling at a time. The process would continue 

from bow to stern, thus ensuring the weight of the 

vessel would be smoothly transferred from the surrounding sediment to the truss. The slings would be 

lined either with foam or neoprene pads to conform 

accurately to the shape of the hull and prevent hull 

weight from resting on vulnerable external component. 

If necessary, OII divers would measure and fit support 

materials to protect hull features such as the diving 

planes, keel weights, and conning towers from the 

rigging elements. Load cells would be placed on the 

starboard side all of the slings to measure the load on 

each one. Data from the cells would be monitored by 

a topside engineer, who, through radio communication, would direct the divers tensioning each sling. This 

system would measure total weight of the load on the 

truss and provide an alarm if loads shifted during the 

recovery. It was also designed to be used during the 

conservation phase. 

The lifting process was reversible and could be 

aborted. The truss could be returned to its position 

on the piles, and it would not be necessary to remove 

the submarine from the slings in case of a hurricane or 

other severe weather event. The truss was designed to 

withstand such forces, and by packing the area inside 

the truss with sandbags, the submarine could be made 

secure, with an estimated completion time of 12 hours. 

Changes Based on Reviewer Concerns

One of the chief concerns raised was that the port 

side of the hull, subject to stress from the weight of 

the interior sediment, might warp due to deterioration 

of the hull plates or rupture due to corroded rivets. 

This deformation hypothesis was based on the FEA 

conducted for the hull filled with sand, which would 

exert an outward force once the sedimentary matrix 

was removed. Based on this data, the proposal was 

amended to include an additional set of slings that 

would be rigged over the port side and attached to the 

truss on the starboard side. These would be tensioned 

to fit snugly against the hull to prevent port-side distortion but not to provide an inward force against the port 

side (see Figure 9.8).

There was considerable discussion of sling spacing 

among the symposium participants. Since there was 

concern over the loss of artifacts from inside the hull, 

OII originally proposed connecting all the slings along 

their edges to provide continuous coverage beneath 

the vessel in order to contain anything that might fall 

out. However, this would interfere with the ability to 

adjust tension on each sling with precision, which was 

vital for the prevention of torsion and deflection of the 

hull. Therefore, the plan was finalized to include slings 

that were spaced closely together to provide maximum 

structural support with the flexibility to distribute the 

load as needed. A semi-permeable membrane would 

be slung beneath the whole truss to catch loose pieces, 

should any breaches be discovered in the hull before 

lifting.

International Archaeological Lifts

Following the conservation symposium, International Archaeological Lifts, LLC, a Mississippi corporation, developed and submitted their proposal for 

the recovery of Hunley. It was the project of Robert 

M. Adams of International Archaeological Consultants 

and Steve James of Pan American Maritime, LLC, a 

subsidiary of Pan-American Consultants, Inc. of Tuscaloosa, Alabama. Both Adams and James were experienced underwater archaeologists. The third underwater 

archaeologist, Richard Swete, also had extensive experience. Their engineering team consisted of Jimmy L. 

Laurence of Laurence and Associates of Corpus Christi, 

Texas, and William P. Ogletree, a licensed engineer 

with 46 years of experience in marine and naval engineering. Also on board were Michael Garvey and Ted 

Price, owners of Crane Company in Columbia, South 

Carolina, which lifted and moved the 18th century 

Brown’s Ferry shipwreck remains for SCIAA. Rounding 

out the IAL team was Stevens Towing Company, the 

largest barge company in Charleston, South Carolina. 

IAL introduced their proposal at a 20 December 

1999 meeting hosted by the Charleston Museum. They 

expressed several concerns with the OII plan and put 

forth a safer method of recovery. Their concerns with 

the truss lift method were numerous, including:

• The removal of sediment from around the hull 

might lead to a hull breach from the weight of the 

sediment inside the hull, which was not structurally 

designed for such a load;

• The degraded condition of the rivets could increase 

the likelihood of a hull breach, causing the hull to 

open like a zipper along the submarine’s longitudinal strakes, forcing the bottom half to separate 

from the top half;

• There was inadequate provision for the comprehensive collection of artifacts outside of the submarine 

and there would be a lack of archaeological data 

collection by using commercial divers;

• There was too much potential for damage to protruding hull features, particularly the propeller and 

rudder assembly, which would be exposed during 

a truss lift; 

• If there were any exposed holes or breaches in the 

hull, interior sediments and artifacts would drain 

out, particularly under the stress of going through 
P R O J E C T H I S T O R Y

61

the water-air interface, when the slings might 

stretch and increase pressure on the structure. 

Overall, the group thought the OII plan posed significant danger to the submarine and artifacts, with a 

real potential for catastrophic failure. 

In their proposal, IAL quoted the original Hunley

site assessment: “Intact recovery can be accomplished 

in several ways. A preferred method would be to 

encase the hull and surrounding sediments in a tube, 

or clamshell lift device designed to completely support 

and stabilize the entire hull length and stern features 

along with their sediments” (Murphy 1998:120). In 

accordance with this guidance, they planned to use 

a lifting cradle with hydraulically actuated plates that 

would capture the vessel and surrounding sediments 

and deposit the full load into a watertight lifting tray, 

which would be transported to the laboratory and 

house the subsequent excavation. 

Prior to implementation, the three known magnetic 

anomalies in the vicinity of the site would be located 

and removed. They would then excavate an area around 

the submarine 56 ft. (17.07 m) in length, 20 ft. (6.10 m) 

in width to a depth not to exceed 7 in. (0.18 m) below 

the upper part of the submarine. Two guide towers 

would be installed, one forward of the bow, one aft of 

the stern, to help position and secure the lifting cradle. 

These were to be constructed of Y-shaped large round 

pipe, with 6 × 6 × 2 ft. (1.83 × 1.83 × 0.61 m) footings 

that would be filled with ballast for stability. The towers 

could be adjusted vertically and laterally as needed for 

aligning the cradle. 

The lifting cradle would then be positioned over the 

wreck and steel reinforced plates pushed underneath 

the submarine, angled at 45°, powered by hydraulic 

rams. The operation would begin with two opposing 

plates positioned at midships, and then plates forward 

and aft of the central plates would be set and closed. 

The cradle would be equipped with partitioned ballast 

tanks, which would be inflated until positive buoyancy 

was achieved. With the cradle thus floating, it would be 

tethered to the guide towers and floated over the lifting 

tray, positioned several feet away. While maintaining 

positive buoyancy, the cradle would be winched down 

into the tray and securely shackled. After retracting the 

plates, the cradle would be moved clear, and the lifting 

tray, now with submarine and surrounding sediments, 

raised and placed on the deck of the recovery platform 

for transport to the conservation facility. 

IAL mentioned several advantages to their proposal, 

including sound structural engineering principles, no 

direct contact with the submarine, and uniform support 

of the vessel, which would maintain its stability even if 

its structural integrity had been compromised through 

the loss of rivet strength. There was no danger of 

artifacts being lost through a hull breach, the rudder 

and propeller assembly would be supported in their 

exact position, and all fluids would be retained. The 

method addressed many of the concerns raised at the 

conservation symposium, and allowed the project to 

remain highly visible to the public by allowing them to 

view the excavation in an aquarium environment. The 

group also offered to demonstrate the lifting technique 

in advance and stressed that the procedure was fully 

reversible—the vessel could be stopped and reversed 

at any time during the recovery (Adams 1999:13). An 

added benefit was the cost, coming in at $1,000,000 

less than the projected recovery costs of OII’s plan 

(Adams 1999, elec. comm.).

Wade Logan, IAL’s Charleston attorney, indicated 

prior to the group’s presentation that the plan disclosed 

proprietary information, including some 14 possible 

patents, and since the document would be subjected to 

public review, certain information could not be shared. 

Adams gave the presentation to members of the SCHC 

and Hunley recovery team, but stated the illustrations 

would be left out of the submitted written proposal. 

However, since many of the specific details about the 

equipment to be used were not available for review, it 

was difficult for reviewers to judge the proposal. 

The IAL plan met several of the initial criteria 

that had been recommended after the 1996 survey—

recovery of the submarine without compromising 

archaeological integrity, along with the surrounding 

sediment as well, so that the submarine and its 

environs could be excavated in controlled conditions 

ashore. It went further than the criteria in suggesting 

the submarine be put in an aquarium-like environment 

where its excavation could be conducted by divers and 

witnessed by the viewing public. They planned to do the 

trial test on 20 May 2000 to demonstrate the feasibility 

of their proposed method, with a recovery date timed 

for Memorial Day, 29 May 2000. Overall, the group 

believed their method closely fit the preferred method 

given by NPS.

Hunley Oversight Committee 

Review 

As stated above, the HOC reviewed both proposals 

extensively. The IAL team was considered highly experienced on an academic and technical level. Their method 

was attractive since it would enable archaeologists 

and conservators to study anaerobic site formation 

processes on an iron hull in a controlled environment. 

However, the committee was unable to evaluate details 

of the proposal since much of it was withheld due to 

proprietary concerns. How the plates would be closed 

and locked into place, how much force this would take, 
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62

and their possible inability to lock securely would be 

detrimental to Hunley and the surrounding archaeological context. There were concerns over pushing rams 

blindly into the sediment, which could damage artifacts 

and destroy site information, since magnetic data 

indicated that there were likely ferrous artifacts outside 

the hull. No weights were given for the lifting tray and 

its contents; therefore it was not possible to determine 

crane and barge requirements or floor load requirements for the WLCC. Reviewers also expressed concern 

that this technology had never been demonstrated. 

Perhaps one of the most significant concerns was 

that of sediment fluidization, as indicated by the analysis 

from geotechnical engineers. Sediment fluidization, or 

soil liquefaction, is a phenomenon that occurs when 

a saturated soil is put under stress and subsequently 

loses strength and stiffness. In the case of sediment 

below sea level, which is saturated with water between 

the grain spaces, the applied stress increases the pore 

water pressure. The water then attempts to flow out 

from the sediment to zones of low pressure. There 

was a real chance that the sediment inside the lifting 

cradle or lifting tray could liquefy, causing the hull to 

lose all support and sink to the bottom of the structure. 

Other concerns were the possibility of an asymmetrical 

lift due to bottom suction and the unpredictability of 

buoyancy lifting, especially with currents running 1 and 

1.5 knots on site. Finally, the lifting tray did not appear 

to leave enough room for archaeologists to excavate 

the sediments, they would be unable to monitor the 

condition of the submarine in the matrix during the 

ramming operation or during lift and transport, and 

excavation in an aquarium might be unsuitable for a 

site with human remains.

HOC’s review of the OII plan also raised some 

concerns. The questions were more specific to details 

of the plan, since OII had provided not only the concept 

but a comprehensive plan. Many of the reviewers’ 

questions were similar to those expressed by the 

symposium participants. The slings were scrutinized as 

to their level of adjustability and spacing, as well as 

the ability of the foam-filled bags to fully support the 

weight of the hull. The reviewers felt more attention 

needed to be paid to the proper support of the conning 

towers and stern assembly. They sought assurance that 

the recovery vessel would be moored in such a way 

to prevent damage to the site, and that the suction 

piles were strong enough to perform as needed. There 

was concern over the effects of wave surge on the 

submarine and truss during the lift and the potential 

for longitudinal flexing of the hull.

From an archaeological perspective, reviewers 

wanted clarification on how the magnetic anomalies 

near the hull would be investigated. They also wanted 

to be sure of containment of artifacts should any spill 

from the submarine and that the capacity of the sluice 

boxes was sufficient for proper artifact collection. It was 

stressed that all excavations immediately around the 

hull should be conducted by archaeologists, and that 

perhaps they should also supervise the placement of 

the truss.

HOC’s recommendations included excavating bow 

and stern areas prior to positioning the truss, recording 

the hull sections prior to sling placement, and possibly 

using a rubber molding compound to hold weak hull 

areas in place and at the same time mold hull features. 

Some suggested using sacrificial anodes to protect the 

hull from deterioration during the excavation. Others 

felt it would perhaps be worthwhile to spend more time 

studying the lift methods and postponing the project. 

The committee recommended OII’s proposal, but 

wanted their final concerns addressed. All in all, the 

OII plan was believed by the Hunley Research Center 

to be based on a sound understanding and interpretation of the results gathered by the last archaeological 

campaigns” (Mardikian 2000, elec. comm.) Mardikian 

preferred the OII plan since the process could be 

“basically controlled and daily monitored.” A representative of the NHC’s Underwater Archaeology Branch 

deemed the engineering plans to be satisfactory from 

an archaeological perspective and recommended 

that, when adequate funding was in place, recovery of 

Hunley should proceed.

Response to Reviewers’ Concerns 

Rivets

Concerns over the strength of the rivets holding the 

plates together was primarily based on one rivet sample 

taken during the ultrasonic thickness survey, which was 

found to be completely degraded. The FEA provided 

several different scenarios for rivet failure. OII used 

the lowest factor in which their system would work, 

basing calculations for their recovery system on at least 

10% rivet strength. Some of the reviewers shared IAL’s 

concern. Lawton (2000, elec. comm.) thought the rivets 

should be assumed to have zero strength and to test 

them not only for shear but eccentric extension as well. 

Others, such as Johnson (2000), did not believe that 

one rivet failure was evidence that the others would fail 

as well. In running the FEA model, it was determined 

that as rivet strength values reached 10%, anything 

lower was beyond the failure range, and calculations 

would be the same for any lift. Only 1 of the 22 rivets 

sampled was completely deteriorated, and although it 

was advisable to look at the worst case scenario, the 

rivets, plates, and concretion layer were expected to 

be stronger than what was modeled. In addition, NASA 

engineers gave an independent review and confirmed 

the results of the FEA model (HRC 2000). 
P R O J E C T H I S T O R Y

63

Hull Deflection

There were also questions about possible deflection of Hunley’s hull. The OII plan hypothesized a 

possible 1 in. (2.54 cm) deflection over the 50 ft. (12.19 

m) length of the truss. In particular, the proposal made 

no mention of what greater deflection would do to the 

hull and its protective concretion. OII answered that 

attempting to create a structure that would reduce the 

deflection to zero would create additional problems of 

fabrication and design time, cost, and weight. A small 

amount of deflection was inevitable, as was recognized 

at the Hunley Conservation Symposium. A taut wire 

system that would be connected to surface readout 

tensiometers was also proposed by OII to monitor any 

stresses on or deformation of the hull in real time. If 

it was discovered at any time that the hull was being 

contorted by the lift, the project could be aborted by 

the project director.

Other Concerns

While some felt a longer planning phase was 

warranted, the decision to raise Hunley in 2000 was justifiable due to the threat of looting and active ongoing 

corrosion (although occurring at a relatively slow rate). 

It was hypothesized that the rivets were corroding at 

a faster rate than the hull itself and, if too much time 

passed between the engineering plan and recovery, 

the technical aspects of the lift would become more 

difficult. Concerns about artifact displacement were 

addressed by proposing to sling a semi-permeable 

membrane underneath the submarine, which would 

allow water to drain but trap any loose artifacts. Large 

breeches in the hull would be covered and plugged 

prior to lifting, and a sprinkler hose system would keep 

the hull wet during transport. Closer sling spacing was 

also initiated, with the assurance that the foam bags 

would expand to fill the spaces in between (HRC 2000). 

Since the entire vessel had not yet been exposed, 

there were some concerns over properly preparing for 

these unknowns, including the weak stern, the prodtruding diving planes, the missing torpedo spar, and 

the known magnetic anomalies close to the hull. These 

concerns were allayed by scheduling archaeological 

investigations of these areas during the month prior to 

the lift, with a plan for locating and removing artifacts 

as necessary. 

OII Plan Selected

The end result of the considerable review of both 

proposals was an endorsement by the HOC of the 

OII recovery plan. The IAL submission did not have 

enough details, and while the technology was innovative, it was also risky. OII provided a detailed and wellthought-out document based on proven methodology. 

Dudley (2000) officially notified the SCHC of the Navy’s 

approval OII’s proposal on 30 March 2000.

The period of planning and review that eventually 

preceded the recovery of Hunley and construction of 

the conservation facility was a laborious but thorough 

and necessary process. It was accomplished in a relatively short time, beginning in the spring of 1999 and 

wrapping up by the beginning of the next year, allowing 

for the commencement of fieldwork in May 2000 and 

completion of the WLCC in time for the lift in August 

2000. The review by experts in the disciplines of archaeology, conservation, materials science, and ocean engineering was an important step in the development of 

recovery and conservation plans, allowing for the anticipation and prevention of many potential hazards.
64

6. Recovery Planning

R o b e r t S . N e y l a n d

Recovery Mission

Three priorities were established for the Hunley

recovery operation. First was the safety of all project 

personnel whether in the water, on the work platform, 

in transit to and from work, or off duty. Safety off the 

job was as important as while on duty. Absences due 

to illness or injury would affect the ability to field the 

required diver teams. Diver personnel were selected 

based on their archaeological and diving skills and 

were organized into diver teams that complied with 

American Academy of Underwater Scientists (AAUS) 

regulations. The second priority was the recovery of all 

cultural materials and archaeological information pertaining to Hunley, the 17 February 1864 sinking, and 

its subsequent burial for 136 years. The third priority 

was the preservation of all archaeological data intact, 

without damage to the submarine or the integrity of 

the crew compartment. All of the project pre-planning 

stipulated that the submarine was to arrive at the 

conservation laboratory as well-preserved as it was 

when found within the sea bed. “If at any time during 

recovery, the submarine is suffering damage, destruction of cultural material, loss of archaeological information, or the integrity of the vessel and intact submarine 

hull and its machinery are jeopardized, the recovery 

will be immediately aborted” (Neyland 2000:4). Warren 

Lasch, Chairman of the Friends of Hunley (FOTH), stated 

many times during the planning and operation, “We 

have only one chance to do it; we have to do it right the 

first time.” This position would be put to the test when 

the original barge slated to perform the lift was found 

to be too unstable (see Chapter 10). To the credit of all 

involved, despite the additional costs it would incur, the 

decision was made to temporarily stand down until a 

stable platform was obtained.

Recovery Operations Team

The recovery operation was both an engineering 

and scientific project and required individuals with 

diverse talents, including scientists, engineers, commercial divers, and equipment operators. The main 

functions of the operation were divided between the 

Hunley Archaeological Team (HAT) and the commercial contractor Oceaneering International, Inc. (OII), all 

under the overall direction of a single project director 

(Figure 6.1). HAT consisted of archaeologists from 

federal, state, and private sectors. Federal agencies 

included the Submerged Resources Center (SRC) and 

Fort Sumter National Monument (FSNM), both of the 

National Park Services (NPS), and NHC’s Underwater 

Archaeology Branch (UAB). State agencies consisted of 

the South Carolina Institute of Archaeology and Anthropology (SCIAA), College of Charleston, and the South 

Carolina Department of Archives and History (SCDAH). 

HAT also included a number of independent contractors and consultants. (A complete listing of all recovery 

operation personnel can be found in Appendix B). The 

OII commercial contractor’s team included an engineer 

and project manager from Advanced Technologies 

Division of Upper Marlboro, Maryland, and commercial 

diving personnel from the Gulf Coast Division, Morgan 

City, Louisiana. Other major commercial contractors 

included Tidewater Marine, LLC of Amelia, Louisiana, 

and Titan Maritime Industries, LLC.

A number of other entities participated in the 

project either through donation of their services and 

equipment or as contractors hired for their unique 

abilities. (Appendix C provides a complete listing of the 

companies who provided essential services.)

Project Leadership 

All recovery personnel, whether federal, state, or 

contractor, worked under the sole direction of Dr. Robert 

S. Neyland, Hunley Project Director, who was also the 

principle investigator (PI). The project director reported 

directly to the Honorable Glenn McConnell, Chairman 

of SCHC; Dr. William S. Dudley, Director of NHC; and 

Warren Lasch, Chairman of FOTH. Authority for all 
R E C O V E R Y P L A N N I N G

65

HAT diving, logistics, work schedules, archaeological 

research, and data collection. He reported directly to 

the project director and coordinated with OII’s project 

manager to develop daily work schedules and coordinate the work between the two teams. The field 

manager was not responsible for work assignments for 

OII personnel. Likewise OII’s project manager did not 

assign work to HAT personnel.

In a project of this scale, internal communication 

was a vital factor in its success and was built into the 

organizational structure. The field manager developed 

the daily work plans and provided them to the project 

director 24 hours prior to beginning each day’s work 

along with daily reports on the overall activities of 

the preceding day. This system of reporting worked 

well until the operation went to a 24-hour operation 

with two 12-hour shifts. In addition, both the HAT field 

manager and OII project manager provided weekly 

reports. HAT’s reports summarized the week’s work, 

the status of data collection, photography, and diving 

logistics, pointed out any and all deficiencies in data 

collection and logistics, made recommendations for correcting deficiencies, and outlined the work to be accomplished in the current week. These reports allowed the 

project director to see if the mission was ahead, behind, 

aspects of the project rested with the project director 

and included archaeological operations, engineering 

operations, press coordination, site security, and safety. 

The PI’s responsibilities included the authority to halt, 

slow, or change work, if continued activities posed 

an immediate or future danger to project personnel, 

Hunley, its archaeological information, and/or the 

human remains on board the submarine. Neyland was 

able to use his discretion to delegate responsibilities 

and authority to other key project personnel. The PI 

had the unique position of being able to represent both 

the Navy and the State of South Carolina on the project 

and thus provide a unified chain of command during 

the recovery. 

HAT Personnel and Organization

HAT daily operations were organized under a field 

manager, with two assistant field managers, a project 

photographer, two equipment managers, and a diving 

safety officer. Dr. David L. Conlin of the National Park 

Service was field manager and was the next in charge 

of the entire operation when the Project Director was 

not on site. The field manager’s duties were to oversee 

Figure 6.1. The project consisted of personnel from multiple sources organized under a single project director. 

(Chart by Emily Haver, NHHC)
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66

or on schedule, and brought to 

light any potential problems 

that required addressing. The 

field manager and his two 

assistant field managers also 

assisted with drafting weekly 

press releases. 

The assistant field manager 

for logistics (AFM-L) was Matt 

Russell, reporting directly to 

the field manager. He was 

responsible for organizing the 

daily dive schedules, structuring 

work so that it accomplished the 

goals of the project director and 

field manager (Figure 6.2). He 

oversaw the daily and weekly 

work plans and worked closely 

with the other assistant field 

manager to facilitate data collection. He also worked closely 

with the diving safety officer in 

maintaining dive and work safety. 

Also reporting directly to the field manager was the 

assistant field manager for data collection (AFM-DC), 

Claire Peachey. Her role involved overseeing data collection and management, including tracking all individual daily reports, the weekly reports of the project 

director and field manager, the photo field log, artifact 

sheets, and artifacts (Figure 6.3). While data collection 

was every archaeologist’s responsibility, the AFM-DC 

had the responsibility to review each HAT member’s 

reports and request that incomplete or insufficient 

work be redone. She could also reassign team duties 

in order to ensure that data was being correctly logged 

and cataloged by all archaeologists. HAT team members 

David Whall and Brett Seymour also assisted Peachey 

with photographing artifacts. Her duties required 

custody of the artifacts and samples, and overseeing 

their proper handling in storage until they and their 

accompanying records were transferred to the WLCC. 

She and the senior archaeologist coordinated with 

one another and maintained a database that inventoried and registered the location and status of artifacts, 

samples, and other records. 

When the project director was absent from the site, 

the field manager assumed the role. In the absence of 

both the project director and field manager, command 

fell to the AFM-L, followed by the AFM-DC. All the 

commercial and private contractors reported to one of 

the archaeologists. This chain of command was established to maintain the scientific mission of the recovery 

project and to prevent salvage from taking precedence 

over the archaeology.

Other key HAT personnel included Brett Seymour 

of the NPS, who oversaw all underwater still and video 

photography for the project, documenting archaeological work both under water and on the surface, as 

well as archaeological features as designated by project 

management. He was responsible for ordering and 

maintaining all project video and photo equipment 

and coordinating with media teams working on the 

project. Stills were primarily shot in 35mm color slide 

and black and white negative film, with limited use of 

digital, which had not yet reached a resolution comparable to film. Video was recorded with a Canon GL1 

3CCD miniDV digital camcorder. Seymour maintained 

the photographic log, providing copies to the AFM-DC, 

Figure 6.2. Assistant field manager for logistics Matt Russell (left) briefs James 

Spirek and Ralph Wilbanks on the day’s dive objectives. (Courtesy of FOTH)

Figure 6.3. Claire Peachey, assistant field manager for 

data collection, finds a dry corner in which to document 

an artifact prior to transport. (Courtesy of FOTH)
R E C O V E R Y P L A N N I N G

67

records for all diving personnel. Although there were 

no dive-related injuries, they were called upon at times 

concerning the health of project personnel and helped 

to keep everyone safe and healthy. 

Hunley Senior Project Manager/Recovery 

Operations Monitoring

Leonard T. Whitlock, a private contractor, was hired 

by FOTH to be the Hunley senior project manager. As a 

program manager at Oceaneering Advanced Technologies, he was instrumental in developing the engineering 

plan for the Hunley lift and bringing OII on board as the 

engineering firm for the operation. After leaving the 

company to start his own consulting firm, he was subsequently hired to assist with the logistics of the recovery 

side of the operation. His expertise in all aspects of 

ocean recovery operations and his industry contacts 

were indispensable to the project. This was particularly 

true when it became apparent the project would have 

to locate another lifting platform. Whitlock traveled to 

the Dominican Republic to personally inspect the barge 

Karlissa-B and negotiate the contract with Titan for its 

use. He also assisted the project director with monitoring the recovery operations, scheduling of resources, 

and budgetary versus actual tracking. In addition, he 

maintained the action item list, provided diving support 

to HAT, was a VIP liaison, advised on security issues, and 

helped with public relations and media coordination. 

He reviewed and provided status reports of daily activities, weekly reports, expenditures, and management of 

resources. His background also made him an excellent 

liaison between HAT and OII personnel. 

Oceaneering Project Management

Oceaneering’s team was led by project manager 

Steve Wright, who oversaw the implementation of the 

OII contract and supervised all of their personnel and 

equipment. Under him were assistant project manager 

Doug Dawson, diving supervisor, Ken Edwards, and 

lead engineer Perry Smith, who designed the recovery 

system and storage tank. OII’s 12 man team included 

6 divers, 3 tenders, 2 supervisors, and 1 superintendent. Wright also oversaw the fabrication of the lifting 

truss and suction piles with the assistance of Smith. He 

supervised the mobilization and demobilization of the 

work platforms Marks Tide and Karlissa-B. He became 

the principal captain of the small crew boat used to 

transfer personnel from shore to the work platforms. He 

reported directly to the project director or his designee, 

providing weekly reports, and coordinated diving and 

recovery activities with the HAT field manager (Neyland 

2000:9–10). 

and analyzed coverage to ensure all archaeological 

aspects of the project were properly documented. Chris 

Amer of SCIAA provided assistance as needed. Personal 

photography was discouraged as interfering with the 

work of the project photographer and the overall work 

schedule. Also, by limiting the number of individuals 

taking photographs, FOTH could control the quality of 

images released to the media. However, as the project 

neared recovery day, these stipulations were found 

increasingly onerous to maintain and individuals were 

allowed to take personal photographs as long as they 

were for personal use only. 

Ralph Wilbanks, private contractor, and Joe 

Beatty, SCIAA, were assigned the duties of equipment 

managers. Their responsibilities were to ensure that 

project equipment such as pumps and boats were 

serviced and operational at all times. They coordinated 

repairs and preventive maintenance with AFM-L. As it 

turned out, Steve Wright of OII also became responsible 

for maintaining one of the crew boats. It was affectionately nicknamed “Little Elián” after the Elián González 

affair in the news at that time and the fact that the 

passengers sometimes felt the need of rescue due to 

its handling in adverse weather conditions.

Harry Pecorelli III was the HAT diving safety officer. 

His responsibility was the safety of the archaeological dive team and in the performance of his duties 

he had the authority to halt a proposed dive, abort a 

dive, and remove individuals temporarily or permanently from active duty on a dive team. In matters of 

safety, he did not have to request the concurrence of 

a higher authority. As collateral duty he was responsible for overseeing overall project safety and safety of 

HAT members both below and above the water. This 

included boat safety as well, ensuring that boats were 

properly equipped and operated safely. Time permitting, 

he assisted with equipment maintenance. He reported 

directly to the project director on matters of safety. In 

his absence, dive safety duties rested with the field 

manager and his assistants. 

While the HAT and Oceaneering diving safety 

officers were responsible for ensuring safe diving 

practices during recovery, ultimately all project 

personnel were responsible for safety as well. All 

divers were expected to assess the diving situation 

and evaluate conditions and tasks against their own 

knowledge of their skills, abilities, and readiness to dive. 

Project personnel could at any time opt out of a dive 

for health or safety reasons. While off duty, personnel 

were requested to conduct themselves in a manner that 

would not impede their ability to work. 

Richard Guobaitis, M.D., and Larry Raney, M.D., 

both with the Medical University of South Carolina, 

volunteered their services as emergency medical 

physicians and agreed to be on 24 hour call during 

the operation. They were provided copies of medical 
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68

Senior Archaeologist 

Two other key personnel who were part of the scientific team were senior archaeologist and senior conservator. Both participated in the recovery operation, 

however, their primary responsibilities involved outfitting the conservation laboratory, which was being 

constructed as the recovery was underway. As senior 

archaeologist, Maria Jacobsen was HAT’s primary 

on-shore scientific contact, and was tasked with 

monitoring incoming communications at the Hunley

Research Center (see below) and at the conservation laboratory. In this capacity she was liaison with 

the primary construction contractor, Davis & Floyd, 

and their sub-contractors, gave coordination and 

oversight for change orders, oversaw the installation 

and operation of equipment, and provided regular 

status briefings to the project director (Figure 6.4). 

She and the senior conservator conducted building 

and equipment inspections and equipment operations 

training on the major systems (mechanical, electrical, 

security, etc.). She also assisted office manager Darlene 

Russo with coordinating phone and computer services 

for the new building. While all this was in progress, she 

also finalized the research design for the upcoming 

laboratory-based excavation of the interior of the 

submarine. She developed sections pertaining to the 

study of site formation processes, hypotheses, objectives, procedures, and equipment requirements. She 

was also primary liaison with the Smithsonian forensic 

team and experts in the field in developing a comprehensive forensic protocol. 

Senior Conservator

Senior conservator Paul Mardikian addressed all 

aspects of conservation of the submarine and its associated artifacts. As part of the outfitting of the conservation laboratory, he purchased all necessary chemicals 

and supplies for the new facility. As mentioned above, 

he reviewed and inspected work by Davis & Floyd and 

their sub-contractors. He assisted with any conservation issue that occurred during the recovery, providing 

on-site expertise as needed, and coordinated with the 

AFM-DC to provide supplies for stabilizing and storing 

the artifacts in the field. He oversaw the collection of 

specific data pertaining to the chemical parameters of 

the environment of the submarine on the sea bottom. 

As artifacts and samples were recovered and transported from the archaeological site to shore, he took 

charge of all artifacts and samples and secured them in 

the conservation laboratory. During this time, he also 

worked to develop the overall Hunley conservation plan 

and was tasked with preparing a report on the subject.

Logistics

Shore Support Facilities

The shore facilities included the Hunley Research 

Center (HRC), an office located at 94 Wentworth Street 

provided by the College of Charleston, the new conservation laboratory (WLCC), and the Hunley Recovery 

Command Post. The HRC was the primary office space 

for the project for the year leading up to the recovery 

and while the conservation laboratory was being 

renovated. Russo supervised this office and managed 

employees and interns. HAT and OII personnel used 

this office as well until the WLCC was ready for occupation. The command post was located in an office trailer 

placed directly behind Fort Moultrie and adjacent to the 

NPS boat landing used by field personnel. The conservation laboratory under construction was a warehouse 

building on the former Charleston Naval Shipyard that 

was undergoing a $2 million renovation while the 

recovery project was gearing up and underway (see 

Chapter 7). Primary renovation was scheduled for completion in mid-May, but the actual occupation of the 

building did not occur until June. After renovations, the 

HRC offices were relocated to the new facility. 

Figure 6.4. Senior archaeologist Maria 

Jacobsen inspects progress on the renovations at the conservation facility. (Courtesy 

of FOTH)
R E C O V E R Y P L A N N I N G

69

Security

The security plan for the recovery project was 

designed and implemented by the South Carolina 

Department of Natural Resources (SCDNR), Marine Law 

Enforcement Division. Major Alvin Taylor of the SCDNR 

Marine Law Enforcement Division coordinated security 

efforts with the Charleston County Sheriff’s Office, 

Charleston Police Department, and the U.S. Coast 

Guard (USCG). Security was broken into two phases: 

Phase I, providing safety for the divers and site protection leading up to the raising of the submarine, and 

Phase II, the security of the submarine and transportation to WLCC. In Phase I, the SCDNR kept unauthorized boats out of the work site by establishing a boating 

exclusion zone mirroring that Regulated Navigation 

Area established by USCG. The area was marked with 

USCG buoys. Law enforcement officers from SCDNR, 

Charleston County, and Charleston City monitored the 

area on a regular basis and the Hunley recovery team 

was provided 24-hour access to an officer as needed. 

Phase II was initiated twelve hours in advance of the lift. 

After Hunley was raised, transport to shore was safeguarded by a moving security escort of nine vessels, 

including USCGC Yellowfin and others provided by 

SCDNR, Charleston County, and the City of Charleston 

(Figure 6.5). An additional two boats were assigned to 

the offload site at Pier Zulu, located at the former Naval 

Shipyard, to ensure that traffic was kept to a minimum. 

Radio communication was via hand-held units supplied 

by Charleston County marine police. 

Media Plan

It was apparent from the beginning that, during the 

recovery, release of information to the media required 

accuracy, continuity, and an unbreakable line of communication. The Public Affairs Liaison (PAL) was established 

as the single point of contact with the media and thus, 

the general public. To fill this role, FOTH contracted the 

services of Mark Regalbuto and his firm, Advent Media. 

A strict media plan was developed to ensure that the 

media could not access information or make requests 

of decision-makers without going through the PAL, so as 

not to undermine his credibility and ability to manage 

the press. The PAL would first consult with the project 

director before making commitments to the press. 

As part of the media plan, a written statement 

was prepared by the project director that outlined 

his concerns in regards to safety and guidelines for 

access and required all media requests be addressed 

to the PAL. In addition, a media kit was prepared that 

included a CD-ROM with 10 images, a videocassette 

of the animated recovery method and design, and 

other pertinent information. The South Carolina Press 

Association assisted with the project by verifying press 

members’ credentials. 

The newly outfitted WLCC was selected as the best 

site to hold press conferences and was equipped with 

the proper staging for both press and staff. A press 

communication center was also established there in a 

visitor conference room that was fully equipped with 

phones, fax, and computer access. The auditorium at 

Figure 6.5. U.S. Coast Guard Cutter Yellowfin was the largest of the security vessels 

providing an escort for the barge carrying Hunley to North Charleston. (Photo by Captain 

James Hoffman, USN)
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70

Fort Moultrie was selected as an alternate site for the 

press briefings, should the conservation laboratory not 

be available.

The decision when to hold press briefings and 

generate releases was dictated by the amount of new 

information to be disseminated. However, it was determined that a weekly briefing would be necessary, particularly during key stages of the recovery effort. The 

official commencement of the fieldwork, anchoring 

of the pylons, lowering of the truss, and eventual lift 

would all potentially require more frequent, even daily 

briefings. Fridays were found to be best for releasing 

new information, as they would allow newspaper 

articles and news reports to be made by reporters for 

the weekend editions. The local newspaper, Charleston 

Post & Courier, requested the project director give daily 

briefings to its primary reporters, Schulyer Kroft and 

Brian Hicks. 

The press releases were sent out by fax and handed 

out at the briefing. The releases were the written, synthesized version of the live briefing and did not differ 

greatly in content. This was to ensure that the press 

received a consistent and clear message and to limit 

the transmission of inaccuracies. The initial information 

for the release was generated by the project staff and 

provided to Neyland for review, editing, and approval. 

The press release was also assessed by John Hazzard 

V, who was legal advisor to the SCHC and communicated with FOTH. The PAL then reviewed the draft for 

grammatical errors and formatting, and sent it back 

to Neyland and Hazzard for final review. Each release 

had to be signed off by, in order: (1) Project Director, 

(2) FOTH Executive Director, (3) PAL, and (4) Project 

Director for final approval. 

Official spokespersons were assigned based on 

their areas of expertise and limited to one person per 

topic in order to provide clear and precise information, 

a consistent voice and a regular contact for the press. 

They were:

• Robert Neyland—Overall Hunley Recovery 

Operation and Archaeology

• Leonard Whitlock—Recovery Engineering

• John Hazzard V—Friends of the Hunley

• Senator Glenn McConnell—South Carolina Hunley 

Commission

• Maria Jacobsen—Hunley Research Center and 

Warren Lasch Conservation Center 

These were the only people designated as official 

project spokespersons. Other HAT and OII team 

members were allowed to speak as project participants about their own personal experiences and 

areas of expertise, but did not identify themselves 

as official spokespersons (Figure 6.6). When recovery 

team members and other project personnel were 

asked questions outside the scope of their expertise or 

knowledge, they were to refer the media to the appropriate spokesperson. 

All of the state and federal agencies involved with 

the project received press releases via broadcast fax. 

These principally included the NPS-SRC, NPS-FSNM, 

NHC, SCIAA, College of Charleston, SCDAH, USCG, and 

City of Charleston. 

Public outreach during the project was a success. 

The media and the public were eager for information 

and followed the progress of the recovery closely. The 

proximity of the site to shore allowed media and VIPs 

to visit and receive project briefings as well as obtain 

video and photographs. Information was disseminated 

effectively through regular briefings and at public media 

events. The project’s news releases were clear, consistent, and accurate. 

There was extensive project planning and coordination with local, state, federal, and private entities. The 

time that went into planning paid off with the successful 

recovery operation and delivery of Hunley to its new 

home at the WLCC.

Figure 6.6. OII project manager Steve Wright, with 

his dog Bosun, gives an authorized interview concerning the engineering aspects of the project. 

(Courtesy of FOTH)
71

7. Warren Lasch Conservation Center

R o b e r t S . N e y l a n d , P a u l M a r d i k i a n , a n d M a r i a J a c o b s e n

The selection and outfitting of the conservation 

facility for Hunley occurred in parallel with the development of engineering and archaeological plans for 

recovery. Conservation was known to be the largest 

long-term project cost and probably the most difficult 

to estimate in terms of cost and time. It was understood 

from the beginning that the submarine could not be 

recovered without having a suitable conservation laboratory to receive it. 

While the Charleston Museum was originally considered to house the facility, ultimately a 46,000 sq. ft. 

(4,274 m2

) warehouse at the former Charleston Naval 

Shipyard was selected (see Chapter 5). Building 255 was 

still relatively new and had never been occupied either 

before the closure of the base or under its subsequent 

proprietor, the State of South Carolina Redevelopment 

Authority (RDA). The lease could be obtained from the 

RDA at an insignificant cost. Initially a 7-year lease was 

acquired but it was decided that a 30-year lease, which 

would cover the life of the building, would provide a full 

return on the state’s investment (SCHC 2000). Renovation of an existing building allowed both recovery and 

conservation planning to move forward at a faster pace 

and saved on construction expenditures—in this case, it 

could be renovated within six months. The renovation 

and laboratory outfitting was carried out by the engineering and architectural firm Davis & Floyd, Inc. The 

State of South Carolina allocated a total of $3,000,000 

in funds designated for the Hunley facility (SCHC 

2000). In addition to the state funds, the Friends of the 

Hunley (FOTH) received several substantial donations 

of services and equipment from private corporations 

and individuals (Mardikian 2004:138).

Building 255 had several advantages over the 

Charleston Museum as a conservation facility. It had in 

place the necessary industrial services and structural 

requirements including compressed air lines, electrical 

service of 120, 208, and 480 volts, and water and wastewater lines of adequate capacity to handle the volumes 

required by a large conservation process. The floor load 

capacity of 650 p.s.f. (3,173 kg/m2

) was sufficient for 

supporting the tank of water containing Hunley. At that 

time Hunley, sediment, water, and lifting frame were 

estimated to be more than 60 tn. (54.4 t). The building 

was large enough for laboratory space, artifact storage, 

shops, storage, and offices. It could also accommodate 

the installation of overhead cranes needed for raising, 

lowering, and moving the submarine. The location was 

suitable for the dirty and industrial nature of the conservation process, whereas the Charleston Museum 

was located in a residential area that might require 

special exemptions from the city building codes. 

In developing cost estimates for retrofitting the 

building and conservation laboratory requirements, 

several conservators were consulted concerning 

necessary equipment and operating costs. These 

included Dr. Donny L. Hamilton from Texas A&M University; Betty Seifert, Head Conservator at the Maryland 

Archaeological Conservation Laboratory; Dr. John 

Leader of the South Carolina Institute of Archaeology 

and Anthropology; Claire Peachey of the Naval Historical Center; and Paul Mardikian of FOTH. The combined 

efforts of these conservators and archaeologists were 

essential to outfitting a state-of-the-art marine archaeological conservation laboratory and in estimating conservation costs for fund raising. 

The conservation laboratory construction was 

underway by December 1999 with an anticipated 

completion date of 28 April 2000, in time for the 

Hunley’s recovery to proceed, well within the initial 

six-month estimate. Davis & Floyd had the design lead 

and oversaw five principal sub-contractors. These were 

local firms with the exception of Mid-Atlantic Crane and 

Equipment Company, who installed the crane support 

systems. C. R. Hipp was hired to develop the process 

piping, mechanical, and plumbing systems. Utilities 

Construction Company would be in charge of the 

electrical work. Dave Matthews of Harbor Town Construction would conduct the building renovations and 

site preparation work. Division 5, based in Hollywood, 

South Carolina, would fabricate the chilled water tank 

according to the design produced by Oceaneering 

(OII), the company also orchestrating the lift of the 

submarine itself. This construction would be monitored 
H . L . : H U N L E Y R E C O V E R Y O P E R A T I O N S

72

(16.76 m) long, 18.5 ft. (5.64 m) wide, and 10 ft. (3.05m) 

high, for a total of 10,175 cu. ft. (288.12 m3), with a 

maximum capacity of 76,109 gal. (288,104 L) or 317.58 

tn. (288.12 t) of water (see Appendix D for plans). The 

interior was painted with a chemical resistant coating. 

Mardikian researched and selected 3M Scotchkote 306, 

a liquid epoxy coating designed to protect metal and 

other surfaces from corrosion and deterioration due 

to a variety of chemicals including sodium hydroxide. 

Starting from a near-white metal blast-cleaned surface 

finish, a coat of 10 to 16 mil (0.25–0.41 mm) of epoxy 

was rolled on, and before completely dry it was followed 

by the second coat that was sprayed on at a 5 to 10 mil 

(0.13–0.25 mm) thickness (Mardikian 2000a). Reverse 

osmosis and deionized water systems were installed for 

removing chemical ions, particularly chlorides, from the 

city water. 

An elaborate pumping system was developed 

for chilling and circulating water in the tank and for 

pumping caustic treatment solutions during the conservation process. At this stage, the builders installed 

by OII engineer Perry Smith. Greg Beasley was assigned 

as the Davis & Floyd contract administrator. During a 28 

February 2000 meeting of the South Carolina Hunley 

Commission (SCHC), Beasley stated that half of the 

renovations were completed and the entire project 

was on schedule for completion. The majority of the 

laboratory construction was completed and installation 

was underway for the analysis equipment, fume hoods, 

darkroom, cold storage unit, x-ray equipment, and the 

laboratory furnishings (SCHC 2000). 

Some demolition was necessary to install windows 

that would allow natural light into the work area. This 

would facilitate the delicate work on artifacts. Window 

glass was chosen that would exclude ultraviolet light. 

The Canadian Conservation Institute tested the glass to 

ensure it filtered the appropriate wavelengths. In the 

warehouse area where the chilled water tank was constructed, a new loading dock was installed with a roll-up 

door sufficiently large to allow Hunley, suspended in 

the recovery truss, to enter and be placed underneath 

the overhead cranes. Outside of the building, security 

fencing, holding tanks, and associated piping for water 

and chemicals were installed (SCHC 2000; Mardikian 

2004:139).

Wet Laboratory

The renovated conservation laboratory included 

space for separate wet and dry work areas. The former 

was located in a large warehouse bay area directly 

inside the exterior roll-up door, which was already 

equipped with a floor drain. This roughly 14,000 sq. ft. 

(1,300 m2

) space could accommodate the treatment 

tank that would house Hunley during the excavation 

of its interior and the subsequent conservation of the 

hull, as well as additional work space. Large loose hull 

components, such as the torpedo spar, could be stored 

and treated in the bay area in their own individual, customized tanks (Figure 7.1). There were two overhead 

cranes in this area that could manipulate heavy objects 

in the work area as well as directly over the Hunley tank. 

Chilled Water Tank

A large steel tank was designed to contain both 

the Hunley and the truss in a fresh water environment during the initial period of examination and the 

following excavation phase. In order to protect the 

organic materials inside, it had to be capable of chilling 

the water enough to slow decomposition. During the 

excavation phase, the water was kept at an optimal 

43.3°F (6.3°C). To provide work space around the 

submarine and truss, the inner dimensions were 55 ft. 

Figure 7.1. The bay area of the wet laboratory held 

a variety of custom treatment tanks, such as this 

unusually long one built to hold Hunley’s torpedo spar. 

(Courtesy of FOTH)
W A R R E N L A S C H C O N S E R V A T I O N C E N T E R

73

the electrical and pumping systems for both phases, 

although the conservation treatment would not begin 

for several years. The initial pumping design included 

sand filters for water purification, but, after algae 

problems developed, it was amended to include diatomaceous-earth filters that filter particles to a 20 μm 

(0.00078 in.) level. A swimming pool skimmer was also 

added to the southeast corner of the tank to keep the 

surface of the water clean. The original commercial 

chiller that was installed failed and had to be replaced. 

The new one was donated by Aqua Blue Pool and 

Pentair (Mardikian 2004:144). 

The risk from a potential spill if a leak occurred 

required a 48 in. (1.22 m) high concrete curb to be 

installed around the tank and bay as a spill retaining 

wall. This curb had doorways that could be closed with 

removable doors. The walled-in area encompassed a 

large general work space, a room for chemical storage, 

a workshop, an air abrasion room, and showers and 

dressing room for staff. 

It was originally proposed to cover the tank water 

to improve energy conservation by reducing surface 

exchange and evaporation loss. A layer of 50 mm 

(1.97 in.) diameter hollow plastic spheres could be 

used to create a floating layer over the 1,017.5 sq. ft. 

(94.53 m2) surface area of the water. However, this 

would have impacted both the scientists’ and the 

public’s ability to monitor and view the submarine, so 

this plan was not implemented (Mardikian 2004:140). 

Mezzanine

Around the top rim of the chilled water tank, a 

1,076 sq. ft. (100 m2

) mezzanine was constructed where 

the scientists could set up computer work stations and 

stage for the excavation (Figure 7.2). The mezzanine was 

rated at 150 p.s.f. (732.4 kg/m2

) with a 10,000 lb. (4,536 

kg) concentrated load (Smith 2000c). An industrial grade 

touch-screen computer was stationed there to monitor 

the chemical and physical parameters of the submarine 

in the truss. The filling and draining sequences could be 

programmed into this computer. The area also functioned as work space during the excavation to facilitate 

the removal and temporary storage of artifacts, and as 

a platform for photography, laser scanning, and hull 

recording. A rolling bridge was designed to fit over the 

tank, capable of movement from one end to another, 

to facilitate excavation and the documentation of the 

hull. The mezzanine would eventually be the means for 

bringing visitors to the site to witness the excavation 

and the submarine. Although not initially intended for 

tourism, the mezzanine and lab did eventually accommodate this purpose with some modification.

The two 20 tn. (18.14 t) top-running double girder 

cranes, which were installed over the submarine for its 

installation, were used during excavation to facilitate 

the smooth recovery of artifacts and sediment from 

the submarine and placement onto the mezzanine, or 

in the case of large items, such as hull plates, directly 

onto the warehouse floor. The cranes could also support 

equipment such as an x-ray tube or Cyrax laser scanner. 

A scissor lift positioned adjacent to the mezzanine 

was used to lower fragile or heavy artifacts from the 

mezzanine floor to the lower level, where they could be 

rolled or carried into the dry lab (Mardikian 2004:139). 

Dry Laboratory

The dry laboratory encompassed approximately 

9,000 sq. ft. (836.13 m2

) of floor space. This area was 

constructed with the philosophy of working from wet 

Figure 7.2. A view of the newly-constructed mezzanine looking down into the 

treatment tank. (Courtesy of FOTH)
H . L . : H U N L E Y R E C O V E R Y O P E R A T I O N S

74

later be used for a museum and gift shop. The second 

level of the building was designed for offices and had 

a ca. 9,000 sq. ft. (836 m2

) office floor plan. This was 

renovated into a suite of offices for archaeological 

and administrative staff with an SCHC office, a library, 

drafting area, and a meeting room. The outside area on 

the rear side of Building 255 required substantial renovation with placement of a concrete pad for a loading 

dock and six water/chemical storage tanks. All outside 

piping was electrically heat traced and insulated to 

prevent freezing. 

Cathodic Protection System: 

Impressed Current

Hunley, in situ off Charleston, was in a low oxygen 

environment, measured at 1.9 ppm dissolved oxygen 

and high salinity of 33 ppt chlorides. The iron structure 

was estimated to be corroding at a rate of less than 

0.2 mils (0.0051 mm) per year (Murphy 1998:11). Once 

recovered, the submarine was placed in fresh water 

with dissolved oxygen content of approximately 8 ppm. 

The presence of oxygen is the primary factor contributing to the rate of metal corrosion. Of lesser concern 

but a contributing factor to differential corrosion is 

the difference in electrochemical potentials between 

the submarine’s cast- and wrought-iron components. 

These corrode at different rates resulting in the cast iron 

potentially being sacrificial to the wrought iron. 

During the 1999 Hunley Conservation Symposium, 

the employment of galvanic protection was discussed 

as a method for preventing further corrosion of Hunley

during the excavation period. This process usually 

requires an anode of zinc, aluminum, or magnesium, 

which have a more negative potential, allowing current 

to flow to a metal with more positive potential, such as 

iron. This was highly impractical, however, for to protect 

the hull and the recovery truss with the required 

current density of 3.5 A, a total of 50 high-potential 

7 × 30 in. (17.78 × 76.20 cm) magnesium anodes each 

weighing 50 lb. (22.68 kg) would be required. Fifty 

anode packages would cover 73 sq. ft. (6.78 m2

) of the 

hull. Other problems with galvanic protection included 

penetrating the concretion to attach the numerous 

anodes to the submarine’s hull, current densities that 

are difficult to control, and excessive ionic by-products 

from the anode reactions that would precipitate on the 

hull and interfere with chloride removal. 

Corrosion engineers recommended using an 

impressed current system, which uses inert anodes and 

an external electrical power supply to produce current 

flow of electrons to the metal to be protected, i.e. the 

submarine (Meier and Mardikian 2004). This method 

and dirty to dry and clean. A roll-up door separated it 

from the wet lab. Upon entering the area was a cooler 

for storage of human remains and organic materials. The 

x-ray cabinet and digital radiograph system were also 

placed at this end of the lab to document the wet concretions and block lifts of sediment containing human 

remains, textiles, and artifacts without contaminating 

the rest of the lab with water or sediment (Figure 7.3). 

They could then be transferred directly to wet storage in 

the cooler or the warehouse. FOTH purchased a mobile 

300keV x-ray tube that could be used in the cabinet 

or directly on the submarine. Fuji NDT Corporation 

donated the digital system, providing state-of-the-art 

x-ray capability to the project (Mardikian 2004:140). 

The far end of the dry lab area held two climatecontrolled storage areas for conserved artifacts, one 

designed for metal artifact storage and the other for 

organic materials. Metals would be kept at a lower 

relative humidity of 30% RH ±5% RH, and organics at 

50% RH ±5%. In the central area of the dry lab were 

rooms designated for textiles and small organics, 

analysis, clean work, chemical storage, a darkroom, 

and several laboratory work tables with overhead fume 

hoods. An office was also provided for the Senior Conservator as well as a break room and staff restrooms. 

A large area of the first floor of the warehouse 

was left undeveloped and a wall constructed partitioning it from the conservation area. This area would 

Figure 7.3. Senior conservator Paul Mardikian inspects 

the newly-installed digital x-ray unit in the dry laboratory. (Courtesy of FOTH)
W A R R E N L A S C H C O N S E R V A T I O N C E N T E R

75

provided a means of reducing the corrosion rate of the 

submarine’s hull using smaller, less intrusive anodes, 

and avoided the use of corrosion-inhibiting chemicals 

that would destroy fragile artifacts in the interior of 

the hull. The expertise of engineer Craig Meier from 

Corrosion Control, Inc. (CCI) and electrochemist Steve 

West from Orion Research Inc. (now Thermo Orion), 

among others, enabled the conservators to customize 

the system for Hunley to ensure optimal protection. 

The impressed current system was installed by 

CCI and consisted of two 40 ft. (12.19 m) long anodes 

placed within pre-drilled PVC pipes. The anode selected 

was 0.125 in. (3.2 mm) diameter wire of inert titanium 

substrate coated with a layer of plasma-sprayed mixed 

metal oxide. The PVC pipes protected the anodes 

from damage and ensured they did not come into 

contact with the mild steel truss or tank. The anodes 

were placed parallel to both sides of the submarine to 

provide the most uniform distribution of current along 

its full length (Meier and Mardikian 2004:6). 

Power for the anodes was supplied by a rectifier 

unit, which converts alternating to direct current, and 

feeds it into the submerged anodes. The current discharges off the anodes and, passing through the water, 

flows through the metal surfaces of the submarine 

and truss. It then passes out through a negative cable 

attached to the bow and another on the truss and 

returns to the rectifier (Figure 7.4). The rectifier, rated 

at 20 V / 5 A, uses a standard 120 V alternating current 

to draw 1.6 A (Meier and Mardikian 2004:6). 

One side effect of using impressed current in the 

presence of chlorides is the formation of chlorine gas 

(Cl2

) at the anode surface. This is formed when the 

electrons are stripped from the chloride ions, lowering 

chloride ion concentrations in the water, and in some 

cases can be problematic without proper ventilation. 

In addition, on the surface of the submarine’s hull and 

truss, electrochemical reduction of water and oxygen 

produce hydroxyl ions and hydrogen ions which evolve 

as gas, potentially loosening the concretion layer. Any 

amount of gas produced was relatively small and never 

presented a safety hazard. 

Careful monitoring of the cathodic protection 

system ensured that conservators maintained a safe and 

balanced reaction. Six silver/silver-chloride permanent 

saturated gelled reference cells were placed along the 

hull for monitoring cathodic protection levels. The level 

of potential in each reference cell was tracked, using 

an LC-4 corrosion voltmeter with variable impedance. 

The rectifier, designed specifically for the project, 

could automatically adjust the output of the anode 

in response to detected changes in water chemistry 

(Mardikian 2004:141–43; Meier 2000:3–4).

Electrolytic Reduction Control 

System

Once the excavation of the interior was completed, 

the original conservation plan called for use of electrolytic reduction, a well-established method for stabilization of large archaeological iron pieces. Therefore, 

although it would be years before Hunley was ready 

for this chemical phase, the wet laboratory was built 

with the necessary infrastructure for generation and 

distribution of the electrolyte, in this case a solution of 

sodium hydroxide (NaOH), sometimes known as caustic 

(Figure 7.5). Plans included a smaller tank referred to 

as the electrolysis tank that would fit inside the chilled 

water tank, which would then become a spill containment tank. Six cylindrical 15,000 gal. (56,781 L) fiberglass holding tanks, 12 ft. (3.66 m) in diameter with 

a height of 18 ft. (5.49 m), with mixing agitators were 

set up outside the building for mixing and holding 

the treatment solution. These could also be used to 

neutralize solutions as needed. The pumping system 

included a 300 gal. per minute (GPM) (1,136 LPM) 

suction pump powered by a 5 hp 115/220 volt, 1,750 

rpm electric motor, 240 gal. per day (GPD) (908 LPD) 

caustic and 240 GPD (909 LPD) acid pumps. A dedicated 

industrial standard PC operated the control system for 

the pumps, valves, tanks, and water filtration systems. 

The electrolysis tank, however, was removed from the 

building plans to save money during the construction 

Figure 7.4. A negative cable for the impressed current 

system was attached to the bow where the spar was 

once mounted. A coating of epoxy protected the exposed 

metal. (Photo by H. G. Brown, NHHC)
H . L . : H U N L E Y R E C O V E R Y O P E R A T I O N S

76

phase, with the intention to construct it at a later date. 

Ultimately, the conservation plan was changed to a 

chemical-based passive soaking treatment, and the 

electrolysis tank was not required.

Treatment Solution

Preparation of the caustic solution was designed 

to be controlled by a combination of manual and 

automatic operations. The operator chooses from the 

PC control terminal the type of water needed for the 

solution (deionized or reverse osmosis), the desired 

tank level, and fill sequence. If required, the control 

system starts the reverse osmosis (RO) system. To 

prevent overfilling, each tank has a level indicating 

controller (LIC) to track the interior liquid level and 

indicate when the filling sequence is complete. Once 

the fill level is reached in any tank, the RO unit automatically shuts down and the control valve returns to 

the closed position. If after a period of five minutes, all 

LICs indicate the tanks are not full, the control valve 

opens and, if required for the solution, the RO unit 

restarts until tank indicators again show they are full; 

then the RO stops and the valves close (Davis & Floyd 

2000).

The operator then completes the solution by adding 

NaOH to the specified mixing tank until the desired pH 

Figure 7.5. Design specifications for the piping system for treatment solution. 

(Diagram by Shea McLean, courtesy of FOTH)
W A R R E N L A S C H C O N S E R V A T I O N C E N T E R

77

is reached. The tank agitator starts and operates continuously until transfer of the electrolyte to the treatment 

tank is complete. A caustic metering pump introduces 

the chemical into the mixing tank, monitored by a pH 

sensor and analytical controller. This system contains 

manual overrides and has the capability to manually 

conduct a quick-fill. If, during the caustic addition 

sequence, a high level alarm point is triggered, the 

pump and solenoid both shut off. Sensors also detect 

high pressure and low levels, shutting off the pump 

and solenoid as needed. The control system continuously monitors the pH and temperature in each tank. 

When the predetermined pH level is attained, the 

metering pump shuts down and the control valve 

returns to the closed position. The water is allowed 

to sit for 15 minutes, known as “dwell time,” and if 

the pH has fallen below the predetermined level, the 

system restarts and corrects it. Once the pH is reached 

and remains constant, the control system indicates 

the solution is prepared and ready for transfer to the 

treatment tank (Davis & Floyd 2000).

Treatment Tank

The system was designed to allow any chemical 

solution into the treatment tank only after an operator 

manually measures the pH and enters the values in 

the control system for record keeping and to ensure 

safety. The operator then initiates the fill sequence from 

the control terminal. The system’s safety features deactivate the transfer pump if at any point during the 

transfer the LIC on the holding tank indicates that the 

pre-determined low level is reached, or the treatment 

tank reaches the high level shutoff. 

Solution in the treatment tank is continually 

monitored for temperature, pH, conductivity, dissolved 

oxygen and chloride level. This data is stored and 

available to the operator for records and planning 

purposes. The instruments for monitoring these parameters were donated by Orion Research and Rosemount 

Analytical. The instruments provide data directly to a 

Rockwell Automation industrial touch-screen computer 

donated by McNaughton-McKay. The software for 

the computer was designed by W. R. Riggs & Associates, Inc. The filling and draining sequences are preprogrammable and do not require manual operations. 

The system could be monitored from offsite by the conservators through an internet connection. Finally, the 

DC power supplies that provide current for electrolysis 

are controlled at a set current based on predetermined 

settings. Exhaust fans operate continuously while the 

DC power supply is operating, exhausting hydrogen 

gas and other fumes originating from the tank (Davis 

& Floyd 2000; Mardikian 2004:139 ). The operator can 

make additions to the solution in the treatment tank by 

performing a makeup water sequence from the central 

computer. The solution can also be transferred temporarily from the treatment tank to a holding tank to allow 

access to the submarine. 

Chemical Disposal

Further infrastructure was developed to adjust the 

pH of the solution to allow for safe disposal through the 

city’s sewer system. The Pretreatment Discharge Permit 

required a pH of 6.5 to 9.5. Solutions under or above 

the required pH range had to be either increased by 

addition of NaOH or decreased with addition of nitric 

acid (HNO3

). Before disposal the solution required 

testing by an independent laboratory and, once 

approved, released into the sewer at a rate of 25 GPM 

(95 LPM) (Mardikian 2004:139).

To prepare the chemical solution for release, the 

operator selects a specific holding tank for acid addition 

and pH neutralization, and the liquid is pumped into it 

from the treatment tank. Once the solution is in place, 

HNO3

 from the acid pump is introduced into the holding 

tank until the requisite pH is reached. The tank agitator 

runs continuously during the acid addition and until the 

draining sequence is initiated. The control system continuously monitors pH and temperature in each tank 

throughout the dumping process. Although much of 

the system is automatic, an operator’s input is required 

to drain the neutralized solution to the sewer (Davis 

& Floyd 2000). During the acid addition and dumping 

process, if either the high level or high pressure alarms 

are activated, the pump stops automatically. 

Final Outfitting

The laboratory renovation was scheduled to be 

completed by 28 April, but testing and construction 

items were still being resolved into July. Mid-Atlantic 

Crane had a 15-day delay in installation of the cranes 

due to a shortage of steel, the delivery of which was 

impeded by weather. There also had to be a change 

order to strengthen the crane support system. By 

12 April, the Hunley team was working extensively with 

Davis & Floyd to finish the laboratory renovations and 

testing the equipment. Most of the construction and 

laboratory outfitting was completed during May 2000, 

although by 27 May, Davis & Floyd contractors were 

still working on a punch list of unfinished items or ones 

in need of repair (Jacobsen 2000a, 2000b; Mardikian 

2000c). Repairs and final punch list items continued to 

be worked on through June, with electrical and cooler 

problems to be corrected, as well as repairs to the 

tank’s coating. Window and roof leaks occurred during 
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78

a 27 June storm and had to be repaired (Mardikian 

2000d). 

As the date of initiating the recovery work drew 

closer, all of the plumbing, circulation, and deionized 

and RO systems still required testing. The chilled water 

tank was leak-tested and the pumping and fill cycles 

were tested. It was found to take four hours for a 

complete fill sequence. Also, the darkroom, fume hoods, 

and sinks had not been checked to see if they were functioning properly. Painting, electrical work, compressed 

air, and safety equipment such as eyewash stations 

still required finishing or installation. The mezzanine 

and tank bridge had not been completed and Smith 

still needed to check the work. All of the necessary 

chemicals, storage containers, supplies, and analytical 

equipment had to be obtained prior to recovery. Bill 

Williams of Newco arranged for a borescope at no cost 

(Caperton 2000). Fiberoptic lighting for the Hunley

tank was obtained through The Schneider Company of 

Columbia, SC. This consisted of two 40 ft. (12.19 m) 

long sections of waterproof Optiance A200 Accent Light 

fixtures containing twenty 3.5 in. (8.89 cm) diameter 

fixtures (Jordan 2000). Radiation safety certification 

had to be obtained through the South Carolina Department of Health and Environmental Control (DHEC) 

and FOTH staff trained in the operation of the x-ray 

unit and radiation safety. The laboratory also had to 

purchase and install phone and security systems. Lists 

of chemicals kept in the conservation laboratory were 

provided to the North Charleston Fire Department 

(Mardikian 2000b).

In addition to completing the initial work, a mechanical and HVAC service agreement was required for maintaining the heating, ventilating, air conditioning, refrigeration, and process equipment. Hipp Mechanical Services, 

Inc. of Charleston provided the periodic inspections 

and maintenance service for $14,355 per year. A crane 

inspection service agreement was also negotiated with 

Mid-Atlantic Crane (Beasley 2000). As of 18 July 2000, 

work on the laboratory punch list was still underway, 

although with fewer items left than previously. Work 

was being done to install the lift and to replace the 

chilling unit that was not working. Although the tank had 

been filled and drained successfully, water below the 

pump pickup had to be removed with a shop vacuum. 

By this time small artifacts from the excavation 

were being received into the lab and were handled 

accordingly (Mardikian 2000e). On 23 June, Bill Williams 

conducted a radiographic survey of the recovered spar. 

This involved removing the x-ray tube from the cabinet 

and establishing radiation safety boundaries. Once 

South Carolina DHEC had been provided with documentation of this survey along with the operating procedures for the x-ray tube outside the cabinet, they 

issued a facility registration approval for mobile use of 

the device (Patterson 2000).

Building Security 

Security for the laboratory was a concern once 

the submarine was inside and artifacts began to be 

recovered from the excavation of its interior. Any item 

from Hunley had monetary value as a collectible historic 

artifact. Particular hull components, such as hatches or 

propeller, would be of high value as would any artifacts 

from the crew. During working hours the building was 

monitored by a guard who controlled visitor access 

and monitored exits. The south entrance was the designated entry point for employees and visitors. This 

entrance was alarmed and could only be entered with 

an access card or through communication with a video 

intercom system. Other entrances on the north, west, 

and east sides were alarmed, and only used occasionally for specific tasks.

The building was outfitted with an alarm system 

with card reader access control, which was monitored 

after working hours by Coastal Burglary Alarm 

Company. The system initially consisted of four zones 

configured so that one or more zones could be deactivated while other zones were left alarmed. Motion 

detectors were installed throughout the building to 

detect movement and glass break detectors installed 

to detect entry by breaking through windows. Four 

outside closed circuit television cameras with pan, 

tilt, zoom, and low light capabilities monitored the 

approaches to the building. Imaging was recorded 

on a VHS video recorder system. The fire system was 

connected to the alarm system, which caused all 

alarm-controlled doors to unlock in the event of fire. 

An auxiliary generator would provide back-up power 

when there was a power failure, although this was not 

initially tied into the security system. An 8 ft. (2.44 m) 

high chain link fence ran the length of the west side 

of the building along the property line, 12 ft. (3.66 m) 

from the building. Once Hunley was inside the facility, 

North Charleston Police set up regular patrols and 

placed a marked K-9 vehicle in front of the building 

24 hours a day (SLED 2000a).

On 16 August 2000, a security survey was requested 

by Senator Glenn McConnell’s office. The survey team 

consisted of Lt. Chip Johnson and Senior Agent Bruce 

Otterbacker from South Carolina State Law Enforcement 

Division, Chief Clayton Spradley and Security Specialist 

Tom Scott from Bureau of Protective Services. They 

made several security upgrade recommendations. To 

improve security outside the building they suggested 

installing motion sensors on the roof, crash barriers on 

the east side of building, and iron bar window protectors and interior blinds on the laboratory area. They 

also recommended expanding the 8 ft. (2.44 m) high 

perimeter fencing to encompass the entire facility with 

card reader controlled access into the parking area; 

this area could also be microwave alarmed to activate 
W A R R E N L A S C H C O N S E R V A T I O N C E N T E R

79

the security system if there was an unauthorized penetration of the area. Additional recommendations for 

exterior security upgrades included: 

• Set camera system to record when movement is 

detected;

• Retain recorded video tapes for 30 days;

• Do not reuse previously recorded video tapes; 

• Retain digital copies of all recordings;

• Tie all cameras, recorder, and alarm system into a 

back-up power system;

• Increase view of camera on northeast corner to 

cover field of view of both rear doors and east side 

of building.

Improvements to security inside the building 

focused primarily on increased monitoring in sensitive 

areas. Recommended upgrades to the security system 

included:

• Additional movement sensors in upper portion of 

the treatment tank area; 

• Additional glass breaking sensors on the windows 

located above the treatment tank on east side; 

• Securing the computer and other monitoring/controlling equipment located on the mezzanine; 

• Two additional pan, tilt, and zoom cameras in the 

treatment area such that the rear doors and the 

computer control system on the mezzanine would 

be covered; 

• Positioning the cameras installed for internet 

viewing of Hunley so as not to disclose any security 

information; 

• An additional camera at south entrance positioned 

to provide full facial recognition of persons entering 

the building; 

• A camera in the north end of the clean lab area to 

provide view of laboratory area and any artifacts 

left out in the workspace; 

• Glass breakage sensors in the office area; 

• A panic alarm for personnel working in the 

treatment tank;

• A ringdown telephone at the receptionist desk 

connected directly to the North Charleston Police 

Department to expedite response time;

• Upgrading alarm wiring to add resistors to the loop so 

that the system cannot be bypassed.

Other recommendations addressed the risk posed 

by those inside the facility. They suggested that one 

staff member should be given security responsibility for 

the building, and that extensive background checks be 

conducted on all potential employees and volunteers. 

Permanent security personnel should be hired, and, in 

that event, a security office should be established and 

the monitoring equipment moved to that location. This 

could accommodate an additional monitor and recorder 

for the camera system, to operate in alarm mode, so 

that a full screen image of an intruder will be recorded 

after capture on the camera system. 

As the excavation progressed and artifacts began 

moving to various locations in the building, they recommended developing a bar coding and inventory system 

for small artifacts that are moved from the storage 

rooms. They also recommended that public viewing 

should be conducted in small scheduled groups, tours 

should be staged in another area separate from the 

lab and chilled water tank area, with members of the 

public escorted into the viewing area as a group by a 

volunteer or employee, and viewing should be through 

a glass panel. In addition, restrooms, which were 

shared between public and employee spaces, should 

be secured on the employee side (SLED 2000b). 

Not all of these recommendations were feasible 

but most were accepted and security was upgraded. In 

addition, after the gold coin was discovered, a system of 

maintaining precious items in bank safety deposit boxes 

was established. The Bureau of Protective Services 

assigned Officer Jay Griffin to be in charge of Hunley

security and provided other officers as weekend relief 

and to police the weekend tours (SLED 2000a).

Conclusion

In summary, the building was renovated and 

outfitted to become one of the most well-equipped, 

spacious, and efficient archaeological conservation laboratories in the United States. This was accomplished 

in record time, four to five months. It was done at the 

same time the final engineering of the Hunley recovery 

was underway and completed in time for the lift. The 

submarine was successfully delivered into the building 

and placed in the fully functional chilled water tank 

without a hitch. Building the conservation laboratory was 

a unique and unprecedented experience for the archaeologists and conservators, but also for the engineers, 

architects, and construction contractors. Building 255 

was renamed the Warren Lasch Conservation Center in 

gratitude for FOTH Chairman Lasch’s efforts to advance 

the recovery and conservation of H. L. Hunley. 
80

8. Preliminary Fieldwork

C l a i r e L . P e a c h e y a n d D a v i d L . C o n l i n

From 27 October through 9 November 1999, a 

team conducted fieldwork on the Hunley site to investigate structural details of the hull and to generate data 

necessary for OII’s recovery plan. The objectives of the 

short project were many: to take thickness measurements of the iron hull plates, to determine the pattern 

and condition of the rivets holding the plates together, 

to assess the extent and nature of corrosion of the 

metal, to partially investigate the previously unexcavated starboard side of the vessel, and to determine 

the structural character of the sediment layers adjacent 

to the submarine. This information was crucial for OII’s 

planning and design of the apparatus that would lift 

Hunley from the seabed, transport it to the laboratory, and support it during many years of conservation 

treatment.

Team members were NHC archaeologist Dr. Robert 

Neyland, NHC/SRC archaeologists Dr. David Conlin and 

Claire Peachey, contract archaeologists Harry Pecorelli 

III and Ralph Wilbanks, OII project manager Steve 

Wright, Hunley project conservator Paul Mardikian, and 

Dennis Donovan of Coastal Inspection Services, a specialist in ultrasonic measurement of boiler structures 

and underwater structures. Both qualitative and quantitative measurements were made to assess the condition 

of Hunley’s metal. These included recording surface 

roughness, testing magnetic pull, measuring electrical 

conductivity, and measuring hull thickness with metal 

and ultrasonic probes. During the short project, the 

team retrieved important technological information 

about Hunley, as well as 36 samples (99-001 through 

99-036). The results of the project influenced the final 

recovery methodology by determining hull thickness 

and sampling of rivets for corrosion analysis. 

As part of the same project, geologists Jim Biddle, 

Card Smith, and Bob O’Kelly from the U.S. Army Corps 

of Engineers, Savannah District, drilled a 60 ft. (18.29 m) 

deep sediment core adjacent to the site from the geological research vessel Explorer, captained by Tony 

Maze. The core was to be used for testing the sediment 

strength, which would directly affect the nature and size 

of the piles needed to support the frame to be used for 

lifting Hunley from the seabed.

Archaeologists conducted dive operations from Wilbanks’s 26 ft. (7.92 m) Parker Diversity using scuba and 

Aquacom full face masks with wireless communication 

for dictating data to the surface. During most of the 

dives the underwater visibility ranged from 0 to 1 ft. 

(0–0.3 m). 

Sample Area

After reacquiring Hunley’s location, the entire 

length of the submarine’s upper surface was exposed 

using a 4 in. (10.16 cm) water induction dredge. In order 

to have access to the submarine’s metal plates and 

rivets, archaeologists removed patches of the obscuring 

marine concretion from ten small areas of the surface, 

approximately 10 × 10 cm (3.94 × 3.94 in.) each. The 

submarine was completely covered in this extremely 

hard, precipitated concretion approximately 1 in. 

(2.54 cm) thick. They used a 3 lb. (1.36 kg) hammer and 

3⁄4 in. (1.9 cm) metal chisel to carefully crack and loosen 

the concretion to separate it from the metal surface. 

The concretion, though extremely hard, cleaved off the 

surface relatively easily once it was broken, because of 

a thin layer of flaky corrosion products between the 

metal and the concretion.

After deconcreting a small test patch, archaeologists chose another area that might hold construction 

details. During the 1996 partial excavation and mapping 

of Hunley, the team had observed a distinct depression 

just forward of the aft hatch on the port side, that was 

thought to be a vertical seam between two metal plates. 

This possible seam intersected the horizontal expansion 

strake, a band of metal added to the original boiler 

plate structure to increase the size of the submarine 

(see Chapter 12). Therefore, in 1999, the team chose 

this seam as a promising area to find rivets and other 

construction features.
P R E L I M I N A R Y F I E L D W O R K

81

Figure 8.1. Portside view showing thickness testing locations 1–6 and 9–10 (Areas 7 and 8 were located on the starboard side). The area where a vertical plate 

seam intersects with the expansion strake (photo, lower right) provided a wealth of useful data for the finite element analysis. The missing rivet allowed for limited investigation of the interior seam structure (reconstruction, lower left). (Diagram and photo by David L. Conlin, NPS)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

82

portion of the rivet shaft surviving. Archaeologists 

retrieved one degraded shaft using a small flat-head 

screwdriver and a pair of tweezers. They later sent this 

rivet to Dr. William Weins at the University of Nebraska, 

Lincoln, who analyzed it and found it to consist entirely 

of corrosion products, with no metal remaining (Weins 

and Makinson 2000). The diameter of the rivet hole 

exposed was 1.5 cm (0.6 in.).

Expansion Strake

Immediately above the expansion strake, a short 

length (6.5 cm, 2.5 in.) of the seam was completely 

cleaned of concretion and found to have an unexpectedly large width of 1.5 cm (0.5–0.625 in.). The depth of 

the seam was 0.6 cm (0.25 in.), reflecting the thickness 

of the hull plates at that seam. The plate edges were 

well preserved, sharp, and slightly beveled. The backing 

plate exposed at the seam had a slightly tacky surface, 

which may be traces of a waterproofing material 

applied either during or after construction.

Time did not permit careful cleaning of the concretion at the top and bottom edges of the expansion 

strake, so the condition and exact dimensions of those 

edges could not be determined at that time. However, a 

rough measurement gave an estimated strake thickness 

of 0.6–0.7 cm (0.25 in.). During a single rare period of 

reasonably good visibility, video footage was taken of 

the newly uncovered features.

Hull Thickness Measurements

A small, L-shaped probe inserted into the hole 

that had contained the heavily corroded rivet (noted 

above) allowed direct measurement of the thicknesses 

of the hull and backing plates in the area next to the 

vertical seam. Both the upper plate and the backing 

plate measured 0.31 in. (0.8 cm) each. There was a 

well-defined gap at the juncture between the two overlapping plates, probably due to corrosion of the plate 

surfaces. The plate thickness measured in the rivet hole 

was very close to the thickness measured at the seam, 

0.25 in. (0.6 cm).

In order to measure the metal thickness at several 

widely-spaced, representative points on the hull, 

including on and below the expansion strake, nondestructive ultrasonic thickness (UT) measurements 

were performed by Dennis Donovan of Coastal Inspection Services. With this technique, the speed of sound 

waves traveling through a material can be used to 

determine the thickness of the material. Each metal 

has a known velocity based on its grain structure. 

Therefore, after calibration of the UT transducers for 

that particular metal, the transducers can measure the 

Indeed, this area turned out to hold a wealth of 

information in an area only approximately half a meter 

square (Figure 8.1). The depression was found to be 

a vertical seam between two butt-joined metal plates. 

The seam was backed by another plate or band of metal 

of undetermined dimensions. The vertical seam had 

rivets on both sides of it, both above and below the 

expansion strake. The expansion strake had rivets along 

its top and bottom edges where it overlay the edges of 

the boiler plates.

Because visibility in the muddy water was negligible, Paul Mardikian acquired a dental molding putty 

(3M Express STD Firmer Set Vinyl Polysiloxane Impression Material Putty #7312) that allowed the team to 

take detailed molds of the surface of the iron, the rivet 

heads, and the seams. A diver mixed the two-part putty 

immediately prior to diving, took it down as a ball, and 

pressed it firmly onto the surface of the metal. It set 

in three to five minutes to produce finely detailed 

molds which recorded subtle features divers could not 

feel with their fingers. From these, the archaeologists 

determined that the metal plates (in the areas tested) 

showed only moderate surface roughness, indicating 

they might be in a good state of preservation.

Rivets 

In total, 21 rivet heads were exposed, which were 

found to be in variable condition. Many could be 

examined only from the dental putty mold, because 

they were flush with the metal plate surface and could 

not be detected by touch (Figure 8.2). The rivet heads 

had a diameter of approximately 1.063 in. (2.7 cm) and 

were spaced 2 to 2.25 in. (5.0–5.5 cm) apart, center 

to center. There appeared to be no difference in the 

size and spacing of the seam rivets as compared to the 

strake rivets. All of the exposed rivet heads were lightly 

corroded, in the form of pitting and metal loss. Two 

heads were completely corroded away, leaving just a 

Figure 8.2. Dental putty mold of the seam 

between two hull plates and the expansion 

strake. A missing rivet is also represented by 

the positive impression in the upper right. 

(Photo by David L. Conlin, NPS)
P R E L I M I N A R Y F I E L D W O R K

83

Figure 8.3. Graphs of the ultrasonic thickness readings from the port side of Hunley’s hull. (Graphs 

by David L. Conlin, NPS)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

84

zero-visibility environment. Next, they tried 

the grinder with a 60-grit 

sanding wheel but also 

found it too abrasive. 

They tested a stiff wire 

brush and even that was 

too abrasive. Finally, they 

settled on hand-sanding 

the metal surface with 

80-grit sandpaper. 

Although the process 

was slow, it produced 

better, more controlled 

results. 

To take the thickness 

measurement, a diver 

pressed the probe, which 

was attached to a cable 

from the surface vessel, 

firmly on the smoothed 

metal surface. Donovan 

remained on the surface 

to monitor the ultrasonic 

instrument and record 

the results. With communication gear, he directed the 

diver to move the probe around on the hull surface 

until a steady reading was obtained, and then to move 

it to the next test location. Donovan captured 38 to 

83 readings from each of the 10 test locations, except 

Area 5, from which he captured only 10 readings (Figure 

8.3). The thicknesses obtained from the ten areas were 

quite uniform, averaging 0.34–0.43 in. (8.64–10.92 mm) 

(Figure 8.4). The range of readings was, however, quite 

large, with the lowest being 0.283 in. (7.19 mm) (Area 3), 

and the highest 0.637 in. (16.18 mm) (Area 10). As an 

experiment, divers took probe readings from Area 4 

time taken for the sound waves to travel from the transducer through the material to the back wall (where an 

air boundary usually exists), and back to the transducer.

The transducer used was the Auto-V, developed 

and calibrated specifically for use on cast and wrought 

iron by Krautkramer Branson of Lewiston, Pennsylvania, manufacturers of UT measurement equipment. 

It was based on an earlier model developed by the 

Hartford Steam Boiler Inspection and Insurance Co., 

Hartford, Connecticut. Because of the irregular, inhomogeneous grain structure of cast and wrought iron, 

such a custom-designed transducer was needed. The 

Auto-V had an array of four transducers, two that gather 

velocity and two that measure thickness; it sampled 

thickness and velocity four times per second and autocalibrated with every reading. It used low frequency 

sound waves, approximately 2 megahertz. To see if it 

would produce accurate readings on historic iron that 

had been submerged for more than a century, Branson 

tested it on a wrought-iron artifact excavated earlier 

in the year from USS Housatonic. The transducer was 

found to have an accuracy of ±5%, confirmed through 

caliper measurements of the test artifact.

The only way to obtain accurate measurements of 

hull plate thickness was to ensure the transducer was 

placed be flat against the metal surface. Therefore, the 

surface had to be smoothed to remove all corrosion 

and roughness in an area slightly larger than the area 

of the probe. Archaeologists experimented with several 

techniques for dressing the hull’s surface. They began 

with a pneumatic grinder with a coarse grinding wheel 

but found it too abrasive and difficult to monitor in the 

Table 8.1. Mean Thickness of Hull Plates

AREA

MEAN 

THICKNESS 

(IN.)

NUMBER 

OF DATA 

READINGS RANGE

Area 1 0.403 44 0.029

Area 2 0.340 38 0.066

Area 3 0.368 83 0.130

Area 4 not determined

Area 5 0.417 10 0.001

Area 6 0.360 48 0.059

Area 7 0.369 47 0.117

Area 8 0.374 47 0.007

Area 9 0.341 53 0.050

Area 10 0.439 56 0.320

Figure 8.4. Ultrasonic thickness values from nine of the ten test areas on Hunley’s hull. 

Data from Area 4 was not useable. (Graphs by David L. Conlin, NPS)
P R E L I M I N A R Y F I E L D W O R K

85

without surface preparation, but the data was not 

useable.

The mean measurements (in inches) from each area 

are listed in Table 8.1. These values correspond to 3⁄8 in. 

(9.53 mm) rolled iron boilerplate. The smaller thickness 

values may have been due to loss of metal through 

corrosion, and the larger values may reflect corrosion 

product buildup or the presence of additional metal 

such as a backing plate.

Qualitative Hull Assessment

To assess the residual metal content of the 

submarine components in a general, qualitative manner, 

archaeologists performed a simple test of magnetism. 

They found that a 6 cm (2.36 in.) diameter disc-shaped 

magnet was strongly pulled when placed near the bare 

metal surface of the hull plates, and could be removed 

only with difficulty. 

To further assess the condition of the metal in a 

qualitative way, archaeologists measured electrical continuity between different areas of the hull. Electrical 

continuity would indicate that the metal components 

were still in contact, not completely separated by nonmetallic corrosion layers. Divers took measurements 

with a standard ohmmeter modified by attaching long 

cables between the meter and the probe tips. Results 

showed that there was electrical contact between 

adjacent metal components, for example between 

different rivets and between the rivets and the plates. 

This indicated that although some rivets may have been 

completely corroded away, others were in good metallic 

condition. Measurements taken from more widely 

separated areas on the submarine did not register continuity, which possibly indicated a discontinuity in the 

structure, but also may have been due to lack of good 

contact with the probe tips. Some readings taken on 

adjacent areas of the same plate did not register continuity, indicating that negative results were suspect. 

Positive results must also be regarded cautiously, as 

electrical continuity requires only one point of metallic 

contact, and is not indicative of overall metallic content 

and structural coherence. This basic test was perhaps 

most instructive in confirming metallic content of the 

rivets, as this had been a question of some concern. 

Sediment Samples

The poor condition of the rivet adjacent to the 

seam provided the unexpected opportunity to take 

several samples of sediments from the interior of the 

submarine, through the empty rivet hole. Samples were 

taken by pushing 12 mm (0.47 in.) outer diameter rigid 

plastic tubing (Tygon) into the sediment, which filled the 

submarine at this level. These samples were placed in a 

freezer and were used for later microbiological analysis.

Following the ultrasonic measurements, the deconcreted portions of the hull metal surface were covered 

with an epoxy product, Ameron Devoe Devclad 182 

Splash Zone Barrier Coating, to prevent prolonged 

exposure to the oxygenated seawater, which would 

accelerate corrosion. The product proved difficult to use 

for this specific application. The epoxy did not readily 

adhere to the metal surface, requiring divers to pile 

sandbags over each patch until it hardened. 

To backfill the site at the end of the project, 

sandbags were positioned around all protruding 

features such as the forward cutwater, hatches, and the 

snorkel box. Reversing the dredging process, spoil from 

the dredge was used to rebury the submarine.

Conclusion

This preliminary work at the site provided valuable 

data about the submarine’s state of preservation and 

structural integrity. From a very short, but focused, 

research effort utilizing novel techniques such as 

dental molding compound and existing expertise for 

corrosion analysis and UT thickness measurement on 

a non-standard material (wrought iron), the team was 

able to produce concrete, scientifically-based information that was key in developing and shaping recovery 

methodologies.

First and foremost, the research indicated that 

the hull plating had sufficient thickness (at least in 

the measured areas) to support the weight of the hull 

during recovery—particularly during the stresses of 

the transition from water to air—when lifted from the 

bottom. The complete disintegration of one of the rivets 

during the examination was of considerable concern, 

as it indicated differential corrosion of a key structural 

element; however, the apparent soundness of adjacent 

rivets mitigated those concerns a great deal. Finally the 

indications from probing through the rivet hole that the 

hull was likely completely (or almost completely) full 

of sediment provided important evidence regarding 

the presumed weight of the submarine for recovery 

planning and also gave the team confidence that these 

sediments provided some internal support to the hull 

that would not have been there if the submarine was 

empty.

In summary the work informed the Hunley 

Oversight Commission’s evaluation of the two recovery 

proposals, and formed the basis of the finite element 

analysis used by the engineers to design appropriate lift 

equipment and procedures.
86

9. Engineering

H e a t h e r G . B r o w n

The recovery of the submarine Hunley represents 

a level of complex engineering that is rarely associated 

with an archaeological project. Equipment adapted 

from oil drilling and marine salvage technologies was 

applied to the recovery of a fragile, 136-year-old vessel, 

requiring a degree of delicacy not generally required 

in commercial industries. Working closely with archaeologists and conservators, the Oceaneering (OII) team 

developed a plan that surpassed all expectations and 

resulted in the safe and successful raising and transportation of an invaluable piece of American history.

Several distinct challenges were faced by the 

engineers planning the lift. First, unlike the competing 

International Archaeological Lifts plan, the OII plan 

called for exposing the vessel and recovering it with 

gear that would come into direct contact with the 

hull (see Chapter 5). The concretion layer that had 

developed on the submerged iron was hard and relatively scratch-resistant, but also brittle, so protecting 

this layer from impact or stress fractures during the 

lift was important. In addition, during its time on the 

seabed, the vessel had gradually filled with sediment, 

making the internal load on the structure much higher 

than it was designed to bear, particularly when out of 

the water. It was, therefore, necessary to distribute this 

additional burden carefully and evenly over the hull to 

prevent breakage, cracking, or distortion. Tests had also 

indicated that rivet strength had been compromised, at 

least in some areas, leading to concerns that the hull 

plates would separate under the added pressure during 

the lift (Weins and Makinson 2000). 

Second, the submarine had settled on the seabed 

canted an estimated 45° to starboard. The post-recovery 

plan was to excavate the interior of the vessel under controlled conditions in the laboratory in hopes of finding 

out what caused it to sink. This would require a detailed 

forensic investigation, including recreating the order of 

deposition of all internal elements. To ensure all possible 

evidence remained undisturbed, it was necessary for the 

vessel to maintain its in-situ position during and after 

transport. Any shifting of position could potentially alter 

the interior relationship between the contents or disrupt 

the stratigraphy of the sediment layers.

Finally, the lift method required that the submarine 

be slung beneath a large metal frame, or truss. This 

system required the truss to rest stably on the seabed 

for a period of several weeks while the hull was being 

rigged. To provide such a stable platform, a structure 

needed to be installed in the sea floor without 

damaging the site. Archaeological experts reviewing the 

proposed plans expressed concern that vibration from 

driving piles into the ground could adversely affect the 

site. In addition, traditional metal piles are normally left 

behind after use; however, this would have left a strong 

metal signature that would disrupt further magnetometer survey of the site after the removal of the vessel. 

To address these issues, a number of the lifting 

components were designed and built specifically for 

the recovery. While customized for the size and shape 

of Hunley, the general design of the equipment and 

Figure 9.1. Cross section of hull based on measurements 

taken at the site in 1996. (OII 2000a:31)
E N G I N E E R I N G

87

was assumed to be sand, and an applied pressure for 

submerged wet sand of 0.5 p.s.i. (0.345 bar) was used 

(OII 2000a:36).

Based on the rivet analysis conducted in 1999, risk 

of rivet failure was deemed high. A number of models 

were generated using different rivet strengths, primarily 

by altering the elastic modulus and elemental thickness 

of the hull. The models showed that even at an 80% 

reduction in rivet strength, there was little chance of 

rivet failure as long as the hull remained uniformly 

loaded (OII 2000a:52). As a result, the recovery plan 

was amended to include additional slings that wrapped 

around the unsupported top portion of the central hull 

area to minimize movement and to apply a uniform 

pressure to the hull (see Figure 9.8). 

Recovery Frame (Truss)

The primary component built for the recovery 

was the frame, which would cradle the hull and bear 

its load. Described by the engineers as “an all welded 

steel tube box truss,” this was a long rectangular metal 

frame from which Hunley would be suspended in slings 

(OII 2000a:2); it was also fitted with legs high enough 

to provide ground clearance for the hull once on land 

(Figure 9.2). The OII design team was led by engineer 

Perry Smith, and fabrication was performed by Able 

Iron Works of Charleston, South Carolina.

The frame was designed using the dimensions of 

the hull gathered during the 1996 site assessment: 

39 ft. 5 in. long (12.01 m) (without propeller and 

rudder assembly), 3 ft. 10 in. (1.17 m) wide, 4 ft. 3 in. 

(1.30 m) high (Murphy 1998:76). Built to accommodate the hull and slings with a span broad enough to 

support the vessel at its in-situ orientation, the frame 

was 50 ft. (15.24 m) long, 10 ft. (3.05 m) wide, and 10 ft. 

(3.05 m) high. Based on the reported dimensions, the 

hull volume was estimated at 400 cubic ft. (11.33 m3) 

(OII 2000b:App. E). From this, the weights of both the 

hull and the sediment/water load contained within it 

were calculated (Table 9.1). Applying a 150% margin of 

adaptations made for the hull’s protection may provide 

a useful model for future archaeological recovery 

operations.

Finite Element Analysis

In order to design the equipment for the lift, the 

engineers needed to conduct a structural analysis of the 

hull based on finite element modeling. This method of 

modeling the behavior of an object or a system under 

various hypothetical stresses provided valuable parameters for planning load distribution and support structures, as well as identifying critical areas of potential 

failure. In particular, they wished to test the inherent 

strength of the hull and to project how much the 

hull would move once its weight was transferred to 

the slings. To perform the analysis, engineers ideally 

needed to know:

• Dimensions, including shape and hull thickness;

• Material properties including modulus of elasticity, 

yield, and ultimate strength of all parts;

• Rivet details, including size and pitch;

• Density and amount of contained material.

As the geometric shape of an object is an essential 

factor in finite element analysis, a cross section was 

developed based on measurements taken during the 

1996 survey (Figure 9.1). Described as “obround,” the 

main body of the hull has two parallel sides with a semicircular top and bottom (OII 2000a:28). Hull thickness 

data was gathered during the preliminary fieldwork in 

November 1999 (see Chapter 8). The hull was made 

of wrought-iron plate, which varied somewhat in 

thickness, but a minimum average thickness was calculated at 0.340 in. (8.636 mm) for use in the model 

(OII 2000a:29).

The material properties had to be supplied based 

on the known properties of wrought iron. The size, 

pitch, and spacing of the rivets were recorded during 

the November 1999 expedition. The material inside 

Figure 9.2. Side view of the construction plan of the recovery frame with bearing seats attached. (After OII 2000b:App. F) 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

88

error to the live load for safety, the truss was designed 

to accommodate a gravity load of 75,000 lb. (37.5 tn., 

34.02 t) (Smith 2001). 

The total weight of the hull, contents, and frame 

needed to be within the capacity of the two cranes that 

would be used to install the vessel in its tank at the 

conservation lab, which were rated to 20 tn. (40,000 

lb.; 18.14 t) each (STI n.d.:1). To minimize the weight 

of the frame itself while maintaining maximum bearing 

strength, it was constructed of a combination of rectangular and square steel hollow structural sections of 

ASTM A500 Grade B steel (Smith 2001). The bottom 

braces, from which the submarine would hang, were 

the most robust, at 8 × 6 × 1⁄2 in. (20.32 × 15.24 × 

1.27 cm). The legs were 6 × 6 × 1⁄2 in. (15.24 × 15.25 × 

1.27 cm), while the diagonal and cross braces ranged 

from 3–5 in. (7.62–12.7 cm) square and 1⁄4 – 3⁄8 in. (0.64–

0.95 cm) thick (OII 2000b:App. E). The finished frame, 

without the bearing seats (discussed below), weighed 

17,730 lb. (8,042 kg) (Smith 2000b). 

From an engineering perspective, the structure 

had to fulfill two roles—while rigged to the suction 

piles under water it was a long span truss, but on the 

surface, supporting the submarine on its legs, it was a 

braced frame (Smith 2001). As part of the long span 

truss, a bearing seat, roughly triangular in profile view, 

was welded to each end of the frame (see Figure 9.2). 

The pieces would anchor the frame to the piles in the 

seabed, creating a level and stable environment for 

rigging the slings. Once the lift was completed, the 

bearing seats would be removed, as they were no 

longer needed and could not fit within the storage tank 

at the conservation laboratory. The full span of the truss 

with the bearing seats in place was 62.5 ft. (19.05 m). 

The top chord plan utilized vierendeel panel 

openings, a structural style that eliminates cross 

bracing, to allow better access for the divers (Smith 

2001) (Figure 9.3). Chevron braces along the sides were 

added to withstand lateral forces from currents, wind, 

and vessel motion, as well as horizontal forces from the 

gravity load of the submarine in the slings. The bracing 

design was so effective that the total displacement of 

the bottom brace after the lift was 0.625 in. (1.59 cm) 

over 50 ft. (15.24 m) (Smith 2001). Ultimately, the frame 

could remain stable in a current of up to 2 knots or 

winds up to 100 mph (161 kph) and “withstand to 2 g

vertically, 0.2 g longitudinally and 0.4 g laterally” (Smith 

Table 9.1. Gravity Load Data

Component Estimated*

Estimated with 

Error Margin**

lb. kg lb. kg

Hunley (hull) 23,975 10,875 25,000 11,340

Sediment Load 34,500 15,649 50,000 22,680

Truss Dead Load 22,000 9,979 22,000 9,979

Total 80,475 36,503 97,000 43,999

* Source: OII 1999b

** Source: OII 2000b:App. E

Figure 9.3. A view of the top of the frame in the chilled 

water tank. The wide openings provided by the vierendeel structure maximized diver access to the 

submarine during the recovery process. (Courtesy of 

FOTH)
E N G I N E E R I N G

89

by oil companies for some time. As discussed above, 

this style of piles could be installed without vibration, 

and could be easily removed so as not to interfere with 

future magnetometer investigations of the site. 

Suction piles are hollow, metal cylinders, or caissons, 

closed on the top with a valve through which water 

can be pumped out. They are placed on the seabed 

and allowed to sink into the seabed under their own 

weight (known as self-weight penetration), which forms 

a seal that will enable the development of differential 

pressure once the pump starts. This pressure drives the 

caisson smoothly into the seabed until the caisson has 

reached desired penetration depth. Once set, the upper 

surface, or caps, of the piles act as table tops to support 

the ends of the lifting truss. The caissons are removed 

simply by reversing the pump, channeling water into 

the caisson, forcing them up out of the seabed, where 

they can be lifted back to the surface by crane. 

All suction piles are individually designed for their 

specific use. Two of the primary factors to consider 

during the design process are the soil composition and 

the required holding capacity. The latter had already 

been calculated for the truss design and came to 

approximately 75,000 lb. (34,019 kg). Sediment properties were gathered from the 60 ft. (18.29 m) core 

samples taken by the Army Corps of Engineers during 

the November 1999 investigation. For predominantly 

clay-based sediments, suction piles are generally long 

and narrow, while for sandy sediments they tend to be 

as wide as they are high (Delft 2006). Analysis of the 

cores allowed for the calculation of skin friction, which 

in turn determined the depth of penetration required. 

In the case of Hunley, another factor was the shallow 

water depth, which called for a large pile cap area, thus 

2001). It would be safe during storm surges associated 

with hurricanes, and, in the event of such a storm developing, the frame could remain in place on the seabed 

and provide some level of protection for the submarine, 

even if only partially rigged. 

Another important consideration in the frame’s 

design was the fact that it would remain submerged 

in the conservation tank during the full duration of the 

interior excavation of Hunley, as well as in a chemical 

solution during the conservation phase, an estimated 

8–10 years. Therefore, all welds had to be made watertight to prevent corrosion, and a corrosion-resistant 

coating compatible with the electrolyte applied to 

the entire exterior surface of the frame. Two coats of 

Sherwin-Williams Dura Plate 235 epoxy were applied 

after an SSPC-10 surface preparation (Smith 2001). The 

straight lines and flat surfaces of the hollow structural 

sections made both processes more efficient and economical (STI n.d.:2).

To keep the submarine wet during transport to the 

laboratory, a soaker system was installed on the truss 

(Figure 9.4). While this system was relatively simple, 

consisting of ordinary lawn sprinklers installed along 

alternate cross braces, connected to hoses supplied 

with seawater, it was thorough and easy to install 

quickly. Hunley was out of water for a total of 9.5 hours, 

during which time it was never allowed to dry out. 

Suction Piles 

A stable support foundation was required to 

support the truss on the seabed while the slings were 

being rigged. The engineers selected suction piles for 

this purpose. It was a proven technique developed for 

mooring deep-water oil rigs and had been safely in use 

Figure 9.4. The soaker system designed to keep the hull wet 

during transport utilized ordinary sprinklers and pumped 

seawater. At left are the burn marks left from removing 

the bearing seats. (Photo by Rand Pixa, courtesy of FOTH) 

Figure 9.5. Three-dimensional cutaway view of 

caissons designed to support the recovery frame. (OII 

2000b:App. D)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

90

the diameter of the pile needed to be wider than the 

penetration depth (Smith 2001). The caissons designed 

for the Hunley by Delmar Systems, Inc. of Broussard, 

Louisiana, were 12 ft. (3.66 m) deep and 18 ft. (5.49 m) 

in diameter. They were made of 1.5 in. (3.81 cm) thick 

ASTM 572 steel with internal bracing (OII 2000b:App. D) 

(Figure 9.5). 

The pile cap was equipped with two 16 in. (41 cm) 

diameter drain valves, a 4 in. (10.16 cm) diameter 

suction pump flange and padeyes for attaching lifting 

cables, features common on most suction piles. For the 

Hunley lift, a specially-designed adjustable tower was 

added to receive the bearing seats of the truss (Figure 

9.6). These platforms, 13 ft. (3.96 m) long by 3.5 ft. 

(1.07 m) wide, could move vertically ±12 in. (0.30 m) for 

a total of 24 in. (0.61 m); horizontally they could move 

15 in. (0.38 m) parallel toward and 24 in. (0.61 m) away 

from the submarine (Smith 2000a), thereby allowing for 

a limited margin for error in placing the piles.

The suction piles were marked with depth indicators so they could be monitored by divers during 

the installation process. A dry land training exercise 

was performed with the recovery equipment so that 

potential problems could be anticipated and corrected. 

For installation, the caissons were rigged topside, then 

lowered by crane to the seabed and guided into place by 

divers (Figure 9.7). The seabed was prepared in advance, 

with an area approximately 20 ft. (6.1 m) in diameter 

and 5–6 ft. (1.52–1.83 m) deep excavated down from 

the mudline to receive the caissons, to ensure stability. 

The divers also monitored the evenness of pile caps and 

penetration rates during suction operations.

Once in proper position, divers closed off the 

flooding valves with blind flanges to prepare the pile 

for pumping the water out of the pile. A submersible 

pump was installed on the pump flange and suction 

operations commenced. One OII diver monitored the 

pile penetration depth while a second monitored the 

pump from the pile cap during water evacuation. Pump 

pressure, gauge pressure, pile level, and penetration 

depth were continually monitored. The penetration 

rate, calculated using 10 p.s.i. (0.69 bar) and 500 GPM 

(1,893 LPM), was expected to be 3 in. (7.62 cm) per 

minute for a total of 48 minutes to suction down each 

pile (Smith 2000a). In practice, the total time was closer 

to 60 minutes. 

The piles were removed with no complications on 

the day after the lift. Divers attached lifting cables to 

Figure 9.6. Profile of suction pile as installed, with adjustable tower table for the bearing seat. (OII 2000b:App E.)

Figure 9.7. Fully rigged suction pile being lowered into 

the water. Depth markings can be seen down the side of 

the pile wall at left. (Courtesy of FOTH)
E N G I N E E R I N G

91

Figure 9.8. Diagram showing proposed placement of 

secondary slings for added stability. (OII 2000b: App. F)

the pile, and a pump attached to the suction pump 

flange. With the crane applying constant pressure to 

the cables and the pump reversed to flood the caisson, 

the skin friction of the sediment was overcome and the 

pile pulled free of the seabed. Both piles were raised to 

the surface and placed on the deck of Karlissa-B, leaving 

the seabed clear of intrusive structures.

Slings

The use of flexible nylon slings to support the 

submarine provided even distribution of weight along 

the whole system while allowing for individualized 

padding and rigging of each segment of the hull. By 

excavating only a short length of the hull at a time, each 

sling was set and tensioned to support the vessel in 

the exact position in which it was resting in the seabed.

The slings were custom made for the recovery by 

LiftAll of Landisville, Pennsylvania, in conjunction with 

Southern Weaving of Greenville, South Carolina. Since 

the slings would be supporting the vessel for the next 

decade to come, they were designed with strength, flexibility, and endurance in mind. Nylon was chosen since 

it would not deteriorate in a sodium hydroxide solution, 

the electrolyte proposed for use during Hunley’s conservation phase (OII 2000a:16). The primary slings, 32 

in all, were rigged beneath the vessel to support its 

weight, and were 12 in. (30.48 cm) wide, spaced on 

15 in. (38.10 cm) centers (OII 2000b:9). They had an 

estimated working capacity of 16,000 lb. (7,258 kg) and 

6% stretch when fully loaded for a maximum stretch of 

1 in. (2.54 cm) (OII 2000a:16). Woven into the fabric at 

regular intervals along the edges were 1 in. (2.54 cm) 

square holes protected by grommets that could be used 

to attach padding elements if necessary. The slings 

were hung from the bottom braces of the frames using 

12 in. (30.48 cm) turnbuckles on the port side and 6 in. 

(15.24 cm) versions on the starboard side, allowing for 

precision tensioning. The turnbuckles had a minimum 

working load of 5,200 lb. (2,359 kg) each (OII 2000a:16). 

A set of six secondary slings, 8 in. (20.32 cm) 

wide, were rigged over the top of the hull between 

the conning towers (Figure 9.8). These slings were a 

response to concerns about weak rivets. The slings 

wrapped around the main body of the hull to counteract any circumferential, or hoop, stress it might 

undergo. They were attached low down on the port 

side to the primary slings, then across the hull to the 

starboard sling rigging, where they were attached with 

turnbuckles and tensioned just enough to compress the 

neoprene pad below.

Compliant Support System

The slings alone were not sufficient to fully conform 

to the shape of the hull. The varying curves, uneven 

concretion surface, and protruding elements of the 

hull all posed difficulties for safely supporting the 

load. A combination of neoprene padding and polyurethane foam was used to ensure the vessel rested 

comfortably in the slings without any shifting or uneven 

pressure. The principal method of stabilizing the vessel 

was a compliant support system based on the use of 

self-hardening foam that was molded to the shape 

of the hull to provide support as needed. At the time 

the system was proposed, an appropriate substance 

for use under water had not yet been identified. Mike 

Gatto, of NCS Supply, a frequent supplier to the U.S. 

Navy, recommended Froth-Pak polyurethane foam. 

Manufactured by Flexible Products, Co., a subsidiary 

of Dow Chemical, this two-part foam is injected into 

a mold and hardens in place. Several days of testing 

were required to determine the product’s effectiveness 

under water and to develop a delivery system. Up to 

that point, there had been little success using polyurethane foam in this environment due to water restricting 

the exothermic reaction of the polymerization process 

(Drukenbrod 2000). OII needed to determine: 

1) How effectively an off-the-shelf, two-part polyurethane foam can be applied underwater;

2) Effects of hydrostatic force on the cured foam’s 

properties;

3) Expansion rate and compressive force of the foam 

due to the chemical reaction of the components 

within a confined space during the set-up period;

4) Dimensional stability of the foam, mixed at a 

set pressure, then brought to the surface. (OII 

2000b:App. H).
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

92

The tests proved the Froth-Pak product would work 

well in the conditions at the site. They then had to 

develop a delivery system to get the liquid foam in place 

against the hull before it began to harden, a window 

of only a few minutes. Vinyl bags were developed to 

contain the foam. They would cover the length of the 

side of the sling that would be in contact with the hull, 

and were attached to the slings with cable ties via 

grommets prior to filling (Figure 9.9). 

As a two-part foam, two hoses had to run from the 

surface, down to the divers below, where they would 

meet at a diver-operated nozzle. When the vinyl bag 

was in position, the diver would inject the foam, which 

then expanded to conform to the hull’s shape. To ensure 

that the vinyl bags were not overfilled and damaged, a 

one-way relief valve was built into the opposite end 

of the bag from the fill valve. In practice, due to the 

restricted visibility, divers would often have to rely on 

counting for so many seconds to know when the bag 

was at capacity. 

Some protruding areas of the hull required more 

customized support, in particular, the starboard diving 

plane. Support material for this area consisted of steel 

standoff blocks fabricated specifically for each sling 

station along the plane. These standoff blocks diverted 

the weight of the submarine and interior load around 

the projecting hull elements and prevented the rigging 

from making contact with them.

The compliant support system proved 100% successful. It could be deployed relatively easily and it set 

up quickly despite the underwater environment. It held 

the submarine exactly in position not only during the 

initial recovery and transport, but maintained its shape 

and firmness during the subsequent eleven years in 

the tank, until the vessel was rotated upright in 2011 

(Jacobsen 2012 elec. comm.) (Figure 9.10).

Load Cells

Each sling station on the truss was equipped a load 

cell, wired to the starboard turnbuckle (Figure 9.10). 

These devices measured the amount of load on each 

sling at all times and relayed the data to the computer 

that was used for monitoring the loads topside. 

OII engineers calculated that the lifting force should 

be less on the ends of the submarine than in the center. 

Based on this model, the weight apportioned to each 

sling could be calculated, resulting in a tension value 

for that sling. After the foam was installed and allowed 

to harden, divers took up the tension on the slings via 

the turnbuckles, as directed by topside personnel, to 

reach the necessary strain values. Once the submarine 

was completely slung, the graphical sling tension display 

on the load-cell monitor screen was bell-shaped (Figure 

9.11). Throughout the entire recovery operation loads 

on all slings were monitored and adjusted as required. 

The load cell system was also utilized during the 

conservation phases of the project. Individual slings 

could be loosened for conservation considerations 

and then re-tensioned to original value. During this 

phase, slings often needed to be removed temporarily 

to allow access for excavation of the interior as well as 

for thorough documentation of the outer hull.

Figure 9.9. Members of the engineering team practice 

fastening a vinyl bag to a sling in land-based trials. 

(Ccourtesy of FOTH)

Figure 9.10. Turnbuckles in place on the frame with load 

cells rigged. (Courtesy of FOTH)
E N G I N E E R I N G

93

Deflection Monitoring

Vertical deflection along the hull’s longitudinal 

axis was monitored during excavation and sling installation. An LVDT (linear variable displacement transducer) system tied in with the load cell data acquisition process recorded deflections in the hull during sling 

installation. Three LVDT’s were installed on truss panel 

points above Hunley; one each at the bow and stern 

and one at the center of the hull. The center and stern 

transducers, however, failed to work properly during 

sling operation. Therefore, the two malfunctioning 

units were replaced with simple vertical rods, which 

rested on the hull surface and would move freely up 

or down if the submarine shifted (Figure 9.12). Manual 

vertical measurements of the rods were then recorded 

to measure any deflection of the hull. Deflections 

recorded throughout the slinging operation were less 

than 0.5 in. (1.27 cm).

Conclusion

The use of experienced engineers is somewhat 

of a luxury in the archaeological field, but it proved 

critical to the success of the mission. Their knowledge 

was essential not only during the design phase, but on 

site as well, for the proper application of the complex 

systems and the ability to solve unexpected problems 

quickly, limiting project delays. Working on site also 

allowed the engineers to gain a better understanding 

of the unique requirements of archaeological recovery. 

The engineering team concluded that the suction 

piles were well suited for this type of recovery (OII 

2000b:7). The dead weight of the piles and stable crane 

made them relatively easy to set. Strong currents and 

winds were not a problem. The piles suctioned down 

and propelled out with no unexpected occurrences. 

Truss end and pile table mating reactions were lower 

than anticipated. Potential problems, such as pile overturning and short-term settlement, did not materialize. 

The sling system, including load cells, foam system, and 

secondary rigging, also performed as intended. Overall, 

no damage to the hull was detected by the archaeologists resulting from the recovery operations. 

The safe recovery of this unique piece of American 

cultural heritage could not have been accomplished 

without thorough planning, expert design and fabrication of components, and mutual respect between the 

engineers and archaeologists.

Figure 9.11. Display of weight distribution on the 

load cells supporting Hunley. (Courtesy of FOTH)

Figure 9.12. Linear variable displacement transducers (LVDTs), left, were 

planned for monitoring any longitudinal displacement of the hull. Two LVDTs 

were replaced with rods for manual monitoring (right). (Courtesy of FOTH)
94

10. Excavation and Recovery

C l a i r e P. P e a c h e y , H a r r y P e c o r e l l i I I I , a n d R o b e r t S . N e y l a n d

The decision to remove Hunley from its original 

context on the seafloor necessitated a comprehensive 

archaeological excavation to collect as much data as 

possible before that context was lost. The archaeology 

and preservation methodology developed required 

forethought equal to that of other project components. With expensive work platforms, and a massive 

engineering and diving component, it was important to 

communicate the research goals clearly to all project 

participants to maintain a successful collaborative team. 

Six primary research objectives were therefore established (Table 10.1).

Field operations began on 5 May and ran until 

9 August, with a hiatus between 24 June and 16 July. 

Sediment samples were taken and environmental conditions recorded before excavation commenced. An area 

of approximately 90 × 40 × 5 ft. (12.19 × 27.43 × 1.52 m) 

was excavated, centered on Hunley. All sediment was 

screened for cultural material. More than 500 artifact 

and sample numbers were assigned. 

The site was recorded in detail and mapped before 

the vessel was removed from the seabed. The diving 

strategy called for a division of labor with the Hunley

Archaeological Team (HAT) conducting the hull documentation and artifact recovery, and commercial divers 

from Oceaneering (OII) undertaking the excavation of 

trenches for the suction piles, placement of recovery 

structures, and rigging. A total of 73 days were spent on 

site. HAT conducted 410 dives for a total of 971 hours 

31 minutes under water. Total man hours for the team, 

including dive time, was 10, 276 hours. Total man hours 

for OII was 2,376, of which roughly half were spent under 

water. Combined personnel averaged 26 people at one 

time, including divers, supervisors, and surface support. 

Despite the challenging sea conditions, only a total of 

two diving days were lost to bad weather (Figure 10.1).

The submarine H. L. Hunley was successfully raised 

and transported to the Warren Lasch Conservation 

Center (WLCC) on 8 August. This feat was accomplished 

through many long hours both above and below water 

and the ability of the Friends of the Hunley (FOTH) to 

overcome some daunting problems, including changing 

recovery platforms in the middle of the project. Despite 

the inevitable logistical difficulties encountered on 

a project of this size, coordination between the two 

teams was effective and efficient, resulting not only in 

the successful recovery of the submarine, but also the 

collection of significant scientific data.

Archaeological Objectives

Prior to commencing fieldwork, HAT developed a 

research design based on the six objectives delineated 

above. For each one, expectations were described and 

procedures for handling each case were outlined, as 

follows.

Artifact Recovery

Three classes were expected to be present at 

the site. The first class consisted of artifacts directly 

Table 10.1. Archaeological 

Research Objectives

1

Recover any artifacts or loose hull components 

associated with, or contemporary with, the 

wreck

2 Investigate and identify magnetic anomalies 

adjacent to Hunley

3

Prepare an overall site plan, plotting the sub- marine’s position in relation to associated 

loose vessel components and artifacts

4 Create accurate hull drawings

5 Acquire biological, geological, and chemical 

samples

6 Monitor hull shape for changes during 

excavation
E X C A V A T I O N A N D R E C O V E R Y

95

in the area of the bow. The excavation plan called for 

any disarticulated components to be mapped and 

removed by HAT archaeologists prior to the recovery. 

The decision whether to remove partially disarticulated 

pieces, if encountered, would be made on a case-bycase basis, guided by the needs of the artifact. 

Magnetic Anomalies

Magnetometer data generated during the remote 

sensing phase of the 1996 survey disclosed that Hunley

produced a multiple component anomaly consisting 

of a single 400 gamma positive and two 200 gamma 

negatives (Figure 10.2). Murphy (1998:88) noted that: 

“Hunley, basically a cylinder, would be expected to 

produce a dipolar (single positive and negative components) magnetic anomaly. The dual negative aspect 

of the anomaly indicates a possibility that there may 

be additional material southwest of Hunley’s bow.” 

In addition, 1999 work on Housatonic and related 

magnetic features of the Hunley/Housatonic engagement site demonstrated that magnetic anomalies of 

very low duration and intensity were not ghosts, but 

were the results of physical structures buried in the 

seabed. For example, a six-gamma target referred to 

as the “fourth anomaly” turned out to be a small anchor 

(possibly a kedge) and chain buried three feet under 

the silt line (Conlin 2005:80). As a consequence, the 

three areas identified as A, B, and C, located within 75 ft. 

(22.86 m) of Hunley, were suspected to contain cultural 

items associated with the submarine. The research 

design called for these areas to be excavated prior to 

the commencement of lifting operations. 

associated with the submarine, either having come 

directly off the exterior of the hull or having escaped 

from inside, through breaches in the hull. The second 

class comprised intrusive anthropogenic materials 

deposited around the hull as it became buried. These 

would represent a variety of sources, including debris 

from Housatonic’s wreckage, flotsam and jetsam 

from the Union blockaders or blockade runners, and 

materials washed out to sea from shore. The third 

class was intrusive material from a later time period 

deposited over the site by fishermen, storms, tidal 

activity, and other sources. All three classes 

would be mapped and documented with 

equal thoroughness, since even intrusive 

material could provide data relating to site 

formation processes.

Loose Hull Components

Since the bow and stern had not yet 

been exposed, the likelihood of finding disarticulated hull components had to be considered. These two areas were known to 

house some of the more delicate external 

features, such as the rudder, spar, and 

propeller shroud, which might have been 

damaged or come loose at the time of the 

sinking or during the subsequent period of 

exposure on the seabed. Surveying with a 

marine magnetometer had revealed that 

magnetic anomalies were present in the 

area around the submarine, particularly 

Figure 10.1. Operating with decks awash was not 

uncommon during operations four miles out to 

sea, but few dive days were lost to bad weather. 

(Courtesy of FOTH)

Figure 10.2. Magnetometer readings around the Hunley site. (Detail 

from Murphy 1998:60)
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96

Site Plan

An overall site plan containing the submarine, 

loose hull components, and artifacts associated with 

the hull was planned. The site plan would document 

the orientation of the submarine and its degree of list. 

All materials recovered would be positioned based on 

direct measurement to datum points placed around the 

submarine’s hull. Primary datum points were planned 

for the bow and the stern, with secondary datum points 

to be added as needed. Measurements of x, y, and z

positions were required of all artifacts, loose hull components, and samples recovered. Once the OII lifting 

frame was in place, the frame itself could be used as 

a backup system of measurement, as it was, in effect, 

a large metal grid with a precise rectangular shape to 

which datum points could be readily added. 

Hull Measurement and Drawings

During the 1996 survey, the exposed areas of the 

hull were measured and mapped, and one cross-sectional view was drawn (Figure 10.3). Following the 1999 

hull survey, in which thickness measurements were 

taken, additional information, such as the expansion 

strake width and two seams for hull plates, was added 

to the original field drawing. This corrected field drawing 

would serve as a baseline map during the final excavation. As part of the excavation plan, time was allotted 

to check the drawing for accuracy and add new hull 

construction features as they were located. During this 

time the hull would also be inspected for damage that 

may have occurred at the time of sinking, such as holes 

in the hull from gun fire and torpedo blast. While much 

of this data was expected be available after the recovery, 

it was important to collect it in situ, as a baseline against 

which to check for changes in the hull after installation 

in the laboratory. In addition, in the event of damage or 

destruction during the lift, this would serve as the only 

complete set of hull measurements from the intact site. 

Sampling

Important information could be gained through 

macro- and micro-biological, geological, and chemical 

sampling. Collection of this type of data was considered relevant to understanding the sequence of events 

surrounding the processes of site formation, hull and 

artifact preservation, and the creation of micro-environments inside the submarine. Information concerning 

the environmental conditions outside the hull was an 

important dataset for evaluating conditions found on 

the interior of the submarine. These data would have 

Figure 10.3. Site plan developed based on the 1996 investigation. (Murphy 1998:77)
E X C A V A T I O N A N D R E C O V E R Y

97

and the HAT divers working within the 20 ft. (6.10 m) 

central section containing the submarine (see Figure 

10.11). Both teams were to use dredges and screen all 

materials removed. Due to concerns about possible 

spillage of internal components from potential holes 

at the bow and stern, it was determined that only HAT 

divers would work in the sections closest to the hull 

until it came time to rig the slings.

The excavation strategy began by removing the 

sandbags and overburden along the top of the vessel, 

where prior work had already taken place. The bow 

and stern components were excavated next, to provide 

enough time to alter the recovery plan should any 

significant breaches be discovered and to design any 

custom supports that would be needed during the lift. 

With the surrounding sediment taken down to a the 

level of the keel along the length of the port side and 

approximately halfway down on the starboard, operations were stopped for the placement of the truss. 

After a one-month delay in operations while a new lift 

platform was acquired (see below), the truss was then 

lowered in place, and excavation began beneath the 

hull in 24 to 36 in. (0.61–0.91 m) increments as the 

slings were rigged. During the delay, sandbags were 

packed around the exposed portion of the vessel for 

protection, but they also served to delineate the areas 

that had not yet been excavated from infilled material.

Dive Operations

As mentioned above, the dive team was divided into 

two groups, scientific divers from HAT and commercial 

divers from OII, with both groups operating simultaneously. All divers are listed in Appendix B. Initially, operations ran 12 hours a day, but increased to 24 hours in late 

July as the rigging phase commenced. Due to equipment 

restrictions, dives were limited to two divers per team 

at any one time. Each team generally conducted three 

dives per day during the initial phase of excavation, and 

six during the extended phase. All diving operations, 

with the exception of underwater photography, were 

conducted using surface-supplied air. 

Surface-supplied diving had numerous advantages 

over scuba. Hunley was located in 8–10 m (26–33 ft.) 

of water, depending on the tide. At this depth, divers 

could remain on the bottom for five hours and thirty 

minutes. A diver averaging one hour per scuba tank 

would have to return to the surface and change tanks 

six times, whereas a diver using surface-supplied air 

could remain on the bottom for the entire time. Each 

surface-supplied diver had an individual tending the 

umbilical hose (Figure 10.4). This link to the diver eliminated the possibility of being swept from the site by 

the current and drifting away without being noticed. 

The helmet also contained a speaker and microphone, 

direct application in finalizing conservation operations for the hull and in assessing the probable state 

of preservation of small artifacts and potential human 

remains within the submarine. Some of this information could also be used in predicting the state of preservation and depositional history of other shipwreck 

sites. Documentation of sedimentary stratigraphy in the 

matrix surrounding the vessel was also planned in order 

to disclose the presence and extent of scour areas or 

the condition of the sea bottom at the time of Hunley’s 

sinking. 

Hull Shape Monitoring 

A system for monitoring changes in hull shape 

during the excavation was developed in conjunction 

with the engineering design. The load cells designed 

by OII for use on the slings would detect any changes 

in load weight and provide information on any sign 

of localized hull distortion (see Chapter 9). A backup 

system of measuring overall longitudinal or lateral distortion was also considered. One option consisted of 

using a taut wire system of measuring overall circumference of the hull. This could be monitored visibly by 

divers or hardwired to an instrument on the surface 

that would measure any increase or decrease in tension. 

A second option was to use a computerized acoustic 

hull measurement system called SHIPSHAPE, which 

was developed for the Navy. This employed transponders and receivers placed on or around the hull that 

would monitor for changes in its position or shape. 

SHIPSHAPE also allowed for the integration of hull line 

drawings, once acquired, into the computer program. 

As discussed below, due to difficult conditions at the 

site, the SHIPSHAPE system was not used; the load cells 

provided sufficient data.

Equipment and Procedures

With the objectives firmly in place, equipment 

was acquired, personnel allocated, and the details of 

where and how the excavation would proceed were 

ironed out. One month was scheduled for excavation prior to beginning the rigging process. Based on 

known dimensions of the hull and the space needed for 

setting the suction piles, a perimeter around the wreck 

was planned to be 40 ft. (12.19 m) wide and 130 ft. 

(39.62 m) long. It was estimated that an area this large 

was needed to provide adequate working room for the 

engineers and to limit extensive infilling of excavated 

areas during the off hours. 

The site would be subdivided, with the team from 

OII excavating the outer 10 ft. (3.05 m) on each long side, 
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98

enabling diver-to-surface and 

diver-to-diver communication. A diver could request a 

tool and have it sent down on 

the umbilical hose without 

having to return to the 

surface. With the lifting truss 

and all of the accompanying 

metal hardware in place, 

the Hunley site became an 

overhead-hazard working 

environment and the dive 

helmets provided necessary 

head protection. One 

drawback to using the surface-supplied system was the 

risk of entanglement. Divers 

had to constantly monitor 

their umbilical hoses in the 

restricted visibility where 

datum pipes, the lifting truss, 

and other divers’ umbilical 

rigs all became snag hazards.

All archaeologists not 

yet certified in surface-supplied diving participated in 

a rigorous training course 

designed to familiarize them 

with the project equipment. 

Conducted by Von’s Diving 

Services of Westwood, California, the dive training 

included tending protocol, diver-to-surface communication, emergency procedures, open water search and 

recovery, and equipment cleaning and maintenance. 

Both dive teams conducted operations from 

the same mobile command trailer. Project protocol, 

however, necessitated that HAT and OII keep their 

dive operations separate, sharing only the air compressors. OII used a dive manifold designed in-house, 

while HAT used an Amron 

AMCOMMAND II portable 

manifold. Both teams used 

Kirby Morgan Superlite 17 

helmets.

HAT divers followed the 

diving standards established 

by the American Academy of 

Underwater Sciences (AAUS) 

to ensure maximum protection of scientific divers from 

accidental injury and/or 

illness. The OII team adhered 

to the guidelines established 

by the Occupational Safety 

and Health Administration 

designed for to safeguard 

the U.S. commercial diving 

industry. In the event of a 

diving emergency, a double 

lock recompression chamber 

was on site at all times 

(Figure 10.5). 

Dive Platforms

During the first phase 

of excavation, dives were 

conducted from the 750 tn. 

(680 t) Marks Tide, a 180 ft. 

(54.86 m) supply ship owned 

by Tidewater Marine of 

Amelia, Louisiana (Figure 10.6). It was moored over the 

Hunley site on a four-point mooring system and acted 

as the main base for diving support and dredging operations. This vessel allowed easy access to the water; 

divers could simply step off the deck into the water 

and return to the deck by climbing a ladder. Facilities 

included an air-conditioned trailer for the OII team, air 

compressors and dredge pumps for both dive teams, the 

Figure 10.4. Senior project manager Leonard 

Whitlock tends to diver and field manager David 

Conlin. (Courtesy of FOTH)

Figure 10.5. Hyperbaric chamber being readied 

for loading onto Marks Tide. (Courtesy of FOTH)

Figure 10.6. Marks Tide moored over the site. 

(Courtesy of FOTH)
E X C A V A T I O N A N D R E C O V E R Y

99

sluice boxes for OII’s team, 

and an artifact storage 

area. Sleeping quarters 

were also available for 

team members. Working 

in conjunction with 

Marks Tide was a 125 tn. 

(113.4 t) floating crane 

barge supplied by Detyens 

Shipyards, which would 

accomplish the heavy 

placement of the suction 

piles, recovery truss, and 

lift Hunley in its truss for 

transport to Charleston.

After the excavation 

was well underway, it 

was found that the crane 

barge did not possess sufficiently stable dynamics 

in offshore seas to safely 

conduct the lifting of 

the suction piles or truss 

without endangering 

Hunley and personnel on 

the crane barge. It was 

determined that only a 

self-elevating, or jack-up, 

vessel could meet the 

requirements for the safe 

lift of Hunley. After looking 

at location and availability of vessels that met project 

requirements, Karlissa-B, a six-legged jack-up from Titan 

Maritime Industries, was chosen based upon availability, 

cost, and arrival time in Charleston (see below).

The second phase of excavation was therefore 

conducted from Karlissa-B (Figure 10.7), which was 170 

× 80 ft. (51.82 × 24.38 m), and when jacked up above the 

water, had a deadweight capacity of 4,245 tn. (3,850 t). 

All portable equipment, including trailers, compressors, and pumps were relocated to this platform upon 

its arrival in July. With the deck of the vessel approximately 30 ft. (9.14 m) above the water, divers had to 

be lowered into and raised from the sea using a winchoperated lift platform, or stage. To keep the HAT and OII 

dredge pumps and water screens closer to the site they 

had to be placed on a separate supply barge. 

Additional Support Vessels

The 52 ft. (15.85 m) stern trawler Anita, owned and 

operated by the South Carolina Department of Natural 

Resources (SCDNR), was made available as a dive 

platform during the first two weeks of fieldwork, prior 

to the arrival of Marks Tide. It also provided further 

assistance and transport periodically throughout the 

remainder of the excavation. Several additional 

vessels were chartered 

during the project, 

primarily for ferrying 

crew, including the 26 ft. 

(7.92 m) Parker Diversity

owned by Ralph Wilbanks, 

47 ft. (14.33 m) Cole-Be

owned by Groboat’s of 

Morgan City, Louisiana, 

and 43.5 ft. (13.26 m) 

Jeremy owned by Steve 

Howard. Finally, a 22 ft. 

(6.71 m) Boston Whaler 

was supplied by the Navy 

for a portion of the project. 

Dredges

OII used two custombuilt 4 in. (10.16 cm) 

dredge systems to 

excavate. The dredge 

systems were powered 

by two jet water pumps 

joined together with a 

manifold to produce up to 

1,000 GPM (3,785.4 LPM) 

of seawater at 200 p.s.i. 

(13.8 bar). Water from the high-pressure manifold was 

directed through two venturi devices called inductors, 

which use high-pressure water to create tremendous 

suction. The OII divers used two long 4 in. (10.16 cm) 

diameter rigid-walled hoses, connected to the suction 

end of the inductors, to excavate sand from the site. 

The output end of the inductors was connected to 

custom-built sluice boxes (Figure 10.8). Sand and 

water blasted into the top of the sluice box and then 

cascaded over three separate screens with graduated 

mesh diameters of 2.6 in. (6.6 cm), 1.7 in. (4.32 cm), 

and 1 in. (2.54 cm). One to two individuals monitored 

the screens for cultural materials at all times. Materials 

recovered were collected and placed in water in plastic 

bags and labeled with the corresponding dredge area. 

Non-cultural material was cleared from the screens 

and went into the bottom of the box, which drained 

overboard through two 6 in. (15.24 cm) rigid-walled 

hoses.

HAT used a 4 in. (10.16 cm) Keene Engineering 

water-induction dredge head to excavate the area 

immediately surrounding the submarine. Water from 

the on-deck jet water pump manifold was pumped 

down to the dredge head through a long flexible 2 in. 

(5.08 cm) diameter fire hose. As sand was sucked, it 

Figure 10.7. Karlissa-B in place over the site along with 

the supply barge, which housed the dredge pumps. The 

truss prior to installation is visible on the supply barge. 

Suction piles had already been placed on the sea floor. 

(Photo by Cramer Gallimore, courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

100

traveled through a 40 ft. length of 4 in. (10.16 cm) 

diameter flexible hose and into a large mesh bag. 

Laundry bags of 1⁄4 in. (0.64 cm) diameter mesh proved 

to be the easiest to come by and most durable. The 

dredge spoil, primarily shells and small cultural material, 

were retained within the bag while sand and silt passed 

through the mesh holes.

When a spoil bag approached three quarters full, 

the diver would replace it with a new one. The full bags 

would be hauled to the surface via a haul line. Once on 

deck, the contents were emptied onto a plastic tarp and 

inspected for cultural material. The remaining contents 

were sorted by material type: macrofaunal, boiler slag, 

coal, bone, iron concretion, wood, and unknown. The 

sorted materials were then stored in water in plastic 

bags and labeled with the corresponding dredge area. 

Archaeologists brought up any large artifacts either by 

hand or supported in a plastic box. 

Documentation 

Direct measurements with metric tapes were 

taken from primary and secondary datum points to all 

artifacts, loose components, and major hull features. It 

was hoped that the acoustic system SHIPSHAPE could 

be used to augment measurements taken with tapes; 

however, this did not prove practical, due to the difficult 

conditions on site. 

HAT divers documented the submarine in detail by 

measuring and sketching features with pencil on sheets 

of Mylar drafting film duct taped to hard plastic boards; 

this was frequently hindered by limited and zero visibility conditions. Finished drawings were sprayed with 

Krylon clear acrylic lacquer after they were rinsed and 

dried, and each record was assigned a consecutive 

log number. One team member transferred relevant 

sketches to the overall site map. HAT documented larger 

artifacts in situ with trilateration or triangulation, and if 

visibility allowed, by sketching and video. 

To record the shape of the hull in situ, prior to each 

sling installation, archaeologists cast the exterior hull 

profile. The procedure consisted of encircling the hull 

with two layers of 4 in. (10.16 cm) wide resin-soaked 

fiberglass cloth from DuraPower Products Inc. (Pipe & 

Hose Repair Kit “Air” Activated Fiberglass Tape). After 

overlaying and tightening the two wraps with a piece 

of 5⁄8 in. (1.59 cm) three-strand polypropylene rope, 

another wrap was applied with a third piece of cloth. 

Once hardened, divers removed the fiberglass profile 

by making a single diagonal cut near the bottom of 

the submarine and lifting the profile off. Once on the 

surface, the profiles were reassembled and traced onto 

paper (Figure 10.9). Using a digitizing tablet, these 

tracings were entered into the computer drawing 

program AutoCAD.

Artifacts

All artifacts had their provenience mapped prior 

to recovery. The original plan called for each artifact 

to be photographed, video documented, and drawn in 

Figure 10.8. Sluice boxes designed by OII for screening 

dredge outflow had three tiers of increasingly smaller 

mesh. (Courtesy of FOTH)

Figure 10.9. From left, Randy Burbage, Senator 

McConnell, and Robert Neyland examine fiberglass profile taken by divers. (Courtesy of FOTH)
E X C A V A T I O N A N D R E C O V E R Y

101

situ as visibility allowed. Visibility was generally very 

poor, however, so photography and videography were 

extremely limited. The assistant field manager, Claire 

Peachey, or a designated archaeologist under her 

oversight was on deck to receive the artifacts, assess 

their state of preservation, and insure they were secure 

and stable. When necessary, field conservation and stabilization was initiated prior to their being transferred 

to the conservation laboratory.

HAT kept an artifact log, assigning a unique number 

beginning with the “HL” prefix to each artifact, group 

of artifacts, or sample. Each artifact or lot was labeled 

with a Tyvek tag and stored in seawater in stackable, 

lidded plastic boxes of various types and sizes. Where 

necessary, archaeologists placed artifacts in polyethylene self-seal bags, wrapped them in polyethylene 

foam, or provided other protection. They catalogued all 

excavation material on artifact or sample record sheets 

as appropriate, sketching significant artifacts on Mylar 

drafting film, usually at 1:1 scale unless the objects 

were too large to fit. 

Loose components were treated as other artifacts: 

p h o t o g r a p h e d , 

drawn, assigned 

an artifact number, 

and mapped into 

the site plan. Any 

minor elements 

that were loose 

but still attached 

to the submarine’s 

hull were carefully 

removed, with 

special attention 

paid to minimizing 

damage to the 

concretion layer 

surrounding the 

hull. The option to 

leave some loose 

material in place 

was considered; 

h o we ve r, d u e 

to the extensive 

coverage of the 

slings this was impractical. In addition, damage could be 

better controlled by a planned removal than by letting 

it break off under its own mass and inertia.

Artifacts were transported to the conservation 

laboratory approximately once a week, weather permitting. In one case, several fragments of rope were 

brought in on the day they were recovered and placed 

directly into frozen storage due to their extreme fragility. 

The assistant field manager or her designee prepared 

a transfer form for each batch of artifacts or samples 

leaving the field site, which was countersigned by the 

receiving party, either the senior conservator or the 

scientist conducting sample analysis. A collection specialist was in place under the senior conservator, whose 

responsibility was maintenance of the overall artifact 

inventory and database, and was accountable for the 

location of all artifacts at all times.

Field Operations

The first phase of operations involved delineating 

the site and establishing datum markers for mapping. 

Six yellow, 32 in. (81.28 cm) steel buoys were deployed 

from Anita to define the perimeter of a no-entry zone 

surrounding the Hunley recovery area. These buoys 

were marked with dusk-to-dawn yellow flashing lights 

and elevated aluminum radar reflectors. Four large 

mooring buoys were also put in place by the U.S. Coast 

Guard in preparation for the arrival of Marks Tide 

(Figure 10.10).

Working from Diversity and the Navy Boston Whaler, 

a small contingent of 

HAT archaeologists 

marked Hunley’s 

bow and stern with 

weighted buoys, 

using previously 

recorded GPS coordinates. HAT, using 

scuba, relocated 

and exposed the 

upper surface of 

the submarine. A 

perimeter was then 

set up using a combination of 0.25 in. 

(6.35 mm) braided 

poly line and lengths 

of 1.5 in. (3.81 cm) 

diameter Schedule 

40 PVC pipe. First a 

centerline was established along the top 

of the submarine, 

extending 13.5 m (44.29 ft.) out beyond either end. 

By triangulating off the centerline, divers were able to 

place 5 ft. (1.52 m) lengths of PVC pipe at the corners 

of the excavation trench, strung with poly line, outlining 

an area 130 ft. (39.62 m) long by 40 ft. (12.19 m) wide. 

With the perimeter defined, HAT used the centerline and the ends of the submarine to triangulate in four 

permanent datums, two off the port side and two off 

the starboard side, just outside of the excavation trench. 

These datums consisted of 10 ft. (3.05 m) lengths of 

1.5 in. (3.81 cm) diameter aluminum pipes driven to 

Figure 10.10. USCGC Madrona prepares to deploy the four mooring 

buoys used to secure Marks Tide safely without risk of damage to 

the site. (Courtesy of FOTH)
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102

Figure 10.11. Layout of excavation boundaries and sample transects at the site. (Diagram by H. G. Brown, NHHC; drawing of Hunley by James W. Hunter 

III, FOTH)
E X C A V A T I O N A N D R E C O V E R Y

103

within 18 in. (45.72 cm) of the bottom. Archaeologists then placed six 10 ft. (3.05 m) lengths of PVC as 

subdatums in an arced array at each end of the submarine’s hull. The twelve subdatums were located 

3 m (9.84 ft.) from each end of the submarine and 2 m 

(6.56 ft.) apart. They were then mapped in using trilateration. These datums and subdatums were used to 

accurately position cultural material discovered during 

the excavation. 

Pre-disturbance Sampling

Prior to conducting further excavation, HAT took 

a series of sediment cores and faunal samples, part of 

the suite of studies to characterize the environment 

surrounding the submarine. HAT placed two transect 

lines diagonally off the submarine, one off the bow to 

the north corner of the perimeter, and the other off 

the stern to the south corner of the perimeter (Figure 

10.11). These transect lines covered areas that had 

not been disturbed in 1996 or 1999. The purpose of 

this sampling strategy was to determine if there was 

any gradient in the biology and sedimentology of the 

site correlating to distance from the submarine. Using 

3 in. (7.63 cm) outer diameter by 1 m (3.28 ft.) long 

aluminum hand core tubes, divers collected sediment 

cores along the two transects at 1 m (3.28 ft.), 3 m 

(9.84 ft.), 5 m (16.40 ft.), 10 m (32.81 ft.), and 20 m 

(65.6 ft.) from the submarine. Project geologist Scott 

Harris then immediately opened and sub-sampled all 

but three of these cores on the deck of Anita. Analysis 

would focus on microbial activity, physical geology, pore 

water content, and dissolved iron content (see Chapter 

13). HAT divers also collected benthic infaunal samples 

from the same transect points, which were immediately 

sieved and preserved on deck by marine biologist Dr. 

Pam Jutte. 

The team sampled the backfill sand and the 

compact mud adhering to the hull concretion to test 

for microbial activity. Several small sections of hull 

concretion were collected in plastic bags, which were 

also analyzed for microbial activity as well as chemical 

characterization. After removing a portion of concretion, a corroded rivet was found in the bow area of the 

submarine that could be removed, thus allowing the 

opportunity to take samples of the interior sediment. 

Once the rivet was removed, divers inserted a series of 

clear, rigid plastic tubes into the rivet hole to remove 

three cores of sediment, which were then transferred 

to the custody of microbiologist Dr. Pam Morris. In 

addition, divers captured several samples of the gas 

bubbles released by deconcreting small areas the 

hull, using a polyethylene bag; the gas was then transferred immediately to a glass flask closed with a rubber 

stopper. 

Since the closest NOAA buoys to the site were 

either along the shore or else about 40 km east (Station 

41004) of the Hunley site, local environmental conditions were not readily available. Therefore, a multiparameter probe from YSI, Inc. was placed on the wreck 

for 48 hours to collect data that would help give conservators a picture of the range of conditions Hunley would 

be exposed to during the excavation once the sediment 

was removed. Knowledge of these conditions helped in 

planning and assessing the post-recovery storage environment for the hull. The device recorded temperature, 

depth, specific conductance, dissolved oxygen, pH, and 

oxygen reduction potential (ORP) in 5-minute intervals 

(Appendix E). 

Anomaly Investigation

The three magnetic anomalies that had been identified during earlier survey work on the site were located 

and investigated by HAT divers during this preliminary 

set-up period to assess their significance and potential 

incorporation into the dive plan. Using a handheld magnetometer, each anomaly was pinpointed. Archaeologists removed sediment down to the level of the source 

of the metallic signature using a jet probe. The source 

of one anomaly was not rediscovered, and the others 

were found to be concreted ferrous can fragments 

at depths significantly shallower than that of Hunley. 

These anomalies were therefore deemed unrelated to 

the submarine and no alteration to the excavation plan 

was required.

Corrosion Potential and Continuity Studies 

Steve West of Orion Research visited the site on 

16 and 17 May 2000, to perform ORP and electrical 

continuity tests on the iron hull plates. The purpose 

of this was to indicate the extent of corrosion of the 

metal. West also measured the pH and ORP of two 

sediment samples collected immediately adjacent to 

the submarine. His report, listing the equipment used 

and a step-by-step account of the measurements, is 

provided in Appendix F. 

West performed the ORP measurements by 

modifying flat-surface, combination platinum probes 

(6.25 mm/0.25 in. diameter) to operate underwater. 

HAT divers cleared concretion from small areas of the 

hull surface using a hammer and chisel to reveal the 

iron plate surface; these areas were relatively smooth, 

but were not polished to remove corrosion and create 

a clean metallic surface as they had been for the ultrasonic thickness measurements. Two divers each placed 

one probe at different points on the hull surface, and 

West operated the pH/mV meter on the boat deck 
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104

and directed the team through voice communication, 

while other personnel handled the cables leading from 

the meter to the underwater probes (Figure 10.12). 

The divers first held Probe 1 at the bow and Probe 2 

at the stern. After stable readings were attained, they 

reversed the positions of the probes, resulting in 

identical readings. They usually had to gently move the 

probe around on the hull surface until a stable reading 

was attained, indicating that contact between the probe 

and hull was not optimal, even though the flat-surface 

probes were of a small diameter. The dive team was successful in recording several readings. West determined 

from these readings that the corrosion potential at the 

bow of Hunley was −379 ± 2 mV vs normal hydrogen 

electrode (NHE), while that at the stern it was between 

−320 and −363 mV vs NHE.

West then connected the same probes to a 

Fluke multimeter to perform continuity tests on the 

hull. Divers once again placed the two probes on the 

patches of cleaned hull plate surface at some of the 

same locations as above, primarily to test continuity 

between the bow and stern and between amidships 

and the vessel ends. The continuity readings were 

erratic and inconclusive, leading West to conclude that 

either poor continuity existed between the different 

sections of Hunley’s hull or that poor contact was made 

between the probes and the hull surface. These results 

were similar to those obtained in 1999. 

Overall it was determined that the corrosion 

potential and oxygen levels were relatively low on 

site, indicating a slow corrosion rate on the seabed, 

but showed the need for an impressed current protection system once in the laboratory tank, where 

readings pointed to a markedly increased corrosion rate 

(Mardikian 2004:141).

Site Excavation

The arrival on site of Marks Tide on 13 May with 

the full team of HAT and OII divers signaled the commencement of the primary excavation effort. The initial 

rectangular 130 × 40 ft. (39.62 × 12.19 m) excavation 

perimeter was subdivided lengthwise by securing two 

lengths of poly line 10 ft. (3.05 m) inside of either long 

edge of the rectangle. As per the excavation plan, the 

outermost zones, which had a much lower probability of 

containing cultural material, were excavated by OII. The 

central area immediately surrounding the submarine 

where the highest density of culturally significant 

material was expected was excavated by HAT. Twenty 

days into the excavation it became apparent that the 

teams were not going to be able to excavate the entire 

length of the area in the allotted time, due in part to 

infilling of sediment over of time, which necessitated 

periodic re-excavation. The site perimeter was therefore 

reduced by 20 ft. (6.10 m) at either end, resulting in an 

excavation zone of 90 ft. (27.43 m) by 40 ft. (12.19 m) 

(see Figure 10.11). This area was still large enough to 

accommodate the suction piles, and, based on analysis 

of dredge spoil already collected from the perimeter 

areas, was considered adequate to locate any cultural 

material associated with the wreck.

After removing the overburden along the top of 

the vessel left from previous investigations on the site, 

divers concentrated on exposing the bow and stern 

of the vessel to evaluate their state of preservation. 

The top of the propeller and shroud were exposed 

on 19 May, and it was noted that the rudder was not 

in position. A large hole in the starboard side of the 

stern was encountered on 20 May, and three days 

later another, smaller, hole was found in the bow, also 

to starboard. Divers packed both with sandbags to 

stabilize and prevent loss of any interior contents over 

the course of the excavation. They would be further 

reinforced prior to the lift as part of the slinging process 

(see below). 

Figure 10.12. Steve West monitors instruments 

during corrosion potential studies conducted at the 

beginning of the excavation. (Courtesy of FOTH)
E X C A V A T I O N A N D R E C O V E R Y

105

Spar excavation 

The largest unexpected 

feature was encountered on 

24 May, by HAT diver Chris 

Amer as he was continuing 

the assessment of the bow. It 

quickly became clear that he 

had discovered the spar that 

had deployed the torpedo and 

that it was still fastened to the 

submarine. Previous investigations had not revealed this 

feature, which was thought to 

have been attached at the top of 

the bow, and initial engineering 

plans were based on its absence. 

HAT archaeologists, however, 

had considered the possibility 

that it could be present at the 

site, possibly detached from the 

vessel as a result of the sinking 

event. Further exploration by 

project director Robert Neyland revealed the surviving 

end approximately 16 ft. (5 m) from the bow. Over the 

next few days the spar was completely excavated and 

documented, showing the piece to be securely attached 

to the hull, bolted to the base of the bow casting with 

a Y-shaped clamp-like fitting (Figure 10.13). One single 

bolt through the casting held this fitting to bow, the bolt 

head on the starboard side and the threaded end and 

nut to port. Measurements were taken to determine 

the angle of the spar to the submarine. It extended 

forward bending slightly to port from the centerline 

with no discernible elevation, although later measurements did detect a rise of approximately 3° as it moved 

away from the bow. 

Due to the overall length of the spar, it could not be 

accommodated within the truss arrangement planned 

for the lift. In addition, being so long and slender, it 

would have been extremely vulnerable to damage if 

lifted with the submarine. Therefore it was decided to 

detach the spar and recover it separately from the hull. 

To determine how best to remove the spar, HAT divers 

mapped the bolt and nut, but important details were 

obscured by concretion. Therefore, on 30 May, senior 

conservator Paul Mardikian came to the site to deconcrete the fitting and make a mold of the bolt and nut 

assembly (Figure 10.14). Based on his findings, it was 

decided that the only way to remove the spar would 

be to cut through the bolt securing it to the yoke. On 

2 June, HAT began cutting on the bolt with a hack 

saw blade. This work was extremely slow because of 

the difficulty in inserting the blade between the yoke 

and spar and working in zero visibility. The cutting 

Figure 10.13. The torpedo spar in its original position attached to Hunley’s bow. 

(Courtesy of FOTH) 

Figure 10.14. Mold of bolt (A) and recovered bolt (B) used to attach spar to main body of the hull. (Courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

106

effort was continued by several dive teams. Eventually it was decided to attempt to put a socket and 

breaker bar wrench on the 1.5 in. (3.81 cm) nut and 

see if some pressure would break the bolt at the cut. 

Several large sockets were supplied by Jerry Franks of 

Charleston International Ports, LLC (a company owned 

by Warren Lasch). One diver increased the leverage on 

the wrench with a cheater bar and attempted to turn 

it counterclockwise while a second diver tapped on 

the socket with a sledge hammer. Unexpectedly, after 

this effort the bolt did not snap, but the nut backed off 

the threaded end of the bolt with very little damage 

to either component. The threads on both were still 

in working condition after 136 years! However, the 

bolt still stubbornly held the spar to the submarine. 

Attempts with a punch and hammer, gear puller, and 

hydraulic jack failed to move the bolt. OII manufactured 

a custom-made wrench and divers eventually were 

able to get the bolt to move with this, shearing it at 

the point where the initial cutting had been made over 

the previous three days. 

OII welders customized an I-beam as a support 

system for raising the spar, and lowered it by crane to 

the seabed, where divers positioned it alongside the 

artifact to minimize the distance it had to be moved. 

The metal of the spar had completely corroded through 

in some places, revealing that, with the exception of 

the first few feet from the yoke, it was tubular rather 

than solid. The worst corrosion was found approximately 80 cm (31.50 in.) from the tip, where the connection was too tenuous to survive a change in position. 

Therefore the distal end was lifted separately. Both 

sections were placed in the cradle, which was then 

moved to the starboard corner of the excavation area 

and left on the sea bottom safely out of the way of 

ongoing dredging operations. Neoprene padding was 

secured to the spar with cable ties and plastic bags were 

placed over the hollow ends to help preserve them 

and to keep supporting mud in place. A long metal rod 

(HL-0463) that had also been discovered on the site was 

placed in the cradle as well, and the whole load was 

secured in place with ratchet straps. On 13 June, the 

spar was raised. A Charleston Harbor Pilot boat came 

alongside the Marks Tide and the first major component 

of the submarine was lowered onto the deck and safely 

transported to the WLCC (Figure 10.15).

Rudder and Other Artifacts Recovered 

Excavation in the stern area continued to exposed 

the propeller and shroud. On 30 May, as the excavation 

at the stern reached the bottom of the vessel, a large 

flat concretion was discovered. This turned out to be 

the rudder, which had unshipped and slipped beneath 

the hull. The piece was documented, protected with 

sandbags, and left in situ until the submarine was completely slung and supported within its straps. It was 

recovered on 4 August and submerged in wet storage 

in a child’s wading pool on the deck of Karlissa-B, until 

it was transported to the WLCC on the day of the 

submarine recovery. 

In addition, the aft cutwater was found on the 

starboard side near where it had been attached to the 

aft conning tower. The snorkel tubes were found on 

23 May about halfway down the hull on the starboard 

side, between the snorkel box and forward hatch. Aft 

of this area, another iron rod-like piece was found. It 

was held to the hull by its concretion and turned out 

to be a section of rectangular bar that connected to 

the propeller shroud. Near the bottom of the starboard 

bow, several fragments of rope and some wood pieces 

were recovered. Two large iron concretions with distinctive clamp-like shapes were found forward of the bow. 

Several of the smaller pieces were removed from the 

site by 10 June, but the larger pieces were protected 

with sandbags and left in place while hull documentation was completed, and not raised until after the truss 

was placed.

Figure 10.15. Hunley’s torpedo spar was removed from 

the bow and raised separately to protect it from damage. 

(Courtesy of FOTH)
E X C A V A T I O N A N D R E C O V E R Y

107

Lift Preparations

With the bow and stern exposed and evaluated, 

and the port side fully cleared, it was nearing time for 

the installation of the suction piles and placement of 

the lifting truss. During the initial weeks of the excavation, the OII dive team had been working to prepare 

the 20 ft. (6.10 m) diameter areas forward and aft of 

the vessel to receive the piles. To accommodate the 

longitudinal angle of the sub, depth of excavation at the 

bow was approximately 6 ft. (1.83 m) and 5 ft. (1.52 m) 

at the stern. The bow section could not be completed, 

however, until the torpedo spar was safely out of the 

way. On 31 May, as Neyland and his team worked 

to detach the spar, HAT field manager David Conlin 

and assistant field manager Matt Russell took on the 

challenge of determining exactly where the engineers 

needed to place the suction piles on the seabed.

Million-Dollar Measurements

For the truss to be properly centered over Hunley, 

the suction piles had to be placed in precisely the right 

position. Divers, therefore, needed to set targets on the 

seabed to help guide them into place. Since the success 

of the recovery hinged on the placement of these 

targets, the crew jokingly referred to them as the “two 

million dollar points.” The first step was to determine 

the geometric longitudinal centerline of the wreck as it 

lay on the seabed. This would represent the center of 

gravity at its post-depositional angle and would need to 

align perfectly with the center of the truss for correct 

positioning in the slings. 

Despite near zero visibility conditions, the dive 

team was able to determine the geometric centerline 

by recording offsets from the architectural centerline 

of the vessel. They first measured the vertical height of 

the stern (124 cm; 48.82 in.), then divided this number 

in half, locating a point 62 cm (24.41 in.) down from the 

natural top of the stern. They then dropped a plumb 

bob at this point, and measured a perpendicular offset 

to the top of the stern. This process was repeated at the 

bow, and both resulted in an offset of 42 cm (16.54 in.) 

(Figure 10.16). A reference point taken from the top 

of the stern or bow, which were the most practical 

landmarks on the site, could then be shifted to port 

42 cm (16.54 in.) to locate the vessel’s resting centerline. 

The data also allowed the team to accurately calculate 

the vessel’s angle of repose, originally estimated at 45°, 

to be 47.36° relative to the horizontal plane.

With the offsets calculated, Conlin and Russell were 

ready on the following day to measure in the center 

points for the suction piles, which needed to be 70.5 ft. 

(21.49 m) apart to accommodate the length of the truss. 

The points were measured using trilateration from two 

datum points at the bow and two at the stern, using a 

tape measure, carpenter’s level and plumb bob. Both 

points were marked with PVC stakes and then checked 

against each other and the vessel. The distance between 

stakes was 70.58 ft. (21.51 m), giving a total linear error 

of just 1 in. (2.54 cm), with a lateral error of 0.39 in. 

(1 cm). With the adjustable tables on the suction piles, 

this error would be inconsequential. 

A small surface buoy was set at the center of 

each pile excavation site, providing a visual target 

for the crane operator to use when setting the piles. 

Divers installed 30 in. (76.30 cm) diameter buoys 10 ft. 

(3.05 m) off bottom and 25 ft. (7.62 m) out from the 

pile center, to act as deadmen supports for the divers 

to guide the piles into correct rotational position. The 

buoys’ anchors, 200 lb. (90.72 kg) clump weights, were 

buried 4 ft. (1.22 m) below the natural bottom using 

an induction dredge jet in order to maintain stable 

positions. With the markers set and the torpedo spar 

safely stowed, the site was ready for the engineers to 

take the lead.

Operations Delayed

On 6 June, with the site cleared and ready for action, 

the floating crane barge, which had been donated by 

Detyens Shipyard, was brought out to the recovery site 

to set the suction piles and lower the recovery truss. 

The donation of this crane was anticipated to save the 

project approximately $200,000. However, the barge 

was designed primarily for harbor use, not open ocean 

operations. As it was towed off shore by a tugboat, the 

crane exhibited a great deal of pitch in the open water. 

Figure 10.16. Measurements taken to determine the 

geometric centerline of the hull as it lay on the seabed. 

(Diagram by H. G. Brown, NHHC)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

108

After anchoring on site, tests of the block and tackle 

indicated that even in moderate seas of 2 ft. (0.61 m) 

the crane hook would move approximately 4–8 ft. 

(1.22–2.44 m) vertically. This movement could transfer 

a significant amount of force to the truss and submarine, 

well over the 2 g’s the truss legs were built to withstand. 

In addition, when swinging the crane, it became 

apparent that when loaded it could easily topple over 

mid-swing. The crane also had a very slow lifting speed, 

which would pose a risk during the initial phase of the 

lift. With the barge moving up and down in the swell, 

a slow crane speed could result in the submarine 

impacting with the seabed during first few feet of the 

lift. Wright and Neyland, with input from Billy Bergeron 

of Delmar, decided to abort the use of the floating crane 

due to excessive risk to the submarine and the safety of 

the crane operator and others on that platform. While 

this would delay the project substantially, as no further 

work could be done until a safe recovery platform was 

located, all the parties—South Carolina Hunley Commission, Naval Historical Center, Friends of the Hunley, 

Oceaneering, and Delmar—agreed that it was the only 

responsible way to proceed. 

When the recovery options had been studied 

initially, it was determined the best crane platform 

would be a self-elevating vessel, often called a jack-up 

barge. These have steel legs called spuds that can be 

extended down to the sea floor and, by continuing to 

extend the spuds, it can lift itself completely out of the 

water, into the air. No longer affected by the sea state, 

a crane can operate from the platform with extreme 

precision. In early plans, a jack-up barge had been 

proposed but was not selected due to availability and 

expense concerns in the face of Detyens Shipyard’s 

offer. It was difficult to locate one of a suitable size 

with a crane meeting the required lifting capacity. While 

common in the Gulf of Mexico, none were available on 

the east coast of the United States. The high expense 

of bringing one from the Gulf or from overseas would 

increase the overall cost of the project. Nevertheless, 

it was the safest option for the successful recovery of 

Hunley.

Two suitable platforms were found, one in the 

Dominican Republic and the other on the Gulf Coast of 

Florida. Transport time to Charleston varied, the Florida 

vessel taking the longest to arrive because it would have 

to go around the Florida peninsula. Also, if it encountered bad weather it would have to go into port and 

wait until the weather improved—all at the expense 

of the project. It also required that a safe harbor be 

provided for it in Charleston, which could be difficult 

since the legs were too tall to fit under the Cooper River 

bridges. This vessel was also only a three-legged jack-up, 

whereas the other candidate had six legs. 

The vessel in the Dominican Republic, Karlissa-B, 

was considered the best choice due to its construction, proximity, and cost. Formerly a U.S. vessel, it was, 

however, currently working under the Belizean flag and 

could not conduct a salvage lift in the United States 

without violating the Jones Act of 1920. In order to 

perform the Hunley recovery, Titan offered to reflag 

their vessel back under the United States, a procedure 

almost unheard of once a U.S. vessel has become foreign 

flagged. Once reflagged, Karlissa-B would be allowed to 

lift the submarine, but provisions of the Jones Act still 

prohibited its use to transport cargo into an American 

port. Although discussions were held with U.S. Customs 

about whether Hunley should appropriately be considered cargo, it was determined the submarine could not 

transported to shore on Karlissa-B. Thus the submarine 

and truss would be placed on the same barge that had 

transported the suction piles and truss to the site. This 

change to the recovery plan resulted in a 32-day project 

stand down as well as increasing project costs. 

The decision to change lifting platforms meant 

that Marks Tide was no longer needed. Captain David 

Fontaine and crew were all extremely disappointed, for 

the Hunley had come to mean more to them than just 

another job. After the exposed portions of the hull were 

protected with sandbags and all equipment removed 

from the site, on 22 June, dive operations were halted 

and Marks Tide was sent back to the Gulf of Mexico. 

The crew boat was also released back to Groboat’s. On 

13 July, Karlissa-B got underway from the Dominican 

Republic, going through the reflagging process while 

in transit. 

During the interim, the site continued to be 

monitored by USCG and video surveillance equipment 

on the Sullivan’s Island lighthouse. In addition, 

personnel from U.S. Navy Special Boat Units 20 and 22 

were assigned to help provide security for the project. 

They did morning and evening visits to the site and in 

one case ran a dive boat away from the site. 

Resumption of Operations

As the lift platform approached Charleston, dive 

operations recommenced on 17 July from the new crew 

boat Jeremy. A small team of four HAT divers went to 

the site and dredged out the sand and mud that had 

filled in the previously-excavated trench around the 

hull to make ready for the suction piles. All of these 

dives were conducted using scuba. Karlissa-B, towed 

by the oceangoing tug Elsbeth III, arrived in Charleston 

on 21 July and went into Detyens Shipyard for mobilization. Over the next two days all of the dive equipment 

formerly on Marks Tide was refitted and loaded on 

board. On 24 July, Karlissa-B was towed to the Hunley

site and positioned southwest of the submarine. This 

was not without some problems as the harbor tugs 

found that the large Karlissa-B was not easy to control 
E X C A V A T I O N A N D R E C O V E R Y

109

in the open ocean. Several of their lines broke during 

the offshore operation and some damage occurred to 

Karlissa-B’s hull when one of the tugs collided with it. 

As the difficulty became apparent, a call was made to 

Great Lakes Dredging, a company performing dredging 

operations in Charleston Harbor, who had a larger 

seagoing tug in the area. This tug tied on to Karlissa-B

and was able to successfully position her over the site.

A 110 ft. (33.53 m) materials barge was towed to 

the site and secured on a four-point mooring to the 

northeast side of Hunley (see Figure 10.7). This platform 

held heavy equipment such as pumps, screens, and generators for the dredging operations, which were welded 

to the deck. The barge also carried the suction piles 

and the lifting truss. In addition, the barge was used 

as a crew staging area. Dive operations, however, were 

conducted from the deck of Karlissa-B. Crewmembers 

would board Jeremy at the Fort Moultrie dock on Sullivan’s Island and travel forty minutes. Once on site, 

they would either offload onto the materials barge 

and transfer by personnel transfer basket (called a “Billy 

Pugh ” after the manufacturer) attached to the crane, or 

access Karlissa-B directly by Jeremy reversing engines 

and holding the stern against the jack-up barge’s ladder 

(Figure 10.17). Both methods of transfer had some risk 

factors, either being hoisted high into the air by a crane 

or maneuvering from the pitching deck of the boat onto 

the barge’s ladder. 

Normal, surface-supplied dive operations resumed 

on 24 July. Due to the delay caused by changing lifting 

platforms, dive operations were stepped up to a 24-hour 

schedule. Hurricane season was rapidly approaching 

and no one wanted to experience the frustration of 

covering and evacuating the site. In the event of a 

hurricane evacuation, the entire exposed portion of 

the submarine was to be covered with sandbags. The 

James Island fire department had generously provided 

the project with hundreds of sandbags, which remained 

at the ready on shore. Two 12-hour shifts were adopted 

that affectionately became known as the day crew and 

the night crew, with one crew always trying to outdo 

the other. 

Placing the Piles

With the positioning markers for the caissons still in 

place from June, and the infill removed from the footing 

areas, the placement of the suction piles could begin 

immediately. One OII diver remained in the water to 

set each pile and maintained contact with the surface 

diver control operator, who in turn directed the crane 

operator. Topside OII personnel positioned the pile by 

adjusting attached lines running through bottomed 

deadman braces and rotating it into proper orientation 

for it to mate with the truss end seat.

At 3:30 a.m. on 25 July, Karlissa-B’s crane placed the 

first suction pile 6 ft. (1.83 m) forward of Hunley’s bow, 

with a placement error of 3 in. (7.62 cm). At 8:45 that 

morning, the crane set the second pile aft of Hunley’s 

stern. This one came down 28 in. (71.12 cm) from its 

target point, outside the acceptable margin of error. 

In only a few hours it was lifted, shifted, and rotated, 

and by mid-afternoon it was placed on its target point, 

5.75 ft. (1.75 m) aft of the stern. 

Over the course of the night, the flanges and pumps 

were rigged, and the caissons were suctioned down into 

the seabed. Optimal pile depths were calculated, taking 

into consideration the fact that the bow was approximately 1 ft. (0.30 m) lower than the stern, the resultant 

angle of the truss, and the adjustability of the slings. 

As a result, the bow pile was set approximately 3 ft. 

(0.91 m) below the top of the bow, the stern approximately 3.5 ft. (1.07 m) below the top of the stern.

Safety during the pile installation operation was 

maintained through proper communication, strict 

adherence to proper procedures, and verification that 

all performance requirements were met. In addition, 

Figure 10.17. Team members transferred from the crew 

boat to Karlissa-B via a crane-lifted Billy Pugh. (Courtesy 

of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

110

equipment inspection and function tests for all gear and 

deck equipment were carried out prior to installation.

Once the piles were fully set, archaeologists 

excavated in the areas where the lifting truss legs would 

extend into the sand. At 1:30 in the afternoon of 26 July, 

the lifting truss was lowered over Hunley; however, the 

area had not been sufficiently excavated to accommodate the truss legs, so the truss stood several feet above 

the suction piles. OII divers removed approximately 2 ft. 

(0.61 m) of stiff clay from beneath the truss legs, and 

the truss was set firmly on top of the suction piles, ready 

for final alignment. Although the process of aligning the 

truss with the piles took longer than expected, two days 

later, OII divers were able to place the first of the lifting 

slings beneath the submarine.

Rigging the Slings

With the truss secured to the tops of the suction 

piles, HAT divers began to excavate, starting at the bow, 

beneath the submarine in preparation for placing the 

lifting slings. To avoid having a portion of the submarine 

hanging unsupported in the water column, archaeologists only excavated enough sediment to place two 

to three slings at a time, approximately 2–3 ft. (0.61–

0.91 m). Work was now hampered overhead by the 

truss and all of the accompanying sling turnbuckles. 

In the restricted visibility, entanglement hazards were 

everywhere, making it difficult for the dive team to keep 

their umbilical hoses free (Figure 10.18). Nevertheless, 

the process went smoothly, and divers excavated and 

cast exterior hull profiles prior to each sling installation 

(as described above) without incident.

Following the profile casting, OII divers placed 

the slings for that section beneath the submarine and 

secured them loosely to the turnbuckles on the truss. 

Next, vinyl bags cable-tied to the inner surface of the 

lifting slings were injected with expandable foam, which, 

when filled, fit the submarine’s lower exterior contour 

perfectly (see Chapter 9). Bill Youmans of Flexible 

Products and Michael Gatto Jr. of NCS Supply were on 

board the Karlissa-B during the initial foaming process 

to ensure all went smoothly (Figure 10.19). The foam 

set up in approximately two minutes. Once the foam 

was in place, the OII team then began tensioning the 

lifting sling. An OII engineer monitored the computer 

load-cell display from Karlissa-B and directed OII divers 

as they tightened the turnbuckles in accordance with 

the load distribution plan devised by Perry Smith. 

Before the lift could be initiated, the holes in the 

hull had to be patched to prevent loss of material from 

the interior of the submarine. In addition to the two 

discovered in late May, there was a third in the forward 

conning tower, which had come to light with the submarine’s discovery in 1995. The largest hole, at the stern, 

spanned several sling stations and required patching 

before the slings could be set. It was covered with a 

large neoprene pad, which was held in place by four 6 

in. (15.24 cm) wide ratchet straps. A strongback of angle 

iron was placed along the port side near the top to hold 

the ratchets away from the hull surface. The strongback extended aft beyond the stern to provide additional protection and rigging support to the propeller 

shroud (Figure 10.20). When the patch was complete, 

the slings were filled and tightened in place. The two 

smaller holes were patched after the slings were in 

place, the bow hole with neoprene and the conning 

tower with filled with expandable polyurethane foam. 

The slinging process was completed on 4 August. A total 

of 32 slings supported the submarine.

The submarine, once free of the bottom, swayed 

gently in its cradle with the flow of the ocean tides. 

The day of the lift was then scheduled for 8 August, 

since weather projections, which were being closely 

monitored, were for optimum conditions. This waiting 

period also provided enough time to accommodate 

the public and press that wanted to view the raising. 

Figure 10.18. Diver working around the forward conning 

tower with truss beams directly overhead. (Courtesy of 

FOTH).
E X C A V A T I O N A N D R E C O V E R Y

111

flooding was successfully implemented on the materials barge 

at the site. Care had to be taken 

to flood the compartments 

equally to maintain stability. 

At the same time, a visit 

was made to a representative 

of Great Lakes Dredging, the 

company that had helped with 

positioning Karlissa-B. Their 

dredging operation used a large 

hopper barge to carry the dredge 

spoil to a designated offshore 

disposal site. They donated the 

services of the hopper barge 

and two seagoing tugs to create 

a temporary breakwater during 

the lift.

Every possible precaution was taken to ensure a safe 

recovery. Law enforcement from 

SCDNR, USCG, and Charleston 

and Mount Pleasant marine 

police organized a security zone 

around the recovery site and a 

moving security zone down the Cooper River to the 

former Charleston Naval Shipyard (see Chapter 6). 

Once Hunley was transferred to shore and transported 

by crane to the WLCC, North Charleston police would 

take over security. They would also maintain security 

for Hunley and VIPs while it was being installed in the 

tank in the laboratory.

Divers spent the remaining days removing any intrusive 

material and installing the secondary slings designed 

to reduce circumferential stresses (see Chapter 9). 

Intrusive material, including loose cotter pins and 

misplaced tools, were collected and removed. This 

step would be very important when, following Hunley’s 

recovery, underwater archaeologists returned to the site 

with a magnetometer to look for additional small iron 

objects whose magnetic signature had been obscured 

by the iron mass of the submarine (see Chapter 11). 

During this brief hiatus in the work, Smith raised 

concerns about the bobbing movement of the materials 

barge that would carry the truss and submarine. When 

first brought to the site, this barge rode low in the water 

from the weight of the truss and piles. However, once 

freed of this heavy load, it began to bob cork-like in 

the waves. The apparent danger was that, as the truss 

and submarine were being lowered, the barge could 

suddenly rise upward and impact the truss with sufficient force to crush a leg and possibly damage the 

submarine from the impact. A 2 ft. (60.96 cm) rise due 

to the waves could equate to a 2 g’s of force on the 

truss. This issue was resolved in two ways simultaneously. Leonard Whitlock, the senior project manager, 

researched how partially flooding the barge’s three 

separate internal compartments would affect overall 

stability. The procedure was tested ashore on an 

identical barge located at Detyens Shipyard with 

guidance from a naval architect on the amount of 

flooding needed in each compartment to maximize 

stability. With the proper fill levels determined, partialFigure 10.20. A patch was placed over the 

starboard stern hole to ensure no loss of interior 

contents. (Photo by Rand Pixa, courtesy of FOTH)

Figure 10.19. Bill Youmans, Michael Gatto Jr., and Mark van Emmerick demonstrate 

the foam setting up around an object. (Courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

112

Raising the Hull 

The recovery date was planned 

as an event for the public and 

press, as there was a great deal of 

interest in and excitement about 

the project. As the meteorologists 

had predicted, 8August was perfect, 

a sunny and calm day with waves 

of 1–1.5 ft. (30.48–45.72 cm). All 

archaeologists, divers, engineers, 

and other personnel arrived on 

Karlissa-B, both to help with the 

lift and to witness the event. The 

two individuals who guided the 

whole operation, Senator Glenn 

McConnell, Chairman of the South 

Carolina Hunley Commission, and 

Warren Lasch, Chairman of the 

Friends of the Hunley, were present 

on site before dawn. Two additional 

vessels arrived on site shortly after 

dawn. The Fort Sumter tour boat 

Spirit of Charleston carried VIPs 

and supporters of the project, while the local charter 

vessel Carolina Clipper carried all the press and media 

personnel. Spirit of Charleston was given the privileged 

position of being closest to the point of lift. The press 

boat was a bit further off but had an expansive view of 

the lift operation. National Geographic personnel and 

contractors, as well as local Charleston Courier reporters 

Brian Hicks and Schuyler Kroft, were the only media on 

Karlissa-B. 

The large hopper barge from Great Lakes Dredging 

was towed on site and held in position by the two tugs 

(Figure 10.21). However, it also became apparent that 

the 102 ft. (31.01 m) long Spirit of Charleston, which was 

stationed very close to the recovery barge, would act 

as a breakwater as well. The interagency security team, 

including the 87 ft. (26.52 m) USGC cutter Yellowfin,

established a perimeter around the site. The security 

zone proved necessary as the number of private boats, 

including kayaks and jet skis, was estimated at 600 

vessels. 

Preliminary dives were done by both OII and HAT 

personnel. OII detached the umbilical that uploaded 

the load cell data and accomplished the final rigging 

for the lift. After a final check on the truss rigging from 

underwater, Perry Smith communicated that the truss 

and sub were ready for the lift. Smith then moved away 

from site to the safety of the diver’s stage. At 8:39 a.m.

Hunley emerged from sea and slowly spun on the cable 

to give a full view to eager spectators (Figure 10.22). The 

submarine was met by the sound of cheering and boat 

horns. Steve Wright timed the setting of the truss on 

the materials barge perfectly with the rise and fall of the 

waves. As soon as it touched down, the crane slacked 

the cable and OII personnel began chaining the truss 

down and welding its legs to the deck of the material 

barge. A quick inspection determined that the lift had 

gone perfectly, with no apparent leaks or damage to 

the hull. Mardikian immediately began setting up the 

sprinkler system to keep the hull wet during transport.

Neyland, Whitlock, and Wright monitored the lift 

from the materials barge, since setting the truss and 

submarine on it would be the most critical part of the 

lift. Lasch and McConnell were the first to transfer over 

to the barge. Eventually all OII and HAT personnel transferred to the materials barge for a triumphant return 

of Hunley. As soon as the truss was safely secured to 

the barge, a tow was attached to two McAllister Towing 

& Transportation tugs, Lewis G. Seabrook in the lead, 

and Brooklyn McAllister behind for added maneuvering 

control. As the tow got underway, the security zone 

closed around the tugs and barge to clear a path among 

the many boats and maintain a safe perimeter. 

As the historic submarine made its way into the 

Cooper River, it was accompanied by several hundred 

private boats (see Figure 16.1). Other than a private 

boat running out of fuel, there were no incidents and 

the moving security zone worked flawlessly. Thousands 

of people turned out at Ft. Moultrie on Sullivan’s Island 

and thousands more lined the shores of Charleston and 

Mt. Pleasant. The traffic over the Cooper River Bridge 

came to a standstill and people got out of their cars 

to view the sight. The procession moved flawlessly to 

Charleston Naval Shipyard and arrived at Pier Juliet at 

2:30 in the afternoon (Figure 10.23). OII personnel then 

Figure 10.21. Aerial view of the raising of Hunley, showing disposition of 

vessels around Karlissa-B. (Photo by Cramer Gallimore, courtesy of FOTH)
E X C A V A T I O N A N D R E C O V E R Y

113

set to work removing the bearing seats from the truss 

with a cutting torch in preparation for its placement into 

the tank. With the truss prepared, it was lifted by one 

of the shipyard portal cranes and carried 

to the WLCC, where it was transferred to 

an overhead crane inside the conservation 

building (Figure 10.24). The truss was then 

lifted, carefully positioned over the tank, and 

slowly lowered inside. The submarine was 

safely in the tank by 6:15 p.m. and Mardikian 

immediately began filling it with water. From 

recovery to placement in the tank, transport 

had lasted a total of 10 hours. Once inside 

the tank, the rigging was removed from 

the truss and the tank filling sequence was 

initiated. Conservators ensured hull was 

kept wet during the four hour procedure. 

Over the next 24 hours the tank water was 

chilled from 20° C (68° F) to 10° C (50° F). 

The only period the submarine had not been 

kept wet was during the transfer from the 

pier to the laboratory tank.

On the following day OII personnel 

began removing the suction piles from the 

seafloor. They were placed on a barge and 

transported to the shipyard. Karlissa-B was 

then towed from the site that evening to a 

Detyens Shipyard pier in North Charleston. On August 

10, OII and HAT teams began demobilizing Karlissa-B

and rigged the mooring anchors for recovery. 

Figure 10.23. The barge carrying Hunley was towed up the Cooper 

River to Pier Juliet at the former Charleston Naval Shipyard in North 

Charleston for transfer to the Warren Lasch Conservation Center. (Map 

by Mari Hagemeyer, NHHC)

Figure 10.22. The submarine H. L. Hunley begins its journey back to Charleston after 136 years. (Photo by Travis Bell, 

courtesy of Travis Bell Photography.)
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Conclusion

H. L. Hunley was successfully recovered without 

any damage or loss of archaeological information. As 

planned, the submarine maintained hull integrity and 

never deviated from its original starboard list, as it had 

rested in the sea bottom for 136 years. The teamwork 

of archaeologists, engineers, and others worked exceptionally well. As Senator McConnell was fond of saying, 

“No slip between the lip and the cup!” The implementation of the engineering design was superb. Even though 

at times it was said that the recovery system was “over 

engineered,” this type of planning and execution was 

precisely what was needed for such a unique and fragile 

artifact. The recovery operation was carried out without 

any injuries to the personnel involved. The Friends of 

the Hunley would receive three awards for safety the 

following year from the South Carolina Occupational 

Safety Council. 

Discovery and recovery of famous shipwrecks 

is always a media event and Hunley’s raising was no 

exception. Providing for the public viewing and media 

coverage of the recovery, with all the logistical, safety, 

and security challenges, was a valuable component in 

generating good will and support for the project. The 

thoroughness of the recovery planning and professionalism of its execution set the standards for the excavation of the submarine’s interior that would follow and 

provided a useful template for future archaeological 

recoveries.

Figure 10.24. H. L. Hunley on its final leg of the journey, 

carried by rail-based portal crane to the WLCC. (Courtesy 

of FOTH)
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11. Post-Recovery Surveys

H a r r y P e c o r e l l i I I I a n d H e a t h e r G . B r o w n

With the recovery of H. L. Hunley, the largest 

ferrous object at the site was no longer present to 

saturate magnetometer readings, and the way was clear 

to re-examine the area. A new remote sensing survey 

plan was designed to locate and identify any additional 

iron artifacts that may have been missed during the 

initial investigation. A preliminary survey was conducted 

in the area surrounding the submarine’s pre-recovery 

position in 2000, followed by a detailed, diver-based 

survey conducted by the Friends of the Hunley (FOTH) 

in the summer of 2002, and final brief site assessment 

in 2003.

For the primary, 2002 survey, FOTH archaeologists Harry Pecorelli and Shea McLean joined Ralph 

Wilbanks and Steve Howard of Diversified Wilbanks, Inc. 

to conduct the investigation. The 10-day field project 

began on 5 August 2002 and was funded by author 

Clive Cussler and an American Battlefield Protection 

Program grant from the National Park Service (Grant 

No. GA225502101). In 2003, a subsequent survey was 

conducted to reacquire and excavate the few remaining 

magnetic anomalies that could not be investigated 

previously.

Background

During the excavation of the Hunley site in June 

2000, archaeologists discovered that a portion of the 

port side of the submarine’s propeller shroud and the 

port shroud attachment bar were missing. Project staff 

hoped that the missing objects would be discovered 

during the recovery excavation; however, this significant part of the submarine’s architecture was never 

found. Because project archaeologists had completely 

excavated the area immediately surrounding the vessel, 

the pieces were assumed to be located outside of the 

excavation area. This resulted in the decision to return 

to the site and conduct additional survey work in hopes 

of locating the missing elements. 

As discussed in Chapter 4, several magnetometer 

surveys had been conducted in the years leading up to 

the recovery (Figure 11.1), primarily with the goal of 

locating the site itself. In 1996, a high resolution survey 

was conducted by NPS in order to detect any undiscovered material associated with the USS Housatonic/H. L. 

Hunley engagement site (Murphy 1998:53). Lanes were 

spaced at 10 m (32.81 ft.) intervals for a total coverage 

area of 400 × 800 m (1,300 × 2,600 ft.) (Murphy 

1998:56–58). The main anomalies noted at the time, an 

anchor and a buoy, were at least 100 m (328 ft.) distant 

from the submarine, with many closer objects masked 

by the signature of the hull itself (Figure 11.2). The data 

collected was entered into GIS software where it could 

be easily compared to post-recovery survey data.

Immediately after the recovery in 2000, the area 

where Hunley had been was resurveyed by Diversified Wilbanks. Several targets were acquired that had 

not been detected in the 1996 survey. These had the 

potential to be either materials left behind from the 

excavation or targets not captured in 1996 due to the 

strength of Hunley’s magnetic signature. To determine 

the nature of the most significant targets, a diver-based 

survey was necessary.

Methods

All 2000 and 2002 survey and dive operations 

were conducted from the vessel Diversity, which was 

launched at the Wild Dunes Marina and Boat Landing 

and docked at the NPS Fort Moultrie’s floating dock on 

the north side of Sullivan’s Island. 

Surface Survey

A 100 × 100 m (328 × 328 ft.) area surrounding the 

submarine’s pre-recovery position was surveyed with a 

Geometrics 881 cesium magnetometer operated at a 1⁄2 
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Figure 11.1. Boundaries of 1996, 2000, and 2002 surveys. 
P O S T- R E C O V E R Y S I T E S U R V E Y S

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Figure 11.2. Magnetometer data from 1996 overlain on the post-recovery site plan. Deeply buried material, such as the grapnel anchor and 

cutwater, did not show distinctive signatures in the shadow of the readings from the hull.
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boundary corners of the recovery site to establish the 

northern boundary line. Archaeologists then used fiberglass reel tapes to physically mark the south and west 

boundary corners. All corners were marked with 1 m 

(3.28 ft.) lengths of 1 in. (2.5 cm) diameter schedule 40 

PVC pipe. These PVC pipes were driven into the seabed 

so that only 15 cm (6 in.) remained exposed above the 

bottom. Lanes were then established at 2 m (6.56 ft.) 

intervals and strung with 3⁄8 in. (0.95 cm) diameter poly 

line. In the restricted visibility environment surrounding 

the site, physical lanes proved necessary to help guide 

the divers conducting the survey.

The 300 m2 (3,229 sq. ft.) area was first surveyed by 

divers using the same magnetometer used in the surface 

survey. Archaeologists held the cable end of the magnetometer sensor and pushed it backwards—fin end 

second sample rate. The magnetometer was towed at 

a boat speed of four knots. Ten transects spaced at 10 

m (32.80 ft.) intervals were surveyed. Sea conditions at 

the time of the survey dictated that all ten lanes were 

run in the same south-to-north direction. 

Diver Survey

Upon completion of the surface survey, the team 

conducted a diver-based, hand-held magnetometer 

survey to collect higher-resolution data from the area 

surrounding the submarine’s pre-recovery position. The 

initial survey area was 25 × 12 m (82.10 × 39.37 ft.). 

Using a survey-grade global positioning system, the 

team placed weighted buoys on the north and east 

Figure 11.3. Area of hand-held magnetometer survey over original position of H. L. Hunley wreck.
P O S T- R E C O V E R Y S I T E S U R V E Y S

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first—along every other transect. While this technique 

produced better-than-average results, problems with 

data acquisition frequently arose whenever the sensor 

wobbled from side to side. Water currents also seemed 

to affect the quality of data; for example, transects that 

traveled with the current produced better results than 

those that ran contrary to it. Archaeologists marked all 

objects with a 1 m (3.28 ft.) length of 3⁄4 in. (1.91 cm) 

diameter yellow fiberglass rod. 

Each transect was then re-surveyed using a 

hand-held Quantro Sensing Discovery Plus proton-precession magnetometer operated at a 2.5 second sample 

rate. This technique produced very accurate results, and 

enabled project staff to identify objects that exhibited 

less than a meter (3.28 ft.) of magnetic influence. Due 

to the improved results, several targets were discovered 

very close to the initial grid boundaries. As a result, the 

grid was expanded to 20 m (65.62 ft.) wide, with lanes 0, 

8, 9, and 10 added to the initial 1–7 (Figure 11.3). The 

entire grid was resurveyed at 1 m (3.28 ft.) intervals, 

ensuring extremely thorough coverage of the area.

Following the magnetometer survey, archaeologists 

replaced each of the fiberglass markers with a buoyed 

cinder block and began probing the surrounding area 

with a 3 m (9.84 ft.) long, 3⁄4 in. (1.91 cm.) diameter 

water jet probe powered by an 11 horsepower water 

pump. No objects were detected with the jet probe. 

After probing operations were completed, archaeologists inserted a 3 m (9.84 ft.) long section of 1 in. 

(2.54 cm) diameter PVC in the seabed next to each of 

the target positions. These posts served as a vertical 

guide for subsequent dredge excavations. Archaeologists employed the use of a 4 in. (10.16 cm) diameter 

water induction dredge to excavate a conically shaped 

test unit around each PVC pipe.

Once exposed, each target’s position was recorded 

relative to the survey grid and assigned coordinate values in Universal Transverse Mercator, North 

American Datum 1983, Zone 17 north. These items 

were subsequently recovered and transported to the 

Warren Lasch Conservation Center (WLCC) in North 

Charleston for conservation and analysis.

Findings

A total of seven targets were identified as cultural 

material in the 2002 survey, while two additional targets 

required a visit the following summer to locate and 

identify (Table 11.1). Two of the targets were discovered 

during the surface survey. The first (2002-01) had been 

noted originally in the 2000 post-recovery survey and 

was relocated approximately 20 m (65.62 ft.) north of 

the site. At 100+ gamma magnitude, it had the potential 

to mask smaller signals nearby, and archaeologists were 

deployed to recover it. The object was identified as 

a 5.26 m (17.33 ft.) long section of 1.5 in. (3.81 cm) 

diameter fence pipe left over from the recovery project. 

It was one of a number of pipes originally intended as 

a component of the sub-datum network developed 

for the submarine’s recovery (see Chapter 10). These 

pipes had proven too difficult to drive into the seabed 

and were either recovered or abandoned on site. A 

5+ gamma ferrous object (2002-02) was also detected 

approximately 25 m (82 ft.) north of the site. Time limits 

prevented investigation of this target until the 2003 

survey (discussed below). 

The diver survey resulted in the discovery of three 

of the original 1.5 in. (3.81 cm) diameter aluminum 

primary datum poles used to delineate the 2000 excavation trench boundary (2002-04, 2003-06, 2003-07). 

Each datum pole still protruded approximately 40 cm 

(15.75 in.) above the sand. In addition to the site 

Table 11.1 Magnetometer Targets Investigated in 2002–2003

Target Distance (m) Direction Gamma (γ) Identification

2002-01 20 NE 100+ Steel fence post

2002-02 25 N 5+ Mushroom anchor (19th c.)

2002-03 5 N 40+ Grapnel anchor (HL-2917)

2002-04 6 NW n/a Aluminum datum pipe

2002-05 5 SW 12+ Dive knife

2002-06 8 SW n/a Aluminum datum pipe

2002-07 6 S n/a Aluminum datum pipe

2002-08 9 S

150+ Iron can fragments / wire

2002-09 10 S Iron can fragments / wire
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datums, archaeologists discovered the original 1⁄4 in. 

(0.64 cm), three-strand synthetic line that delineated 

the boundary of the site. Portions of the line were 

buried as deep as 30 cm (11.81 in.) below the seabed. 

In addition, four iron objects were discovered 

within the survey area. One target (2002-05), a 

12+ gamma ferrous object detected 5 m southwest of 

the bow position, could not be pinpointed by divers and 

was added to the 2003 survey (see below). Two targets 

proved to be small iron fragments and wire, buried 10 

to 20 cm (3.94–7.87 in.) below the surface of the sand 

(2002-08, 2002-09). These iron fragments varied in size, 

although they averaged approximately 0.2 cm (0.08 in.) 

in thickness, and all had a slight curvature to them, consistent with the can fragments recovered from many 

locations around the site during the 2000 excavation 

(see Chapter 15). They were transported to the WLCC 

for documentation then discarded. Similar fragments 

were also detected at shallow depths during the prerecovery magnetometer survey conducted in 2000 (see 

Chapter 10), and may be a relatively common feature in 

the sediments close to the outflow zone of Charleston 

Harbor. 

The most significant discovery during the 2002 

survey was a five-tined iron grapnel anchor (Target 

2002-03; Artifact HL-2917), found roughly 5 m 

(16.40 ft.) north of Hunley’s original midship position. 

The anchor shank was located 1.8 m (5.91 ft.) below 

the seabed; three of the tines were partially dug into 

a 10 cm (3.94 in.) thick shell lens. The center of its 

tined end was buried 1.8 m (5.91 ft.) below the seabed 

and located 14 m (45.93 ft.) from the southern end of 

lane one. The ring at the end of the shank was positioned 13.9 m (45.60 ft.) from the southern end of lane 

one. The grapnel’s lower half was heavily concreted 

with large shells from the shell lens in which it was 

embedded, which appears to be part of the same shell 

layer that was found surrounding the bottom of the 

submarine during the 2000 recovery excavation. The 

grapnel’s shank was oriented level with the bottom, 

with the attachment ring pointing toward the forward 

hatch of the submarine (197°). The ends of the grapnel 

tines were flattened to form flukes. The grapnel has an 

overall length of 85 cm (2.79 ft.) and exhibits attributes 

consistent with 19th century manufacture (see Chapter 

15). Given its depth of burial and its general characteristics, it is likely this anchor was deposited on the site 

at some point close to or soon after Hunley’s loss. It is 

possible it was lost during attempts to locate Hunley or 

during salvage work on the Housatonic wreck.

2003 Site Visit

In 2003, the FOTH team returned to the site for one 

last offshore survey and limited excavation. The purpose 

of the survey was twofold: 1) investigate the nature of 

certain magnetic anomalies discovered near the site 

during the 2000 and 2002 remote sensing surveys; 

Figure 11.4. Illustration from diver notes of the mushroom anchor and length of 

chain discovered near the Hunley site and left in situ. (Drawing by James W. Hunter 

III, courtesy of FOTH)
P O S T- R E C O V E R Y S I T E S U R V E Y S

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and 2) ensure that no ferrous objects were missed that 

could be associated with the wreck site. This survey 

paved the way for removing maritime restrictions at the 

battle site that had been in place since the submarine’s 

discovery. 

No objects were found that are believed to be 

associated with Hunley, but Target 2002-02 may be 

roughly contemporary with the submarine. It was 

a large, convex iron object weighing an estimated 

250 lb. (113.4 kg), located approximately 25 m (82 ft.) 

north of Hunley’s original position on the seabed. The 

object, which was 30 in. (76.2 cm) in diameter and 7 in. 

(17.78 cm) thick, most likely represents a buoy weight 

of the type sometimes referred to as a mushroom 

anchor or sinker. Attached to the top of the convex side 

was an 8 in. (20.32 cm) iron chain fastened to a metal 

bar. Only a portion of the bar and chain assembly was 

exposed, but its buried length extended at least 50 ft. 

(15.24 m) from the point where it disappeared into 

bottom sediment. Since the object was found on the 

same shell lens that the submarine once rested on, it 

is likely that it, too, dates to the Civil War era. Because 

this type of weight was commonly used for anchoring 

not only buoys but also submerged mines during that 

period (Schiller 2011:190), the dive team refrained from 

following the chain all the way to its end. The exposed 

portion of anchor, bar, and chain were documented in 

situ and reburied. Scaled drawings were made based 

on the divers’ notes (Figure 11.4). 

Target 2002-05 was also found buried 1.5 m 

(4.92 ft.) below the seabed and identified as a modern 

diver’s knife embedded in a sandbag. During the excavation of Hunley, sandbags were placed on the site to 

protect the exposed areas of the hull during excavation. 

Just prior to the submarine’s recovery, the sandbags 

were removed from the site. To simplify the process, 

divers cut open each one, discharged its contents, and 

brought it to the surface. It appears that one of the 

divers lost his knife in the process and was unable to 

locate it in the restricted visibility around the site. The 

effectiveness of the hand-held magnetometer survey 

was demonstrated by project archaeologists’ ability to 

locate such a relatively small object within the vast area 

comprising the Hunley site.

The 2000, 2002, and 2003 surveys were an 

important follow-up to the recovery. They provided 

additional data regarding possible activities occurring 

after the sinking of Hunley, such as the U.S. Navy 

dragging for the submarine (see Chapter 4), and 

reassured the archaeologists that the recovery had 

been as thorough as possible in locating all of the 

cultural material from the sinking event.
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12. Site Description

H e a t h e r G . B r o w n , M i c h a e l S c a f u r i , a n d H a r r y P e c o r e l l i I I I

The submarine H. L. Hunley was buried beneath 

approximately 3 ft. (0.91 m) of sediment. An area 90 × 

40 ft. (27.43 × 12.19 m) was excavated around it, and 

the sediment screened for artifacts. The vessel rested 

at an angle of approximately 47° to starboard, with the 

bow angled approximately 0.5° downward. The majority 

of the sediment was sand mixed with organic concretion and shell. The bottom of the vessel and part of the 

starboard side were embedded in a stiff mud topped 

with a tough shell lens. 

A total of 341 artifact lots and 167 samples were 

collected. From the screened sediment, shells and 

natural concretions were discarded, while coal, boiler 

slag, wood fragments, fish and animal bones, and metal 

concretions were retained (Table 12.1). Samples were 

primarily sediment, but gas, metal, and water samples 

were also collected. Larger artifacts, such as hull components and concretions, were recovered by hand, 

while smaller materials were retrieved from dredge 

spoil. For a complete list of materials recovered, see 

Appendix G.

No formal trench designations were assigned, but 

the site was subdivided into regions based on location 

and excavation teams—the starboard and port sections 

directly adjacent to the hull that were excavated by 

the Hunley Archaeological Team (HAT); the starboard 

and port sections 10 ft. (3.0 m) out from the hull that 

were excavated by divers from Oceaneering International (OII); and the two holes for the suction piles, 

approximately 6 ft. (1.8 m) forward and aft of the hull 

(see Figure 10.11). These were all excavated down to 

the dense mud/shell layer in which the bottom of the 

submarine was embedded.

All artifacts were measured in by triangulation 

using a combination of fixed datum points and key 

points on the hull itself. The geographic position of the 

hull was pinpointed with GPS readings on the bow and 

stern. As per the research design, a three-dimensional 

site plan was created with the locations of significant 

artifacts and loose hull components using Rhinoceros 

software. A two-dimensional site plan was generated 

from this data and drawn by James Hunter (Figure 12.1).

Table 12.1. Number of Artifact Lots Collected by Material Type

Organic Inorganic

Bone 17 Ceramic 3

Caulking 1 Glass 5

Coal 58 Metal - fragments/concretions 104

Coral 1 Metal - hull components 14

Nutshell 6 Miscellaneous - modern materials 9

Rope 2 Miscellaneous - natural materials 5

Wood 48 Slag (boiler) 65

Unidentified Material 3

Total 136 Total 205
S I T E D E S C R I P T I O N

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Figure 12.1. The site plan was created using triangulated measurements of artifact positions, which were plotted in three-dimensional software. A twodimensional plan was then drawn by hand. (Drawing by James W. Hunter III, Courtesy of FOTH)
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Figure 12.2. Plan and profile views of Hunley. Letters indicate significant measurements included in the text. For larger version, see foldout at the end of the volume.

(Source drawing by Michael Scafuri, courtesy of FOTH; adapted by H. G. Brown, NHHC)
S I T E D E S C R I P T I O N

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case USS Housatonic. From the forward end of the spar 

attachment tang to the aftermost point on the rudder 

attachment (B), Hunley has a length of 41.375 ft. in. 

(12.61 m). The hull measures 40.063 ft. (12.21 m), from 

the forwardmost point on the bow to the aft-most point 

on the stern (C). The spar attachment tang extends 

12 cm (4.72 in.) forward of the extreme end of the bow. 

The propeller and shroud extend 27.8. cm (10.94) aft of 

the aftermost point on the stern. 

The overall height of the submarine (H), from the 

hatch top to the bottom of the keel weight, is 5.58 ft. 

(1.70 m). The height of the hull at the center of the crew 

compartment (I), including the keel weights, is 4.25 ft. 

(1.293 m). Its maximum width (G) is 3.625 ft. (1.10 m). 

Main Body

The center portion of Hunley’s hull was found to be 

made of a series of six pairs, or courses, of hemispherical 

plates, for a total of twelve plates. All plates are joined 

along the edges with single-riveted butt joints underlain 

by a butt strap, and riveted along the bottom edges to 

an expansion strake that ran down the center along both 

sides. Three plates are 82 cm (32.25 in.) in width, two 

are 81 cm (31.875 in.) and one is 76 cm (29.94 in.), with 

an average thickness of 0.6858 cm (0.27 in.). 

The two expansion strakes are approximately 

35.93 ft. (10.95 m) long (not considering taper), 8.625 in. 

(0.22 m) wide, and appear to be constructed from a 

single length of rolled wrought-iron plate per side, 

although that cannot be confirmed until deconcretion 

of the hull has been completed. The average thickness 

is 0.90 cm (0.36 in.), but there may have been some 

metal loss due to erosion prior to burial. The addition 

of expansion strakes to the sides of the submarine’s hull 

increases its interior headroom and gives the compartHull

The most significant “artifact” recovered from the 

site was the hull itself, designated HL-0708 (Figure 

12.2). While many features had been revealed during 

the 1996 site investigation, the complete exposure of 

the hull revealed its full dimensions for the first time. 

It was covered in a layer of concretion that varied in 

thickness, but was usually no less than 1 cm (0.39 in.). 

All measurements given below include the concretion 

layer, unless otherwise specified.

Structurally, the hull can be divided into five basic 

sections: the main body, primarily made up of wroughtiron hemispherical plates, which comprised the crew 

compartment; bow and stern sections made up of 

tapering wrought-iron quarter plates, which housed the 

fore and aft ballast tanks; and the cast-iron bow and 

stern pieces and their associated assemblies, including 

the weapons system forward, and the propeller and 

rudder aft. 

Other external features include two conning towers 

on top of the vessel providing access to the fore and 

aft ends of crew compartment. An apparatus known 

as a snorkel box was mounted on top just behind the 

forward conning tower to allow for the admission of 

air into the interior. Two long blades, or diving planes, 

were mounted on the sides, at about center height of 

the body, just aft of the forward conning tower. An iron 

torpedo spar was attached to the bottom of the bow 

casting. The submarine was weighted with an external 

cast-iron keel made up of eight distinct blocks bolted to 

the bottom of the hull. 

Hunley would have had an overall length of approximately 59 ft. (17.97 m) from the forward tip of the spar 

to the aftermost point of the rudder (A). An explosive 

charge would have been mounted at the end of the 

spar until its deployment against another vessel, in this 

Figure 12.3. Diagram of the riveting style used on Hunley compared to the 

more standard industrial riveting method common at the time.
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126

ment a somewhat elliptical shape, formally known as 

“obround” (see Figure 9.1).

All rivets along plate boundaries are flush-riveted, 

or countersunk, a relatively uncommon style for the 

period. This means that each rivet hole in the submarine’s main assemblage was beveled to allowing the top 

of the rivet head to fit level with the exterior surface of 

the hull plate (Figure 12.3). The rivets average 1.25 in. 

(3 cm) in diameter and are spaced approximately 

2.125 in. (5.5 cm) on center.

Crew Compartment

The crew compartment (D) is located in the center 

of the hull and begins just forward of the forward 

conning tower. It terminates at a point slightly aft of the 

aft conning tower. Internally, it is defined by bulkheads 

at each end, which are composed of two pieces, perpendicular to the tapering hull. This results in a slightly 

V-shaped top profile and two distinct length measurements. From the top center of the bulkhead, the overall 

length is 22.56 ft. (6.88 m). From the top corners, the 

overall length is 22.64 ft. (6.90 m). 

Light entered the crew compartment through five 

pairs of 6.1 cm (2.375 in.) diameter glass deadlights 

set into the top of the upper hull plates. Each port is 

spaced 10.5 cm (4.13 in.) from Hunley’s centerline to 

the center of the glass. All but one of the deadlights 

appears undamaged; the exception—located on the 

starboard side of the submarine in the fourth set of 

ports aft of the forward conning tower—is cracked. The 

source of this damage remains undetermined. 

 Conning Towers

The crew entered the vessel through two elliptically shaped, cast-iron conning towers, which consist 

of a relatively short vertical wall or hatch coaming and 

a hinged hatch cover (Figure 12.4). The conning towers 

measure approximately 60 cm (23.62 in.) fore-and-aft 

and 41.8 cm (16.46 in.) wide, including the concretion 

layer. They rise approximately 39.74 cm (15.66 in.) from 

the top of the hull. A small lip or flange surrounds the 

base of the tower where it is attached to the hull plates. 

The hatch covers are shallowly dome-shaped and fit 

inside the hatch coaming, sealing closed over a rounded 

lip. Both hatches open toward the center of the submarine’s crew compartment. The aft hatch cover is 56.7 cm 

(22.32 in.) in length, 38.5 cm (15.16 in.) wide, and 

ranges from 12 to 15 cm (4.72–5.91 in.) high. Hunley’s 

builders placed a single glass deadlight in each hatch 

cover, along the centerline, but closer to the hinged 

side, centered approximately 18 cm (7.09 in.) from the 

hinged edge (Figure 12.5). Two hinge arms, part of the 

casting, extend from the cover, approximately 16 cm 

(6.30 in.) apart, and align with two hinge arms cast into 

the coaming. The hatches were secured from the inside, 

with no external latch or handle.

Several glass viewports are situated in each hatch 

coaming. Both conning towers have a viewport in 

the starboard and port sides. Those in the forward 

tower are low down near the bottom of the coaming, 

approximately 12 cm (4.72 in.) above the top of the 

hull (measured to the bottom of the glass). Those in 

the aft tower are up near the top of the coaming. The 

bow tower also has two ports facing forward on either 

side of the cutwater, toward the top of the coaming. All 

viewports are made up of a flange 4 in. (10.16 cm) in 

diameter holding a glass insert averaging 2 in. (5.08 cm) 

in diameter and 0.31 in. (0.8 cm) in thickness. 

Figure 12.4. Idealized view of the forward conning tower with cutwater and intact forward 

viewport. (Diagram by Mari Hagemeyer, NHHC).

Figure 12.5. Top of aft hatch cover after deconcretion. The glass from the deadlight was removed and 

conserved separately. (Photo by Johanna Rivera, 

courtesy of FOTH).
S I T E D E S C R I P T I O N

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hole. The bolt head, approximately 5 cm (1.97 in.) 

square, is on the port side and does not rest flush 

against the side of the casting, but protrudes roughly 

6 cm (2.36 in.) (Figure 12.7). This suggests there is 

an object missing that was once held in place by this 

piece of hardware. There is evidence of another lateral 

through hole, approximately 12 cm (4.72 in.) down from 

the top of the casting, that has been partially eroded 

away along the forward edge leaving an indentation 

Bow and Stern Quarters

At either end of the crew compartment, the sides 

of the hull begin to taper sharply toward the bow 

and stern (E and F). The forward tapered portion is 

3.04 m (9.97 ft.) long; the aft tapered section has an 

overall length of 3.08 m (10.11 ft. in.). While the taper 

begins with the panels holding the conning towers, the 

majority of these two sections were divided off from 

the crew compartment via a partial bulkhead. The 

space fore and aft of the bulkheads acted as ballast 

tanks, providing for the intake or expulsion of water 

to control the submarine’s depth in the water column. 

Only the submarine’s width is affected by the taper, as 

the vessel height remains relatively constant over its 

entire length. 

The tapering at each end is completed over a series 

of four narrowing courses made up of 4 wrought-iron 

quarter plates each, for a total of 32 quarter plates. The 

quarter plates are flush riveted along all edges, with 

the sides butt joined, in the same fashion as the central, 

hemispherical plates. The top and bottom of the panels 

are lap joined to the expansion strake at center height, 

and to metal strips called strongbacks along the top 

and bottom of the vessel. Like the expansion strake, the 

strongbacks are located on the exterior of the vessel, 

covering the seams between the plates. The quarter 

plates are affixed to the cast-iron pieces at the bow and 

stern using a single-riveted lap joint, with the quarter 

plates placed over the casting.

Bow Casting and Spar Assembly

The submarine’s builders achieved the knife-like 

edges that characterize the bow and stern by casting 

them out of iron. The bow casting 

measures approximately 63 cm 

(2.07 ft.) in length. At the point where 

it is riveted to the quarter plates, it is 

approximately 19.7 cm (7.75 in.) wide 

and tapers to a point approximately 

2–3 cm (0.79–1.18 in.) wide. There is 

a significant amount of scour erosion 

along the forward edge, making precise 

measurement difficult (Figure 12.6). 

A hole penetrates the upper forwardmost portion of the bow casting 

laterally. With concretion, it measures 

approximately 5 cm (1.97 in.) in 

diameter, but a larger dimension is 

expected once the hull has been 

deconcreted. It is 6.3 cm (2.48 in.) 

from the top of the casting, and 18 cm 

(7.09 in.) from the surviving forward 

edge. An iron bolt laterally penetrates 

the casting immediately beneath the 

Figure 12.6. Portside view of the bow casting, 

showing deterioration of leading edge (rivet 

spacing approximate). (Diagram by Mari 

Hagemeyer, NHHC).

Figure 12.7. A substantial bolt laterally penetrates the bow casting. (Photo 

by H. G. Brown, NHHC).
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128

approximately 4 cm (1.57 in.) deep. This hole and the 

surviving bolt are likely mounting points for hardware 

used to hold a rigging boom in place (see Chapter 14).

At the bottom of the casting, a Y-shaped cast-iron 

yoke with a square tang extending forward is bolted to 

the bow, 13.8 cm (5.43 in.) from the base of the submarine’s prow (Figure 12.8). The yoke fits over the casting 

and is held in place by two through bolts, approximately 

16 cm (6.30 in.) apart on center. The tang protrudes 

approximately 12 cm (4.72 in.) beyond the bow, and 

is 6.5 cm (2.56 in.) high, and 6.2 cm (2.44 in.) wide 

before it narrows to 2.7 cm (1.06 in.) wide to receive the 

spar. The yoke arms are 33.5 cm (13.19 in.) long, 7 cm 

(2.76 in.) high, and taper down from 3.2 cm (1.26 in.) 

thick at the bow to 1.5 cm (0.59 in.) at the after ends. 

The tang held a multi-component iron spar, still 

bolted in place when excavated, with a preserved length 

of 4.89 m (16.05 ft.) (Figure 12.9). Heavily concreted, 

it was recovered in two pieces, the longer portion 

attached to the bow, and the shorter end, 69.73 cm 

(27.45 in.), still in its original position but deteriorated 

to the point that it separated from the rest of the spar. 

Once deconcreted, conservators discovered the 

spar was originally made up of three distinct pieces. 

The first is a solid, cast-iron rod, 1.075 m (3.53 ft.) long 

and 5.68 cm (2.24 in.) in diameter, bifurcated at the 

proximal end to fit over the tang at the forward end of 

the yoke. A single bolt penetrated both pieces horizontally to secure the spar while providing a pivot point 

for raising and lowering it. The distal end narrowed to 

4.8 cm (1.89 in.) diameter for the final 14.5 cm (5.71) 

so it could be inserted into the rolled wrought-iron 

pipe or tubing that made up the remainder of the spar 

and bolted in place. The first section of tubing is 1.8 m 

(5.91 ft.) in length, and the second, 2.15 m (7.05 ft.) 

long. They were joined together with a 6.4–6.6 cm 

(2.52–2.6 in.) iron coupling, for a total hollow length of 

3.96 m (12.99 ft.). At the tip of the spar, conservators 

found a fragment of copper sheathing from the torpedo 

it carried bolted to the iron, indicating the preserved 

spar length is very close to its original length (FOTH 

2013:4). 

Stern Casting, Propeller, and Steering 

Assembly

The stern casting, like that of the bow, is also solid 

cast iron, 63 cm (24.80 in.) long, 123 cm high (48.43 in.), 

widening to approximately 19.7 cm (7.76 in.) where it 

meets the quarter plates, and attached to the stern 

quarter plates with a single-riveted lap joint (Figure 

12.10). One lateral hole near the top aft portion 

may correspond in size and shape to that in the bow 

casting, but it is currently too concreted to know for 

certain. Two longitudinal openings, or glands, were cast 

Figure 12.8. Spar attachment yoke based on measurements taken prior to 

deconcretion. (Diagram by H. G. Brown, NHHC)

Figure 12.9. Outline of spar showing main sections and surviving hardware. (Diagram by Amanda Quinn, NHHC)
S I T E D E S C R I P T I O N

129

through it to accommodate the propeller shaft and 

the steering rod. The steering rod gland begins 16 cm 

(6.30 in.) from the top of the casting, and is approximately 8.5 cm (3.35 in.) in diameter at the after edge. 

Concretion extends several inches beyond the after 

edge of the casting, suggesting that a small portion of 

the steering rod may survive. The propeller shaft gland 

begins approximately 55 cm (21.65 in.) from the top 

of the casting and is approximately 15 cm (5.91 in.) in 

diameter at the after edge of the casting. The propeller 

hub appears to rest flush against the gland, but details 

are currently obscured.

Seven of the submarine’s eight-man crew turned an 

iron crankshaft attached to a roughly 69 cm (27.165 in.) 

diameter, three-bladed cast-iron propeller. The blades 

had a maximum width of approximately 19 cm (7.48 in.) 

and a thickness of 2–3 cm (0.79–1.18 in.). An iron 

shroud originally surrounded the propeller, of which 

only just over half survives, primarily on the starboard 

side. It measures approximately 20 cm (7.87 in.) wide 

and 1.5 cm (0.59 in.) thick, with a diameter of approximately 76.6 cm (30.16 in.). The shroud was mounted to 

the stern casting with a pair of Y-shaped yokes similar 

to, but smaller than, the one used to secure the spar 

to the bow casting. The dimensions of the arms, as 

estimated through the heavy layer of concretion, are 

20 cm (7.87 in.) long and 5 cm wide (1.97 in.). The yoke 

arms meet aft of the stern casting and extend into a 

flat, horizontally-oriented iron bar or bracket, approximately 6 cm (2.36 in.) wide and 2 cm thick (0.79 in.), to 

which the shroud was fastened. The end of each shroud 

bracket continued beyond the after edge of the shroud 

to provide a means for mounting the rudder (Figure 

12.11). Only the lower mounting point appears to have 

survived, though this will be clearer once the conservation phase is completed. The surviving portion of the 

upper bracket extends 27.5 cm (10.83 in.) beyond the 

after edge of the stern casting, while the lower bracket 

extends 30 cm (11.81 in.).

Attached to the starboard side of the shroud was 

one of two long rectangular iron bars that originally 

connected to the top edge of the expansion strake 

about 2 m (6.56 ft.) forward of the aft end of the stern 

casting and likely helped prevent the propeller from 

fouling. It was heavily concreted and still tenuously 

Figure 12.10. Idealized port-side view of stern casting (rivet spacing 

approximate). (Diagram by Mari Hagemeyer, NHHC).

Figure 12.11. Propeller as exposed 

by loss of the port side of the 

shroud. The brackets holding the 

shroud also provided mounting 

points for the rudder. (Photo by 

H. G. Brown, NHHC)
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130

connected to the hull, but inverted, so the after end 

was positioned forward of the aft conning tower, about 

80 cm (31.50 in.) below the centerline of the vessel. 

In its concreted state, it measures 1.78 m (5.84 ft.) in 

length, 3.0 to 3.6 cm (1.8–1.42 in.) in width, and 1.49 cm 

(0.59 in.) thick. The forward end of the bar showed 

evidence that it had been pulled forward, deforming 

the metal where it attached to the hull. The piece was 

detached from the hull during excavation and recovered 

separately (HL-0660). The corresponding port bar was 

not present.

At some point following the wrecking event, 

Hunley’s iron rudder (HL-0686) became unshipped 

from its position behind the propeller and came to rest 

beneath the stern end of the hull, where archaeologists located it, roughly 70 cm (27.56 in.) forward of its 

original position. The rudder is approximately 78 cm 

(30.71 in.) high, 53 cm (20.87 in.) wide, and ranges 

in thickness from 0.65–0.75 cm (0.26–0.30 in.) after 

deconcretion. It is possible there was some overall 

metal loss, suggesting the original material may have 

been a standard 3⁄8 in. (0.95 cm) iron plate. After deconcretion, many important features of this piece came 

to light (Figure 12.12). Two iron pieces are fastened 

to either side of the top and bottom corners of the 

rudder, which appear to be part of the hardware that 

attached the rudder to the propeller shroud mounts. 

Both were broken off along the edges of the rudder, so 

evidence of the attachment joint itself is not present. 

The upper piece is at an angle of approximately 45°. 

An oblong hole was found in the center, approximately 

8 cm (3.15 in.) long and 1 cm (0.39 in.) wide, that is 

original to the piece. There is an iron strap on each side, 

bolted or riveted together through the hole. These likely 

connected to a vertical steering arm aft of the rudder 

and could move fore and aft in the hole as the rudder 

changed position (see also Chapter 15).

Other External Features

Diving Planes

The submarine’s two cast-iron diving planes are 

located beneath the snorkel box. They served as the 

primary control surfaces for directing the vertical 

movement of the submarine in the water column. Both 

are mounted along the approximate horizontal centerline of the hull, on opposite sides of the vessel (Figure 

12.13). Each diving plane measures approximately 2 m 

(6.56 ft.) in length, and range in width from 25 to 31 cm 

(9.84–12.20 in.) due to erosion and concretion. They are 

2.3 cm (0.91 in.) thick. While the starboard plane was 

found in a level position, the port plane was inclined 

slightly upward.

Fixed fins or skegs are located forward of the diving 

planes to protect the leading edge. They measure 

40–42 cm (15.75–16.53 in.) in length where they attach 

to the hull, and project horizontally 18–20 cm (7.09–

7.87 in.) at the widest point. The port skeg lacks the 

well-defined triangular shape of the starboard one—

this is very likely the result of the submarine’s list to 

starboard, which exposed the upper port side of the 

submarine to prolonged sand abrasion while protecting 

its counterpart.

Air Exchange Systems

A raised box was attached to the top of the crew 

compartment, 20 cm (7.87 in.) aft of the forward 

conning tower. This cast-iron component, known as the 

air box or snorkel box, incorporated two adjustable iron 

pipes that allowed the exchange of fresh air into the 

crew compartment while the submarine operated just 

below the water’s surface (Figure 12.13). It is 40 cm 

(15.75 in.) on each side and 21 cm (8.27 in.) tall. The 

remains of two packing glands are located on the port 

and starboard side of the box. The packing glands 

housed the two pipes, or snorkel tubes, that could 

either lie flat against the hull or be positioned vertically 

while submerged. As with the conning towers, a small 

lip or collar surrounds the box to aid in mounting the 

piece to the hull. Further details on the joints used will 

be clear once the deconcretion process is completed.

Portions of both tubes were recovered, though 

neither is fully intact. They were found along the 

starboard side of the hull, parallel to each other, but 

Figure 12.12. Idealized view of 

surviving elements of the rudder (HL0686), port side. Attachment points 

and steering hardware do not survive. 

(Diagram by Mari Hagemeyer, NHHC)
S I T E D E S C R I P T I O N

131

offset approximately 65 cm (25.59 in.), with the outer 

tube further forward. They were roughly 70–80 cm 

(27.56–31.50 in.) below the top of the hull, in the dense 

shell layer encasing the lower portion of the submarine. 

The aft end of the outermost tube was 9 cm (3.54 in.) 

starboard of the hull, and the forward end 39 cm 

(15.35 in.) to starboard. As the plating is beginning to 

taper inward at this point, it appears the tubes came to 

rest roughly parallel to the hull. The preserved length of 

the first tube (HL-0616) is 140 cm (55.12 in.); the second 

tube was recovered in two adjoining pieces (HL-0614, 

HL-0615) for a total length of 148.5 cm (58.46 in.). Both 

have an inside diameter of 4.1 cm (1.61 in.). There is 

evidence that both ends of the snorkels were threaded. 

Cutwaters

Two cutwaters were originally positioned on the 

top of the hull along the centerline, each abutting the 

forward side of one of the conning towers. These triangular sheets of metal tapered down forward to the 

top of the hull, most likely to prevent fouling of the 

conning towers and their viewports (see Figure 12.4). 

The aft cutwater (HL-0555) became dislodged from the 

hull following Hunley’s loss and was discovered lying to 

starboard of the submarine during the recovery project. 

It measures 1.6 cm (0.63 in.) thick, 112 cm (44.09 in.) 

long where it attached to the hull, and extended vertically 22 cm (8.66 in.) up the leading edge of the 

hatch coaming. The bow cutwater is of comparable 

dimensions.

Keel

The submarine’s keel is made up of a series of eight 

cast-iron blocks affixed to the bottom exterior surface 

of the hull (Figure 12.14). An additional small wooden 

wedge was inserted between the fifth and sixth blocks. 

Together, these blocks run approximately the length 

of the crew compartment over a distance of 22 ft. 

(6.71 m). The forwardmost and aftermost keel weights 

(KB1 and KB7) taper sharply at each end and are fitted 

carefully to match the curvature of the underside of 

the hull. Both are 124.5 cm (49.02 in.) long at the centerline, 11 cm (4.33 in.) thick, with an average width 

in the non-tapering portion of 55.5 cm (21.85 in.). KB1 

weighs 237 kg (522.50 lb.). The remaining blocks are 

rectangular and smaller, with most (KB2–KB5) running 

78 cm (30.71 in.). One block, KB6, is only slightly shorter 

at 77 cm (30.31 in.), while KB1A is considerably smaller 

Figure 12.13. Idealized plan view showing position of diving planes and their protective skegs, in 

addition to the forward conning tower and snorkel box. (Diagram by Mari Hagemeyer, NHHC).

Figure 12.14. Layout of keel weights, based on 3D data collected prior to deconcretion. All blocks are cast iron, and the 

small wedge between KB4 and KB5 is made of wood. (Diagram by Mari Hagemeyer, NHHC).
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

132

at 28 cm (11.02 in.). Together they vary in width from 

54 cm (21.26 in.) to 58 cm (22.83 in.). All average 11 cm 

(4.33 in.) thick. 

According to historical sources, Hunley’s keel 

weights were designed to be unbolted from inside 

the crew compartment if the submarine took on an 

excessive amount of water ballast. Theoretically, the 

submarine would be able to resurface once rid of the 

extra weight created by these ballast blocks. Square 

bolt heads are clearly visible in the center of nearly all 

the keel blocks, supporting the presence of this design 

feature. In practice, the system did not work very well, 

as evidenced by the loss of the submarine’s second 

crew in October 1863 (see Chapter 2). 

Condition

Upon recovery, the hull was entirely covered in a 

concretion layer that varied from approximately 1 cm 

(0.39 in.) thick to as much as 10 cm (3.94 in.). Some 

areas that demonstrate thicker patches of concretion encase small intrusive objects that came to rest 

against hull and became concreted to it. This certainly 

happened in several cases with tin cans (see Chapter 

15). It is also possible these areas represent additional 

hull components that were dislodged from their original 

position or features that protrude from the hull. 

The glass from all but one of the deadlights was not 

fully concreted and was visible to divers upon the submarine’s discovery. Most of the viewports in the conning 

towers were only partially concreted over, although 

those on top of the hatches and one on the forward 

conning tower were completely covered (Figure 12.15).

Large areas of the hull were also covered with 

marine growth, the most distinctive being the white 

remains of colonies of star coral (Astrangia danae) and 

the horse oyster (Ostrea equestris) (Murphy 1998:150–

51). The upper areas preserved more evidence of 

colonies growing on the hull itself, while the lower 

areas, in the region of the Pleistocene mud layer, were 

covered in a thick shell/mud conglomerate. A few areas 

were relatively smooth with minimal shell coverage, 

such as portions of the bow casting (Figure 12.16). This 

apparent lack of colonization may be the result of high 

energy water flow during the period prior to the vessel’s 

burial (see Chapter 13).

Holes in Hull

As excavation progressed, a total of three significant 

hull breaches were recorded. The first, in the forward 

conning tower, had already been discovered during the 

1996 site investigation (Figure 12.17). It is roughly 10 cm 

(3.94 in.) high in the center, and 11 cm (4.33 in.) at its 

widest point, close to the hatch cover. This area once 

held the forward, portside viewport. Original speculation was that this damage was caused by small arms fire 

from Housatonic (Murphy 1998:80), and this possibility 

cannot be been ruled out, based on tests conducted at 

the Warren Lasch Conservation Center.

The other two holes are located along the starboard 

side, one near the bow, one near the stern, both in the 

vicinity of the boundary between the cast-iron ends 

and the wrought-iron plates. These appear to have 

developed after the submarine had settled into its final 

position, as a result of a complex interaction of erosion 

and corrosion processes (see Chapter 13). The bow hole 

Figure 12.15. The viewport (A) on the starboard side of 

the forward conning tower was partially exposed, while 

the forward viewport (B) was completed covered over. 

Remains of star coral colonies are densely packed over 

the top of the hatch. (Courtesy of FOTH).

Figure 12.16. Horse oyster shells can be seen at the top 

of the port side of the bow casting, but the area below 

has been worn smooth by hydrodynamic forces. (Photo 

by H. G. Brown, NHHC).
S I T E D E S C R I P T I O N

133

is trapezoidal in shape, measuring 27.4 cm (10.79 in.) 

at its widest point and 26.6 cm (10.47 in.) high (Figure 

12.18). It begins 26.5 cm (10.43 in.) from the top of the 

hull, and 57.7 cm (22.72 in.) aft of the surviving edge 

of the bow casting.

The stern hole is somewhat ovoid in shape, 

beginning 3 cm (1.18 in.) down from the top of the 

vessel and 32 cm (12.60 in.) forward of the after edge 

of the stern casting (Figure 12.19). It measures approximately 90 cm (35.43 in.) at its widest point with a 

maximum vertical expanse of 50 cm (19.69 in.). It 

crosses the boundary between the stern casting and 

the aftermost starboard top quarter plate. The steering 

rod can be seen through the upper third of the opening, 

running horizontally along the vessel’s centerline.

Other Damage 

Several of the protruding elements of the vessel 

also showed damage, most notably the rudder, which 

was fully detached from its mounting. The hardware 

connecting the steering rod to the rudder was also not 

evident. Possibly related is the damage to the propeller 

shroud, which is almost entirely missing on the port 

side, and is torn on the upper quarter on the starboard 

side with the forward edges bent upward (Figure 12.20). 

This type of damage is less likely to have been part of 

the natural degradation of the hull, and may be related 

to the initial explosion, subsequent search attempts, or 

simply an accidental anchor snag. The disarticulation of 

the starboard shroud attachment bar and loss of the 

port attachment bar may be related to the same event 

or events that damaged the shroud. 

Another anomaly is the arrangement of the diving 

planes. Designed to move in parallel to each other, 

maintaining the same angle of inclination, the planes 

are now out of sync with one another. The starboard 

diving plane is positioned exactly along the vessel’s horizontal axis, in line with the skeg. The port diving plane, 

however, is inclined slightly upward, its forward edge 

approximately 3 cm (1.18 in.) above its skeg, yet it does 

not appear bent (Figure 12.21). It is possible the port 

plane was snagged by a passing anchor at some point, 

or that the prolonged pressure from the ebb current 

on the exposed plane gradually pushed it up in relation 

to the starboard plane, which was protected by being 

planted in the Pleistocene mud layer. Further research, 

after deconcretion is complete, may shed light on the 

cause for this apparent discrepancy.

Several areas of the hull show degradation from 

erosion in the post-depositional environment. The 

leading edge of the bow casting, as mentioned above, 

Figure 12.17. Hole in the forward conning tower 

encompassing the total loss of the port viewport 

(Courtesy of FOTH).

Figure 12.18. Hole in bow, along boundary between 

wrought- and cast-iron components. Deterioration of 

the leading edge of the casting is also visible at right. 

(Photo by H. G. Brown, NHHC).

Figure 12.19. The largest hole was at the stern near the 

top, crossing the boundary between the wrought- and 

cast-iron components, causing the loss of several rivets 

and exposing the steering rod. (Courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

134

was reduced from its initial straight vertical line to a 

concave profile. In addition to the two holes on the 

starboard side, the outer front edge of the port diving 

plane is worn down. This is the most significant area 

of erosion on the port side of the hull. The starboard 

hatch attachment arm on the aft hatch shows noticeable metal loss, particularly on the bottom side.

Surrounding Sediment Matrix 

Due to its excellent preservation, very few artifacts 

in the surrounding sediment were directly related to 

Hunley. Despite several holes, no objects from inside 

the submarine were found outside the hull. A number 

of loose hull components were recovered, primarily 

from the starboard side or beneath the stern. Intrusive 

artifacts included contemporary glass and ceramic 

wares, as well as modern items such as a standard brass 

screw (HL-0393) and even a plastic astronaut figurine 

(HL-0525). Material from intervening periods was also 

collected, including early 20th century ceramics and a 

5 m (16.40 ft.) long galvanized rod, discovered in the 

lower layers on the port side. A possible explanation 

for the rod is that it was lost during previous surveys 

for Hunley, which got close to the magnetic anomaly 

but failed to recognize it (Browning and West 1982; Hall 

1995). 

All sediment from the dredging operations was 

carefully screened. It contained a mixture of shells, wood 

fragments, coal, and slag. While shell was discarded, 

the latter three categories were retained for analysis. 

Coal, slag, and wood were found in all areas of excavation. There were noticeable clusters of these materials 

around the starboard bow and beneath the propeller at 

the stern, trending to starboard (see Chapter 13). 

The majority of loose hull components were located 

in the starboard HAT trench, the only exception being 

the rudder, which was found under the stern, spanning 

the port/starboard dividing line. Fewer artifacts were 

found on the port side, but much of the ceramic assemblage was found there. The port area, however, was 

extensively disturbed during the prior excavation in 

1996 (see Figure 13.5). At that time, sediment was 

removed from the central area between the conning 

towers in a wedge shape down the port side to the 

keel and was not screened. Therefore, artifacts found in 

the port midships area may have come from backfilled 

sediments. The bow and stern areas were not disturbed 

prior to the 2000 field season.

Wood

The wood fragments consisted of a combination 

of naturally occurring branches and sticks, along with 

heavily weathered or eroded fragments that appear to 

have been part of man-made objects (Figure 12.22). 

Of this material, none could be linked directly to the 

submarine. Harbor outflow may account for much of 

the material. Several larger wooden pieces were found 

closer to the submarine, including a barrel cant (HL0587), which represent material culture, but could not 

be tied directly to the submarine. 

 One long, thin piece (HL-0505) was found adjacent 

to the starboard side of the bow. Roughly trapezoidal in 

cross section, the piece is 68 cm (26.77 in.) long, 10 cm 

(3.94 in.) wide and 6 cm (2.36 in.) high (see Figure 

15.22). One end is well persevered with a clear diagonal 

cut, while the other is heavily worn by teredo damage. 

Two cut marks run perpendicular to the grain along the 

wider side, approximately 27 cm (10.63 in.) from the cut 

end. The possibility that this was part of the spar boom 

Figure 12.20. Damage to the top starboard quarter 

of the propeller shroud. (Photo by H. G. Brown, NHHC).

Figure 12.21. The port side diving plane is in a slightly 

raised position. (Photo by H. G. Brown, NHHC).
S I T E D E S C R I P T I O N

135

was investigated, but deemed unlikely after comparing 

the dimensions of the piece to those of the brackets 

that would have held it in place. 

Coal and Slag

Coal and coal slag were found in abundance around 

the site (Figure 12.23). This material was collected from 

the dredge outflow, weighed and counted. While it did 

not originate from Hunley itself, some may have been 

transported from the nearby Housatonic wreck. The 

material varied greatly in size, and, in the case of slag, 

density. The distribution of this material was plotted 

and compared to other environmental data to help 

reconstruct the post-depositional processes affecting 

the site (see Chapter 13). The most noticeable clusters 

of coal and slag were found under the propeller and 

immediately to starboard, at the very bow down around 

the spar, and along the starboard forward quarter, particularly below the hole in hull. Some was even found 

inside the hull, carried in with the rest of the sediment 

as the interior gradually filled.

Concretions

Another common material present at the site was 

metal concretion, particularly in thin flake form. Some 

of these flakes may have been related to the hull itself, 

but there is evidence to suggest that many of these 

pieces, found at a variety of depths and sometimes 

quite distant from the hull, are remnants of tinned iron 

or steel cans. These fragments are generally slightly 

magnetic, but with little metal surviving, and gently 

curved profile. On many, the outer surface had an 

irregular or rough, granular texture, while the interior 

surface was smooth and black with occasional orange 

iron staining or an iridescent, cellophane-like film.

At least sixteen lots of iron fragments can be 

confirmed as cans, primarily due to shape and the 

presence of lead solder, a common component of 

cans until the late 20th century (Table 12.2).1

 Seven of 

these were found through radioraphy to be complete or 

nearly complete: HL-0427, HL-0653, HL-0654, HL-0700, 

1 American manufacturers began voluntarily eliminating lead from 

cans in the 1980s, but it was not formally prohibited until 1995 (21 

CFR 189); however, designs successfully isolating a can’s contents 

from contact with exterior solder had developed by the early 20th 

century.

Figure 12.22. Sample of a wood lot collected from 

dredge outflow during the excavation. This material did 

not prove diagnostic. (Photo by H. G. Brown, NHHC).

Figure 12.23. Typical collection of slag (left) and coal (right) collected from sediment 

surrounding Hunley. (Photos by H. G. Brown, NHHC)
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136

HL-3288, HL-3667, and HL-3678 (Figure 12.24). Fifteen 

additional lots consisting of small fragments and no lead 

have also been classified as cans based on their shape 

and texture, but no diagnostic features remain. While 

this material is not directly related to Hunley, as with 

the coal and slag, an examination of the distribution 

of the cans has contributed to a reconstruction of the 

post-depositional processes at the site (see Chapter 13).

Ceramics and Glass

Very little ceramic or glass was recovered from 

matrix surrounding the submarine. In all, only five glass 

and three ceramic artifact lots were found. Of these, 

three were found to starboard of the hull, five to port. 

Only one, a stoneware bottle (HL-0661), was fully intact. 

None could be directly tied to Hunley, although one 

group of glass fragments (HL-0506) was reconstructed 

Table 12.2. Iron and Lead Concretions Identified as Historic Cans 

ID # Surviving Elements Provenience

HL-0413 11 pcs, largest 7.2 × 4.6 × 0.9 cm; including 

two end pieces of hole-and-cap style

Starboard of aft hatch, down 

near metal rod [HL-0660]

HL-0427 Cylindrical object in 9 pieces; circular bottom 

and some walls intact in main piece

Starboard side, near propeller, shell layer

HL-0468 29 pcs, largest 6.7 × 5.0 × 1.7 cm; 

some pieces of lead solder

Starboard side of stern suction pile area.

HL-0485 19 pcs, largest 7.0 × 4.8 × 1.6 cm; some lead 

solder remaining; may be related to HL-0468

Stern suction pile hole, between 

starboard subdatums S1 and S2

HL-0617 1 pc iron concretion with strip of 

lead solder; 3.6 × 1.9 × 1.2 cm

Starboard bow aft of Sling 5, excavating 

around snorkel tubes HL-0615 and HL-0616

HL-0627 1 pc, concave, 5.1 × 4.4 × 1.7 cm; loose 

lead solder along curved edge

Under hull for slings 6-7 after jetting 

- probably fell in from above

HL-0644 4 pcs, largest 5.4 × 5.4 cm; lead 

solder strip, folder over

Port, under keel between slings 18-19

HL-0653 Fragile, cracked cylindrical concretion. h. 20 cm, d. 14 cm (with concretion); lead 0.3 × 0.1 cmConcreted to underside of keel in midships area.

HL-0654 Slightly flattened cylinder in 3 pcs; h. 28 

cm, “long” d. 28 cm, “short” d. 20cm 

(based on oblong shape of can)

Concreted to port side of keel, 

directly on side/bottom junction

HL-0678 15 pcs, largest 6.7 × 5.0 × 1.2 cm; lead solder 

on lip preserved on several fragments

Starboard stern, aft of sling 25

HL-0681 Lead ring, max. diam. 4.8 cm, int. diam. 

3.5 cm, th. 0.1 cm w/o concretion 

Starboard stern, aft of sling 25

HL-0682 Lead strip with frags of iron concretion adhering, triangular cross sectionStarboard stern, aft of sling 25

HL-0700 Complete cylinder preserved approx. 

11 cm diameter and 14 cm tall 

Starboard side of extreme stern edge, 

66 cm down from top of stern

HL-3288 Complete cylinder with lid (and 

cap) survive; bottom not intact

Removed from iron conglomerate 

HL-0582, off starboard bow

HL-3667 Complete but flattened cylinder with 

preserved vented cap and side seam

Concreted to center of keel block 6; 

removed during conservation phase

HL-3678 Upper or lower half of a complete cylinder; 

preserved rim and side seem; flattened

Concreted to starboard side of plate 

CB6 near the expansion strake; removed 

during conservation phase
S I T E D E S C R I P T I O N

137

Conclusion

The archaeological data collected at the site 

provided valuable supplementary data to the environment analysis (Chapter 13). The presence and positions 

of scour pockets on the starboard side of the submarine 

were initially noted by divers and could be roughly 

delineated based on the mapping of cultural material 

around the submarine. The condition of the hull itself 

also served as document attesting to the conditions 

encountered in the years after its sinking.

Access to the entire submarine, even in its 

concreted state, allowed for a more detailed analysis 

of Hunley’s features and construction, particularly in the 

face of the disparate historical accounts that could only 

be confirmed or refuted by data from the submarine 

itself (Chapter 14). There are still many questions to 

be answered, but the preliminary data reported above 

provide an important starting point for future studies 

of this remarkable vessel.

and identified to be a 19th century U.S. Navy condiment 

bottle, which could have come from Housatonic. The 

remaining lots in this category were only fragments. 

Most pieces recovered represent items of late 19th or 

early 20th century manufacture (see Chapter 15). 

Figure 12.24. A radiograph of HL-0653, showing 

diagnostic seams that confirm identification as a 

tinned iron can. (Courtesy of FOTH).
138

13. Site Analysis

M . S c o t t H a r r i s , H e a t h e r G . B r o w n , R o b e r t S . N e y l a n d

Analysis of the geologic and archaeological data 

collected at the H. L. Hunley site provided additional 

means by which to interpret both the events of the 

submarine’s loss and its post-depositional context 

and preservation environment. Building on geologic 

data collected prior to the recovery, many of which 

are discussed in the National Park Service reports 

(Murphy 1998, Conlin 2005), geologist Scott Harris used 

samples collected immediately prior to the recovery 

to reconstruct the depositional history of the site. His 

conclusions were supported by an examination of the 

fauna at the site as well as the distribution of artifacts 

that collected around the submarine as it was slowly 

encased in the seabed.

Site Geology: Survey and Sampling 

Data: Types and Sources

A variety of geologic data sources, including acoustic 

sub-bottom profiles, drill cores, vibracores, pound cores, 

and the observations of divers working on site, were 

collected and analyzed at various stages during the 

recovery project. During the 1996 season, the site was 

surveyed with a marine magnetometer, side-scan sonar, 

and sub-bottom profiler. In addition three hand-driven 

cores were taken—two adjacent to and one directly 

over Hunley. Two radioisotope studies of cores collected 

near the submarine were conducted in conjunction 

with macrofaunal analysis of encrusting organisms on 

the submarine’s hull. The results were revealing: 210Pb 

studies indicate that only the upper few centimeters of 

sediment covering the submarine have been disturbed 

in the last century (± 20 years) (Murphy 1998:158–62). 

In May 1999, the United States Geological Survey 

Center for Coastal Geology and Regional Marine Studies 

collected high resolution sub-bottom profile data, and 

500 kHz side-scan sonar over the area of the Hunley

and Housatonic wrecks. A series of 20 ft. (6.1 m) long 

vibracores was taken—five near Hunley and three near 

Housatonic (Hansen et al. 2000). Yet another series of 

cores had to be taken by the United States Army Corps 

of Engineers (Savannah District) to gather information 

to be analyzed by soil engineers to determine the size 

and depth of the piles to be placed. 

All of the sediment samples collected during the 

surveys were analyzed for textural variability following 

the conventions of Wentworth (1922) and the UddenWentworth scale (Figure 13.1) (Wentworth 1922). This 

is the scale typically used in the United States to define 

classes of particles by size such as colloid, sand, clay, 

silt, gravel, pebble and even boulder. These can have 

further graduations from very fine, fine, medium, and 

coarse. Textural analyses were performed on sediment 

samples collected from the cores using standard sieve 

(Krumbein 1932) and pipette (Creager and Steinberg 

Figure 13.1. The Udden-Wentworth scale provides 

a standard comparative scale for clastic sedimentary materials based on grain diameter. Both 

metric and φ (-log2

 of mm) scales are provided for 

reference.
S I T E A N A LY S I S

139

by measuring with a line and tape pulled from the stern 

and bow of the submarine (see Figure 10.11). 

Each pound core was collected by the following 

method: project staff utilizing surface-supplied or scuba 

diving equipment used weighted slide hammers to drive 

standard 3 in. (7.6 cm) aluminum irrigation pipes into 

the seafloor. Water-extraction holes drilled at equal 

intervals along each aluminum pipe were covered with 

Teflon tape to reduce sample contamination; black 

plastic tape was placed over these holes to increase the 

overall strength of the device during the coring process 

(Figure 13.2). A core catcher was installed at the base of 

each tube to hold sediment in place while the tube was 

removed from the seafloor and lifted through the water 

column to the deck of the research vessel. 

Rivets were drilled to release the core catcher, and 

sediment was extruded onto a plastic gutter for sample 

collection. Samples were taken from the base of the 

core first; subsequent material was obtained from each 

successive overlying sediment layer. The distance from 

the base of the core to the sediment-water interface 

was calculated as follows: the total core length was 

established as the bottom depth and the “zero” depth 

marker coincided with the seafloor. Water samples were 

collected from each pound core with a sterile syringe 

and placed in sterile Nalgene containers. Bacteriological 

samples are extremely sensitive to outside contamination; consequently, these specimens were collected 

from each core prior to the textural analysis sampling 

process. This ensured that no additional contamination 

of sediment by oxygen and/or bacteria occurred while 

each core was being sampled in the field. 

Sediment samples that consisted primarily of sandand gravel-sized particles were sieved using standard 

sieving methods. Those that contained an abundant 

percentage of mud (<63 μm [0.0025 in.]) were analyzed 

with a pipette method that determined the amount 

1963) methods. Samples were also viewed under a 

microscope to determine primary composition and 

mineralogy. Following consultation with the project’s 

principal investigators, the decision was made to not 

conduct iron analyses of the pore waters. This decision 

was based on the probability of cross-contamination 

from water flow along the outer edge of the pound core 

during the elapsed time after the sample was collected. 

Three dominant stratigraphic layers characterize 

the portion of the continental shelf where the Hunley

site is located (Harris et al. 1994) (see Figure 3.5). Prior 

studies indicate a definite and distinguishable series of 

strata that exist in the local Charleston area, although 

the internal organization of these strata is often heterogeneous in nature (Harris et al. 1994; Gayes et al. 1998). 

The oldest of these layers consists of Tertiary aged marls 

and semi-consolidated sedimentary strata. The younger 

layers contain various back-barrier and shelf deposits 

of Pleistocene age that were deposited when sea levels 

were higher. The youngest layer, created during Holocene 

(modern) times, consists of multiple layers of sand, mud, 

and shells, in a variety of combinations. The distribution of the Holocene and Pleistocene units is scattered, 

creating regional strata that exhibit an extremely heterogeneous configuration. In general, recent sand and 

occasional mud layers exist over semi-consolidated 

Pleistocene muddy sands and sandy muds (estuarine 

and shelf deposits). These sediments in turn overlie the 

dense Tertiary marls, muds, and limestones (Popenoe 

et al. 1987; Harris et al. 1994; Weems and Lewis 2002). 

Macrofaunal specimens taken during the 1996 

survey consisted of colonies of Star Coral (Astrangia 

danae) and Horse Oyster (Ostrea equestris). The size of 

the coral and oyster colonies indicated that the upper 

portion of Hunley remained exposed for a period of 

10 to 15 years, was gradually buried, and once completely buried was not exposed again until its discovery. 

Pollen was also sampled from the sediment around 

the submarine and revealed primary arboreal pollen 

types consistent with what would be expected had the 

submarine been buried within 20–25 years of sinking 

(Murphy 1998: 147–67). Despite the large number 

of tropical storms and hurricanes that have passed 

through the region since 1864 (see Figure 3.7), the 

submarine remained completely buried within a significant “cap” of sediment following its loss. Consequently, very little post-depositional impact—natural 

or otherwise—affected Hunley following its burial. 

Sediment Sampling During Recovery

At the beginning of the 2000 recovery season, ten 

pound cores were collected from the Hunley site along 

two previously undisturbed transects during diver operations. Divers recorded the position of each pound core 

Figure 13.2. Drs. Pam Morris and Scott Harris prepare 

cores for sampling. (Courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

140Table 13.1. Pound Cores Taken from around the H. L. Hunley in May 2000

CORE 

ID^

Total 

Length

From 

Bottom 

(cm)

From 

Seafloor 

(cm)

Sample 

Type^^

Sample 

Number Other Method

Mean 

(mm)

Mean 

(phi)

Sorting 

(std. 

dev.)

Skew

-ness Kurtosis % gravel % sand % mud % silt % clay

T1-1 5 cm 0-5 cm S ** HL 0270 s 0.12 3.01 0.76 0 8.59 0.2 93.2 6.6

2.5 cm W* HL 0258

T1-3 20 cm 10 cm W* HL 0259

20 cm W* HL 0260

20-25 cm 15-25 cm S ** HL 0273 2A, 2B s 0.11 3.18 0.89 0.22 5.67 0.1 86.7 13.2

10-20 cm 5-15 cm S ** HL 0272 3A, 3B s 0.12 3.03 0.85 0.06 7.7 0.4 90.1 9.6

0-10 cm 0-5 cm S ** HL 0271 5A, 5B s 0.16 2.61 1.29 -1.24 5.9 4.9 87.3 7.8

T1-5 30 cm 30 cm W* HL 0261

20 cm W* HL 026210 cm W* HL 0263

20-30 cm S ** HL 0274 6A, 6B s 0.11 3.18 0.89 0.22 5.67 0.1 86.7 13.2

10-20 cm S ** HL 0275 7A, 7B s 0.14 2.83 1.02 -1.43 9.24 2.4 91.1 6.5

0-10 cm S ** HL 0276 8A, 8B s 0.14 2.84 1.12 -1.13 7.38 2.5 88.3 9.2

T1-10 35 cm 30 cm W* HL 0264

20 cm W* HL 0265

0-10 cm 25-35 cm S ** HL 0277 9A, 9B s + p 0.09 3.41 2.41 -1.12 2.57 15.8 19.4 64.8 64.8 0

10-20 cm 15-25 cm S ** HL 0278 10A, 10B s + p 0.09 3.43 1.36 -0.76 4.31 1.8 64.5 33.7 33.7 0

20-30 cm 5-15 cm S ** HL 0279 11A, 11B s 0.15 2.78 0.94 -1.2 9.02 1.1 93.7 5.2

30-35 cm 0-5 cm S ** HL 0280 12A, 12B s 0.12 3.07 0.88 -0.35 8.01 0.6 89.6 9.8

T1-20 20 cm 10 cm W* HL 0266

10-20 cm S ** HL 0281 13A, 13B s 0.13 2.92 0.94 -0.64 8.51 1.3 90 8.7

0-10 cm S ** HL 0282 14A, 14B s 0.11 3.14 1.42 -0.85 4.58 3 72.5 24.5

T2-1 25 cm 30 cm W* HL 0267

20 cm W* HL 026810 cm W* HL 0269

20-25 cm 15-25 cm S ** HL 0283 15A, 15B s 0.12 3.06 0.9 -0.18 7.43 0.6 88.7 12.7

10-20 cm 5-15 cm S ** HL 0284 16A, 16B s 0.13 2.9 0.82 -1.25 11.05 0.7 94.8 4.5

0-10 cm 0-5 cm S ** HL 0285 17A, 17B s 0.15 2.75 0.72 -1.33 13.67 0.8 96.6 2.6
S I T E A N A LY S I S

141

CORE 

ID^

Total 

Length

From 

Bottom 

(cm)

From 

Seafloor 

(cm)

Sample 

Type^^

Sample 

Number Other Method

Mean 

(mm)

Mean 

(phi)

Sorting 

(std. 

dev.)

Skew

-ness Kurtosis % gravel % sand % mud % silt % clay

T2-3 25 cm 20 cm W* HL 0316

10 cm W* HL 0317

0-10 cm 15-25 cm S ** HL 0326 18A, 18B s + p 0.11 3.21 1.5 -0.68 3.8 2.8 65.4 31.8 28.2 3.5

10-20 cm 5 -15 cm S ** HL 0327 19A, 19B s 0.14 2.79 1.22 -1.1 6.44 3.2 86.6 10.2

N/R 0-5 cm S ** HL 0328 s

T2-5 25 cm 20 cm W* Hl 0318

20-28 cm 15-25 cm S ** HL 0329 s 0.16 2.68 1.22 -1.07 5.66 2.7 89.8 7.4

10-20 cm 5-15 cm S ** HL 0330 s 0.14 2.85 1.17 -0.75 6.11 1.9 85.9 12.1

0-10 cm 0-5 cm S ** HL 0331 s 0.18 2.48 1.26 -1.24 5.9 4.9 89.2 5.9

T2-10 50 cm 40 cm W* HL 0319

30 cm W* HL 032020 cm W* HL 032110 cm W* HL 0322

40-50 cm S ** HL 0332 s 0.12 3.04 0.88 -0.15 7.23 0.3 89.9 9.8

30-40 cm S ** HL 0333 s 0.14 2.81 0.76 -1.44 13.15 0.7 96.1 3.2

20-30 cm S ** HL 0334 s 0.13 2.91 0.82 0.08 7.87 0.2 92.4 7.4

10-20 cm S ** HL 0335 s 0.14 2.81 0.9 -0.79 9.09 0.9 92.6 6.5

0-10 cm S ** HL 0336 s 0.15 2.72 1.45 -1.17 5.2 7.2 80.5 12.3

T2-20 45 cm 40 cm W* HL 0323

30 cm W* HL 032420 cm W* HL 0325

40-45 cm 35-45 cm S ** HL 0337 s 0.13 2.96 0.97 -0.76 8.42 1 89 10

30-40 cm 25-35 cm S ** HL 0338 s 0.12 3.1 0.89 0.24 6.07 0.2 87.7 12.2

20-30 cm 15-25 cm S ** HL 0339 s 0.15 2.78 0.98 -1.13 8.12 1.1 93 5.9

10-20 cm 5-15 cm S ** HL 0340 s 0.14 2.86 0.95 -0.56 8.07 0.9 90.7 8.4

0-10 cm 0-5 cm S ** HL 0341 s 0.14 2.86 1.11 -1.04 7.65 2.7 86.9 10.4

^ T1-3 refers to transect one, three meters away from H. L. Hunley hull^^ S = Sediment Sample; W = Pore Water Sample* depth from base of core** 0 is at seafloor, higher numbers are below sediment-water interface“Other” refers to samples collected by P. Morris of MUSC, Ft. Johnson CampusN/R = no recovery
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

142

of silt (4–63 μm [.00016–.0025 in.]) and clay (<4 μm 

[.00016 in.]) in each (both methods are described 

in detail in Lewis and McConchie 1994). All numeric 

data were entered and analyzed through a sediment 

analysis program that utilizes the moment methods 

(see Friedman 1979). Percentages of the following attributes were calculated for each sediment sample: gravel, 

sand, mud, mean (φ), mean (mm), sorting, skewness, 

and kurtosis (Table 13.1). 

Approximately 30 g (1.06 oz.) of sediment were 

sampled from each bag and placed in 50 mL (1.69 fl. oz.) 

Pyrex beakers to obtain the wet sample weight of each 

core. These sediment samples were dried in a Fisher 

Scientific Isotemp oven at approximately 60–70° C for 

24 hours and then weighed to obtain the dry weight of 

each sample. 

Sediment samples that consisted primarily of sand 

were wet-sieved with distilled water through a #230 

(63 μm, 1/16mm [.0025 in.]) U.S.A. Standard Testing 

Sieve. Muds that washed through the sieve were not 

collected; their loss recorded the amount of mud (grains 

smaller than 63 μm) in the sample. Washed sediment 

was placed back into 50 mL (1.69 fl. oz.) Pyrex beakers 

and dried for 24 hours in an Isotemp oven at 60–70° C 

(140–158° F). 

Each dried sample was weighed and the percentage 

lost due to wet sieving was calculated to determine its 

mud content. Grain size was documented in phi (φ), a 

unit based on the diameter of individual grains relative 

to 1 mm. These samples were sieved through a series of 

-1 φ to 4 φ sieves at 1⁄2-phi intervals using an RX-86 sieve 

shaker for 10 minutes. Each was then removed from the 

sieve screens and sediment weights were obtained for 

each phi interval. 

Samples with a high mud content were analyzed in 

two phases. The entire sediment sample was washed 

(wet sieved) with distilled water through a #230 Standard 

Testing Sieve measuring 63 μm (1/16 mm). Silts and clays 

that were washed through the sieve were collected in 

a 1,000 (33.81 fl. oz.) mL graduated cylinder and set 

aside. The remaining material was placed back into a 

50mL Pyrex beaker and dried for 24 hours in an oven at 

60–70° C (140–158° F) to obtain the weight of sediment 

greater than 4 φ. 

Using the Stokes equation for settling particles 

(Craeger and Steinberg 1963), the liquid portion of the 

sample was analyzed by taking samples from suspension. Because of differing settling velocities of various 

particle sizes, muddy water samples collected at various 

times from the same depth in the column can be used 

to calculate suspended sediment concentration. The 

slurry was placed in 1,000 mL (33.81 fl. oz.) settling 

tubes and stirred to obtain even dispersal of silts and 

clays. A pipette was inserted 10 cm (3.94 in.) below the 

water’s surface so that a 25 mL (0.85 fl. oz.) aliquot, or 

portion, of muddy water could be collected for analysis. 

The sample obtained immediately after the stirring 

process was used to determine the amount of silt in 

the water; another sample collected 120 minutes later 

was used to determine the amount of clay. Each of the 

25 mL (0.85 fl. oz.) aliquots was placed in a separate 

pre-weighed 50 mL (1.69 fl. oz.) beaker and dried for 

24 hours in an Isotemp oven at 60–70° C (140–158° F). 

The resulting dried samples were weighed to determine 

the mass of sediment that had not settled below the 

10 cm (3.94 in.) level. 

Results 

Textural analyses were performed on bulk 

sediments collected from the pound cores (Table 13.1). 

Raw sieve and pipette measurements were derived 

utilizing standard moment methods for mean (first 

moment), standard deviation (Table 13.2; second 

moment), sorting (Table 13.3; third moment), and 

kurtosis (fourth moment). Additionally, calculations 

for the percent gravel, percent sand, and percent mud 

were determined for each individual sample. 

Cumulative frequency diagrams were plotted to 

help visualize differences between the distributions of 

sediment grains (Appendix H). Overall, sediment grain 

Table 13.2. Values and Description 

of the Standard Deviation (Sorting 

Parameter, 2nd moment)

< 0.35 phi Very well sorted

0.35 – 0.50 phi Well sorted

0.50 – 0.71 phi Moderately well sorted

0.71 – 1.00 phi Moderately sorted

1.00 – 2.00 phi Poorly sorted

2.00 – 4.00 phi Very poorly sorted

> 4.00 phi Extremely poorly sorted

Table 13.3. Values and Description of the 

Skewness Parameter (3rd moment)

> +0.30 Strongly fine skewed

+0.30 – +0.10 Fine skewed

+0.10 – -0.10 Near symmetrical

-0.10 – -0.30 Coarse skewed

< -0.30 Strongly coarse skewed
S I T E A N A LY S I S

143

size ranged from 0.09 in. (3.41 φ) to 0.18 in. (2.48 φ) 

mean grain size. Standard deviations (such as those 

produced by sorting) ranged from 0.76 φ (well sorted) 

to 2.41 φ (poorly sorted). Skewness ranged from -1.54 φ 

(strongly coarse skewed) to 0.24 φ (finely skewed). The 

majority of the samples fell within the coarsely skewed 

range. Trends for mean grain size, standard deviation, 

and skewness have been plotted for each sediment 

core to highlight the compositional variability within 

each (Appendix I). The sample group included both 

modern and fossil shell remains, the condition of which 

ranged from pristine to highly abraded. Calcareous 

(shell) material tends to comprise the overall gravel 

content of the assemblage. Thirty examined samples, 

with the exception of T1-10 (depth 0–10 centimeters), 

contain organics and mica. In general, the texture of 

seafloor materials was highly variable and ranged from 

2 to 24% mud at the seafloor/water column interface 

(averaging approximately 10%). Down-core trends in 

texture ranged from fining to coarsening to generally 

heterogeneous.

Diver Observations

A pit profile was generated during excavation based 

on diver observations relayed via two-way communication between the geologist and diver (Figure 13.3). 

Sediments observed in the profile closely resembled 

those identified in the vibracores. 

The types of sediments identified during diver 

operations exhibit attributes—including textural 

parameters, faunal assemblages, and arrangement—

that are typical to the region encompassing Charleston 

Harbor. The three-dimensional arrangement of strata 

appears normal, and few recognizable trends were 

observed among the shallow cores. In general, textural 

parameters indicate that most materials deposited in 

the vicinity of Hunley were the result of reworking 

of sediments deposited across the ebb-tidal delta of 

Charleston Harbor’s entrance. This process resulted in 

the overall presence of lag deposits consisting of sands 

and very sandy mud. 

Discussion 

The composition of sediment cores analyzed during 

the Hunley recovery project exhibit similarities to cores 

recovered from the seafloor in and around Charleston 

Harbor during previous scientific investigations (Gayes 

et al. 1998). By contrast, internal lithologies vary from 

site to site. Each of the four aforementioned moment 

parameters enables geologists to describe the distribution of sediment grains based upon the mean grain size 

of the sample. In addition, these parameters provide 

some measure of the processes involved in the depositional history of site sediments. The overall fine-grained 

nature of these sands is typical, and likely resulted from 

a lack of coarse-grained sediment in the source area. 

The presence of coarse skewness—not necessarily 

coarse-grained sediment—indicates that a general lag 

deposit was created at the site. A lag deposit typically 

results from the winnowing away of fine materials from 

sediments during depositional processes. Although 

there is strong indication that fine-grained material 

intercalated (formed in distinctly alternating layers) into 

the site’s coarser sediments after deposition, comprehensive analyses suggest that the sediments that characterize the site are the result of an overall accumulation of sediment and subsequent winnowing of that 

sediment into a lag deposit. 

Distinct stratigraphic boundaries, delineated by a 

marked increase in the percentage of mud as opposed 

Figure 13.3. Excavation profile measured from 

seafloor, approximately 2.5 ft. (0.76 m) above 

stern, 20 ft. (6.10 m) astern and 10 ft. (3.05 m) 

starboard. Description provided by diver (H. 

Pecorelli) to geologist (S. Harris) through seafloor 

communication and post-dive interviews. Samples 

collected within distinct beds.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

144

to other sediment types, were noted in some of the 

longer core sections. The presence of mud layers within 

the seabed is not surprising, as they are quite common 

and scattered throughout the region. Most appear to 

be the result of the late 19th century redirection of the 

harbor ebb-tidal delta into the area immediately surrounding the Hunley site. 

No textural trends (with respect to the distance 

along a coring transect originating at the submarine) 

were observed, nor were any distinct trends down the 

length of the core observed. Project scientists were able 

to develop a close estimate of the amount of coarse 

sediments and shell material that had accumulated 

around the submarine since its loss. However, the 

scattered nature of the sedimentary body precluded 

identification of any specific trends that deposited these 

materials on site. This lack of trend does not discount 

diver observations, but rather it demonstrates the heterogeneous nature of the shelf outside the hydrodynamic influences of a large object on the seafloor. 

Faunal Samples

An abundance of marine macrofauna was identified within the sediment samples taken by Harris, who 

provided a general characterization of the species 

he encountered. Approximately 61% of the samples 

contained Spisula solidissima (surf clam) shell halves 

and/or broken shells belonging to this particular species. 

Other marine macrofauna species observed within the 

31 sediment samples include the following: four Ensis 

directus, one duck clam, one tube worm, one ark shell, 

one bryozoa cluster, three echinodea, one Crassostrea 

virginica, two Divaricella quadrasulcata, two gastropods, 

and one piece of material tentatively identified as slag 

from burnt coal. Other broken and unidentifiable shells 

comprised 68% of the sample group. 

Samples specifically targeting benthic infauna 

were taken during the 2000 recovery operation by 

Pam Jutte, biologist with SCDNR, and reveal a range of 

invertebrates. Two replicate samples were taken along 

the same transect lines as the sediment samples, at 

points adjacent to the hull and 1 m, 3 m, 5 m, 10 m, 

and 20 m from the hull on both transects. They were 

collected using a core 7.6 cm (3.00 in.) in diameter 

and 15 cm (5.91 in.) deep, for a sample volume of 

680.47 cm3 (41.55 cu. in.) in order to be comparable 

to other studies already conducted in the region (Jutte 

et al. 1999, Van Dolah et al. 1992, 1994). The samples 

were sieved through 0.5 mm (0.02 in.) mesh and all 

macrofauna and sediments retained on the sieve were 

preserved in a 10% buffered formalin solution with rose 

bengal stain. The family, genus, and, where possible, 

species of individuals present in each sample were identified and counted (Appendix J).

Several measures of benthic communities were calculated for each sample location based on combined 

counts of the replicate samples (Table 13.4). The 

samples were also assessed by percentage of polychaetes, amphipods, and mollusks in conformance 

with other benthic studies in the region (Van Dolah et 

al. 2004, 2006, 2013). Environmental data collected 

over a 48-hour period at location T1-0M resulted in a 

mean temperature of 21.72 °C (71.10 °F) and a mean 

pH of 8.13. The mean dissolved oxygen content over a 

24-hour period was 6.39 mg/L. 

The most abundant taxon present overall was Polychaetes, a class of marine annelid worms commonly 

referred to as bristle worms because of the many 

fleshy protrusions. Polychaetes are a robust and wideTable 13.4. Benthic Infaunal Sample Analyses by Transect and Distance from Submarine 

Category* T1-0M T1-1M T1-3M T1-5M T1-10M T1-20M T2-0M T2-1M T2-3M T2-5M T2-10M T2-20M

Species Abundance 62 45 46 53 64 90 73 125 78 69 36 77

Species Richness 14 16 8 9 17 16 9 10 10 11 9 12

Shannon (H’) 2.001 2.3 1.634 1.306 2.416 1.738 1.07 0.79 0.927 1.143 1.662 1.433

Evenness (J’) 0.758 0.83 0.786 0.594 0.853 0.627 0.487 0.343 0.403 0.477 0.756 0.577

Percent Polychaetes 73% 69% 83% 74% 58% 68% 88% 93% 94% 93% 86% 90%

Percent Amphipod 6% 0% 0% 4% 9% 16% 3% 1% 3% 3% 3% 0%

Percent Mollusk 3% 2% 0% 6% 9% 8% 3% 2% 0% 0% 0% 4%

Percent Other Taxa 18% 29% 17% 17% 23% 9% 7% 4% 4% 4% 11% 6%

Percent Silt/Clay** n/r 6.6% 9.0% 9.2% 6.7% 24.5% n/r 3.9% 10.2% 10.0% 12.3% 9.1%

* Species distribution analyses were generated using BiodiversityR (Kindt & Coe 2005) in R (R Core Team 2013).

** Based on top 15 cm of sediment samples or nearest measured equivalent (0–5 or 0–10 cm) from Table 13.1; a weighted average was used to combine two samples of 

uneven sizes (italics).
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spread class, with more than 10,000 species. The most 

populous species present among the Hunley samples, 

Spiophanes bombyx, is of this class, with a total of 

444 individuals identified. This widespread bristle 

worm, also known as the Bee spionid, lives in tubes 

that protrude slightly from the seabed and feeds on 

suspended particles in the water column as well as 

deposits (Dauer et al. 1981). On transect 1, the species 

was most abundant beginning 5 m from the hull, while 

on transect 2 there was no significant increase or 

decrease in relation to distance from the hull. 

The second most populous group was the genus 

Mediomastus, also of the class Polychaetes. Another 

common worm, this genus is found throughout the 

world, except in areas of extreme high latitude, and 

is generally found in shallow sandy-mud and muddy 

environments (Warren et al. 1994). Along transect 1, 

individuals were more populous within 3 m of the hull, 

and became much sparser further away, thus reversing 

the trend demonstrated by Spiophanes bombyx (Figure 

13.4). There was, however, no significant pattern of distribution along transect 2. 

Six species of amphipods were represented. 

Organisms in the order Amphipoda are malacostracan 

crustaceans identified by the absence of a carapace, a 

laterally compressed body, and appendages that differ 

unlike the isopods in which all the thoracic legs are 

similar. Amphipods range in size from 1 to 340 millimeters (0.039 to 13 in.) and are mostly detritivores or 

scavengers. Only one species of the order Isopoda was 

found. Isopods are relatively small crustaceans with 

seven pairs of legs of similar size and form, bodies that 

are usually (but not always) flattened dorso-ventrally, 

and a reduced carapace that covers only the head. 

Bivalves and gastropods, representatives of the 

largest marine phylum, Mollusca, were both observed 

in the samples. Two species of bivalves and three 

species of gastropods were noted. Bivalves are a class 

that includes both marine and freshwater mollusks, 

such as clams, oysters, and mussels, which possess a 

hinged shell and laterally compressed body. Gastropods 

include snails and slugs and are the most highly diversified class in the phylum. They thus exhibit a high degree 

of variability in anatomy, reproduction, and behavior. 

Those animals with shells usually have only one and 

were formerly known as univalves

Overall, these fauna do not seem to have affected 

the condition of Hunley to any significant extent. 

Burrowing animals could have the effect of aerating the 

shallow sediment to a limited extent. However, once the 

submarine became buried by 3 or more feet (0.91 m) of 

sea floor sediment they would have had no effect. This 

is also supported by the lead isotope analysis, which did 

not reflect any disturbance from either hydrodynamic 

forces or bioturbation. 

Microbial Analysis of Sediment from Cores 

and Hunley Interior

Sediment samples taken from both outside and 

inside the submarine were analyzed by Dr. Pam Morris 

to see whether different types of iron reducing bacteria 

(FeRB) were present at the site based on variations in a 

specific region of their 16s rDNA. Since these bacteria 

can affect the integrity of the metal, the analysis would 

help inform conservation planning, influencing the 

specifics of the treatment applied to the submarine. The 

research was carried out at the Department of Biology, 

Grice Marine Laboratory at the College of Charleston. 

Some genetic analysis was conducted on the samples 

by Jeremy Goldbogen (Appendix K). Samples were 

taken from all sediment cores taken along Transects 

1 and 2 except T1-0M and T2-0M. Additional samples 

were taken from inside the submarine during the hull 

thickness and rivet sampling survey. 

To select for FeRB, sediment samples were introduced into a goethite media under anaerobic conditions prepared from a mixture of hydrolyzed Fe(NO3

)

3

• 

9H2

O, and 5M KOH. This was then incubated for eight 

Figure 13.4. Distribution of Mediomastus sp. and Spiophanes bombyx counts along Transects 1 and 2 shows no statistically significant pattern. (Graphs by H. G. Brown, NHHC)
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months, after which a volumetric reduction of the Fe 

(III) matrix to the more compact Fe (II) structure was 

noted. Nucleic acids were then extracted and amplified 

using polymerase chain reaction (PCR) with a set of 

universal eubacterial primers that target the V9 323-bp 

region of the 16S rDNA. Extraction and amplification 

were achieved in all samples except 3m. Successful PCR 

products were then analyzed using denaturing gradient 

gel electrophoresis. The genetic analysis revealed that 

a variety of different FeRB were present in the samples. 

The presence of FeRB in samples up to 20 m (65.62 ft.) 

from the hull indicates that the FeRB occurs naturally 

in the sediment. 

Site Formation Processes

When reconstructing the processes that have 

affected a site over time, multiple lines of evidence must 

be examined, including sediment stratigraphy, artifact 

distribution, current and wave action, regional storm 

history, and human activity at the site. The insights gained 

from understanding the post-depositional processes that 

affected the hull can allow investigators to separate what 

hull damage was directly related to the sinking from what 

came after, over century beneath the sea. Using evidence 

derived from the hull condition, distribution of artifacts, 

and surrounding sediment, a general picture of what 

took place after Hunley’s loss can begin to take shape. 

The primary lines of inquiry include how soon after the 

sinking was the submarine buried, how and when it 

canted roughly 45° to starboard, and at what point were 

the disarticulated hull components lost.

The largest factor affecting the site was the excavation itself. Based on records from the submarine’s initial 

discovery in 1995 (Hall 1995), the site investigation in 

1996 (Murphy 1998) and HAT’s site visit in 1999, the 

sediment directly above the hull was disturbed in order 

to identify and assess the vessel (Figure 13.5). The full 

length of the top was exposed in 1996 along with the 

port side down the level of the diving plane, except one 

section near the aft conning tower that went down to 

the keel. The dredged material was not screened. Care 

was taken to minimize dredging around the bow and 

stern, where it was believed the most fragile elements 

would be found, and along the starboard side for fear 

of undercutting the support keeping the hull in position 

(Murphy 1998:17). In 1999, excavators attempted to 

stay within the previously disturbed area, but did need 

to expose a roughly 2 m (6.56 ft.) length along the 

starboard side to acquire vital engineering data for the 

recovery (see Chapter 8). Overall, the loss of context 

was kept as minimal as possible, and the matrix around 

the lower levels of the submarine remained intact 

except for the small section of keel port side. Despite 

the extent of prior disturbance, trends in the sediment 

matrix were still discernable. 

Figure 13.5. Areas of sediment disturbed during the initial assessments of H. L. Hunley. (Diagram by H. G. Brown, 

NHHC) 
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Artifact Distribution

By examining where intrusive material came to 

rest around the vessel, the hydrodynamic forces that 

affected them can, in part, be reconstructed. Anthropogenic material collected at the site can be divided easily 

into classes based on different characteristics that affect 

their behavior on the seabed. Coal and slag behave in 

a similar fashion to naturally occurring sediment, functioning essentially as gravel-sized particles introduced 

from a variety of source locations surrounding the site. 

Ceramics and glass are relatively dense and, when fragmented, nearly flat, making long-distance transport less 

likely without a high-energy event to move them. Tin 

cans are denser than the surrounding environment, 

but their cylindrical shape facilitates post-depositional 

surface movement. Finally, the pieces that became 

disarticulated from the hull represent the largest and 

densest objects found at the site, and the only ones 

that can be traced with certainty back to their original 

position.

Coal and Slag 

As discussed in Chapter 12, the sediment around 

Hunley contained a significant amount of coal, coal 

slag, bone, shell, and wood, mostly in small particle 

form. The shell was considered non-diagnostic and not 

retained for study. The bone specimens represented 

a mixture of marine and terrestrial animals. At least 

three mammal bones were found to have probable cut 

marks characteristic of butchering and likely represent 

discarded food waste originating either from passing 

ship traffic or washed out from the harbor through the 

jetty system. The material was spread throughout the 

site, with no distinctive clustering. 

Most of the wood was in small fragments, too 

small or damaged to assess whether they were natural 

or from a man-made object. In addition, establishing 

provenience for this material was difficult as some of it 

may have washed in during the dredging process. While 

some was no doubt contemporaneous with Hunley’s 

sinking and burial, there was no reliable method of 

ascertaining exactly what percentage. The two closest 

sources of contemporary worked wood were the wreck 

of Housatonic and the Stone Fleet. Reports on early 

salvage efforts indicate that Housatonic’s wooden 

components deteriorated rapidly, primarily due to 

marine borers, and that by the 1870s work focused 

on recovered scrap metals, such as copper bolts 

(Conlin 2005:189–90). Such salvage activity could have 

dislodged fragments of the weakened wood and set 

them loose in the water column. In December 1861, a 

collection of old, wooden vessels, known as the Stone 

Fleet, was sunk across the main shipping channel south 

of the Hunley site to disrupt Confederate access to the 

port. These deteriorated quickly and may also have contributed to the amount of worked wooden debris in 

the area.

The most abundant intrusive organic material in 

the sediment matrix surrounding the hull was coal 

and coal slag. As a particulate matter, its behavior is 

similar to natural sediment, but since its grain size is 

larger than the surrounding sand and mud, it provides a 

class of heavier particulate matter to study. The heavier 

materials require higher energy to initiate suspension 

or bedload transport, and sink more readily through 

unconsolidated fine material. It was also introduced 

into the seabed roughly contemporaneously with the 

wreck, functioning to a limited extent as a particle 

tracker. It is not ideal, however, because the original 

position of the material when it was introduced into 

the system cannot be determined.

This material is relatively common in the seabed 

off Charleston, and is frequently found in core samples 

taken in the area, particularly around dredge spoil 

areas and shipping lanes. Coal usage increased with 

the expansion of steam power in first half of the 19th 

century, and coal-powered steamships plied the coastal 

Atlantic waters in abundance well before and after the 

advent of the Civil War. Nevertheless, the extensive 

blockade enforced by the U.S. Navy represents a significant period of increased steam traffic in the area. 

Slag, sometimes referred to as clinker, is the waste 

material produced from burning coal, and is generally 

a silica-based, vitreous material that varies widely in 

composition and density depending on the source 

coal and conditions in the furnace. There was a grate 

below the fire through which the pieces of slag would 

fall, whereupon it was collected and discarded. In the 

case of steamships, this meant “tossed overboard.” To 

calculate exactly how much slag was deposited on the 

seabed off Charleston by the blockading squadron is 

an impossible task—the amount of slag produced by 

any one ship varies greatly depending on the size and 

characteristics of the engine, the quality of coal used, 

the temperature of the furnace, the distance traveled, 

the sea conditions, and a number of less quantifiable 

factors. 

Between 24 December 1861 and 1 July 1865, a 

minimum total of 132 Union vessels spent some period 

of time on blockade duty off Charleston, Bull’s Bay just 

to the north, or Stono Inlet to the south (Figure 13.6). 

The maximum number reportedly present at one time 

was 43 on 15 February 1865, immediately prior to 

Charleston’s surrender on the 18th of that month (ONR 

1.16:244–46). On average, 20% of the vessels present 

at any one time were sailing vessels, which produced a 

relatively minor amount of slag from their galley stoves 

and any smithing operations they might perform on 

board. The rest of the fleet was divided into classes, the 

largest ships being 1st class, down the smallest 4th class 
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vessels. Most of the ironclads were 3rd class vessels, 

and their accompanying tugs were 4th class. 

Two cases can help give an indication of how 

much coal was used, and how much ash discarded, 

while also highlighting the shortcomings of the data. 

Steam logs for two vessels that participated on the 

blockade were examined, although not for the period 

of the blockade itself (DON 1858, 1865). USS Wabash, 

a 301.5 ft. (91.90 m) screw steamer, with a diplacement of 3,274 tn. (2,970 t), a crew of 523, and 46 guns, 

was considered a first class vessel. USS James Adger, a 

215 ft. (65.5 m) sidewheel steamer with a displacement 

of 1,151 tn. (1,044 t), a crew of 120, and 8 guns, fell into 

the second class. 

Wabash spent the summer of 1858 in the Mediterranean. Between 8 June and 29 September the engines 

consumed 2,524,224 lb. (1,262 tn.; 1,145 t) of coal and 

dumped 376,282 lb. (188 tn.; 171 t) of coal ash into 

the sea. These figures reflect a considerable number 

of days actively cruising. However, many of the blockading vessels spent little time actively traveling, but 

rather stayed at anchor, only shifting positions closer 

to shore at night, and relocating out of gun range at day 

break. Thus the tonnage of waste produced may not 

be comparable to that produced by ships on blockade 

duty. The data do show that Wabash discarded approximately 15% of the original weight of coal consumed 

into the sea as waste. This is a figure that varies widely 

from ship to ship and even between batches of coal. 

For example, the log shows that during the first half of 

the period, they were dealing with an inferior batch of 

coal that produced approximately 18% waste; they then 

refueled in Gibraltar with Welsh coal, a high quality 

steaming coal, and their waste percentage dropped to 

12%. Despite the variation, these figures can be used to 

develop a range of expected waste material produced 

based on their average consumption. We also know that 

during the war years, the blockading squadron burned 

almost exclusively anthracite, since it burned without 

producing tell-tale smoke that might have given away 

their positions, and thus the variation in waste percentages, at least within an individual vessel’s records, might 

have been significantly less during that period.1

The surviving steam log from James Adger covers 

the period of 2 October to 31 December 1865, and 

records time spent in and around Colón, Panama, as 

well as at least one return cruise to Cartagena, Columbia. 

In this period, James Adger consumed 681,420 lb. 

(341 tn.; 309 t) of coal and dumped 186,980 lb. (93 tn.; 

85 t) of ash from the boiler, producing an average of 

27% of the original fuel in waste material. For a period 

of 8 days, the engine room kept up a head of steam, 

1 Anthracite was also preferred due to its higher density, providing 

more heating units per volume of stowage, and its superior hardness, 

making it less prone to crumble and deteriorate during transport and 

stowage (Nicolls 1904:305).

Figure 13.6. Number of U.S. Navy vessels on station off Charleston, Stono Inlet, and Bull’s Bay, based on periodic reports 

from the commander of the South Atlantic Blockading Squadron. See Appendix M for complete listing of vessels. (Graph 

by H. G. Brown, NHHC)
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but the vessel did not travel. During this period, they 

consumed an average of 7,013 lb. (3,181 kg) of coal per 

day, and produced and average of 2,048 lb. (929 kg) 

of ash per day. This is an excellent proxy for blockading duty, since vessels frequently had to keep the 

boilers hot and the steam up to maintain readiness to 

chase and intercept blockade runners. As discussed in 

Chapter 2, standing orders on Housatonic were for the 

engine room to maintain 25 pounds (11.34 kg) of steam 

in the boilers throughout the night, the best time for 

blockade runners to try and make it through the fleet 

(DON 1864a:0534).

Using factors garnered from the steam logs, as well 

as several references to coal consumption in official correspondence, an estimated use of coal for a full day of 

steaming was developed as follows: 1st class—32 tn. 

(29 t); 2nd and 3rd classes—22 tn. (20 t); 4th class—15 tn. 

(13 t); tugs—8 tn. (7 t). James Adger consumed approximately 15% of its normal rate on days it maintained a 

head of steam with no travel. Thus, reducing each class’s 

daily consumption by this factor, and multiplying by the 

total number of vessels of each class on station each 

day, a minimum of 58,000 tn. (52,617 t) of coal would 

have been burned off the coast of Charleston between 

24 December 1861 and 1 July 1865. If one assumes an 

average of 15% of that was converted to ash, then, at 

the very least, roughly 8,700 tn. (7,893 t) of material 

was deposited on the seabed outside of Charleston 

Harbor during the war years.

In addition to this, there was slag deposited during 

normal ship traffic before and after the war, slag from 

the inner harbor that worked its way out to sea through 

normal processes of sediment transport, and slag from 

dredge spoil taken from the inner harbor and dumped 

outside the bar. These quantities, unfortunately, are 

impossible to estimate, but doubtless contributed to 

the material that came to settle around the Hunley site 

as the vessel was slowly buried.

Unburned coal was also found in the matrix surrounding Hunley. There are several ways coal found its 

way into the seabed. Very small pieces, often found 

at the bottom of coal storage bins, were frequently 

generated through the wear and tear of shoveling 

and stowing the material. These small pieces could 

fall through the grate in the bottom of the firebox and 

end up in the ash pit without being consumed. Larger 

pieces generally found their way into the sea through 

shipwreck or spillage. Hunley’s victim USS Housatonic, 

for instance, went down with a significant quantity of 

coal on board, some of which, no doubt, found its way 

to the submarine’s resting place. Blockade runners that 

were run ashore by Union forces were often plundered 

and their less valuable or portable contents, including 

coal, tossed about on the beach (e.g. Daly 1968:142). In 

such cases, some of this coal was likely caught up in the 

sediment transport system and made its way offshore. 

There was occasionally also loss at sea during refueling. 

During the blockade, coaling ships came directly out 

to the vessels at their stations and transferred the fuel 

on the open sea, where conditions were not always 

stable. Such an incident was recorded in the steam log 

of Wabash, when 6,720 lb. (3,048 kg) of coal was “lost 

overboard in consequence of rough weather” while 

coaling in Marseilles (31 August 1858).

Twelve coal samples, four from the Housatonic site 

and eight from the Hunley site, were sent to Rod Hatt of 

Coal Combustion, Inc., Versailles, Kentucky, for analysis 

(Appendix L). Of these, only six were viable, three from 

Housatonic and three from Hunley. All three of the 

former were identified as anthracite, consistent with 

U.S. Navy practice for the period. Of the Hunley samples, 

one was anthracite of similar physical and chemical 

characteristics to those from Housatonic. The second 

sample was identified as medium volatile bituminous 

coal, and the third as low volatile bituminous coal, both 

of which were commonly found in the eastern Appalachian Mountains. 

A total of 32.29 kg (71.19 lb.) of slag and 14.33 kg 

(31.59 lb.) of coal was collected from sediments 

excavated around Hunley. Using the Udden-Wentworth scale of grain size (see Figure 13.1), the pieces 

recovered ranged from fine gravel (-2 to -3 φ) to cobble 

(-6 to -8 φ) in size. Because pieces were recovered by 

hand, primarily from dredge screens, materials smaller 

than -2 φ were not collected. Once recovered, coal 

and slag were separated into lots based on the excavation position in relation to the hull as recorded by diver 

observation, resulting in somewhat generalized provenience. In analyzing the data, the lots collected immediately following the one-month hiatus were omitted; 

these represent material that washed in from the surrounding area during the work stoppage, and slipped 

down through the sandbags left on site to protect the 

hull. A small percentage of the overall material most 

likely washed in during the excavation process, but the 

majority was found in situ.

All selected lots were plotted in ArcGIS to show distribution by count of coal and slag separately (Figure 

13.7 and Figure 13.8). A polygon was created for 

each lot, based on reported size and position of each 

dredging area. The number of coal and slag pieces for 

each lot was distributed evenly over the area of the 

corresponding polygon. This method, therefore, does 

not take into account variations in weight for each piece, 

instead focusing on relative abundance and position 

relative to the wreck. Since much of the sediment 

along the centerline and the port midships region were 

disturbed during the 1996 and 1999 field seasons, it is 

not surprising that these areas contained a relatively 

small amount of coal and slag. However, the area below 

the level of the top of the hull on the starboard side was 

not disturbed during the earlier excavations. Similarly, 
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150

Figure 13.7. Distribution of coal around the Hunley site based on raw counts. White patches represent areas where data was not collected.
S I T E A N A LY S I S

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Figure 13.8. Distribution of slag around the Hunley site based on raw counts. White patches represent areas where data was not collected.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

152

the deeper levels along the port side were largely undisturbed, particularly at the bow and stern. 

The areas of densest concentration were found to 

be below and just to starboard of the stern, along the 

path of the spar, and starboard of the bow below the 

level of the top of the hull. Several areas were revealed 

to have had minimal data collection, primarily along the 

boundaries between the HAT and OII excavation areas; 

these two sections were left relatively intact in the form 

of a raised, berm-like area until late in the excavation, 

at which point the focus was primarily on preparing the 

hull for lifting. Comparing the two plots, it is evident 

that the denser coal collected lower down into scour 

pockets close to the hull, while the slag, which tended 

to be lighter, was more widely distributed. 

There also appears to be an area of moderate 

density east of the hull, stretching roughly 5 m (16 ft.) 

eastward from the stern scour pocket. This may 

represent residual particles that began to settle as the 

turbulent waters around the scour pockets began to 

slow further from the submarine. However, due to the 

gaps in data, this trend cannot be verified.

Ceramics and Glass 

The distribution of ceramic and glass is somewhat 

haphazard (Figure 13.9). The density of bottle glass 

is generally between 2.4 and 2.8 g/cm3 and ordinary 

ceramics of the type found at the site are in a similar 

range, making both likely to sink through fine sand 

layers. The wide, flat shapes of dish fragments such as 

HL-0448 and HL-0451 are more resistant to transport 

either as suspended or bedload, suggesting they were 

either deposited nearby originally, perhaps as trash 

from a passing ship, or were transported during a very 

strong storm event. A ceramic bottle (HL-0661) was 

found close to the stern on the port side, and may 

have rolled from the south or southwest and become 

blocked by the submarine. Two other glass fragments 

were found in this area, a base (HL-0662) and wall shard 

(HL-0675). If these two were part of a larger whole 

when originally deposited, they may also have rolled 

into Hunley and become trapped. 

The whiteware fragment HL-0451 has a stamped 

date of 1912, making it the only intrusive artifact with a 

known terminus post quem for deposition (see Chapter 

15). It was found above the level of the top of the hull, 

suggesting a relatively stable sediment depth covering 

Hunley by the second decade of the 20th century. 

Tin Cans

Another class of cylindrical artifact common to 

the site is the tinned iron can. With a density of 7.85, 

iron is even more likely to work its way down through 

unconsolidated fine sand layers. The addition of a lead 

(11.34 g/cm3

) or lead/tin (8.8 g/cm3) solder increases 

the overall density of the can. However, its hollow cylindrical shape also lends itself to ease of transport along 

the seafloor. With one open end, it must eventually fill 

up with sand and become buried, but it is impossible 

to predict how long this would take. 

Figure 13.9. Positions of ceramic and glass artifacts recovered from the wreck site. (Site plan by James W. Hunter 

III, annotated by H. G. Brown, NHHC)
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Of the cans that were identified at the site, most 

were fragmentary in nature but often found in small 

clusters, indicating they had come to rest relatively 

whole and then broke down as the thin iron wall 

corroded. Seven were nearly complete, though in 

some cases slightly flattened. Of these seven, four were 

concreted to the hull on or near the keel along the 

port side (HL-0653, HL-0654, HL-3667, HL-3678). The 

other two were found to starboard of the hull, one 

at the bow (HL-3288) and one at the stern (HL-0700). 

HL-3288 had become concreted to an iron bracket 

from the hull (HL-0582) and also had trapped a small 

wooden handle fragment (HL-3289) inside it. Three 

were identified from the stern suction pile area, from 

various depths, primarily starboard of the hull, and two 

from the bow suction pile area. Overall, the material 

clustered to starboard of the bow and the stern, with 

a third cluster along central portion of the port side 

(Figure 13.10). 

Most of the cans were relatively low down in the 

matrix, starting about halfway down the vessel height 

down to the dense shell layer. The level of preservation of the complete cans suggests they were buried 

relatively quickly and did not experience subsequent 

periods of significant exposure, while the fragmented 

cans may have had longer or intermittent periods of 

exposure to the water column.

The collection most likely represents a wide variety 

of dates and products, none of which were directly 

associated with Hunley. However, a few cans can be 

roughly dated by their technological features to the late 

19th century (see Chapter 15).

Hull Components

Although the submarine remained remarkably 

intact for over a century in the seabed, many of the 

exterior components became disarticulated from the 

hull, either through natural processes or human interaction. These include the rudder (HL-0686), its mounting 

hardware and steering gear; both shroud attachment 

bars, only one of which was found (HL-0660); the 

cutwater from the aft conning tower (HL-0555); both 

snorkel tubes (HL-0614, HL-0615, HL-0616), and two 

apparent mounting brackets from the bow (HL-0526, 

HL-0582). Knowing their point of origin makes these 

pieces valuable in reconstructing the forces in play 

around the submarine prior to its burial. 

Most of the disarticulated components came to rest 

to starboard of the hull, close to their original location 

(Figure 13.11). The starboard shroud attachment bar 

never detached fully from the hull, but was apparently 

bent forward while the metal surface was still exposed, 

as it was found concreted to the hull in several spots 

along its length. The event that caused this displacement may be related to the damage on the starboard 

side of the propeller shroud.

The rudder was found directly beneath the stern, 

along with one concretion (HL-0683), which appears 

to be part of one of the shroud attachment bars or 

steering assembly (HL-0683). It was lying diagonally 

across the center line, approximately 1 m (3.28 ft.) 

forward of the after edge of the propeller shroud, with 

the port side upward and the top corner of the leading 

edge toward bow. It is possible that the rudder fell off 

through gradual deterioration of the mounting points, 

Figure 13.10. Positions of complete, partial, and fragmentary cans recovered from the wreck site. (Site plan by 

James W. Hunter III, annotated by H. G. Brown, NHHC)
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and it migrated forward as it scoured down to the Pleistocene mud layer. Due to its weight (38.3 kg [84.44 lb.]) 

and flat profile, however, it is possible natural hydrodynamic forces were not enough to have pushed it so far 

out of position. 

Another scenario is that the damage to the steering 

assembly also involved the rudder itself, although the 

piece shows minimal damage. The mounting brackets 

show no deformation but do appear to have snapped 

cleanly off rather than eroding gradually, while the 

steering arms concreted to the rudder show deformation at the trailing edge trending upward and to 

starboard. If the port side of the propeller shroud and 

the steering rod were pulled away by a snagged anchor 

traveling northward, the rudder might have been 

wrenched off to starboard and come to rest slightly 

forward and to starboard of the stern while Hunley

was still upright. Once it canted over to its 47° position, 

it then covered the rudder, which had already settled 

down to the mud layer. 

The cutwater was found approximately 61–76 cm 

(24–30 in.) starboard of the hull roughly northeast of 

its original position, with its port side down. There 

does not appear to be any deformation of the metal, 

suggesting the piece corroded along its attachment 

points and fell off the submarine naturally. Since the 

forward cutwater remained solidly in place, however, it 

is possible additional force was required to dislodge it. 

There is a small section of metal loss along the hypotenuse, but it is difficult to determine whether it was 

caused by corrosion or an impact event. 

The snorkel tubes were found parallel to the hull, 

forward of their original position. These elements did 

not show any sign of damage from external forces, 

and likely corroded naturally, most likely at the point 

where the wrought-iron tubes connected to the 

cast-iron snorkel box, where a galvanic cell would have 

formed. The fact that the port snorkel tube came to 

rest to starboard of the hull indicates that they came 

loose after the hull canted to starboard. The apparent 

movement toward the bow suggests that a northwestward flow dominated their deposition. 

The bow brackets show an unusual distribution 

pattern. The after bracket was bent about halfway 

down one arm, and both arms broke off around the 

fastener holes; however, it came to rest very close to its 

original position, 35 cm (13.78 in.) starboard and 5 cm 

(1.97 in.) forward of the bow. The forward bracket was 

found disarticulated from the hull, approximately 2.0 m 

(6.56 ft.) forward and 1.4 m (4.59 ft.) starboard of the 

bow, but with its fastener in place and no sign of metal 

deformation. The through hole for this bracket was 

compromised at some point, either through erosion or 

breaking from impact or strain, a possibility that can’t 

be more fully examined until the hull is deconcreted. 

Given the damage to the aft bracket and the position 

of the forward bracket, it is likely that the boom, or 

possibly rigging elements attached to the boom, was 

snagged after deposition, pulling the hardware away 

from the bow northward. 

Hull Erosion

The hull itself showed significant areas of metal loss 

that are directly tied to the flow of water and suspended 

sediment around it. The leading edge of the bow casting, 

formerly a straight vertical edge, was worn into a scallop 

shape. Even the nut holding the spar on to the bow was 

heavily worn (Figure 13.12), attesting to the strong flow 

along the port side of the bow. The skeg in front of the 

port diving plane was also somewhat eroded, and it 

is possible the diving plane itself was pushed upward 

out of horizontal alignment from the currents flowing 

Figure 13.11. Site plan showing locations of the disarticulated components, with red arrows indicating their point 

of origin. Due to the steep cant of the wreck, the shroud attachment bar (HL-0660) appears to be beneath the hull 

in this view. (Site plan by James W. Hunter III, annotated by H. G. Brown, NHHC)
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around the bow. The port side of the stern does not 

demonstrate such severe erosional damage, although 

the rounded edge of the broken propeller shroud 

attests to some flow-related wear. 

A study conducted at the Warren Lasch Conservation Center took an in-depth look at the two holes 

on Hunley’s starboard side and linked them to scour 

(Jacobsen et al. 2012). Analysis of the sediment inside 

the hull revealed that these two holes were not formed 

as a result of the sinking, but formed much later. There 

were several factors that contributed to an accelerated degradation rate in these areas. Both holes 

formed along the boundary of the cast-iron end caps 

and the wrought-iron plates, a likely environment for 

the formation of a galvanic cell. This natural corrosion 

system was enhanced by the turbulent flow around 

the bow and stern, which pelted the hull surface with 

granular material as it pushed past. Controlled laboratory studies on metal plates of similar consistency to 

Hunley’s wrought iron tested rates of corrosion, erosion, 

and combined erosion-corrosion processes. It was 

found that 

[t]he mass loss rate for the plate exposed 

to erosion-corrosion is 18 and 10 times 

greater than plates exposed to corrosion and 

erosion conditions. The primary reason for 

this is probably due to the constant removal 

of surface oxide layers, thus exposing the 

underlying metal and leading to accelerated 

mass loss. (Jacobsen et al. 2012:44)

Essentially, the continual abrasion of the hull 

appears to have prevented the formation of a protective concretion layer in an area already predisposed to 

an increased corrosion rate due to contact between 

two different metals. Both holes are near the top of 

the hull, which may give an indication of the depth of 

the submarine’s initial burial, as the lower hull seems 

to have been protected from these effects, perhaps by 

its list to starboard. 

Scour and Burial

Scour is a phenomenon involving the interaction 

of moving water, sediment, and an object in contact 

with the seabed. The object, in this case Hunley’s hull, 

obstructs the current flow, causing the water to slow 

down as it approaches, then speed up as it pushes 

around and over. The dynamics of scour are complex 

and even with detailed environmental data can be 

difficult to predict. However, understanding the general 

behavior of scour is important in interpreting the disposition of artifacts at the site.

As velocity slows on the incident side of the 

obstruction, causing some deposition of suspended 

load, pressure increases; on the lee side, pressure drops 

significantly and velocity rises, increasing lift force. In 

addition, the direction of flow is severely disrupted, 

and the relatively laminar flow becomes turbulent. 

Horseshoe vortices develop on the incoming side of the 

obstruction that wrap around the ends of the obstruction, and wake vortices form on the lee side (Rory Quinn 

2006:1420). These forces can cause localized erosion of 

the seabed resulting in hollows or pockets of sediment 

loss that extend away from the wreck, usually in the 

direction of current flow. The direction and size of these 

pockets are determined by many factors, including the 

shape of the object, the direction of the currents, wave 

action, and the composition of the seabed. 

Idealized projections of scour zones outlined for a 

simplified ship shape were generated by Rory Quinn 

(2006:1423). These take into account unidirectional, bidirectional, and rotary flow with the object at various 

angles to the flow direction (Figure 13.13). The area 

around Hunley is characterized by a rotary current, 

where the direction of current rotates in a clockwise 

direction over the course of the tide cycle. Therefore, 

one might expect uniform scour around the base of the 

submarine. However, since the duration and speed of 

the rotary current is asymmetrical, some characteristics 

of bi-directional current could be expected. 

The site development history is further complicated by the fact that there were two distinct phases 

of predominant tidal direction during the period when 

the submarine was on the seafloor. At the time Hunley

sank, the ebb tide set roughly northeastward (ca. 73°) 

at the beginning of the cycle, but quickly circled round 

to southeast by east (ca. 120°–130°) for the second 

quarter and part of the third, tailing off to south by east 

by the final quarter (USCS 1856). The flood tide ran in 

two primary directions—west by south (ca. 256°–259°) 

Figure 13.12. Erosion is evident on the outer surface of 

the nut that connected the spar to the hull at the base 

of the bow casting on the port side. (Courtesy of FOTH)
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for the first half and west-northwest (293°–303°) for the 

second half of the cycle. Thus scour pockets would most 

likely have developed around the base of the submarine, 

with larger extensions trending roughly southeast of the 

stern and west to west-northwest of the bow (Figure 

13.14, top). The construction of the jetties altered the 

dominant currents, which were described in 1900 as 

follows: “Off the bar the flood current sets 3 hours 

southwestward, then westward, and the last hour 

northwestward. The ebb for the first 3 hours sets northeastward, then eastward, and for the last hour southeastward” (USCGS 1900:78) (Figure 13.14, bottom). In 

addition, the ebb flow was now noticeably stronger 

than the flood (Conlin 2005:140). Scour pockets arising 

from tidal currents that developed after the influence 

of the jetties, therefore, would be expected to trend 

roughly northeastward around the vessel ends, with a 

deposition zone trailing off eastward.

Figure 13.13. Generalized scour patterns for unidirectional current striking a shiplike object at 90°, 

45°, and 0° (left), and 90° bidirectional and rotary current (right). (After Rory Quinn 2006:1423)

Figure 13.14. Idealized projections of how the tidal current affected scour around Hunley both 

before and after construction of the jetties at the habor entrance. (Diagram by H. G. Brown, NHHC)
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Studies on cylindrical mines in fine 

sands off Martha’s Vineyard, however, 

identified wave action rather than tidal 

currents as the primary driver of scour on 

the mines (Traykovski et al. 2007). Wave 

energy off Charleston is generally low due 

to the breadth and shallow slope of the 

continental shelf in that area (see Chapter 

3), but severe storms can significantly 

increase wave height, period, and direction 

in the short term, increasing scour around 

an obstruction. A large storm-related 

scour pocket developed at shipwreck site 

31CR314, believed to be Queen Anne’s 

Revenge, in North Carolina after the 

passage of Hurricane Bonnie in 1998. The 

pocket developed northwest of the site, 

in contradiction to the natural longshore 

current coming from the northeast, and 

had not yet filled in by the time of publication (McNinch et al. 2006:298–99). Reburial 

at this site may have been slowed by the 

site’s position in an active ebb-tidal delta. 

As discussed in Chapter 3, a number 

of tropical storms and hurricanes passed 

close to the Hunley site in the 50 years 

following the sinking. The earliest hurricane 

to have affected the site was in June 

1867, which made landfall just east of 

Charleston as a Category 1 storm (NOAA 

n.d. a). In September 1874, a Category 1 

hurricane developed in the Gulf of Mexico 

and traveled northeastward, with the eye 

passing very close to Charleston on its 

way past (Partagás and Diaz 1995:40–41). 

Another storm made landfall southwest of 

Charleston as a Category 1 in September 

1878 (NOAA n.d. a). Two small hurricanes 

made landfall near the South Carolina coast 

in 1881, one to the southwest and one 

to the northeast, but only one, which hit 

northern Georgia heading west, had severe 

effects in the Charleston area (Partagás 

and Diaz 1996:11–17). In 1885, a storm 

came up from the south, making landfall 

near Beaufort, South Carolina, likely as a 

Category 2 hurricane, and turned northeast 

reaching Charleston as a Category 1 or 

2, and heading up the coast toward the 

Carolinas (Mayes 2006:48–60). Two hurricanes hit in 1893, one in August, the other 

in October. The first was the strongest event 

to hit Charelston in the period under review 

and became known as the Sea Islands 

Hurricane. It traveled off the Florida coast 

northward and made landfall just south of 

Figure 13.15. Hurricane activity affecting Charleston in the late 19th 

century, clustered by probable dominant wave direction. (Basemap 

from Esri et al., annotated by H. G. Brown with data from NOAA NHC)

World Ocean Basemap (No Labels) Esri, GEBCO, NOAA, National Geographic, DeLorme, NAVTEQ et al.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

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Savannah, Georgia, as a Category 3, devastating the 

coastal island communities (NOAA n.d. a). The storm 

continued northward straight through central South 

Carolina, leaving Charleston on the stronger, eastern 

side of the storm (Mayes 2006:63). The hurricane of 

October 1893 approached from the south, making 

landfall likely as a Category 3 at Bull’s Bay, just north of 

Charleston, and therefore it did not have as damaging 

an impact as the previous hurricane of that year (Mayes 

2006:69). Given that wave directions during a hurricane 

do not correspond directly with wind direction, but are 

influenced by the direction of the storm’s movement, 

and that the significant wave heights are more intense 

in the right forward quadrant of the system (Ochi 

2003:53–59), one would expect the strongest wave 

activity to have trended to the north in 1874 and 1885; 

the northwest in 1867, 1878, and August 1893; and the 

west in 1881 and October 1893 (Figure 13.15). 

As long as the wreck remained proud of the surface, 

scour pockets caused by storms remained exposed and 

open to alteration by changes in hydrodynamic conditions. Over time, however, they filled in, until both 

the submarine and the scour pockets were fully buried. 

This was a gradual process, with alternating periods 

of scouring and infilling. The Martha’s Vineyard mine 

study demonstrated that after the course of a year, one 

test mine, which was 2 m (6.56 ft.) long and 0.533 m 

(1.75 ft.) in diameter, and its scour pocket were fully 

buried and overlain with a 10 cm (3.94 in.) layer of fine 

sand (Traykovski et al. 2007:157). The scour pockets 

contained a higher percentage of silts and clays (35%) 

than the surrounding seabed (3%) (Traykovski et al. 

2007:157). Sediment suspension and scour at the test 

site, which was 11–12 m (36.09–39.37 ft.) in depth, 

were primarily linked to high wave events. The authors 

observed that fine particles settled into the scoured 

areas after the wave event ceased, but were subsequently washed out by peak tidal currents; however, 

over a series of these events there was ultimately a net 

gain of accreted material in the scoured area (Traykovski 

et al. 2007:163). Since periods of high energy waves at 

the site were most common in winter, infilling generally 

occurred afterward, “during a period when the seasonal 

waveheight envelope was decreasing” (Traykovski et al. 

2007:158). Prior to burial, the mines reoriented themselves over the course of several weeks into a position 

perpendicular to the direction of wave propagation 

and eventually rolled into the scour pit that developed 

on the lee side, contributing to the rapid rate of burial 

(Traykovski et al. 2007:159). This was facilitated by their 

cylindrical shape. Due to its weight and the flat keel, it is 

unlikely Hunley shifted orientation after coming to rest 

or rolled into a scour pit. 

Another factor in burial is liquefaction of the bed, 

which develops with increased pore water pressure, 

causing heavy objects to sink into the substrate. 

Wave action is the primary cause of liquefaction in 

saturated soil, although it can also result from earthquakes, shocks, and motions of structures under cyclic 

loading (Sumer and Fredsøe 2002:447–48). The higher 

pressure initiated by the flow on the incident side of 

Hunley may have increased sheer stress enough to 

cause liquefaction of the surficial sand layer, leading 

to the submarine settling down to the compact Pleistocene mud. However, it is also possible seismic waves 

from the Charleston Earthquake of 1886 liquefied 

the substrate. The epicenter of this quake was 29 km 

(18 mi.) northwest of the Hunley site, with a meizoseismal area of roughly 50 × 35 km (31 × 22 mi.) trending 

NE, putting Hunley well within the affected area (Stover 

and Coffman 1993:348–49). If the submarine had not 

yet subsided into the seabed by this point, it is likely this 

event would have completed the task. 

Discussion

There are a number of unknown factors that make 

reconstructing the sequence of events affecting Hunley

difficult. The submarine likely came to rest on a shallow 

layer of Holocene fine sand, but there is also a chance 

the Pleistocene mud layer was exposed at the time (see 

Chapter 3). It may also have landed on an even keel or 

come to rest immediately at the 47° angle found during 

excavation. Based on Chapman’s painting, which shows 

the boat resting on its keel blocks with no side supports, 

it appears the vessel could rest easily in an upright 

position. Evidence from the inside the hull indicates that 

the vessel was upright when the hole in the forward 

conning tower was made, but, based on sediment accumulation, the vessel was canted over very early in the 

post-depositional time scale (Jacobsen et al. 2012). 

The submarine came to rest at a heading of 297°. 

Despite differing testimony about the tide state at the 

time of the explosion, the Court of Inquiry determined 

it was at 1⁄2 ebb (DON 1864a:0588), putting it directly in 

line with the wreck’s centerline, suggesting the vessel 

was drifting sternward with the ebb current when it 

went down. In this orientation, scour pockets would 

have formed predominantly to the bow and stern, in 

which case the pockets would not have been a significant factor in the burial process. As currents altered in 

response to the jetties, the dominant northeastward 

ebb would have struck the hull at a roughly perpendicular angle, causing scour pockets to form starboard 

of the bow and stern trending nearly paralellel. 

Actual scour pockets at the site were identified 

close to the hull by divers during the excavation at the 

bow and stern, where they noted a change in sediment 

characteristics and increased artifact density. In a fine 

sand environment, an increase in silts and clays into the 

30–40% range has been noted above as characteristic 
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159

of infilled scour pockets. Of the samples analyzed by 

Harris, T1-10, T1-20 and T2-3 match these characteristics. Since the depth of these samples is above the 

level of the submarine, if these are the result of scour, 

it most likely occurred after Hunley was buried, caused 

by small-scale obstructions that are no longer present. 

We cannot discount the possibility that these developed 

in response to equipment used during the work done 

at the site in 1996 or 1999. 

Without an array of sediment samples around the 

site taken at hull depth, the scour pockets were primarily 

identified by clusters of heavy anthropogenic materials. 

These arise when heavier objects, transported as part 

of bed load, get trapped in scoured depressions, either 

by settling into the newly deposited fine sediments or 

simply being too heavy to be lifted back out during the 

next high energy event. Artifact density beneath and 

to starboard of the stern was particularly noticeable to 

divers, and was also evident in the coal and slag distribution map (see Figure 13.16). Another area of density 

was apparent starboard of the bow, in the vicinity of 

the eroded hole in the bow casting. The high incidence 

of cans at the bow suggests that they rolled in with the 

ebb tide and could not overcome the incline to keep 

moving. It is also possible the angle created by the hull’s 

starboard list increased the propensity to trap larger 

materials. The distribution of glass and ceramics shows 

that the relatively flat fragments are randomly distributed, but the complete or partially cylindrical material 

collected against the port side of the stern. 

The distribution of artifacts along the port side is 

scanty and limited primarily to bottles and cans very 

low down near the keel of the vessel. A narrow band of 

scour directly adjacent to and surrounding the hull likely 

developed soon after deposition under the initial rotary 

current conditions, and may have provided a zone for 

trapping glass bottles and cans. However, based on 

the positions of the disarticulated hull components 

and the coal and slag, it appears that seasonal storm 

activity or the post-jetty, northeast- to east-setting ebb 

tidal current had more impact at the Hunley site than 

the predominant wave direction, which runs from east 

northeast to southwest, which would have initiated 

scour erosion to port of the submarine.

The overall pattern revealed by artifact density 

suggests two asymmetrical scour pockets trending to 

starboard of the hull. The smaller one was located along 

the bow quarter, but did not extend fully beneath the 

hull. The larger one encompassed the stern, with an 

area of density directly beneath the hull, and trending 

roughly northward, with a zone of increased coal and 

slag deposition trending eastward. This asymmetrical 

pattern is mirrored in the erosion-corrosion holes on 

the starboard side, also products of the hydrodynamic 

action around the hull—the stern hole is nearly three 

times longer than that at the bow. The direction and orientation of the pockets, which were found only on the 

starboard side and trended toward each other, suggests 

the primary driver of scour was unidirectional wave 

action roughly from the south, which is consistent with 

the dominant wave forces generated during the hurricanes of 1874 and 1885 (Figure 13.16). This timeframe 

coincides with the advent of increased sediment load 

collecting around Hunley from the jetty outflow. It is 

tempting to conclude that the submarine must have 

been fully buried prior to the Sea Islands Hurricane of 

1893 with its dominant northwest-trending wave action; 

however, there are too many variables in the behavior 

of individual storms to make a conclusive determination in that regard.

The relative lack of anthropogenic material in the 

starboard midships area suggests that the two pockets 

did not remain exposed long enough to converge before 

they filled in. This rules out the possibility that Hunley’s 

starboard list came from rolling into a scour pocket the 

way the mines studied at Martha’s Vineyard did. The 

sharply angled zones of greatest intensity may have 

been influenced by the hull shape, with the very narrow 

ends initiating a sharper angle of scour than the blunt 

or rounded ends more commonly modeled for studies.

The hull most likely had tipped over at the latest by 

the earthquake of 1886. The starboard shroud attachment bar appears to have been damaged prior to the 

rotation of the hull, since it would have been very 

difficult to swing it 180° forward with the starboard 

side angled toward the seabed. The condition of the 

stern assembly suggests that it was snagged while the 

submarine was still upright, breaking the steering rod 

and vertical steering arm, unshipping the rudder, and 

damaging the attachment bar. This might have occurred 

as early as November 1864, when William Churchill used 

the drag ropes to search for Hunley (see Chapter 4). He 

reported snagging on something heavy, although, upon 

further examination, divers found only “a quantity of 

rubbish” (ORN 1.15:334). This type of event may have 

pulled the hull over to starboard, or initiated a slight lean 

that was augmented later through scour or liquefaction. 

If there was a sand layer present when Hunley

came to rest, it was unlikely to have been deep 

enough to bury the submarine. The complete burial 

was dependent on an overall increase in sediment 

load brought about by the jetty construction. The cans 

concreted to the bottom of the keel can be roughly 

dated to the last two decades of the 19th century, coinciding with the construction period and provide additional evidence that the vessel had tipped over by then. 

The intact condition of these cans suggests a relatively 

quick burial after deposition, with little or no post-depositional exposure or disturbance, consistent with the 

burial model discussed in Chapter 3 and supported by 

the lead isotope analysis (Marot and Holmes 2005) and 

biological assessment (Murphy 1998:148–51). 
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160

Figure 13.16. Idealized projections demonstrating asymmetrical, convergent scour pattern similar to those identified at the Hunley site are based on an angle of 

incidence of approximately 45° (A). Comparing 1856 current data from a nearby station (B) shows no vectors that correspond to the projected angle of incidence (C) required to generate the documented scour areas, suggesting storms coming up from the south may have been a significant factor in the formation of the site. (Coal and slag distribution map provided by J. Enright, SEARCH Maritime Archaeology Division, annotated by H. G. Brown, NHHC) 
161

14. Hull Analysis

H e a t h e r G . B r o w n a n d R o b e r t S . N e y l a n d

These fall into several categories: descriptions by those 

involved with building or operating the vessel; accounts 

by eyewitnesses or those who interviewed someone 

involved with Hunley; and diagrams and illustrations. 

The primary publicly-available description of 

Hunley’s construction and its significant features came 

from William Alexander (see Chapter 2). A mechanical 

engineer in the Confederate army, he was assigned 

to work on the submarine project when it was still 

in Mobile. At the turn of the century, in order to set 

the increasingly muddled record straight, Alexander 

published an article in a number of periodicals (1902a, 

1902b, 1902c , 1902d), in which he gave both the operational history of the vessel as well as some dimensions 

and construction information. Some have been critical 

of this account because of inaccuracies in dates and 

dimensions, caused by committing the details to paper 

nearly four decades after the fact (Chaffin 2008). Nevertheless, his overview of the various components of 

the hull and how they worked have generally proved 

consistent with archaeological findings and his insights 

With the submarine safely placed in controlled 

laboratory conditions, a closer examination of the hull 

was possible. This allowed for the first time, a detailed 

comparison between the historical descriptions of the 

hull and the actual vessel itself. While a comprehensive 

analysis must wait for the completion of the hull deconcretion and a full examination of data collected from 

the excavation of the interior of the vessel, a number 

of observations can be made about Hunley’s design 

and construction. A closer look at the hull in conjunction with known accounts as well as other submarines 

of the period can clarify the historical record, provide 

insights into the surviving features of the vessel, and 

help identify possible missing features. 

Historical Sources

Prior to the submarine’s rediscovery, many attempted 

to reconstruct the vessel based on historical sources. 

Figure 14.1. Published drawings of H. L. Hunley based on sketches by William Alexander 

(ORN 1.15:338)
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162

modern researchers recognize what components of the 

vessel were similar to or adapted from technology in 

everyday use. 

Several diagrams of the vessel were generated 

over the years, which show both the overall shape and 

exterior features of the vessel, along with the basics 

of its interior layout and functional aspects of the propulsion system and pumps. These include drawings 

by Alexander from the early 20th century, adapted 

and published by the U.S. Navy (Figure 14.1); a sketch 

by Baird (1902:846) based on his discussions with 

McClintock, although Alexander (1902e) claimed this 

represented the boat McClintock built in New Orleans; 

and a drawing by Lake (1899). There was also a sketch 

developed by McClintock (1872) for his meeting with 

the Royal Navy (1872) and annotated by several of the 

officers there, that purports to be a representation, not 

to scale, of the submarine that sank Housatonic but substituting an engine instead of a hand crank. It 

While these diagrams do convey the overall 

concept of the submarine and many of its significant 

features, they do not allow the viewer much insight into 

the many small alterations made to ordinary technology 

to accommodate life in a cramped, underwater environment, nor to see what innovations were developed for 

the vessel. Many things were taken for granted by the 

creators of the diagrams, or considered unnecessary 

for communicating a basic understanding of how the 

boat worked.

The most valuable image documenting the exterior 

of Hunley is the painting by Conrad Wise Chapman, a 

Confederate soldier and artist who painted a series of 

scenes based on sketches he made during his army 

service (Figure 14.2). It has proven remarkably accurate 

when compared to features documented archaeologically and may prove the best source for identifying 

possible features lost during or after the sinking. In 

addition, a study for the painting, dated 2 December 

1863, survives and shows details, particularly in the 

steering system, that are not as clear in the oil (see 

Figure 14.10). Many later depictions, including the 

watercolor wash by R. G. Skerrett published as a frontispiece in the Official Records of the Union and Confederate Navies (ORN 1.15), were adapted from Chapman’s 

work, but significant inaccuracies were introduced in 

each iteration (Figure 14.3). 

Two other important images are drawings of 

Pioneer, from after it was dragged from Lake Pontchartrain and documented by U.S. Navy staff. One was the 

schematic enclosed in Fleet Engineer Shock’s report 

based on work by Second Engineer Alfred Colin (see 

Figure 2.5). The other was a pencil sketch with several 

detail views captured by Ensign David M. Stauffer in 

March 1865 (see Figure 2.6). This eyewitness documentation provides a unique opportunity to examine design 

changes between the prototype and the final vessel. 

as to the purpose behind the design of certain features 

must be given some credence. It was the primary source 

upon which most models were built until the vessel was 

found in the 1990s.

Another detailed account, not widely available 

until recently, was given to officers of the Royal Navy 

by James McClintock in 1872, and is on file at the 

British National Archives in London. McClintock, the 

only surviving member of the initial building team, 

met secretly with British officers in Halifax, offering to 

build them a submarine along similar lines as Hunley

but correcting critical deficiencies. The dimensions 

he supplied in describing Hunley were more accurate 

than Alexander’s, but the description of its construction and operation is not as thorough. His analysis of 

the problems Hunley experienced is illuminating in 

regard to the submarine’s capabilities and limitations. 

It must be noted that, according to Alexander (1902e), 

McClintock did not have much direct operational experience with Hunley and thus his observations likely 

pertain primarily to Pioneer and possibly Pioneer II.

Most eyewitness accounts give rough estimates 

of dimensions, and describe the obvious features of 

the vessel without getting into too much detail. Nevertheless such narratives occasionally offer a piece of 

information lacking or not featured prominently in the 

aforementioned accounts, generally influenced by the 

writer’s personal interest. These sources include an 

1863 letter from Confederate officer George Gift, who 

helped haul the submarine out of the water in Mobile 

and put it on the train to Charleston (Turner 1995); 

an article by G. W. Baird (1902), an engineer with the 

U.S. Navy who interviewed McClintock after the war; a 

narrative by Simon Lake (1899, 1918) based upon a discussion with former Hunley crewmember and survivor 

of the second sinking, Charles Hasker; an article by C. 

L. Stanton (1914), former lieutenant in the CSN and 

shipmate of Lt. Payne on the Chicora; and an interview 

with D. W. McLaurin, member of the 23rd Alabama Volunteers, stationed on Sullivan’s Island, who was asked 

to go aboard one day “to help adjust some machinery” 

(Confederate Veteran 1925). 

An interesting unpublished summary of a description by eyewitness William G. Mazyck of Charleston 

was also brought to light soon after Hunley’s recovery 

by Patrick McCawley, an archivist at South Carolina 

Archives and History Center. In 1957, G. Robert Lunz 

sent a letter to the archive describing a meeting he 

had in 1935 with Mr. Mazyck (Lunz 1957). As a boy, 

Mazyck had seen the submarine up close in Charleston 

and even managed to get a look inside. His account 

(Appendix N) was remarkably accurate, particularly 

given he was nearly 90 years old at the time, with 

measurement estimates coming surprisingly close to 

documented figures. His descriptions of some of the 

components, e.g. “an ordinary cistern hand pump,” help 
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Figure 14.3. Sepia wash drawing produced by R. G. Skerrett in 1902 based on Chapman’s painting. Aside from 

the obvious increase in scale, representational errors include a round, rather than oval, hatch cover; placement 

of the shroud attachment bar in the center of the expansion strake; and a chain running from the steering rod 

to the rudder arm, rather than a solid metal piece. (Courtesy of Navy Art Collection, NHHC)

Figure 14.2. Oil painting by Conrad Wise Chapman depicting H. L. Hunley in Charleston. (Courtesy of The 

Museum of the Confederacy, Richmond, Virginia)
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State Museum, it was originally thought to be Pioneer, 

although this has since been discounted based on 

comparison to drawings of Pioneer made by Colin. 

While its true identity has not been established, the 

Louisiana State Museum vessel most likely dates to the 

early period of the Civil War, before New Orleans fell 

to Union forces in 1862 (Wills 2000:187). 

The vessel was fully documented by Richard 

Wills (2000) in 1999. It is a closed-capsule submersible, propelled by a manually-operated crankshaft 

connected to an axially mounted four-bladed propeller 

(Wills 2000:138). Measuring 20.17 ft. (6.15 m) in length, 

3.21 ft. (0.97 m) in beam (Wills 2000:109), it is about 

half the length of Hunley, and has a length to beam 

ratio of 6.3:1. The hatch cover and possible conning 

tower do not survive, but the preserved height of the 

hull is approximately 6 ft. (1.84 m) (Wills 2000:109). The 

interior has been partially filled with cement, and, at 

the time of documentation, the vessel was mounted on 

large cement stands, limiting access to data concerning 

the keel and lower extremities (Wills 2000:108). 

On the Union side, Intelligent Whale was designed 

by Scovel S. Merriam and construction was begun in 

1863, in hopes of selling it to the U.S. Navy (Figure 14.4). 

After a complicated series of ownership and builder 

changes, it was finally granted an official trial for the 

Navy in 1872, although based on stories from owner 

Oliver Halsted’s family, it was in working order in 1866 

(Hitchcock 2002:83ff). The trial was deemed unsuccessful and the vessel remained unused at the Brooklyn 

Navy Yard until the yard’s closure in 1965, whereupon 

it was moved to the Washington Navy Yard, and finally 

Archaeological Parallels

Three other American-made submersible craft 

survive from the 1860s that are available for study. 

As a group they help to show the range of innovation 

happening during this period of rapid development and 

experimentation. These vessels fall into two general 

categories based on function—the diving bell sub and 

the closed-capsule sub. The former developed from 

the stationary diving bell, already in use since at least 

the 17th century, and is based on the need to allow 

people to enter and exit while it is submerged. These 

vessels were primarily designed for salvage and aquacultural operations and, in war time, for sabotaging 

enemy shipping or clearing defensive obstructions. 

They generally had a hatch opening in the bottom and 

required a method for pressurizing the air inside to 

keep it from flooding. Interior space was optimized in 

these vessels at the expense of traveling speed and 

streamlined hull design.

The closed-capsule vessel type remained fully 

sealed while submerged, with its primary application limited to underwater attacks on enemy vessels 

via towed or spar-mounted explosives. These vessels 

tended to optimize speed and handling over interior 

space. A hydrodynamic hull was particularly important 

since they were hand powered, requiring maximum efficiency in cutting through the water to cover any significant distance.

The earliest surviving Confederate submersible is 

likely the unidentified submarine recovered from Lake 

Pontchartrain in 1878. Now housed at the Louisiana 

Figure 14.4. Intelligent Whale on display at the New York Navy Yard, photographed on 27 July 1915. (NHHC Photo Archives #NH 53244)
H U L L A N A LY S I S

165

to the National Guard Militia Museum of New Jersey 

(Hitchcock 2002:105–110). It was fully documented by 

Peter Hitchcock (2002) between 1996 and 2002. 

This is a diving-bell type submersible, propelled by 

a manually-operated central crank shaft connected to a 

three-bladed propeller, and equipped with compressed 

air and two rectangular access hatches in the bottom at 

midships. It measures 29.02 ft. (8.85 m) in length to the 

aft end of the propeller shaft, with a maximum breadth 

of 7.25 ft. (2.21 m) and a height at midships of 6.98 ft. 

(2.13 m), resulting in a length to breadth ratio of 4:1 and 

a length to height ratio of 4.16:1 (Hitchcock 2002:113). 

A small conning tower rises 11.75 in. (29.85 cm) from 

the top along the centerline, just forward of midships 

(Hitchcock 2002:131). A report on the trial states the 

boat could be operated by six people, but could hold 

up to thirteen people, although Hitchcock believes 

that would have been a very tight squeeze (Hitchcock 

2002:3–4, 102).

The last parallel is Sub Marine Explorer, designed 

by German immigrant Julius H. Kroehl (Figure 14.5). 

Construction began in 1864 with hopes of persuading 

the U.S. Navy to adopt his vessel design for use against 

Confederate forts and harbors (Delgado 2006:245–

46). Navy interest, however, did not develop, and the 

boat was completed with backing from the New Yorkbased firm Pacific Pearl Company, who shipped it to 

Panama in 1866 to work the dwindling pearl beds in 

the area (Delgado 2006:247). In or around 1869, it was 

abandoned on the shores of Isla San Telmo, Panama, 

where it remains today. The site, whose history had 

been lost over time, was first brought to the attention 

of Dr. James Delgado in 2001. He subsequently identified the vessel, then organized a team to document it 

between 2004 and 2008 (Delgado 2006, 2012). 

Another diving-bell submersible, Sub Marine 

Explorer was propelled by hand most likely by a single 

operator at the crank (Delgado 2012:199). It was 

36 ft. (10.97 m) in length, with a maximum breadth of 

10 ft. (3.05 m) and width at the keel of 8 ft. (2.44 m), 

resulting in a length to breadth ratio of 3.6:1 (Delgado 

2006:235). Vessel height was reported as 10.54 ft. 

(1.99 m) (Delgado 2012:189), but access to the bottom 

levels was limited due to its partial burial in a surf zone. 

A conning tower, 1.42 ft. (0.44 m) high, remains along 

the centerline, although the hatch cover has been lost 

(Delgado 2006:236). 

Despite various levels of disrepair and deterioration, these vessels allow access to a level of knowledge 

unavailable in the historical documents. Sketches 

and plans do not fully record metallurgical processes, 

construction techniques, and the everyday work of 

the engineers that can only be found in the material 

remains of the vessels themselves. 

Analysis of Features 

Based on Alexander’s statement that Hunley was 

made from “a cylinder boiler which we had on hand,” 

it has been implied over the years that the vessel 

must have been relatively makeshift and rudimentary 

(e.g. Mazet 1942:665). However, once Hunley was 

Figure 14.5. The remains of Julius Kroehl’s Sub Marine Explorer on a beach in 

Panama. (Photo by Todd A. Croteau for the Historic American Engineering Records, 

National Park Service, available from Library of Congress, HAER-CZ-5-2)
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166

recovered and closely examined, it 

became apparent that its hull was 

much more than just a modified 

boiler shell. A great amount of 

skill, ingenuity, and labor went 

into adapting contemporary technology for the deadly and unforgiving environment of the open sea. 

The wartime environment limited 

access to resources, forcing the 

mechanical engineers to the utmost 

of their creativity to complete a 

working weapon of war.

Hull Design

The designers of underwater 

vessels in the late 19th century 

faced many challenges. They 

gained insights from anywhere they 

could—the naval architecture of 

surface ships, published accounts 

of previous attempts by other pioneering submariners such as Bushnell, contemporary 

knowledge of physics and mechanical engineering, and, 

in some cases, even from the bodies of sea creatures.

There are several factors that must be considered 

in a successful submarine design. In order for a vessel 

to remain upright while fully submerged, its center of 

gravity must fall below its center of buoyancy. There 

must also be accommodations for making it stable 

at the surface. To travel efficiently through the water, 

it must minimize drag. And it must retain sufficient 

interior room for crew, activities, machinery, and ballast 

tanks, while still allowing the crew to move inside 

without upsetting longitudinal stability. Balancing all 

these needs is a challenge and one that was resolved 

differently by the various designers of early submarines. While 19th century designers did not have the 

benefit of decades of advanced engineering studies to 

guide them, there are several features of Hunley that 

represent the beginning of that journey.

Shape

Many studies have been conducted since the 

advent of long-range submarines on the ideal hull 

shape for minimizing drag, thereby providing the 

most efficient movement through water (Arentzen 

and Mandel 1960; Friedman 1984; Burcher and Rydill 

1994; Joubert 2004). Current opinion is that this is a 

cigar-shaped vessel, with a rounded, elliptical bow and 

parabolic stern gradually tapering aft to a point at the 

stern, with a length to beam ratio in the range of 6:1 to 

7:1, exemplified most notably in USS Skipjack (SSN-585) 

built in 1956 (Burcher and Rydill 1994:105–6, Joubert 

2004:17–18) (Figure 14.6). Since such a form calls for 

a constantly varying diameter, even modern builders 

frequently adopt a parallel midbody form to save construction costs and time (Burcher and Rydill 1994:106). 

The Hunley team’s original design, Pioneer, incorporated a parallel midbody with a circular cross section 

(McClintock 1872). The most geometrically ideal shape 

for bodies under pressure is the sphere; however, 

given the spatial limitations imposed, a cylinder is the 

most practical alternative as it experiences relatively 

uniform pressure while providing adequate interior 

space for functional requirements. This concept was 

well known to 19th century engineers, as it lay behind 

nearly every boiler design in use (Wilson 1875:7ff). 

For Hunley, the circular cross section was altered to 

obround in order to add 7.5 in. (19.05 cm) in height, 

but a parallel midbody was retained. This is an early 

example of a longstanding quandary for submarine 

designers—accommodating the needs of the vessel’s 

occupants and functions, while maintaining, as much 

as possible, an efficient hydrodynamic shape. Hunley

was not expected to go to depths requiring significant pressure resistance, which, along with the relatively small scale of the boat, likely contributed to the 

success of this design; an elliptical cross section was 

attempted in the early 20th century and failed due to 

insufficient strength (Friedman 1984:19). 

Other submarines from the period also deviated 

from the ideal (Figure 14.7). Intelligent Whale came 

closest to achieving a cigar-shaped hull, with a constantly varying shape that reflects care and expense 

Figure 14.6. USS Skipjack (SSN-585) utilized a parabolic bow and gradually 

tapering body that is hydrodynamically ideal but costly to produce. (NHHC 

Photo Archives)
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167

Figure 14.7. Relative sizes and shapes of surviving American submarines built in the 1860s. (Diagram by Mari 

Hagemeyer, NHHC)
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168

in its construction. However, in order to incorporate 

its diving bell function, it had a wide, flat bottom at 

midships, and relatively flat sides for a large section 

of the midbody. Submarine Explorer incorporated 

a parallel midbody, with a curved top, but a wide, 

flat bottom and flat, angled sides to accommodate 

several diver access ports. This allowed for maximum 

workspace inside the vessel, but reduced hydrodynamic efficiency. The Louisiana State Museum vessel 

shows the most irregular, almost organic shape, with 

elongated, flat sides that taper gradually over the length 

of the crew compartment, then curves in quickly as it 

heads to the stern. The cross section is shaped like a 

teardrop, with a semicircular top that transitions into 

a deeply plunging V-shaped bottom. This asymmetrical 

design most likely was an attempt to solve the underwater stability issue, increasing the area below the 

center of buoyancy and providing space for ballast as 

low down as possible; however, it must have severely 

increased its drag. It is interesting to note that Lake 

(1918:153) felt the Louisiana State Museum Vessel, 

while seriously over-weighted, “should have been very 

stable . . . and could have been successfully navigated 

had she been properly ballasted.”

The bow and stern also presented a challenge to 

designers of this new type of vessel. Lessons from 

surface ships at the time suggested that a sharp bow 

was best for speed. Adapting that concept to a body 

that was completely submerged seems to have resulted 

in an instinct for cone-shaped ends. Intelligent Whale, 

the Louisiana State Museum vessel, and Pioneer all had 

conical ends. Hunley’s designers, however, learned from 

the experience with Pioneer that the conical ends were 

not ideal for handling underwater, due to severe longitudinal instability (Baird 1902:846). McClintock (1872) 

described their first vessel as “faulty in shape” and 

reported that the second vessel was built with square 

sides “to obtain more room as well as to correct the 

faults of the first Boat.” He also noted that the shift 

to wedge-shaped ends was intended to “make her 

Easy to pass through the water” (McClintock [1871]). 

Time would eventually prove that a rounded cylindrical 

bow would have been more efficient hydrodynamically; however, Hunley’s wedge-shaped design was an 

improvement over the conical ends. The fleet submarines of World War II also used a similarly shaped bow 

as it aided running on the surface, a requirement for 

early long-range subs that needed to recharge their 

batteries by running their diesel engines above water.

While an ideal hull form reduces resistance of a 

vessel’s motion through water from form drag, another 

source of resistance is skin friction drag (Burcher and 

Rydill 1994:104). The best way to reduce this is by minimizing hull surface area, and therefore is somewhat at 

odds with the demands made by the hull form itself; 

however, skin friction can also be reduced by maintaining as smooth a surface as possible and avoiding 

discontinuities (Burcher and Rydill 1994:104). 

Hunley’s designers accomplished this by using countersunk, or flush, rivets. This was not a new idea—iron 

surface ships had been constructed with flush rivets 

as early as the 1840s (Quinn 2010:91). Smith (1861) 

specified use of flush rivets in his call for submarine 

designs, and both Intelligent Whale and Submarine 

Explorer also employed them. They were not frequently needed in boilers, but were used in areas where 

appendages, such as manholes, needed to be attached 

to the outer shell (Shock 1880:144–45; ITC 1902:315). 

As countersinking rivets increases construction time, 

their use represents a conscious design choice. Further 

examination of the deconcreted hull may reveal other 

measures used to smooth the outer plating, such as 

polishing marks or traces of paint.

Another measure for eliminating discontinuities 

was the use of edge-to-edge, or butt, joints. Butt joints 

were very common in boilers of the period, and the 

skills needed to create snug, watertight joints between 

plating would have been well known to Hunley’s 

builders. Early iron shipbuilders tended to use lap joints, 

as they were found to be stronger in the face of the 

rough conditions at sea and required less metal usage 

than their edge-joined counterparts (Claxton 1845:23). 

However, the early submarines were designed for use 

in nearshore environments, where turbulent surface 

conditions were not as much of a concern. With the 

limited hand-power of these early vessels, minimizing 

drag was a more important consideration. 

Of the other submarines of the period, Intelligent 

Whale used butt joints and flush rivets, speaking to the 

designer’s attempt to optimize the vessel for efficient 

movement under water. The plates on the Louisiana 

State Museum vessel were lapped toward the stern and, 

while the rivets were nearly flush, it appeared that this 

was “due to differential corrosion” (Wills 2000:123). Lap 

seams would have been faster to construct, and, given 

its small size and consequent low motive power, might 

not have slowed the vessel significantly. The plates comprising the top shell of Submarine Explorer were lapped 

and double riveted, a robust construction consistent 

with its use as an underwater work platform that did 

not need to move quickly (Delgado 2006:239).

It is important to note that “resistance due to 

appendages no matter how streamlined and carefully 

executed, approaches and may exceed, 50% of the bare 

hull resistance” (Joubert 2004:16 citing Daniel 1983). 

Thus, features such as Hunley’s two conning towers, 

the snorkel box, and the diving planes, which could not 

be omitted from the design, were significant forces of 

resistance to forward motion. No amount of surface 

smoothing could counteract that; nevertheless, the 

designers clearly made an effort to balance the forces of 

drag as much as possible while maintaining functionality.
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169

Materials

Hunley’s hull was made up primarily of 3⁄8 in. 

(9.53 mm) wrought-iron plate. With the nascence of the 

American steel industry just beginning at the outbreak 

of war, iron was still the primary industrial material of 

the 1860s. The physical demands of temperature and 

pressure on boiler shells required both tensile strength 

and ductility, and as few slag inclusions as possible. 

Wrought iron was the best material for the job, and, 

when produced well, boiler plate was the best quality 

iron available. Even plate manufactured specifically for 

ships was considered inferior (Wilson 1875:32). 

Gauges of boiler plate generally ran from 1⁄4 in. 

(0.64 cm) to 11⁄4 in. (3.18 cm) thick (Shock 1880:214). 

Both Pioneer and Pioneer II were constructed of 1⁄4 in. 

(0.64 cm) plate (McClintock 1872). It is not clear 

whether Hunley’s increased thickness was a design 

choice or an issue of materials availability. Thinner plate 

was easier to form into to custom shapes. Thicker plate, 

however, would improve strength, an important consideration for a vessel 33% longer than its prototype; 

however, the overall weight would also increase. This 

weight gain was offset by power attained from the additional crank stations, possibly even resulting in a net 

gain in propulsive efficiency. No accounts survive about 

the characteristics of Pioneer II, which was nearly as 

long as Hunley but with the thinner shell, that might 

shed any light on the builders’ choice of thicker plate. 

A variety of thicknesses are represented in the 

other submarines of the period. The Louisiana State 

Museum vessel was made up of 1⁄4 in. (0.64 cm) plate, 

similar to Pioneer, also built in New Orleans. Given the 

unusual teardrop shape of this vessel, thinner plate may 

have been desired for ease of customization, but would 

also have made the hull lighter. Intelligent Whale was 

made of 1⁄2 in. (1.27 cm) plate (Hitchcock 2002:127), a 

challenging thickness for the complex curvature the 

designers achieved. Submarine Explorer consisted of 

several different plate thicknesses, the thickest (13⁄4 in. 

[4.45 cm]) at the bottom, and the thinnest (1⁄2 in. 

[1.27 cm]) at the top, thus building a low center of 

gravity into the very shell of the vessel itself (Delgado 

2012:190–94).

The Boiler Question

Many secondary accounts of Hunley have repeated 

Alexander’s description of the submarine’s hull being 

built from a cylindrical, riveted boiler that was cut in 

half longitudinally and expanded at the center with a 

strip of iron to increase the height of the vessel. He 

is the only person directly connected on Hunley to 

state this outright. McClintock makes no mention of 

it, and other accounts simply state that it was made 

from boiler iron (Stanton 1914:398, Confederate 

Veteran 1925, Lunz 1957). Gift, when directing his correspondent to envision Hunley, says only “imagine a 

high pressure steam boiler,” but does not assert it was 

actually built from a pre-existing one (Turner 1995:6). 

Baird (1902:845), who helped measure Pioneer after 

its recovery by Union forces in New Orleans, described 

that vessel as being “built of iron cut from old boilers.” 

Recycling plates from a used boiler shell would 

have posed several problems, including the potential 

for weak points, particularly around used rivet holes, 

and inconvenient placement of pre-existing holes for 

access points and other accessories (Figure 14.8). These 

would not have been insurmountable, however, and in 

the face of a shortage of materials, might have been 

worth addressing. Once the hull has been fully deconcreted, it may be possible to determine if the plates 

were recycled by examining evidence such as patched 

Figure 14.8. This flue boiler from Hutton (1897:443) provides an example of 

the number and position of rivets penetrating a typical boiler plate, making 

reuse challenging.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

170

holes, manufacturer’s stamps (if found), tool marks, and 

metallurgical composition.

Boiler construction involved some of the most 

skilled engineers and the highest quality materials 

available at the time. Shells needed to be watertight, 

withstand large amounts of pressure, and maintain 

structural integrity in the face of intense heat and 

intermittent cooling cycles. The many tales of makeshift 

repairs and worn out materials should not obscure 

the fact that the underlying technology was far from 

rudimentary and crude. Successful recycling of such 

materials in the face of wartime shortages should be 

seen as a credit to the engineers’ resourcefulness in a 

time of need rather than a slight to their skills. Several 

additional features of Hunley, discussed further below, 

reflect adaptations of boiler technology. 

Conning Towers

The idea of a raised compartment that offers 

the pilot a forward view both above and below the 

waterline was not a new concept when Hunley was built. 

Early submarine designs such as Bushnell’s Turtle and 

Robert Fulton’s Nautilus included this feature, although 

it is not clear from drawings exactly how they were constructed. The conning towers that survive on Hunley, 

therefore, represent some of the earliest surviving 

examples of what would become one of the most distinguishing features of a submarine. 

Drawings of the original Pioneer show that the pilot 

house was a separate, raised box forward, while the 

access port was an ovoid opening with a lower profile 

aft. The combination of the two features into a single 

component provided higher freeboard for the access 

hatch, helping to prevent water from getting into the 

vessel while the crew entered and exited. It also reduced 

the number of openings, and thereby possible points of 

leakage, in the hull. Both the Louisiana State Museum 

Vessel and Sub Marine Explorer combined the access 

port with the pilot house. Intelligent Whale separated 

them, but both were located close to midships, where 

the vessel was at its widest to accommodate its diving 

bell features (Hitchcock 2002:135). 

William Mazyck described Hunley’s hatches as 

“hinged smoke-stack covers” (Lunz 1957), but Hasker 

noted they were “much the same as a boiler manhole” 

(Fort 1918), from which they were clearly adapted. 

Access for cleaning the interior of boilers was required 

for the longevity and safety of the equipment. They 

were commonly oval-shaped, which allowed for the 

cover to be passed through the hole and fastened on 

the inside of the boiler, a common arrangement to deal 

with the outward pressures being exerted on the cover. 

In addition, to reduce stress on the shell, designers 

aimed for the smallest opening possible that would 

still admit a person. According to mechanical engineer 

Frederic Hutton (1897:416):

Measurements show that the average man 

is fourteen inches on the axis of the longest 

dimension through the articulations of the 

hip-joints with the pelvic bone. The shoulder 

dimension, though naturally larger, is flexible 

and contractile, and any man can pass 

through a hole through which his hips will 

pass. The dimension at right angles to the line 

through the hip-joints is normally less than 

the other, and is a flexible one when it is not 

less. Hence the manhole received an elliptical 

shape with its long axis 14, 15, or 16 inches 

long, and its short axis 9, 10, or 11 inches, or 

four or five inches less than the other.

While Hunley’s hatches are larger than this (roughly 

21 × 15 in. [53.34 × 38.10 cm]), ease of access was likely 

more of a consideration than stress reduction for the 

submarine. Another adaptation for the vessel was the 

orientation of the hatch. Oval hatches were usually 

positioned with the long axis running laterally across 

boilers to minimize strains across the grain on boiler 

plates under pressure (Hutton 1897:418); however, 

on Hunley they were placed longitudinally, likely due 

to space restrictions on the narrow hull, as well as 

being more hydrodynamic. The conning towers on the 

Louisiana State Museum vessel and Sub Marine Explorer

were also oval-shaped, with the same longitudinal orientation as on Hunley, while the designers of Intelligent Whale opted for round, perhaps because it was 

not being used as an access port. 

The glass viewports were likely an adaptation from 

shipbuilding, where watertight openings in the hull 

for light and air had been common features for many 

years. Remnants of similar viewports were found in 

Submarine Explorer’s conning tower, 4 in. (10.16 cm) 

in diameter (Delgado 2006:236). Intelligent Whale’s 

conning tower held four small ports, 4.5 in. (11.43 cm) 

in diameter (Hitchcock 2002:131–33). The similarity in 

size may reflect some level of standardization present 

in the shipbuilding industry.

Of the three other surviving submarines, all had 

only a single conning tower, located at or near midships. 

The double conning tower design of Hunley, while 

increasing drag, was a necessary accommodation to 

improve ease of access for the greater number of men 

aboard. Only Sub Marine Explorer had a comparable 

crew capacity. This vessel had a much larger conning 

tower (5 ft. [1.52 m] on its long axis), facilitating loading 

of both men and gear, as well as housing piping for the 

interior pressurized chamber. In addition, in case of 

emergency, the access ports in the bottom could be 

used for emergency egress in most cases. 
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171

On Hunley, two triangular sheets of wrought iron, 

dubbed cutwaters, were attached to the forward face 

of each conning tower, tapering down forward. They 

were most likely added to prevent fouling of the 

conning towers and their viewports. This feature does 

not appear in either drawing of Pioneer, suggesting it 

was developed in response to situations experienced in 

the field. The use of a towed torpedo may have posed 

an additional fouling risk. None of the three other 

surviving submarines of the period show evidence of 

such a feature. The diving bell submarines may have 

relied on divers for their anti-fouling needs. 

Keel

As discussed above, the main method for keeping 

a submarine upright in the water column is to keep the 

center of gravity low. Even today, submarines are built 

with the heaviest materials as low down as possible in 

the hull, and often additional ballast is needed to attain 

proper trim (Burcher and Rydill 1994:40–42). Hunley’s 

builders created a system of cast-iron weights that fit 

together along the underside of the hull to resemble 

a keel. As such, it is not a structural element like a traditional keel, but primarily functions as ballast. The 

estimated total weight of all eight keel blocks is roughly 

2,740 lb. (1.37 tn.; 1243 kg), providing substantial transverse righting action, particularly at the surface, where 

wave action could have been problematic. The external 

placement kept the weight as low down as possible, and 

provided several added benefits: it maximized interior 

space for crew activities; it provided a stable, flat 

platform for transporting or working on the submarine 

out of the water; and it allowed for the weights to be 

dropped from the hull in case of emergency. 

The concept of releasable external weights can 

be found as early as Turtle, which carried a 200 lb. 

(91.72 kg) lead weight on a 40–50 ft. (12.19–15.24 m) 

line that could be dropped by the pilot, enabling him 

“to rise instantly to the surface, in case of accident” 

(Bushnell 1799:304). McClintock and Watson also hit 

upon this type of safety mechanism early on, as Baird 

(1902:846) reports that Pioneer’s keel, which was made 

up of five lengths of railroad iron, was detachable from 

inside. The concept was carried over into Hunley, which 

was equipped with a system of T-headed bolts that could 

be unscrewed by the men at the cranks (Alexander 

1902b:165–66). There are, however, no accounts of 

the feature being used successfully. Based on examination after the second sinking, it was noted “[t]hey 

tried to release the iron keel ballast, but did not turn 

the keys quite far enough, therefore failed” (Alexander 

1902b:169). Drawings showing three levers in the floor 

of the submarine, attested archaeologically, may indicate 

there was an attempt to improve the release mechanisms after this incident. The irregularities in shape of 

some of the keel blocks may reflect the insertion of new 

castings to accommodate new release levers.

The main drawback of an external, flat-bottomed keel is the addition of drag (Burcher and Rydill 

1994:107). The castings on Hunley reflect an effort to 

make it as streamlined as possible, with the fore and 

aft blocks molded with a smooth, rounded taper. This 

would have been an improvement over the more rudimentary, rectangular keel on Pioneer. 

Hunley’s keel system was unique among its contemporaries. The Louisiana State Museum vessel, the 

only other closed-capsule submarine, has only a small 

internal keel, approximately 1 × 2 in. (2.54 × 5.08 cm), 

which seems to have functioned more as a traditional 

framing element and did not provide a significant 

source of weight (Wills 2000:122). The vessel appears 

to have relied on the teardrop hull shape to lower its 

center of gravity. As a diving bell submarine, Sub Marine 

Explorer was entirely flat on the bottom, incorporating a 

single cast-iron keel plate 1.75 in. (4.45 cm) thick, with 

a maximum length of 34.4 ft. (10.49 m) and maximum 

breadth of 8 ft. (2.44 m) (Delgado 2006:235, 238). By 

using very thick plating at the base, the builders were 

able keep the center of gravity low while maximizing 

area available for diver hatches. 

The closest comparison to Hunley’s design was 

Intelligent Whale, which did have a central, keel-like 

piece, 12 in. (30.48 cm) sided and 4 in. (10.16 cm) 

molded, that ran a length of 9 ft. (2.74 m) along the centerline between its two diver access ports (Hitchcock 

2002:122). There were also two 8 ft. (2.44 m) long longitudinal skids, 4 in. (10.16 cm) square, outside the two 

access ports (Hitchcock 2002:123). They were incorporated into the bottom plate, possibly as a single casting, 

and provided much needed basal weight as well as 

a platform to help stabilize it on land. The elements 

were not detachable, and with three separate protruding elements, the drag would have been increased 

significantly.

Diving Planes 

One of the challenges early submarine designers 

faced was controlling the vessel’s position along the 

z axis. Many designers turned to inspiration from fish 

and marine mammals and, in the case of Hunley, they 

chose to develop a horizontal control surface mimicking 

the functionality of pectoral fins (Alexander 1903:746). 

As this was not a feature surface ships had to contend 

with, there was little by way of precedents for deciding 

on a fin shape and position, or even what to call it. 

The different names applied in the various eyewitness accounts attest to the novelty of the feature—

fins (Alexander 1902a, Fort 1918, Lunz 1957), wings 
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172

(McClintock 1872), vanes (Baird 1902:845), blades 

(Alexander 1903), flanges (Stanton 1914), and hydroplanes (Lake 1918).

 Modern studies have determined that these 

control surfaces, or diving planes, are best positioned 

toward the bow, forward of the neutral point, at low 

speeds (below approximately 2 knots) and at the stern 

for faster speeds (Burcher and Rydill 1994:168–69). 

Early designers were forced to experiment, taking 

into consideration hull shape, interior configuration 

for control mechanisms, and the functional needs 

of the vessel. Hunley’s designers chose 6.5 ft. (2 m) 

long, narrow blades that were mounted just aft of the 

forward conning tower. Given the speeds achieved by 

Hunley, this placement was probably ideal for handling, 

though it meant the transverse rod around which they 

pivoted obstructed easy access to the crank stations 

from the forward conning tower (Fort 1918:459). The 

planes were mounted asymmetrically, with the portion 

aft of the pivot point roughly 11 in. (28 cm) longer than 

the forward section. This appears to have been an intentional design choice, since the planes are depicted with 

an exaggerated asymmetry on the Royal Navy sketch 

from the meeting with McClintock. The proximal edge 

of the planes follows the outline of the hull as it narrows 

forward of the axis and the fore and aft exterior corners 

are rounded, suggesting an attempt to make them more 

streamlined for smooth running.

This was a shift from Pioneer, which, based on 

both historical sketches, had relatively short diving 

planes, mounted along the leading edge. They are also 

depicted as having been mounted low down on the 

body rather than at the central axis, where they would 

have provided equal benefit while diving and rising 

(Burcher and Rydill 1994:179–80). Given the difficulties in control caused by the conical ends, the designers 

may have decided that, in addition to the change in hull 

shape for Pioneer II, longer diving planes placed higher 

up would improve control. The trailing edges on Pioneer

appear to have been squared off, or nearly so, which 

may indicate they were inefficient, since the corners 

were rounded off on Hunley.

Of the three other surviving submarines of this 

period, two utilized horizontal control surfaces, while 

the third, Sub Marine Explorer, relied solely on its 

ballast tanks for vertical positioning (Delgado 2012:195). 

The Louisiana State Museum vessel had two roughly 

semicircular diving planes that rotated around a central 

shaft positioned in the forward third of the vessel (Wills 

2000:152). Intelligent Whale incorporated diving planes 

into the stern assembly, where they were placed perpendicular to the rudder just forward of the propeller, 

with the leading edge mounted on a horizontal shaft 

passing through the stern ballast tank, and the proximal 

edge tapered to follow the curve of the hull (Hitchcock 

2002:164–67). The wide variety of shapes and positions 

represented in these three vessels attests to the difficulties designers faced in optimizing their vessels for the 

undersea environment.

One additional feature found on both Pioneer and 

Hunley was a fin-like projection mounted to the hull 

in front of the planes. These prevented fouling of the 

blades in a similar fashion to a skeg on a rudder. The 

diving planes on Intelligent Whale were also equipped 

with similar protective fins (Hitchcock 2002:167). They 

do not appear in any of the sketches of Hunley, which 

tended to highlight the components directly involved 

in submarine operations. Smaller, utilitarian features 

such as these skegs reflect the more practical adjustments designers made based on their experience with 

the operation of their craft.

Overall, Hunley’s diving planes were a precursor to 

the control surfaces still in use on submarines today; 

however, they had not yet reached their optimal form. 

McClintock reportedly “found that, in practice, he got 

better results by placing the ‘pectoral’ vanes near the 

center of displacement; that his purpose was as well, 

and easier served, by sinking or rising bodily on an 

even keel as by diving” (Baird 1902:847). Alexander 

(1902c:86) also noted it was easier to surface by 

expelling water ballast rather than by elevating the 

diving planes. Their length in relation to the total length 

of the hull may have exceeded requirement, doubtless 

increasing drag and perhaps making handling difficult, 

as just a small shift in the control rod shaft would have 

led to a significant change in plane application. This sensitivity may have been a contributing factor in Hunley’s 

first sinking, as one report claimed that it was caused by 

the pilot stepping on the diving plane control lever (Fort 

1918:459). The planes were also less important once 

the vessel was refitted with a spar mounted torpedo 

and no longer expected to dive below enemy ships.

Bow and Stern Casting Holes

The 2 in. (5 cm) diameter hole in the upper 

portion of the bow casting may have been used as an 

attachment point to secure a mooring or tow line. A 

similar hole exists in the aft casting and was depicted 

in Chapman’s painting. Neither hole is mentioned in 

textual accounts of Hunley, although we know that 

it was frequently towed (ORN 1.15: 334–35). In the 

drawing from McClintock’s meeting with the Admiralty, 

there is a small circle depicted in the bow casting that 

most likely represents this hole, but there was no label 

or explanatory text. 

Most other submarines from the period had 

sturdy brackets, or rigging eyes, riveted to the top of 

the hull that could function as a tow or mooring point. 

The Louisiana State Museum Vessel was equipped 

with two rigging eyes, one toward the bow and the 
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173

other toward the stern. They were made up of 30 in. 

(76.20 cm) lengths of iron strap, bent at the halfway 

point to form a semcircular eye 1.5 in. (3.81 cm) in 

diameter, bolted to the hull plating along the longitudinal centerline (Wills 2000:134). The eye section was 

deliberately smoothed and rounded to prevent damage 

to lines (Willis 2000:134).

Intelligent Whale has a 6.5 in. (16.51 cm) diameter 

ring affixed to the tip of the nose cone, as well as a 

rigging eye, made up of a 12 in. (30.48 cm) iron strap 

bent to form a 3 in. (7.62 cm) eye in the center, riveted 

to the top along the longitudinal centerline of the hull, 

between the second and third frames aft (Hitchcock 

2002:137–40). A similar piece may have been present 

toward the bow, based on surviving penetrations in the 

plating. Hitchcock points out that the piece was “most 

likely used for mooring purposes and was not intended 

as a lifting point, as the rivets would not [have] been 

able to support the weight of the vessel” (Hitchcock 

2002:140). Sub Marine Explorer had four iron rings, 6 in. 

(15.24 cm) in diameter, mounted in brackets at the top 

of the bow and stern quarters (Delgado 2012:194). 

As with Intelligent Whale, these rigging points do not 

appear to have been strong enough to lift the vessel out 

of the water, so must have been limited to mooring and 

possibly towing functions (Delgado 2012:194).

A rigging eye similar to the ones on Intelligent Whale and the Louisiana State Museum vessel 

appears in Stauffer’s sketch of Pioneer and was labeled 

“Fastening for Towline.” There is no evidence for such 

hardware on Hunley, although this cannot be confirmed 

until deconcretion is complete. However, there are 

also no signs of rigging eyes in the Chapman painting, 

suggesting this feature was deliberately omitted by 

Hunley’s builders. If so, it may have been an attempt to 

minimize snag hazards or reduce drag. Since cast iron 

was generally more brittle than wrought iron, it seems 

risky to have incorporated a function so high in tensile 

stress into the body of the vessel itself. Also, securing 

a tow line so far from where the crew could reach is 

not practical; however, the loss of Pioneer II during a 

tow with no hands aboard, suggests the submarine was 

towed empty, in which case a line at the bow would not 

have been problematic.

Two iron shackles were recovered from near the 

bow and were most likely part of the hardware used for 

an upper boom that functioned as part of the weapons 

system (discussed below). The Chapman painting shows 

two pieces apparently affixing the boom to the bow 

casting (Figure 14.9). The remains of a second hole is 

visible along the eroded remains of the leading edge 

of the bow casting. Further analysis after deconcretion 

may be able to determine if one or both holes were 

part of the original casting or if they were added later. 

If inherent to the casting, it is possible that the hole was 

designed as a rigging element and later coopted into 

service for the new spar torpedo system. 

Propeller and Shroud

Alexander (1902a) stated that Hunley was equipped 

with an “ordinary propeller”—in this case, a threebladed, cast-iron screw propeller roughly 27 in. (69 cm) 

in diameter. While there was much experimentation in 

propeller design during this period, most of that was 

in relation to large vessels with steam engines that 

induced a good deal of strain on the propeller, joints, 

and shaft. For smaller vessels, a three-bladed propeller 

was very common (Peabody 1912:84). 

All of the comparable surviving vessels of the 

period also had a single axially-mounted screw propeller 

at the stern. The Louisiana State Museum vessel, Sub 

Marine Explorer, and Pioneer all had four-bladed propellers, while Intelligent Whale had three (Table 14.1). 

The fact that Hunley’s designers reduced the number of 

blades from Pioneer suggests there was an advantage 

to such a change, although the complexity of factors 

influencing propeller design, including blade area, pitch, 

and position relative to the hull, make it difficult to 

speculate what improvement was achieved. Analysis 

currently being undertaken at WLCC in conjunction 

with the University of Michigan’s Naval Architecture and 

Marine Engineering department may provide insights 

into this question.

Hunley’s propeller was surrounded by a metal ring, 

or shroud, which according to Alexander (1902b:166) 

served to protect the blades from snagging, as well 

as from damage if struck by passing debris or underwater obstruction. A note on the Royal Navy sketch 

from the meeting with McClintock (1872) indicates the 

ring also helped “prevent the disturbance of the Water 

Figure 14.9. Two iron brackets recovered from the site 

most likely correspond to bow hardware depicted in 

Chapman’s painting. Based on the painting, additional 

hardware may have been affixed to the leading edge of 

the bow (Diagram by H. G. Brown, NHHC. Inset: detail 

from H. L. Hunley by Conrad Wise Chapman, courtesy 

of the Museum of the Confederacy, Richmond, Virginia)
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174

from being seen, should the boat be working near the 

surface.” In addition to the shroud itself, there were 

also two additional metal bars that extended from the 

sides of the shroud back to the hull, connecting at the 

top of the expansion strake that would guide loose 

objects away from the shroud and the suction at the 

propeller. These may also have protected the shroud 

from damage and stabilized it during operation, if the 

sides were subjected to torque under the hydrodynamic 

forces of the propeller action.

The designers of Intelligent Whale took similar precautions by surrounding the propeller with a sort of 

protective iron cage or basket (Hitchcock 2002:140). No 

such accessory survives on the Louisiana State Museum 

vessel, but there was much damage to the propeller 

area before the vessel was documented. Drawings of 

Sub Marine Explorer also do not include any similar 

feature; however, the relatively wide stern and the 

proximity of the propeller to the hull may have afforded 

sufficient protection from damage, and the ability of 

divers to exit the hull while submerged allowed for the 

clearance of snags without surfacing.

The drawings of Pioneer show no shroud around 

its propeller, suggesting that the feature was added to 

Hunley based on experience. It is possible that the twin 

steering rods on Pioneer provided some level of protection from snagging. The long, sharply tapered ends 

of both vessels left the propeller relatively exposed 

compared to vessels such as Sub Marine Explorer.

Rudder

The rudder was the least well-documented of 

Hunley’s exterior features. In most diagrams, even 

those by McClintock and Alexander, the rudder was 

depicted with a height to length ratio of approximately 

4.2:1. Only Chapman’s painting and sketch come close 

to capturing its true ratio of 1.5:1. This may be indicative of the relatively small consideration they gave 

to rudder design. The simplicity of a flat, rectilinear 

piece of metal must have remained unquestioned, as 

no special mention was made in any narrative of its 

design features. While this period saw the advent of 

balanced rudders on naval vessels such as USS Monitor, 

such innovation, designed to reduce the stresses on the 

steering gear, was primarily focused on large steampowered ships (Thearle 1877:368–70). The simple 

unbalanced rudder, mounted along the leading edge, 

was sufficient for the speeds achieved by Hunley.

No rudder has survived intact on any of the archaeologically comparable vessels, no doubt a consequence 

of the vulnerability of the exposed position. Based on 

historical sources and archaeological evidence, Intelligent Whale had a rudder mounted below the hull, 

forward of the propeller, mounted to a shaft that penetrated the hull vertically, so the cable and pulley system 

that controlled it could be situated inside the vessel 

(Hitchcock 2002:129, 161–64). Such a position would 

also provide some protection to the rudder by the hull 

itself and the propeller cage, located aft of the rudder. 

The Louisiana State Museum vessel had two small, 

roughly semicircular rudders, one at the bow and one 

at the stern, mounted along the centerline low down 

below the level of the propeller, just above the keel 

(Wills 2000:119). Such a design is reminiscent of a fish’s 

pelvic and anal fins, and shows a shift in concept away 

from surface ship design. Such placement also left the 

rudders vulnerable to damage from below, although 

this might not have been a large concern in the relatively even, muddy bottom of Lake Pontchartrain.

The rudder on Sub Marine Explorer was lost but 

archaeological evidence shows that it was controlled 

using cables connected to a yoke (Delgado 2012:198–

99). Based on historical records, the original intent 

was to use James Cathcart’s design of a propeller that 

rotated on a universal joint instead of a true rudder, but 

this apparently did not work well, and was replaced 

(Delgado 2012:196–98). The new rudder was mounted 

aft of the propeller on fixed brackets extending aft 

above and below the propeller, and was controlled by 

two horizontal steering rods to port and starboard of 

the centerline connected to a yoke on top of the rudder 

shaft (Delgado 2012:199). Thus this rudder is most 

Table 14.1. Comparison of Early Submarine Propellers

Vessel

No. of 

blades

Prop. 

Diam. (in.)

Vessel Max. 

Breadth (in.)

Pioneer 4 n/a 48

Hunley 3 27 43

Louisiana State Museum Vessel 4 36 38.5

Intelligent Whale 3 40 87

Sub Marine Explorer 4 42 120

Sources: Hitchcock 2002:161; Wills 2000:142; Delgado 2013:199
H U L L A N A LY S I S

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similar to that of Hunley, although the dual steering 

arm configuration is actually closer to Pioneer’s design.

Hunley’s horizontal, single-shaft rudder control 

mechanism was unique among the vessels compared. 

A steering shaft penetrated the stern casting just above 

the upper propeller mounting bracket, extending aft of 

the propeller to the top of the rudder. Based on both 

the Chapman sketch and the McClintock drawing, the 

steering rod resolved into a ball joint connected to a 

vertical metal arm that descended aft of the rudder, 

which in turn reached an additional joint that was 

attached to a pair of parallel horizontal arms that 

joined together through a horizontal slot roughly in 

the center of the rudder (Figure 14.10). These paired 

arms were preserved, concreted to the rudder itself, but 

the remaining hardware is missing, with the possible 

exception of one concretion (HL-0683), found near the 

stern and similar in shape to the preserved arms. It is 

interesting to note that there appears to be an error in 

Chapman’s painting at this point, namely the presence 

of an additional metal arm that is depicted running 

from the central joint to the bottom of the rudder, a 

piece that does not appear in his original sketch for the 

painting and does not make sense mechanically. 

Hunley’s complex rudder mechanism was an 

evolution from Pioneer, which had two parallel steering 

rods extending from the top of the hull meeting at 

a yoke mounted to the top of the rudder shaft. The 

conical shape of Pioneer necessitated the exposure 

of a significant length of the steering rods in order to 

position the rudder aft of the propeller, increasing the 

risk of damage. The dual rod system, while simpler to 

design, was more vulnerable to damage.

Rudder position is also an important factor in propulsion efficiency. It has been noted that “[m]ounting 

forward of the propeller produces a noise-producing 

wake from each control surface, affecting smooth 

propeller behavior” (Joubert 2004:31). In both Hunley

and Pioneer, the rudder was mounted aft of the 

propeller, the ideal position for that component. Only 

Sub Marine Explorer had a similar position for its rudder, 

and only after the original propeller design failed. The 

other two contemporary submarines mounted the 

rudders closer to the hull, reducing exposure of the 

blade itself as well as its control components. In the 

case of Intelligent Whale, with only a single rudder 

blade below and forward of the propeller, propulsion 

may have been adversely affected. For the Hunley team, 

the risk of placing the rudder outside of the protected 

lee of the stern area must have been outweighed by the 

gains in performance.

Snorkel Box

A method for replenishing air inside the vessel 

while submerged was a new feature that could not 

simply be adapted from known naval architecture or 

Figure 14.10. This sketch by Conrad Wise Chapman shows Hunley with the forward hatch removed and possibly smoke 

coming from the aft hatch that may represent the submarine being cleaned and refitted after the second sinking. 

This is the clearest depiction of the rudder assembly that has been found. (Sketch of of H. L. Hunley, V.41.49.190, The 

Chapman Collection, The Valentine, Richmond, Virginia)
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boiler features. One solution was a floating hose that 

ran from submarine to surface, as attested by an 1861 

defense directive issued after a failed submarine attack 

on USS Minnesota in Hampton Roads: “Or should it pass 

outside the net, the tube which floats on the surface 

to supply the inmates with air would be caught on the 

A spars and the supply of fresh air cut off, causing suffocation” (ORN 1.6:393). A short iron stack survives 

on top of the Louisiana State Museum vessel forward 

of the hatch, which may have been part of a floating 

hose system, possibly aided by some sort of bellows 

device to draw in air (Wills 2000:161–62). Intelligent 

Whale may have used this system in addition to the 

compressed air it carried for its diving bell function 

(Hitchcock 2002:155). Sub Marine Explorer also had 

the benefit of compressed air, but, beyond that, had a 

pump to spray a mist of sea water that was intended 

to purify the air on the principal that the water would 

absorb the “carbonic acid gas” in the cabin and release 

the oxygen it contained (Delgado 2012:203–4). 

The drawing of Pioneer in Shock’s letter shows 

two compartments, between the crew section and 

ballast tanks, identified as being for compressed air. 

This contradicts Baird’s (1902:846) account in which 

he claims McClintock reported the occupants “might 

have remained several hours under water without being 

seriously inconvenienced and without any storage of 

air.” It is possible compartments were initially built for 

compressed air, but were found to be unnecessary or 

unworkable. No other means of providing external air 

is visible in the surviving drawings of Pioneer. 

By the time Hunley was built, the design team had 

incorporated two iron pipes, or snorkels, that could be 

raised and lowered from inside while submerged, to 

introduce fresh air from the surface. Instead of having 

the pipes laterally penetrate the hull plates and cross 

the crew compartment, a raised box was installed just 

aft of the forward conning tower, where they would 

not interfere with interior access while remaining close 

to the pilot’s station. The snorkels could either lie flat 

against the hull or be positioned vertically to allow the 

exchange of fresh air into the crew compartment while 

the submarine operated just below the water’s surface. 

If McClintock’s claim that no additional air was needed 

in Pioneer, the system may have been added to combat 

the air consumption of a much increased crew complement combined with the longer running distances 

required for an attack upon the blockade.

Alexander included the feature in his drawing for 

the Navy, labeled “air box,” although he positioned it 

erroneously midway between the two conning towers. 

The air system was omitted from Lake’s drawing 

(1899), Baird’s drawing (1902), and, most importantly, 

McClintock’s drawing (1872) and description ([1871]), 

suggesting that the snorkel system was a late addition to 

the design, developed after McClintock’s close involvement with the project. Alexander made no mention in 

his account of how well the system worked in practice.

 The two snorkel tubes were recovered from the 

site, and found to be roughly 5 ft. (1.52 m) in length and 

threaded at both ends. This accords with both Alexander 

(1902b:166) and Hasker (Fort 1918:459), who both 

stated they were 4 ft. (1.22 m) long. However, at least 

two eyewitness accounts estimated their length at 10 ft. 

(3.05 m): Gift, who encountered the boat in Mobile 

(Turner 1995:7), and Mazyck, who saw the boat when 

it first arrived in Charleston (Lunz 1957). This suggests 

that longer tubes may have been used originally. Since 

both ends were threaded, the design team may simply 

have coupled two lengths of pipe, as they did later with 

the spar. Baird (1902:847) stated “the boat was easily 

managed under water, and, when submerged 10 feet 

[3.05 m], she was not sensibly affected by the surface.” 

Thus snorkel tubes that allowed ventilation at this depth 

may have seemed ideal in theory, but not in practice. It 

is tempting to infer that the tubes were shortened after 

Beauregard required the boat to be used at the surface 

rather than submerging it (see Chapter 2). However, as 

Hasker’s account from August 1863 predates that order, 

the shorter tubes appear to have been in use soon after 

the vessel reached Charleston. The crew may have 

found that running at a depth of 10 ft. (3.05 m) was 

not necessary in Charleston Harbor, or perhaps, as with 

other aspects of the vessel, the longer tubes were more 

of a potential snag hazard than a benefit. Nevertheless, 

the fact that the short tubes were found with Hunley

seems to indicate that the air system was not entirely 

abandoned and that, despite his orders to remain at the 

surface, Dixon kept the tubes ready for at least shallow 

submergence in case of emergency.

Weapon System

Delivering a killing blow from beneath the surface 

in a closed-capsule submarine was a challenge that 

often seemed easy to solve on paper, yet proved 

very difficult in practice. Problems with successful 

execution hindered the willingness of naval authorities to accept submarines as a viable weapon of war 

for many decades. The earliest offensive strategy for 

underwater boats, such as that of Cornelis Drebbel, may 

have depended on boring through an enemy hull from 

below causing it to take on water and sink (Mersenne 

1644:208), although others interpret original accounts 

to construe an explosive ram (Harris 1997:11). Bushnell’s Turtle was designed to allow men to screw a keg 

of black powder with a timed detonator to an enemy’s 

hull without opening or leaving the submarine. Due to 

copper sheathing, strong currents, and other factors, 

operators repeatedly failed at this task, and use of the 

submarine was discontinued (Bushnell 1799). Fulton’s 
H U L L A N A LY S I S

177

original design for Nautilus involved positioning the 

submarine beneath the enemy vessel and driving 

a metal spike with an eye into the hull; as Nautilus

pulled away, a rope, threaded through the eye, would 

drag a torpedo against the ship, which would explode 

on contact (Parsons 1922:26–27). In a later report, 

however, Fulton says the submarine vessel was not 

intended to “go under or near the vessels which are 

to be attacked,” but rather should be used to approach 

an enemy anchorage secretly and “there anchor her 

cargo of submarine bombs under water, or leave them 

to the tide, or use them in any other way which time 

and practice may point out” (Parsons 1922:67). This 

suggests that his original delivery method proved less 

than successful.

According to Baird (1902:845), Pioneer was 

designed to carry a torpedo “of the clock-work type” 

that would be affixed to an enemy hull using screws 

that were “gimlet pointed and tempered steel,” similar 

to Bushnell’s strategy. Surviving sketches show a rack 

designed to carry the torpedo on top of the vessel, 

aft of the pilot station and forward of the entry hatch. 

McClintock reportedly completed several successful 

tests, blowing up “a small schooner and several rafts” 

(Baird 1902:845); however, surviving accounts have 

little to say about the performance of this weapon 

system. As it was subsequently abandoned by the 

design team, it was most likely found to be impractical.

A new design was adopted for Pioneer II and, subsequently, Hunley, which called for the submarine 

to tow a torpedo. The submarine would submerge 

and dive under the enemy ship, trailing the floating 

torpedo behind. The latter would make contact with 

the hull of the target and explode, while leaving the 

submarine unimpaired on the opposite side of the 

enemy vessel and protected from the explosion. There 

is very little extant information regarding the specifics 

of the torpedo’s design, such as where the tow line was 

attached, or how it was deployed, though Alexander 

(1902b:166–67) recalled that it “was a copper cylinder 

holding a charge of ninety pounds of explosive, with 

percussion and friction primer mechanism, set off by 

flaring triggers . . . [towed] with a line 200 feet [61 m] 

after her.” Based on the inaccuracy of many other 

dimensions in his account, however, these details 

are suspect. Gift, who witnessed a practice run in 

Charleston, noted “[b]ehind the boat at a distance of 

100 to 150 feet [30–45 m] is towed a plank and under 

that plank is attached a torpedo” (Turner 1995:7). In 

trials, the towed method successfully sank several 

test targets without injury to the submarine (Maury 

1894:79, Alexander 1902c:83). However, problems with 

the towed torpedo were manifest during early trials in 

Charleston. The fault apparently lay with the maneuvering speed of the submarine and the strong currents. 

Tomb reported that the last time his vessel towed 

Hunley with its trailing torpedo they were at risk when 

the “torpedo got foul of us and came near blowing up 

both boats before we got it clear of the bottom, where 

it had drifted” (ORN 1.15:335). Alexander (1902b:167) 

noted that “in rough water the torpedo was continually 

coming too near the wrong boat.” 

In Hunley’s last months of service the weapon 

system was changed to a spar torpedo. This change was 

at the direct order of General Beauregard (1878:154), 

who, after Hunley’s second tragic sinking, ordered it to 

be used as a semi-submersible rather than a submarine 

and to be fitted with a “Lee spar torpedo,” in a similar 

fashion to CSS David (see Chapter 2). Beauregard 

was a strong supporter of the use of mines and spar 

torpedoes, developed by a member of his staff, Captain 

Francis D. Lee, that were deployed by steam-powered 

small craft, such as the semi-submersible David and the 

more traditional surface-running CSS Squib types.

Prior to the discovery of Hunley’s torpedo spar, 

many thought it was attached to the upper bow. This 

configuration was shown in Lake’s (1899) drawing, 

and can be mistakenly interpreted from the Chapman 

painting, since it shows a short spar or boom attached 

to the top of the bow and nothing extending from the 

bottom. Models and illustrations produced prior to 

the excavation continued to amplify this interpretation. However, makers of the 1999 TNT-produced movie 

“Hunley” accurately positioned the torpedo spar when 

trials of the full-sized replica made it apparent that the 

lower spar configuration was the only workable method 

of deployment (Neyland 2007).

The question was put to rest when the torpedo 

spar was recovered with Hunley in 2000. It comprised 

three separate parts that combined into an overall 

length of approximately 16 ft. (4.9 m). The majority 

of the spar was made up of two lengths of seamed, 

rolled wrought-iron pipe, joined by a coupling, bolted 

to a solid cast-iron section (see Chapter 12). One end 

of the cast-iron section fit over a tang mounted to the 

bottom of the bow, where it was attached with a single, 

horizontal threaded bolt, allowing the spar to pivot up 

and down as needed. 

This arrangement is similar to that described in 

other accounts of spar torpedoes used by the Confederacy. David’s spar was reportedly 14 ft. (4.27 m) long, 

3 in. (7.62 cm) in diameter, and made from a boiler tube 

(Glassell 1877:230, Tomb 1914:168). An officer on the 

surface vessel CSS Palmetto State reported that its spar 

torpedo extended 20 ft. (6.10 m) from the stem and 

pivoted upon a “gooseneck” (Parker 1985:327). This 

length was typical for the surface torpedo boats being 

put into service in Charleston at this time (Campbell 

2000:37). The hollow section of Hunley’s spar was likely 

also made of lengths of boiler tube, as its diameter of 

5.68 cm (2.24 in.) is consistent with dimensions of fire 

tubes from naval boilers of the period (Figure 14.11). 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

178

On the forward end was fastened a long 

steel spar 15 to 20 feet [4.57–6.10 m] long. 

This was stayed to the boat with iron stays. 

On the end of this spar, the torpedo was 

carried by means of a hook. On the deck of 

the boat, just forward of the forward hatch 

was a reel carrying a steel cable. The distal 

end of the cable was attached to the trigger 

of the torpedo. The proximal end, in some 

manner ran through the deck so that the 

torpedo could be operated from the inside 

(Lunz 1957).

 Just such a reel or windlass is visible on the 

Chapman painting, although positioned aft of the 

forward conning tower, and likely served only to control 

the spar position, rather than for detonation. While the 

exact method of detonating the torpedo has not been 

determined, if a lanyard-activated trigger was used, 

it is not likely to have been wrapped around a spool, 

which could delay the transmission of force through 

the line. The reel’s position aft of the conning tower 

may indicate it had originally been related to the towed 

torpedo system. 

Of the known spar diameters, Hunley’s is the smallest, 

perhaps to reduce weight at the bow or limit drag by 

lowering surface area. A lighter spar was also desirable 

for reducing strain on the spar rigging. 

Very little survives archaeologically of the rigging 

that controlled Hunley’s spar. On Palmetto State, an 

iron davit was used to raise and lower the spar so the 

torpedo could be carried above the waterline until 

needed (Parker 1985:327). CSS David was equipped 

with a windlass and lines that allowed the raising and 

lowering of the spar from the safety of inside (Campbell 

2000:66). The CSS Squib torpedo vessel type also 

mounted a spar with a gooseneck arrangement that 

was adjusted with a line passing over a sheave on top 

of the stem to a winch inside the boat’s cuddy (ORN 

1.9:601). This design would have been beneficial in both 

protecting the torpedo until it was ready for use in an 

attack and for removal and installation at berth.

Witnesses described a similar arrangement 

for Hunley. McLaurin observed “[t]he torpedo was 

fasteened [sic] to the end of an iron pipe . . . which 

could be extended in front and withdrawn with ease by 

guides in the center of the boat to hold it in place” (Confederate Veteran 1925). Mazyck described it as follows: 

Figure 14.11. Diameters of fire tubes from marine boilers, in blue (Isherwood 1865), 

compared to known spar diameters, in red (Tomb 1914:168; ORN 1.19:631; ORN 2.2:688).
H U L L A N A LY S I S

179

Images of David show rigging points located 

approximately half to two-thirds of the way along the 

spar. Lee’s sketch of a proposed triple torpedo mount 

shows the rigging points at the distal end of the spar 

(Figure 14.12). No definitive rigging points have been 

found on Hunley’s spar, but there are several areas of 

loss in the last meter (3.28 ft.), which could correspond 

to points where hardware was once attached. If the 

cable reported by Mazyck was part of the spar rigging, 

his association of it with the torpedo suggests that the 

rigging points were near the end of the spar. Once the 

hull has been fully deconcreted, fittings for spar control 

may be discovered inside Hunley.

One additional component of the spar system was 

a short spar or boom at the top of the bow, as shown in 

the Chapman painting, allowing for better leverage and 

stability in managing the spar. This would likely have had 

some sort of sheave or roller for rigging lines to pass 

over smoothly. Two D-shaped metal brackets (HL-0526 

and HL-0582) were found near the bow, which may have 

served to secure the boom to the bow. The arm of one 

bracket is bent, suggesting that the boom may have been 

torn off during or after the explosion (see Chapter 15).

Preserved at the extremity of the spar is a portion 

of the torpedo itself, in the form of a segment of 

copper sheathing wrapped around the spar and fixed 

in place with a bolt. Contrary to popular stories of 

Hunley embedding a barbed spear into Housatonic’s 

hull and backing away to detonate with a lanyard, this 

evidence proves that the torpedo exploded directly 

against the hull. Several successful contact fuses had 

been developed during the war that would have been 

reliable alternatives to a manually-triggered system. 

Even Hunley’s towed torpedo could have been contact 

fused as well, despite accounts to the contrary (Turner 

1995:7), and may explain Tomb’s and Dixon’s fear of the 

torpedo floating into their vessels.

There were two main types of contact fuses utilized 

for spar torpedoes developed in Charleston. One was 

based on a sensitive primer developed by General 

Gabriel Rains using a compound of potassium chlorate, 

antimony trisulfide, and powdered glass that would 

detonate with 7 lb. (3.18 kg) of mechanical pressure 

(Schafer 1996:75–76). Impact with the side of a hull 

would depress a plunger against a thin copper cap 

against the primer, which would ignite the magazine of 

black powder (Barnes 1869:124). Captain Lee helped 

develop a highly successful chemical fuse, based on 

a design by Moritz Hermann Jacobi and utilized by 

the Russians in the Crimean War (Tucker 2006:257). 

Lee’s fuse consisted of a lead, or, later, brass tube containing a hermetically sealed glass vial of sulfuric acid. 

Packed around the vial within the tube was a mixture 

of potassium chlorate, powdered sugar, and fine rifle 

powder. The tube was capped with a thin, convexshaped piece of lead that, upon impact, would collapse, 

break the vial, and release the acid, which would ignite 

the compound in the fuse and subsequently detonate 

the torpedo (Beauregard 1878:148–49). 

Most spar torpedoes were fitted with multiple 

detonators distributed around a hemispherical head 

to increase the chance of the torpedo exploding in 

case a detonator failed or the angle of impact varied. 

The torpedo casings were generally made of copper 

and cylindrical in shape, with a socket at the after end 

that would fit over a spar (Figure 14.13). Those used in 

Charleston usually contained between 60 and 100 lb. 

(27–45 kg) of powder (Beauregard 1878:149). 

In the case of Hunley, however, another source of 

torpedo technology was available. One of its investors, 

Edgar Collins Singer, was part of a group from Texas that 

made stationary torpedoes on a contract basis for the 

Confederate army. Sometimes known as the FretwellSinger torpedo, it has been described as “perhaps the 

most successful torpedo used by the rebels during the 

war” (Barnes 1869:70). The fuse of the Singer torpedo 

contained a spring-loaded metal rod, held apart from a 

percussion cap by a pin; attached to the pin by a string 

was an iron lid on top of the torpedo, which, when 

dislodged by the current of a passing ship, would fall, 

pulling the pin with it, releasing the rod into the percussion cap. The Singer team became involved with the 

Hunley team in Mobile, and presumably began adapting 

their design to a towed torpedo. It may have taken the 

form as that described by Edmund Ruffin (1989:183) in 

Figure 14.13. Drawing of a Civil War-era spar torpedo 

with multiple fuses distributed around a hemispherical 

head. (NHHC Photo Archives #NH 59421)

Figure 14.12. A sketch by Francis Lee shows two 

rigging points, both close to the distal end of 

the spar (ORA 1.28(2):252).
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

180

October 1863, a “torpedo, in a copper case, cylindrical, 

with conical ends.” When Hunley was rigged to carry a 

spar torpedo, Singer appears to have adapted his design 

once again. A drawing was found among Confederate 

papers at the National Archives labeled “Singer Torpedo 

Used for blowing up the ‘Housatonic’” (Figure 14.14). It 

clearly depicts a spar-mounted, cylindrical torpedo filled 

with 135 lb. [61.24 kg] of black powder and armed with 

three spring-loaded fuses mounted in the center of the 

forward end. It was mounted at an angle, allowing the 

spar to be lowered below the depth of the submarine, 

while maintaining the horizontal position necessary for 

proper contact between the centrally-positioned fuses 

and the enemy hull. Unfortunately, the key explaining 

the letters marking the detonators does not survive, so it 

is unclear whether it was activated by a lanyard, impact, 

or some other method. Whether Hunley was outfitted 

with this type of torpedo or one of Lee’s on the night it 

sank Housatonic has so far not been determined.

In summary, although questions remain regarding 

the conversion of Hunley to a spar torpedo vessel, 

evidence points to a design adapted from the spar 

systems used on Confederate small surface boats and 

the semi-submersible David types. This allowed the spar 

to be lowered to a depth well below the waterline of 

the ship, ensuring that the blast would be propelled 

upward into the enemy hull. With this improved angle 

of attack, possibly combined with contact fuses, which 

had already been proven reliable, Dixon and his crew 

would have been confident of their ability to survive 

the explosion. Previous trials, as well as evidence from 

the attack on New Ironsides supported this conclusion. 

Missing Features

Based on what we know from historical accounts 

and archaeological evidence, it appears several of the 

submarine’s external components are still missing. 

The port side shroud attachment bar, attested in 

Chapman’s painting, was completely disarticulated 

from the hull and not found at the site. The steering 

rod is only preserved for several inches beyond where 

it emerges from the hull. Additionally, the vertical arm 

that descended from the end of the steering rod was 

not found at the site.

The boom that was mounted on the top of the bow, 

depicted in Chapman’s painting, was not preserved. Its 

presence at the time of sinking is supported by the 

two iron brackets and corresponding mounting points 

found at the bow. A threaded hole in the top of the 

aft mounting bracket suggested that something was 

screwed into the material below, which could mean the 

boom was made of wood. Based on the width of the 

surviving brackets, it had a diameter of approximately 

5 in. (12.70 cm). While the boom served as a rigging 

point for raising and lowering the spar, little is known 

about exactly how it was configured. Neither Mazyck 

(Lunz 1957) nor McLauren (Confederate Veteran 1925) 

made mention of an additional boom. Perhaps the 

boom was considered part of the whole rigging system 

and did not merit special note.

Figure 14.14. Sketch of Singer torpedo adapted for 

use on a spar. Note letters E and F near the trigger 

are not annotated. (Courtesy of NARA, RG 94, 

Quincy Adams Gallimore papers)
H U L L A N A LY S I S

181

Another component depicted in Chapman’s 

painting was the aforementioned reel described by 

Mazyck as being rigged with a steel cable (Figure 14.15). 

In Chapman’s original sketch, there is only a straight 

rod in the same position, which may have been the 

mounting point for a separate spool. No reel or rod was 

attached to the submarine when discovered, nor was 

one located in the surrounding sediment. Once the hull 

has been fully deconcreted, it may be possible to tell 

whether the reel was lost after the sinking or if it had 

been removed, for some reason, prior to leaving port.

Design Problems

After the war, several of Hunley’s operational limitations were brought to light. Aside from the obvious 

drawback of being powered by hand, navigation was 

very difficult. In a letter to Matthew Fontaine Maury, 

McClintock described his experience with the compass, 

“which at times acted so slow, that the Boat, would at 

times alter her course for one or two minutes, before 

it would be discovered, thus losing the direct source, 

and so compell [sic] the operator, to come to the top 

of the water, more frequent than he otherwise would” 

(McClintock [1871]). This likely reflects McClintock’s 

early involvement with the project, prior to its oversight 

by Confederate military, which had more resources and 

experience in equipping metal vessels with compasses. 

Alexander (1902c:83) noted that they used an “adjusted 

compass,” suggesting this problem had been addressed 

sufficiently not to be a concern in Charleston.

McClintock also reported that “when under weigh 

beneath the surface it is quite impossible to ascertain 

whether the vessel is progressing” (Royal Navy 1872). 

He recalled several occasions where “they continued 

working the crank when all the time the boat was 

hard and fast in the mud” (Royal Navy 1872). The navy 

officers he met with seemed to think this would be an 

easy problem to overcome, again showing the value of 

Figure 14.15. Detail from Chapman’s 

painting of Hunley showing a reel positioned aft of the snorkel box. (Detail from 

H. L. Hunley by Conrad Wise Chapman, 

courtesy of The Museum of the Confederacy, Richmond, Virginia)

having the resources of a navy involved in the project. 

Alexander did not comment on this problem, but as the 

spar-based runs were conducted from the surface, he 

may not have been unduly hindered by it.

Lake’s (1918:152) assessment of Hunley was that 

“she lacked longitudinal stability, and during her experimental trials twice dove head first to the bottom.” The 

true design flaw, in his view, was not the length itself, 

but the internal water ballast tanks, which were not 

sealed off from the main body. 

If free surfaces exist in the water-ballast 

tanks, the slightest change from a level keel 

causes the water to flow to the lower end 

of the ballast tank. This is apt to augment 

the inclination still further, and cause the 

vessel to dive. . . . The movement of the 

crew forward and aft, or the effect of the sea, 

which imparts a vertical motion to the water 

beneath the surface, all tend to destroy both 

trim and equilibrium to such an extent that 

many failures have resulted in vessels of this 

type (Lake 1918:154 ).

This flaw was also singled out by Alexander (1902e) 

in his letter to the Navy as the “fatal error in this boat. . . . 

Had the [bulkheads] been built close up the Hunley

crew would not have been lost.” 

Conclusion

Hunley clearly demonstrated the experience the 

design team gleaned through two previous iterations 

of their submarine vessel—it was streamlined, better 

balanced, equipped with anti-fouling devices, and able 

to function in open sea, not just in harbors or inland 

waterways. Still, there was a fragile balance between 

safety and disaster that required expert, careful handling. 

By examining the structural changes from Pioneer

to Hunley, one can clearly see development and innovation based on experience gained from many hours in the 

water. The survival of the U.S. Navy’s documentation of 

the salvaged Pioneer has provided a unique opportunity to study the early evolution of submarine design. 

Even though these boats did not directly influence 

future builders, such as Holland and Lake, together they 

provide a glimpse into the minds of late 19th century 

engineers and their transition from experts adapting 

their knowledge of boiler technology and surface ship 

design to authorities in the new field of submarine 

vessel development. It would have been interesting 

to see what advances could have been achieved had 

McClintock succeeded in his post-war goal to build a 

new submarine.
182

15. Artifact Assemblage

Shea McLean, Heather G. Brown, Robert S. Neyland , and Ben Rennison

The number of artifacts found during the recovery, 

a total of 341 lots, was relatively small for an archaeological excavation, especially one that went on for 

almost three months. Of the artifacts recovered, 

most were intrusive to the Hunley site, representing 

materials dropped in the area after the submarine’s loss 

or that were carried along the bottom by the current 

until lodging against the hull or in the scour pockets 

that formed at the bow and stern. There were a small 

number of objects that came from the submarine 

itself, such as the rudder, snorkel tubes, and two metal 

brackets. Several other finds, including a section of rope 

and a piece of wood with tool marks, lacked diagnostic 

features enough to associate them with the submarine, 

but are consistent with materials that may have been 

employed on the vessel. All artifacts were brought 

to the Warren Lasch Conservation Center (WLCC) for 

cataloging and conservation. The primary diagnostic 

or potentially diagnostic artifacts are detailed below. 

A complete list of recovered materials is supplied in 

Appendix G.

Metals

HL-0378/-0381/-0386/-0428/-0432 — Iron Rod or Hoop

A cluster of concretions were recovered, primarily 

starboard of the bow, that preserved the original iron, 

in part, or the hollow mold of a cylindrical rod or wire 

with a diameter of ca. 0.5–0.6 cm (0.2–0.24 in.). One 

piece (HL-0432) was consistent in size and composition, but was found near the stern; however it showed 

a fresh break, suggesting it had been dislodged from 

its original position. The pieces curve gradually and 

likely originally formed a ring or hoop. Based on the 

largest preserved segment (HL-0428), the diameter 

was approximately 32 cm (12.60 in.) (Figure 15.1). The 

combined segments form a preserved circumference 

of roughly 82 cm (32.28 in.), or 81% of the projected 

total circumference. 

The material was found just above the level of the 

bow, prompting the consideration that it was related 

to the spar rigging system. However, one would expect 

braided cable there, rather than solid iron. In addition, 

the thickness of the metal is too robust for wire, suggesting the piece acted as a stationary strengthening 

component. It seems unlikely that a solid iron hoop was 

employed anywhere on the exterior of the submarine. 

The metal is similar in gauge to a bucket handle, or bail, 

but those are semicircular, and the surviving pieces 

form almost an entire ring. Bails for canning jars involve 

a more complete circle around the neck, but generally 

are on a smaller scale than represented here. While its 

original use may never be learned, it is most likely that 

the object is intrusive to the site. 

— HGB

Figure 15.1. Radiograph of HL-0428, the 

largest fragment of a heavily concreted 

curved iron rod. (Courtesy of FOTH)
A R T I F A C T A S S E M B L A G E

183

and its threaded end exhibits an interior diameter of 

0.34 cm (0.13 in.). Again, the threaded end compares 

favorably with a standard pipe fitting—in this case a 

5/16 in. male attachment.

Three sets of drill holes are present on the artifact. 

One set is located on the smaller-diameter section, 

immediately adjacent to the point where both components meet, and corresponds to holes drilled in 

the large-diameter rod. These holes have a preserved 

diameter of 0.66 cm (0.26 in.) and contain a small, 

square-headed metal pin with a preserved diameter 

of 0.48 cm (0.19 in.). The pin fastens the two sections 

of rod to one another. The remaining set of holes is 

located 13.26 cm (5.22 in.) from the small rod’s proximal 

(obscured) end. It presumably would have held both 

sections together when the smaller section was pulled 

out to extend the overall length of the artifact. A band 

of rust around the circumference just below the joint 

may indicate where a clamp or bracket once held the 

rod in place (Figure 15.3).

Initially, project staff believed that the artifact 

was made of copper and may have been associated 

with the submarine’s spar assembly. This was based 

primarily on its provenience (immediately adjacent 

and parallel to the spar) and the resemblance between 

its concretion layer and copper sulfide corrosion 

products. However, elemental analysis using x-ray 

fluorescence (XRF) revealed that its surface composition is approximately 2% lead, 4% iron, and 94% zinc. 

This indicates that HL-0463 was manufactured from 

galvanized steel. 

The concept of coating ferrous objects with zinc 

to protect the iron from corrosion, known as galvanization, was developed more than 250 years ago. 

The most common process for doing this in the 19th 

century was “hot-dip galvanizing,” a process of dipping 

the object into a molten zinc bath. Hot-dip galvanizing 

HL-0463 — Galvanized Rod

A long, cylindrical, unidentified metal object was 

discovered just 1.5 m (4.92 ft.) to port of Hunley’s bow, 

resting at an angle, from approximately 22 to 60 cm 

(8.66–23.62 in.) below the top of the hull (Figure 15.2). 

It has an overall preserved length of 4.97 m (16.31 ft.) 

and is composed of two sections of hollow metal rod 

joined together with what appears to be a modern 

cylindrical bolt or screw with a square head. The artifact’s narrower section terminates in a shallow (approximately 25°) bend that does not appear intentional. Both 

sections of rod are approximately the same length, 

but have different diameters. The smaller section has 

a maximum preserved exterior diameter of 1.4 cm 

(0.55 in.); the larger section is consistently 2.2 cm 

(0.87 in.) in diameter for its entire length. 

When recovered, the artifact was completely 

encased in a hard, thin matrix of gray corrosion products. 

To observe features obscured by concretion, conservators at the WLCC took x-ray images at four different 

points along its length. These included both ends and 

the area where the artifact’s two sections are joined. 

Radiographs revealed a number of significant attributes 

that assisted project archaeologists in their analysis 

of the item. For example, each end of the artifact is 

threaded, drilled holes are present at two locations 

along its length, and 65.35 cm (25.73 in.) of the proximal 

end of the smaller component is loosely recessed into 

the larger section. The large diameter section has an 

overall length of 2.95 m (9.68 ft.), an interior diameter 

of 1.70 cm (0.67 in.), and an average wall thickness of 

0.10 cm (0.04 in.). The interior diameter of its threaded 

end is 1.60 cm (0.63 in.)—the exact size of a standard 

5⁄8 in. threaded male pipe fitting. The narrow component 

is slightly shorter, with a preserved overall length of 

2.68 m (8.79 ft.). It has an interior diameter of 0.91 cm 

(0.36 in.), an average wall thickness of 0.20 cm (0.08 in.), 

Figure 15.2. Galvanized steel rod found near the submarine’s bow. Radiographic images show structural points of 

interest. (Illustration by James W. Hunter III)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

184

was first patented in France in 1836, but only became 

possible on an industrial scale after effective processes 

for cleaning iron and steel surfaces were developed 

(Habashi 2003). By the 1850s, the technique had 

been adopted in the manufacture of some of Great 

Britain’s earliest telegraph cables (Celoria 1978). After 

1890, hot-dip galvanization was a mainstay of the steel 

industry in the United States. Electroplating was also 

developed early, but was not practical on a commercial 

scale until the early 20th century (Bonney 1905:191). 

A hot vapor-based process called sherardization was 

patented in 1902 (Patent US701298 A).

Currently, the identity of the artifact remains 

unclear; however, attributes of its manufacture and construction revealed by radiographs strongly suggest that 

it is modern intrusive debris and not associated with 

Hunley. In overall appearance, it most closely resembles 

two sections of modern pipe that were modified into 

a single, adjustable object. The telescoping function 

suggests that it might have been a fishing outrigger, but 

the lack of any hardware for running line is problematic. 

It may have been electrical conduit for a deck light or 

other instrument. The previously unsuccessful surveys 

for Hunley undoubtedly involved probing in an attempt 

to locate magnetic anomalies, and it is also possible 

this object was used as an impromptu probe by divers, 

though its depth of burial suggests it may have been 

lost closer to the beginning of the 20th century. 

— SM

 HL-0526 — Bracket 

A largely intact wrought-iron, D-shaped bracket 

assembly was discovered buried in coarse sand approximately 2.35 m (7.71 ft.) northwest of the upper edge 

of the starboard bow. It is composed of multiple components, including two straps, a round-headed rivet 

and a square-headed pin. The bracket has an overall 

length of 29.3 cm (11.54 in.) and a maximum width of 

13.3 cm (5.24 in.). The straps comprising the bracket 

range in width between 2.4 and 6.3 cm (0.94–2.48 in.), 

depending on their level of preservation. The preserved 

thickness of each strap ranges between 0.4 and 1.1 cm 

(0.16–0.43 in.).

The flat nature of the metal points to its use as a 

bracket rather than a shackle, which would have had 

rounded edges to allow rigging lines to pass smoothly 

through it. Project archaeologists hypothesize that 

this piece of hardware, in conjunction with another, 

similar piece (HL-0582, below), probably held Hunley’s 

wooden boom in place along the upper surface of 

the bow. A semicircular depression located along the 

forward upper extremity of the bow is most likely the 

remnants of a hole through which the bracket’s iron 

pin was inserted and affixed to the submarine’s hull 

(Figure 15.4). The bracket is closed, with no breaks or 

distortions, indicating the piece remained in place on 

the hull until erosion of the bow casting compromised 

the integrity of the hole through which it was attached 

(Figure 15.5).

Two fasteners bind the straps together and 

complete the bracket. The largest is a wrought-iron pin 

that has an overall length of 17.1 cm (6.73 in.) and a 

maximum preserved of 3.1 cm (1.22 in.). The head of 

the pin appears square in profile, exhibits a maximum 

Figure 15.3. Photograph of the joint shows a band of 

rust incidicating the position of a possible clamp or 

bracket. (Photo by Michael Scafuri, courtesy of FOTH) 

Figure 15.4. Project staff hold bracket 

HL-0526 against its hypothesized position 

on the submarine’s bow casting. Note the 

square-headed fastener or nut for bracket 

HL-0582 immediately beneath the hole in 

the bow casting. (Detail of photograph by 

Susanne Grieve, courtesy of FOTH.)
A R T I F A C T A S S E M B L A G E

185

A cut or gash approximately 2.0 cm (0.79 in.) long is 

visible on the surface of the peened side of the pin. This 

damage may have occurred at the time of the engagement (i.e., debris from the explosion caused by Hunley’s 

torpedo glanced off the pin, marring it). Conversely, it 

may have occurred at some point following the submarine’s loss and deposition on the seafloor. The mark 

does not appear to have been intentionally produced 

at the time the bracket was constructed. 

— SM

HL-0555 — Aft Cutwater

A flat triangular shaped piece of heavily concreted 

wrought iron was identified as the submarine’s aft 

cutwater, a piece that was originally mounted along the 

centerline of the hull, attached to the leading edge of 

the aft conning tower to prevent fouling (Figure 15.6). 

The artifact was discovered forward of the aft hatch, 

100 cm (39.37 in.) below the top of the hull on the 

starboard side. The piece became dislodged from the 

hull following Hunley’s loss and was discovered during 

the excavation. 

At its longest point, the piece measures 108 cm 

(42.52 in.), it is 26 cm (10.24 in.) high where it abutted 

the conning tower. The surviving length of the hypotenuse is 106 cm (41.73 in.), but there is some metal 

loss along this edge, particularly at the end that was 

in contact with the conning tower, and there is a semiwidth of 4.6 cm (1.81 in.) and a maximum preserved 

thickness of 2.0 cm (0.79 in.). Conversely, the pin may 

be round-headed and have a threaded end to which a 

square-shaped nut is affixed. Ferrous concretion and 

mineralized deposits obscure the point at which the 

pin, square-shaped head or nut, and bracket strap 

meet; consequently, an accurate assessment of the 

pin’s construction is presently impossible. A small 2.3 

cm (0.91 in.) long round-headed rivet holds both straps 

together at the apex of the bracket. The rivet has a 

maximum preserved diameter of 2.0 cm (0.79 in.) and 

appears to have been peened on both ends to hold it 

in place. According to Bruce Thompson (pers. comm.), 

the bracket’s construction attributes suggest that it was 

assembled by one of the following two scenarios:

A) Two wrought-iron straps with 2.5 cm (1 in.) 

diameter holes cut into the face of one end were forged 

together, and further secured with an iron rivet. The 

rivet head was located on the exterior surface of the 

strap, while the peened end rested against the interior 

surface. This composite strap was then bent on an 

11.2 cm (4.41 in.) diameter round to form a U-shape. A 

square-headed pin was then inserted through the end 

holes and peened over on the outer strap surface.

B) The construction process was exactly identical 

to that outlined above, except that a round-headed 

pin was inserted through the end holes (in place of a 

square-headed pin) and a square nut used to cinch the 

straps in place.

Figure 15.5. Forward spar assembly bracket (HL-0526). (Illustration by 

Bruce Thompson.)
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circular area of loss about halfway down its length. 

The average thickness of the metal plate is 0.80 cm 

(0.315 in.). The bottom corner of the cutwater was cut 

away to fit over the seam where the conning tower 

attached to the hull plate. A bolt or rivet hole survives 

approximately halfway down the back edge to assist in 

the mounting of the piece to the hatch coaming. 

Two through bolts are attached to the object along 

the midline of the cutwater. The bolts are positioned 

(A) 32 cm (12.60 in.) and (B) 83 cm (32.68 in.), respectively, aft of the forward end of the piece. Bolt A stands 

off 5.4 cm (2.13 in.) from the starboard surface, and 

originally stood off 5.74 cm (2.26 in.) from the port 

side, although 3.7 cm (1.46 in.) of that is preserved only 

as a silicon cast. The head of bolt A measures 1.3 cm 

(0.51 in.) in diameter, and the attached nut measures 

2.64 x 2.82 cm (1.04 x 1.11 in.) with a thickness of 

1.3 cm (0.51 in.). Bolt B protrudes from the starboard 

side and is bent aftward, with a length of 4.91 cm 

(1.9 in.). Its head measures 1.0 cm (0.39 in.) in diameter. 

Project archaeologists believe the aft bolt point may 

have been used to hold the aft hatch cover open by a 

section of chain or rope. The forward bolt may have 

also been used for this purpose, although access to it 

from inside the submarine would have been restricted 

by the open hatch cover. It may have also have been a 

mounting point for a stay or other hardware related to 

the original towed torpedo design. The object is still in 

conservation limiting a closer inspection at this point.

—BR

HL-0582 — Bracket

A fragmented and heavily degraded wroughtiron bracket, similar in size and construction to 

HL-0526 (see above), was located in coarse sand 

immediately adjacent to the extreme forward end of 

Hunley’s starboard bow. It comprised the majority of a 

ferrous concretion that also 

contained a tin can (HL-3288) 

and a wooden tool handle 

(HL-3289). The artifact has 

an overall preserved length 

of 24 cm (9.45 in.) and originally had a maximum width 

between 13 and 14 cm (5.12–

5.51 in.). Unlike HL-0526, 

HL-0582 appears to have 

been formed from three 

wrought-iron straps. These 

components were welded 

or otherwise joined together 

on either side of the bracket, 

near its apex. One arm of 

the U-shaped strap is bent 

outwards—likely the result 

of violent action—and increases the maximum the 

distance between the strap ends to 20.6 cm (8.11 in.) 

(Figure 15.5). The composite strap that comprises the 

bracket exhibits a preserved width ranging between 2.5 

and 7.4 cm (0.98–2.91 in.), and a maximum preserved 

thickness of 1.3 cm (0.51 in.).

Neither of the fasteners observed on HL-0526 is 

evident on HL-0582; however, the remnants of two 

2.4 cm (1 in.) diameter fastener holes are located near 

the base of the composite strap. These holes presumably held the iron pin that affixed the bracket to the 

hull. A wrought-iron bolt similar in size and appearance 

to the large iron pin on HL-0526 is affixed to Hunley’s 

upper bow structure. Based on the aforementioned 

attributes, project archaeologists believe that this bolt 

marks the location on the submarine where the bracket 

was originally attached. 

A 1.7 cm (0.67 in.) diameter circular hole is located 

slightly off center from the apex of the bracket. The hole 

contains four 0.2 cm (0.078 in.) threads and would have 

accepted a threaded bolt of the same size. The purpose 

of this bolt is presently unclear; however, it may have 

penetrated the wooden support boom to help secure 

it in position against the upper surface of Hunley’s bow. 

The reason why this bracket held a threaded bolt and 

the other a peened rivet remains an open question. 

There is clear evidence that the bracket was badly 

damaged either during, or after, the submarine’s loss. 

The bent strap arm and broken fastener holes both 

strongly suggest that the piece was violently wrenched 

from its original position. This hypothesis is further reinforced by the bracket’s iron pin, which remains firmly 

attached to the hull. Whatever removed the piece from 

the submarine exerted enough force to bend the strap 

and break the holes through which the pin was inserted, 

but was not strong enough to remove the pin from the 

hull. 

— SM

Figure 15.6. Starboard side of aft cutwater (HL-0555). Bolts A and B likely functioned 

as rigging points. (Photograph by Paul Mardikian, courtesy of FOTH)
A R T I F A C T A S S E M B L A G E

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HL-0614/HL-0615 and HL-0616 — Snorkel Tubes.

Three sections of heavily degraded wrought-iron 

pipe were discovered on the starboard side of the 

submarine lying approximately 80 cm (31.50 in.) below 

the top of the hull and 39 cm (15.35 in.) to starboard 

(Figure 15.6). Based upon their size, shape, and composition the items have been identified as sections of 

the air intake and exhaust pipes formerly connected to 

the snorkel box (see Figure 12.13). 

Artifacts HL-0614 and HL-0615 appear to be from 

one piece of pipe that broke into two sections after disarticulation from the hull. The two sections measure 

66.5 cm (26.18 in.) and 82 cm (33.07 in.) respectively. 

HL-0616 measures 140 cm (55.12 in.) as one whole 

section. Each of the sections is cylindrical in shape 

and has open ends that were completely filled with 

sediment when discovered. The exterior surfaces were 

heavily covered in marine concretion. Once this was 

removed it became apparent that both ends of each 

pipe were threaded. Their interior diameters measure 

4.1 cm (1.61 in.) and they correspond with the two 

mounting points that can be clearly discerned on the 

snorkel box. It is likely that the tubes became disarticulated from the submarine after it came to rest and 

canted to starboard, since both pipes were found to 

starboard of the hull.

—BR

Figure 15.7. Aft spar assembly bracket (HL-0582). (Illustration by Bruce 

Thompson.)

Figure 15.8. Field drawing of snorkel tubes showing their heavily concreted state. (Illustration 

by Shea McLean, courtesy of FOTH.)
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188

HL-0660 — Shroud Attachment Bar

A long, thin metallic concretion was found roughly 

parallel to the starboard side, connected to the hull at 

one end, just forward of the aft stern hole, near the 

top edge of the expansion strake. The detached end 

terminated 14 cm (5.51 in.) forward of the aft conning 

tower. Due to the fragility of the connection point, the 

piece was detached from the hull prior to lift. The concretion was removed to expose a long, flat iron bar 

or strap , measuring 1.78 m (5.84 ft.) in length, 3.0 to 

3.6 cm (1.8–1.42 in.) in width, and 1.49 cm (0.59 in.) 

thick (Figure 15.9). The edges of the artifact show signs 

of deterioration. 

The object was identified as the starboard shroud 

attachment bar, originally running from the propeller 

shroud to the expansion strake near the seam of the 

second and third quarter plates from the stern. Labeled 

as “Shroud Guard” in the sketch from McClintock’s 

(1872) meeting with the British Admiralty, the piece was 

apparently designed to prevent fouling of the propeller 

and damage to the shroud. It may also have provided 

some lateral stability to the shroud, 

which was mounted to the stern at the 

top and bottom. 

At some point after sinking, the 

piece was detached from the shroud 

and bent forward nearly 180°, deforming 

the metal at the point of attachment to 

the hull plating. Given its final position, 

it seems unlikely that this could have 

occurred after the submarine’s tilting 

to starboard. The surviving length is too 

short to reach the propeller shroud and 

no adjoining piece was found adjacent 

to its final position, suggesting that a 

portion of the bar broke off during the initial incident 

that pulled the attachment bar forward on its axis.

—HGB

HL-0683 — Length of Iron Bar

A heavy concretion was found at the starboard side 

of the submarine, near the aft stern hole. The concretion was removed to reveal a section of flat, wroughtiron bar, most of which was preserved metal (Figure 

15.8). One end contained a void from which a polyurethane cast was made. The artifact measures 46 cm 

(18.11 in.) in length, with a maximum thickness 0.6 cm 

(0.24 in.). The width tapers from 3.5 cm (1.38 in.) at its 

widest point to 2.2 cm (0.87 in.) at the cast end. The 

wider end tapers sharply to a rounded point, though 

whether this was its initial shape or a result of post-depositional processes is difficult to determine. No fastener 

holes or other attachment points were found. 

Conservator Paul Mardikian (2014 pers. comm.) 

noted that the x-rays did not show the usual distinct 

demarcation of the original surface of the object and 

that the concretion layer closely conformed to the areas 

of damage and metal loss. He suggested that the object 

might have suffered some damage after it had begun 

to concrete, and subsequently a new concretion layer 

formed over resulting areas of fresh metal exposure. 

The end recovered through casting shows evidence of 

elongation, possibly reflecting a deformation related to 

its disarticulation from the submarine.

The piece is consistent in width with the starboard 

shroud attachment bar (HL-0660), although it is 0.89 cm 

(0.35 in.) thinner, so it does not appear to be the 

missing adjoining piece of that component. The piece 

may be related to the rudder steering assembly, but it 

is less than 1 cm (0.39 in.) narrower than the various 

wrought-iron pieces concreted to the rudder (HL-0686). 

While its original position on the submarine cannot be 

determined, its material and shape is consistent with 

elements from Hunley and likely was associated with 

the steering assembly. 

—BR/HGB

Figure 15.9. Paul Mardikian holds starboard shroud 

attachment bar (HL-0660) in corresponding port position 

on a full-scale print of the submarine. (Photo by Philippe 

de Vivies, courtesy of FOTH)

Figure 15.10. Cast of a wrought-iron bar (HL-0683) found near the rudder. 

(Photo by Virginie Ternisien, courtesy of FOTH)
A R T I F A C T A S S E M B L A G E

189

 HL-0684 — Rivet Head

A s m a l l 

ferrous concretion 

was found 80 cm 

(31.50 in.) below 

and 27 cm (10.63 

in.) to starboard 

of the top of the 

stern. Its overall 

size is 7.3 × 5.0 

× 5.0 cm (2.87 × 

1.97 × 1.97 in.). 

X-rays revealed 

that the concretion contains the 

remains of an iron 

rivet head and 

partial shaft (Figure 15.11). The maximum preserved 

width is 2.37 cm (0.93 in.) and maximum preserved 

length is 1.83 cm (0.72 in.). Its size and the flattened 

mushroom shape are consistent with Hunley’s hull 

rivets as they appear on the interior surface of the 

hull plates. Positioned almost directly below the hole 

in the stern, this piece most likely originated from the 

seam between the cast-iron stern piece and the upper 

starboard quarter plate. As the metal deteriorated from 

the erosion-corrosion processes affecting the stern 

(Jacobsen et al. 2012), the rivet was dislodged and 

deposited on the seabed. See also HL-0705.

—HGB

HL-0685 — Iron Spike

A small ferrous concretion was found 80 cm 

below and 30 cm to starboard of the top of the stern. 

Its overall size was 14.0 × 9.0 × 6.5 cm (5.51 × 3.54 × 

2.56 in.). Based on x-ray imaging, it was determined that 

no original metal survived and a polyurethane cast was 

made of the void (Figure 15.12). The preserved shape 

proved to be a rectangular shafted spike with a square 

head with a raised dome in the center. The surviving 

length of the shaft is 12.5 cm (4.92 in.), although it 

appears the tip was broken off. The square head is 

approximately 1.4 × 1.4 cm (0.55 × 0.55 in.). The rectangular shaft is consistent with late 18th to late 19th 

century production. This type of spike is ideal for use 

in wood; however since no other hardware from the 

rudder has yet been found, its use as part of the rudder 

assembly was considered. This was ultimately ruled out, 

as the moving joints would require cylindrical hardware. 

The spike is more likely intrusive, possibly from the 

wooden-structured Housatonic.

—HGB

HL-0686 — Rudder

 The rudder was discovered directly beneath the 

stern of the submarine, lying diagonally across the keel 

line. It was heavily concreted with a large amount of 

shell encrustation (Figure 15.13). Its overall measurements, after deconcretion, are 78 × 53 × 0.6–0.75 cm 

(30.71 × 20.87 × 0.26–0.30 in.) and it weighs 38.3 kg 

(84.44 lb.). The rudder is of a flat rectangular shape and 

made of a single piece of wrought-iron plate, most likely 

originally 3⁄8 in. thick, the same gauge as the hull plating. 

The remains of one cast-iron mounting bracket 

is located on the leading edge of the rudder, 12 cm 

(4.72 in.) below the surviving top edge, canted at 

approximately a 45° angle. The bracket arms are 0.6 cm 

thick on each side of the rudder plate. The bracket 

body, forward of the rudder’s leading edge, is 4.4 cm 

(1.73 in.) thick and appears to have broken off. Its 

surviving length is 6.2 cm (2.44 cm). A single rivet or 

peened bolt, 2.6 cm (1.02 in.) in diameter, secures the 

bracket to the rudder plate. The remains of a second 

mounting bracket are positioned vertically along the 

Figure 15.11. Radiograph of 

concreted rivet (HL-0684). 

(Courtesy of FOTH)

Figure 15.12. Cast of a dome-headed spike or nail (HL-0685) found in a concretion near Hunley’s stern. (Photos by 

Paul Mardikian, courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

190

bottom corner of the leading edge, broken off at the 

bottom edge for a surviving length of 6.3 cm (2.48 in.). 

It is 4.1 cm (1.61 in.) wide, and the rivet or bolt head is 

2.6 cm (1.02 in.) in diameter. The mounting points do 

not resemble a traditional pintle-and-gudgeon design. 

In the center of the rudder is a horizontally-oriented oblong hole, roughly 8.1 × 0.9 cm (3.19 × 0.35 in.). 

Partially overlapping this are two wrought-iron straps, 

one on each side, with a surviving length of 33.4 cm 

(13.15 in.) connected by a rivet or bolt, that extend aft 

at a slight incline beyond the after edge of the rudder. 

These straps likely originally pivoted up and down as 

part of the steering mechanism. The metal at the after 

end of the straps appears somewhat deformed upward, 

suggesting the adjoining steering arm was torn away. 

While both the mounting brackets and the steering 

component were all broken, the rudder plate itself 

shows little damage. The trailing edge has the most 

loss, including diagonal breaks at both corners. There 

are numerous semicircular patches of metal loss, the 

largest of which are one 8.7 cm (3.43 in.) long, 2.4 cm 

(0.94 in.) down from the surviving top edge, and one 

6.6 cm (2.60 in.) long, approximately 17 cm (6.69 in.) up 

from the surviving bottom edge. The remaining edges, 

particularly the top and bottom, are well preserved, 

although there is a roughly rectangular break at the 

upper forward corner above the top mounting bracket. 

Both plate faces have many small patches of minor loss 

due to delamination and pockmarks but none that penetrates the full thickness of the metal.

—HGB

HL-0705 — Rivet Head

A small ferrous concretion was recovered from 

dredge spoil from the starboard side of the stern, 

roughly below the hole in the hull plating. Its overall size 

is 8.3 × 6.0 × 5.0 cm (3.27 × 2.36 × 1.97 in.). X-ray images 

revealed that the concretion contains the remains of an 

iron rivet head (Figure 15.14). The maximum preserved 

width is 2.30 cm (0.91 in.) and maximum preserved 

length is 1.92 cm (0.76 in.). It is similar in size and 

shape to the rivet found in HL-0684, but the shaft is 

more deteriorated and the top of the head is somewhat 

distorted. Despite poor preservation, the rivet is still 

consistent with Hunley’s hull rivets as they appear on 

the interior surface of the hull plates. As with HL-0684, 

this piece most likely originated from the seam between 

the cast-iron stern cap and the upper starboard quarter 

plate. As the metal deteriorated from the erosion-corrosion processes affecting the stern (Jacobsen et al. 2012), 

the rivet was dislodged and deposited on the seabed. 

—HGB

HL-2917/HL-2918 — Grapnel Anchor and Iron Ring

During the magnetometer survey that was 

conducted in 2001, a year after Hunley was recovered, 

the sensor detected a deeply buried magnetic anomaly 

at the edge of the original excavation boundary to 

starboard of Hunley. Upon investigation, this anomaly 

was found to be a concretion containing a wroughtiron grapnel (HL-2917) (Figure 15.15). It was embedded 

in the Pleistocene mud at the same level as the keel. 

Three of the five arms had been caught in the Pleistocene mud, one of which was distended by at least 

Figure 15.13. Port side of rudder (HL-0686) before conservation (left) and after conservation (right). (Photos by M. 

Scott Harris (left) and Johanna Rivera (right), courtesy of FOTH)

Figure 15.14. Radiograph of 

concreted rivet head (HL-0705). 

(Courtesy of FOTH)
A R T I F A C T A S S E M B L A G E

191

7 cm (2.76 in.) and the others had extended above 

the sea floor (Thompson 2005). The latter arms were 

heavily concreted with marine growth and were more 

corroded in contrast to the buried ones, which were 

better preserved. It appeared is if the anchor had buried 

three hooks in the mud when it was lost. 

The grapnel was located approximately 5 m 

(16.40 ft.) from the submarine. The shank of the grapnel 

pointed toward the hull roughly in the direction of 

the forward conning tower. The grapnel has a shank 

length of 83 cm (32.7 in.) with lower and middle shaft 

diameter of 4.1 cm (1.6 in.) and upper shaft diameter 

of 5 cm (1.97 in.). The hole in the end of the shank that 

received the iron ring is 2.5 cm (1 in.) in diameter. The 

ring (HL-2918) has an outer diameter of 11.2 cm (4.4 in.) 

and inner diameter 8.5 cm (3.36 in.) and thickness of 1.5 

cm (0.6 in.). The anchor weighs only 8.1 kg (17.86 lb.).

The curved arms each had a length of 45.7 cm 

(18 in.) and diameter of 1.9 cm (0.75 in.). Maximum 

distance between opposing arms is 50 cm (19.69 in.). 

Only two flukes survived intact, the largest of which 

had a length of 6.4 cm (2.52 in.) and breadth of 3.8 cm 

(1.5 in.), and thickness of 1 cm (0.4 in.). The flukes 

were created by hammering the wrought-iron claw to 

form two lobe-like protrusions rather than attaching a 

separate piece of metal for the fluke. The grapnel was 

forged from wrought-iron bars hammered together to 

form a single construction. Grapnels, particularly those 

used for anchors, sometimes have a reinforcement 

band placed around the lower shank and beginning of 

the claws for added strength and reinforcement (Jeanne 

Willoz-Egnor, pers. comm. 2012), though that feature 

was lacking on HL-2917.

There was no evidence of chain links attached to 

the ring. Only the iron ring for attaching the rope or 

chain to the grapnel was found. Although, since the 

ring was not intact, it is possible it could have broken 

away from the chain. A grapnel used for anchoring a 

boat would possibly require a length of chain to help 

hold fast to the bottom. 

The use of grapnels on ships for anchoring, salvage, 

and combat is quite ancient. In the 17th and 18th 

centuries ship’s boats were each issued a grapnel 

depending on the boat’s size. The 33 ft. (10 m) longboat 

of a First Rate ship would have a grapnel of 84 lb. (38 kg) 

and a 33 ft. (10 m) pinnace one of 56 lb. (25.40 kg). 

In the 1800s, a 74-gun ship’s barge of 32 ft. (9.75 m) 

would have a grapnel of 84 lb. (38 kg) and the launch 

of 31 ft. (9.5 m) one of 56 lb. (25.40 kg). Other smaller 

boats were to carry one each of 40 lb. (18.14 kg) (Lavery 

1987:228). There are three types of grapnels mentioned 

by David Steel in The Elements and Practice of Rigging 

and Seamanship (1794). These consist of boat anchor 

grapnels, fire and hand grapnels, and creepers (Figure 

15.16). Each serves a different purpose: 

GRAPNEL, or GRAPPLING, is like a small 

anchor, with four or five flukes, or claws, 

used in small vessels or boats to ride at.

FIRE-GRAPNELS resemble the former, are 

from eighteen to twenty pounds weight, and 

have strong barbed claws, with a chain to the 

ring. They are used by fire-ships. 

CREEPER is like a small anchor, with four 

hooks, or claws, used in recovering any 

thing from the bottom of rivers, &c. (Steel 

1794:80)

Boat grapnels are in weight from 112 lb. 

Figure 15.15. Five-tined grapnel anchor (HL-2917) and ring (HL-2918) after conservation treatment (Photo by Chris Watters, courtesy of FOTH).
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

192

[50.80 kg] to 36 pounds [16.33 kg]. Fire 

and chain grapnels weigh about 70 pounds 

[31.75 kg], and bear the same proportion with the hand and chain; grapnels and 

creepers are made of wrought-iron, and 

shaped agreeably to the plate. The shanks are 

round, and have an eye wrought in the upperend, to receive the ring, the ring being put 

through, and the ends firmly shut together. 

The shank is left longer than the nett length 

above, for weldiug [sic] on the claws. Flukes 

are shut on the extremities of the claws of 

boat-grapnels, and barbs are made from the 

solid of fire-grapnels. The claws are welded 

on to the lower-part of the shank, and spread 

from the same, at the end, one-third the 

length of the shank, in boat-grapnels; threefourths in fire-grapnels; and half the length of 

the shank in creepers (Steel 1794:82).

Fire grapnels were fixed to the yard arms or thrown 

by hand to secure the fire ship to its adversary or by 

other ships to hold the combatants fast for boarding 

(Falconer 1769:128, 140). The 18th century naval 

warfare employment of fireships had been out of use 

for some time by 1864, thus the fire grapnel type would 

not apply to HL-2917. The exaggerated, barbed flukes 

of this type were also lacking on the example from the 

Hunley site. It would appear HL-2917 was either a small 

boat grapnel or a creeper type used in salvage. 

None of the known accounts of Hunley’s operation 

mention it carrying an anchor of any form. It is not 

unlikely that this would have been a recognized need to 

prevent being swept out to sea by the current. However, 

deploying an anchor from a vessel with a low freeboard 

would have caused some risk of swamping. The other 

possibility for the grapnel is that it was lost by the U.S. 

Navy during attempts to drag for the submarine (see 

Chapter 4). Navy records report that the area was 

dragged for 500 yd. (457 m) around the wreck of Housatonic in an attempt to locate the submarine. Although 

drag ropes reportedly caught something heavy in one 

instance, the snag was identified by a diver as nothing 

but debris (ORN 1.15:334).

U.S. Navy ships carried grapnels of various sizes on 

its ships. The size of these was to be determined by 

a ratio in relation to the weight of the bower anchor. 

For a bower over 7,500 lb. (3,402 kg) the ship would 

have two grapnels each weighing between 140 to 70 lb. 

(63.50–77.11 kg). In contrast, a ship with a bower less 

than 800 lb. (363 kg) would require a grapnel of 25 lb. 

(11.34 kg). Anchor buoys deployed by the ship also 

required grapnels of from 15 to 10 lb. (6.80–4.54 kg), 

depending on the size of the bower anchor (DON 

1864b:37; 1890:14). Besides recovering lost objects 

from the bottom, light grapnels were used to locate and 

detonate mines (Barnes 1869:180; Stotherd 1872:272). 

They have also been used to anchor fishing nets.

Grapnels used as small boat anchors work best 

Figure 15.16. A grapnel, fire grapnel, and creeper as illustrated in Steel (1794).
A R T I F A C T A S S E M B L A G E

193

in rocky bottoms or on a beach where they can take 

purchase in a crevice. Today they are used for boats 

of not over 3 tn. (2.72 t) displacement, are not considered efficient anchors, and do not work well in sandy 

or muddy bottoms such as that found in the area of 

the Hunley/Housatonic engagement site (De Kerchove 

1961:335; McEwen 2006:190). At roughly 18 lb. (8 kg), 

HL-2917 seems too light to effectively hold Hunley or 

any boat except one that is very small. In addition, no 

chain to hold the line down to the bottom indicates it 

was not used as an anchor. It is likely that it was lost 

during the Navy’s attempts to drag for the Hunley and 

is an indication that the dragging occurred near and 

perhaps over the submarine. The arms buried in the 

Pleistocene mud also suggest that there was not a great 

deal of sediment over this mud layer at the time of loss.

— RSN

Tin Cans

Several complete iron cans, partial cans, and many 

can fragments were recovered from the sediment 

matrix surrounding Hunley. At least four cans, HL-0653, 

HL-0654, HL-3667, and HL-3678, were found concreted 

to the hull itself. The first three of these were found 

on the port side or bottom of the keel; the last was 

found on the starboard side, roughly 125 cm (49.21 in.) 

forward of the aft conning tower, at the level of the 

expansion strake. HL-0700 was found 37 cm (14.57 in.) 

starboard of, 15 cm (5.91 in.) forward of, and 66 cm 

(25.98 in.) below the top of the stern. HL-3288 was 

found adjacent to the starboard bow.

Historic cans are most easily dated by their labels, 

which do not survive in this case. Rough periods of production can be gleaned from manufacturing technique, 

including cap style, seam type, and solder application. In 

the case of Hunley cans, the primary surviving diagnostic 

features are lead solder and cap style. While canned 

goods were invented in the late 18th century, their production and distribution increased substantially during 

and after the Civil War (Busch 1981:97). The earliest 

cans were assembled by hand, with simple overlapping 

seams soldered manually (Rock 1984:99). The introduction of machine soldering of side seams in 1883 allowed 

for smaller, more regular seams (Rock 1984:103). 

Cap styles were dictated in part by the can’s 

contents. Dry goods, such as tobacco and coffee could 

have a simple removable lid that fits over the walls 

of the can as needed, sometimes called an external 

friction or slip lid (Rock 1987:10). For liquid and perishable foodstuffs, the hole-and-cap style was most 

commonly used. In this design, a lid with a ca. 1–2 in. 

(2.54–5.08 cm) diameter hole in the center was fixed to 

the body of the can, usually by folding the metal edges 

over each other and sometimes reinforcing them with 

solder. The contents were then inserted through the 

central hole, which was filled with a smaller cap that 

was soldered in place. When the contents needed to 

be heated for proper preservation, a small vent hole 

was punched in the secondary cap for steam to escape. 

Once heating was complete, the hole was sealed with 

a small drop of solder (Figure 15.17). The open top 

sanitary can, which incorporated a single-piece lid, with 

or without a vent hole, was introduced in 1904 and had 

almost completely replaced the hole-and-cap design by 

1920 (Busch 1981:98). 

Of the cans recovered at the Hunley site only four 

were complete enough to preserve dimensions of the 

original can; approximate measurements were extrapolated for two additional crushed cans (HL-3667 and 

HL-3678) (Table 15.1). Due to irregularities in preserved 

surfaces, measurements were rounded to the nearest 

eighth of an inch (3.18 mm). Three (HL-0654, HL-0700, 

and HL-3288) could be clearly identified as vented 

hole-and-cap cans with machine-soldered side seams. 

Based on manufacturing style, the cans appear to date 

between 1885 and 1920. The secondary cap on HL-3288, 

however, appears to have been hand soldered, placing 

it in the earlier half of that time range.

Some attempt to record common can sizes and 

their contents has been made (University of Utah et al. 

1992; Rock 1987:76–90); however, dimensions were not 

standardized until the early 20th century, when cans 

Figure 15.17. A radiograph of the heavily concreted 

HL-3667 shows a preserved vented cap typical of late 

19th century manufacture. (Courtesy of FOTH)
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were given numerical designations from smallest to 

largest. The most common of which were No. 2, No. 21⁄2, 

No. 3, and No. 10. The dimensions of these sizes were 

measured to the closest sixteenth of an inch (1.59 mm) 

and changed somewhat over the years, making identification of unmarked cans challenging. In addition, it can 

be difficult to acquire measurements on archaeological 

cans from underwater environments to the precision 

used by the manufacturers, due to deterioration, concretion, and distortion.

By comparing the dimensions of Hunley cans to 

other known can sizes, we can also see a late 19th to 

early 20th century date range (Figure 15.18). A group 

of canned goods recovered from the 1865 wreck of the 

steamship Bertrand in the Missouri River provides comparative size data for cans contemporary with Hunley

(Petsche 1974). A partial inventory of the collection 

gives an excellent idea of the types of canned products 

available at the time (Table 15.2). Based on surviving 

labels, the majority of the cans were manufactured in 

Baltimore, Maryland. The vented hole-in-cap cans in 

the collection generally contained fruit products and 

frequently came in 2 lb. (0.91 kg) portions, so the can 

dimensions may have been influenced by a product’s 

volume per weight rather than desired container size.

It is not until the widespread use of canning 

machines and the separation of can manufacturers 

from canning plants in the last two decades of the 19th 

century that we begin to see the standardization of can 

sizes. A list of standard sizes from 1917 (Rock 1987:92) 

has been used as proxy data for post-1880 mechanized 

production. HL-0700 and HL-3288 are within range of 

standard dimensions (No. 3 [5 1⁄2]1

 and No. 2 1⁄2, respectively) from 1917, suggesting post-1880 deposition. 

HL-0653, HL-3667, and HL-3678, are larger than the 

standard No. 10, making them difficult to identify, but 

one is near in size to one of Bertrand’s coffee cans. 

While it is possible some of the cans found at the 

Hunley site came from the wreck of Housatonic, manu1  There were three No. 3 can sizes, each with the same diameter 

but different heights: 4 7/8, 5, and 5 1/2 inches.

Figure 15.18. Comparison of known can sizes to those found at the Hunley site.

Table 15.1. Dimensions of Cans 

from the Hunley Site

Can ID# Height Diameter 

in. cm in. cm

HL-0653 7 7⁄8 20.00 5 1⁄2 13.97

HL-0654 11 27.94 n/a n/a

HL-0700 5 1⁄2 13.97 4 1⁄3 11.00

HL-3288 4 7⁄8 12.38 4 10.16

HL-3667 9 7⁄8 25.08 4 3⁄4 12.07

HL-3678 7 7⁄8 20.00 5 7⁄8 14.92
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Table 15.2. Canned Goods from the Steamship Bertrand

Contents No. Found Shape Lid Type Manufacturer Location Source

Coffee 24 Cylindrical EFS Cincinnati, OH R 

Cranberry Sauce - Cylindrical HAC Bridgeton, NJ R 

Essence of Coffee 30 Cylindrical EFS Philadelphia, PA R 

Gooseberries 6 Cylindrical VHAC Baltimore, MD R 

Lard 15 Rectangular HAC - R 

Lemonade 150+ Cylindrical EFS Boston, MA R 

Mustard 7 Cylindrical EFS Boston, MA R 

Oyster 40+ Cylindrical VHAC New York, NY; 

-Baltimore, MD R 

Peaches 2 Cylindrical HAC - R 

Peaches 4 Cylindrical VHAC Baltimore, MD R 

Peaches 40+ Cylindrical VHAC Baltimore, MD R 

Peaches 15 Cylindrical VHAC - R 

Peaches 20+ Cylindrical HAC Baltimore, MD R 

Percussion Caps 60+ Cylindrical EFS London, UK R 

Pineapple - Cylindrical VHAC Philadelphia, PA R 

Sardines 1 Rectangular - Les Sables-d’Olonne, FR R 

Shoe Blacking 1 Cylindrical EFS - R 

Shoe Blacking 17 Cylindrical EFS Philadelphia, PA R 

Shoe Blacking 14 Cylindrical EFS - R 

Strawberries 2 Cylindrical VHAC - R 

Strawberries 15 Cylindrical HAC Baltimore, MD R 

Tomatoes 1 Cylindrical HAC Baltimore, MD R 

Tomatoes 15 Cylindrical VHAC Baltimore, MD R 

Wagon Grease 30+ Cylindrical EFS - R 

Yeast 600+ Cylindrical EFS Boston, MA R 

Cherries 24+ - - - P 

Cod Liver Oil 72 Cylindrical/

Rectangular - - S

Cream of Tartar - - - - P 

Gunpowder - - - Saugerties, NY P 

Peach Marmalade - - - Philadelphia, PA P 

Pepper - - - New York, NY P 

Pie Fruits 24 - - Philadelphia, PA P 

EFS – External Friction Slip Lid; HAC – Hole-and-Cap; VHAC – Vented Hole-and-Cap

Sources: (R) Rock 1987:76–90; (P) Petsche 1974:50–71; (S) Switzer 2013:155
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Figure 15.19. Metal can recovered from 

iron conglomerate HL-0582. (Illustration by 

Bruce Thompson, courtesy of FOTH.)

facturing and size data suggest that the cans accumulated around the site in the last two decades of the 19th 

century. This is consistent with the geological evidence 

supporting a gradual burial of the submarine as a result 

of increased sediment load brought in by the construction of the jetties at the mouth of Charleston harbor.

—HGB 

HL-3288 — Tinned Iron Can

 Only one can, HL-3288, recovered from the Hunley

site was deconcreted and studied in detail. It was 

removed from the iron conglomerate recovered from 

coarse sand immediately adjacent to the extreme 

forward end of the starboard bow that also contained 

HL-0582 and HL-3289. The surviving elements of the can 

consist of very thin and fragile iron partially covered by 

a mixture of a hard, clay-like substance and ferrous concretion (Figure 15.19). Approximately two-thirds of the 

can’s exterior surface was exposed for documentation 

purposes; the remainder is still obscured by concretion. 

The can measures 12.4 cm (4.88 in.) in overall 

length, exhibits an average preserved wall thickness of 

0.4 cm (0.16 in.), and has base and mouth diameters of 

10.1 cm (3.98 in.) and 10.6 cm (4.17 in.), respectively. 

A radiograph of the artifact revealed the presence of 

three circular welded rings along its exterior surface 

(Figure 15.20). Two concentric rings are located at 

one end, while the third surrounds the opposite end. 

A single weld line connects the outermost base ring 

to the mouth ring. The 

regularity of this seam 

suggests machine production. The cap seam 

shows two areas of hand 

solder, suggestive of the 

use of prefabricated lead 

solder strips that were 

curved into a circle and 

closed by hand, similar 

to the process described 

in the 1871 patent of 

Edward Lang (US Patent 

112054). The radiograph 

also revealed a weld 

spot in the center consistent with the vented 

hole-in-cap can design 

common in the late 19th and early 20th centuries.

While the can is not directly associated with Hunley, 

its presence in an iron conglomerate that also contained 

one of the brackets that supported the spar torpedo 

boom suggests that it is at least contemporaneous 

with the submarine’s loss and subsequent burial in the 

seabed.

— SM/HGB

Wood 

HL-0505 — Wooden Plank

A thick wooden plank was found adjacent to the 

starboard bow, 42 cm (16.54 in.) below the top, and 

extending 27 cm (10.63 in.) forward of the bow casting 

(Figure 15.21). It has a maximum length of 67.3 cm 

(26.50 in.), maximum width of 12.2 cm (4.80 in.), and 

maximum thickness of 5.8 cm (2.28 in.). One end is 

cut at roughly a 35° angle and retains visible cut marks 

(Figure 15.22). The opposite end is heavily deteriorated, 

with no original surface surviving. Two parallel scoring 

marks are present across one face approximately 

Figure 15.20. Radiograph of 

metal can HL-3288, showing 

the locations of specific 

manufacturing features. 

(Courtesy of FOTH)

Figure 15.21. Wooden plank (HL-0505) found close to 

starboard bow. (Photo by Michael Scafuri, Courtesy of 

FOTH)
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27 cm (10.63 in.) from the eroded end. The marks are 

3.15–3.9 cm (1.24–1.54 in.) apart. Another, shallower 

set of scoring marks are found on the opposite face, 

roughly the same distance from the end and the same 

distance apart.

Given the object’s proximity to the bow, it was 

important to determine if it could represent a portion 

of the boom that was originally mounted at the top 

of the bow casting as part of the spar rigging system 

(see Chapter 14). The dimensions of the boom were 

estimated from the surviving brackets (HL-0526 

and HL-0582) to be a maximum of 13.3 cm (5.24 

in.) wide and 14–15 cm (5.51–5.91 in.) thick. The 

wooden piece recovered is comparable in width, being 

only 1 cm (0.39 in.) smaller, but is less than half the 

expected thickness. Since both faces are reasonably 

well preserved, it is unlikely this discprepancy can be 

explained by post-depostional deterioation. In addition, 

while the score marks might have been caused by some 

sort of bracket, they are too narrow to have been 

caused by the brackets recovered at the site, which 

were 6–7 cm (2.36–2.76 in.) wide. It is therefore likely 

that this piece is intrusive and not part of the submarine’s weapon system. 

—HGB

HL-0587 — Barrel Cant

A largely intact wooden staved container 

component called a “cant” was located immediately 

adjacent to Hunley’s starboard bow (Figure 15.23). 

Cants are semicircular pieces of wood used in conjunction with “middles” and “quarters” to form the 

head of a barrel or cask. The artifact has a maximum 

preserved length of 40.9 cm (16.10 in.), maximum 

width of 15.6 cm (6.14 in.), and is 2.0 cm (0.79 in.) thick. 

It is beveled along the edge of its interior surface and 

exhibits a curved shape that would have corresponded 

to a set of “croze grooves” located around the periphery 

of the barrel’s interior ends. Croze grooves are V-shaped 

notches cut into the interior surface of each end of a 

barrel stave. When a series of staves were placed 

together to form the shape of a barrel, their corresponding notches accommodated and locked the head 

of the barrel against the rest of the container. 

The cant recovered from Hunley was likely part of a 

three-part head with an estimated diameter of approximately 17 in. (43.18 cm), based on an archaeological 

rim chart. This is very close to the standard U.S. dry 

barrel defined in 1915 as having a head diameter of 

171⁄8 in. (43.50 cm), a stave length of 281⁄2 in. (72.39 cm), 

and circumference of bulge of 64 in. (162.56 cm) (15 US 

Figure 15.22. Side view showing angled cut (left) and cross section (right) of HL-0505. (Photos by Johanna 

Rivera, courtesy of FOTH)

Figure 15.23. Wooden barrel cant recovered near the starboard side of the submarine. (Illustration by James W. Hunter III, courtesy of FOTH)
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Code §234). These barrels were intended for fruit 

(except cranberries), vegetables, and other dry goods. 

The dimensions were taken from the apple barrel, 

defined in 1912 (15 US Code §231) and likely in relatively common use before that period.

Barrels and casks were used aboard ships to carry 

items ranging from water and foodstuffs to gunpowder 

and nails. Examples of goods packed in barrels from 

the steamship Bertrand, wrecked in 1865, include flour, 

sugar, beef, pork, pecans, almonds, syrup, china, lamp 

bases, black powder, nails, and white lead (Petsche 

1974:53ff.). In addition to their common role as repositories for shipboard staples and goods, staved containers—especially large water barrels—were stowed 

in the lowest part of the hold and used as ballast. Once 

water casks and barrels were emptied of their contents, 

they were typically reused as storage containers. 

“Sprung” (damaged or leaky) staved containers were 

often disassembled and, if the damage to their components was extensive enough, discarded overboard. 

It is likely this piece was lost off a passing ship, and is 

intrusive to the site.

— SM

HL-3289 — Possible Tool Handle

A small, cylindrical wooden piece was found 

embedded in the same iron conglomerate that 

contained artifacts HL-0582 (iron bracket) and HL-3288 

(metal can). Based on its size, appearance, and composition, project archaeologists have tentatively identified 

it as a wooden tool handle (Figure 15.24). The handle 

exhibits an overall preserved length of 10 cm (3.94 in.) 

and maximum and minimum preserved diameters of 

2.2 and 1.5 cm (0.87 and 0.59 in.), respectively. A 6.5 cm 

(2.56 in.) slot passes lengthwise through the approximate center of the artifact and is believed to have once 

accommodated the tang of an iron implement such as 

a chisel, file, or awl. The slot is square in profile and 

retains a maximum preserved width and height of 

.38 cm (0.15 in.). The exterior surface of the handle is 

poorly preserved; consequently, its exact identity and 

function cannot be positively ascertained. It is likely 

intrusive to the site, although its association with the 

shackle conglomerate suggests a possible (but very 

tenuous) association with the submarine. 

—BR

HL-0594 — Wooden Plank

A broken and worn wooden plank (Figure 15.25) 

was found 77 cm (30.32 in.) aft of and 92 cm (36.22 

in.) below the top of the bow, to starboard. The piece 

measures 65 cm (25.59 in.) in length, 15 cm (5.91 in.) 

in width and is 1.5 cm (0.59 in.) thick. One end was 

cut into an asymmetrical V shape, most likely by a saw 

based on the parallel tool marks. The edges appear 

beveled, although this follows the grain and may 

therefore represent natural deterioration. The sawn 

point measures 6 cm (2.36 in.) and 5 cm (1.97 in.) along 

each face. The opposite end measures only 2.4 cm (0.95 

in.) in width, due to the loss of a longitudinal section of 

wood along a split in the grain beginning 37 cm (14.57 

in.) from the sawn end. Several other splits along the 

grain are present. No fastener marks were found. 

The piece curves gently along its length, similar to a 

barrel stave; however, the pointed end is not consistent 

with stave design. It resembles a classic fence picket, 

but other uses are possible. Association with the upper 

spar support mechanism is unlikely.

—BR

Other Organics

HL-0581 — Rope Fragment

A piece of natural fiber rope was found 60 cm 

(23.62 in.) below and 43 cm (16.93 in.) aft of the top of 

the bow, approximately 18 cm (7.09 in.) to starboard, 

parallel to the hull. When recovered, the segment was 

7.5 cm (2.95 in.) long and 1.3 cm (0.51 in.) in diameter 

(Figure 15.26). This results in a circumference, while 

saturated, of 4.08 cm (1.6 in.). The end closest to the 

bow was frayed, while the after end appeared broken 

off and most likely was once connected to one of the 

Figure 15.24. Sketch of wooden tool handle (HL-3289) 

showing socket for tool. (Illustration by Bruce 

Thompson, courtesy of FOTH)

Figure 15.25. Worn wooden plank with pointed end (HL0594). (Photo by Johanna Rivera, courtesy of FOTH)
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fragments recovered in a separate lot (HL-0585). There 

was no visible evidence of tar or other preservative. The 

fragment appears to be made up of yarns Z-twisted into 

strands, three of which were laid together to form a 

plain rope in an S-twist; three of these were further 

closed together to form a cable with a Z-twist. Based on 

terminology outlined by Sanders (2009:6–9), the rope 

appears to be a left-laid cablet, or cable-laid rope of 

“less than 9 inches (229 mm) in circumference.” Cablelaid rope was reputed to have greater resistance to 

chafing and “were relatively impervious to water, being 

known as ‘water-laid’” (Sanders 2009:8).

Hemp was the most common material used for 

maritime cordage in the United States until the late 

19th century, when Manila (abaca) began to take over 

the market. Cotton and flax were also used on occasion, 

although they were more commonly used ashore. For 

maritime use, cotton was found to be weaker and more 

apt to rot (Luce 1877:53). Hemp itself did not stand 

up well to salt water conditions, and was therefore 

generally coated in a layer of tar for shipboard use. 

Untarred hemp, or “white-rope,” was used for lead lines 

and log lines, as well as ensign and pennant halyards 

(Luce 1877:49). 

This rope cannot be directly tied to the submarine, 

but it is consistent with production from the period. It 

cannot be excluded as originating from Hunley’s spar 

rigging. Dixon specifically requested two small batches 

of cotton rope among his requisitions for supplies 

for Hunley while refitting it after the second sinking; 

however, the majority of cordage requested was 

unspecified, suggesting it was hemp (Ragan 1995:87). 

The fact that the specimen does not appear to have 

been tarred suggests it was not part of a regular ship’s 

rig, but may have come from a lost line. It is also possible 

the rope was attached to the lost grapnel (HL-2917) and 

settled near or became entangled with the hull prior to 

its being buried.

—HGB

 HL-0585 — Rope Fragment

 Additional fragments of natural fiber rope, which 

likely represent an extension of HL-0581, were located 

approximately 60 cm (23.60 in.) below and 55 cm 

(21.65 in.) aft of the tip of the bow, 10 cm (3.94 in.) 

starboard of the hull. Upon recovery, the lengths were 

approximately 28.5 cm (11.22 in.), 27.5 cm (10.83 

in.), and 11 cm (4.33 in.); all were 1.3 cm (0.51 in.) 

in diameter. There was no visible evidence of tar or 

other preservative. The composition is identical to that 

described for HL-0581.

A sample was examined by Susan Heald, textile conservator with the National Museum of the American 

Indian using a Nikon Eclipse polarizing microscope. 

Since the rope had been conserved with silicone oil 

prior to examination, the light was unable to penetrate 

the fibers well (Figure 15.27). Nevertheless, it was 

evident that the fibers were not inconsistent with hemp, 

although several other bast fibers, such as jute and flax, 

demonstrate similar patterns. Abaca, however, as a leaf 

fiber, and cotton, as a seed fiber, can be ruled out.

 —HGB

Figure 15.26. Fragment of Z-twist rope (HL-0581). (Courtesy of FOTH)

Figure 15.27. Sample of rope fiber (HL-0585) 

examined under cross polarized light. (Image by Susan 

Heald, National Museum of the American Indian)
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200

Ceramics and Glass

HL-0447 — Bottle Body Fragment

 A clear glass shard was found in the starboard OII 

perimeter trench, roughly in line with the bow of the 

submarine. It very likely originated from a bottle of indeterminate type and form. It has a maximum preserved 

length of 5.4 cm (2.13 in.), a maximum preserved width 

of 4.45 cm (1.75 in.), and is 0.15 cm (0.06 in.) thick. 

The fragment is curved along both its longitudinal 

and lateral surfaces, suggesting that it may have once 

comprised part of the shoulder of a cylindrical bottle. 

With the exception of a slightly raised straight line at 

one of its ends, the shard is undecorated. Not enough 

of the line is preserved to determine what diagnostic 

attribute, if any, it represents. Two small conchoidal 

fractures are present on the fragment, as are a small 

number of gas inclusions (or “seeds”) in the glass body. 

Its lack of distinct diagnostic attributes precludes a discussion of the artifact’s type, origin, and cultural and 

temporal affiliation. 

— SM

HL-0448 — Yellow Ware Bowl Fragment

A large ceramic sherd was recovered from the 

starboard OII perimeter trench, roughly in line with the 

bow of the submarine. The piece makes up approximately one-third of a slip-banded American yellow 

ware bowl (Figure 15.28). It retains many of the vessel’s 

important diagnostic attributes, including significant 

portions of the rim and base, as well as a number of 

decorative elements. The sherd measures 14.3 cm 

(5.62 in.) (linear distance) from the bottom of the foot 

ring to the top of the rim, and has a maximum preserved 

width of 26.2 cm (10.32 in.). Its body thickness ranges 

from 0.6 cm to 1.05 cm (0.24–0.41 in.). A rim chart 

indicates its original diameter was approximately 30 cm 

(11.81 in.). The rim is undecorated and has a width and 

thickness of 2 cm (0.79 in.) and 1.3 cm (0.51 in.), respectively. The base consists of a plain circular foot ring with 

a beveled interior surface. The foot ring has a maximum 

thickness of 1.5 cm (0.59 in.) and an estimated diameter 

of 14 cm (5.51 in.). No diagnostic markings are evident 

on the preserved portion of the base.

The sherd has a dark, yellowish-brown body with 

numerous inclusions of various sizes and types. Except 

where broken, the specimen is completely covered in 

clear (presumably alkaline) glaze. Three annular bands—

two composed of white slip and one of dark brown slip—

are located between the lower edge of the rim and the 

approximate middle of the sherd (Figure 15.29). Both 

white bands are 1.4 cm (0.55 in.) wide; the brown band 

is 0.4 cm (0.16 in.) wide. All three bands exhibit areas 

where the slip was accidentally disrupted or disturbed 

during the manufacturing process. Although the vessel 

was likely wheel-thrown, no rill marks are evident on 

either the interior or exterior surface of the sherd. 

American yellow ware is refined earthenware that 

was first produced during the latter half of the 1820s. 

By the 1850s, the type was being manufactured in a 

variety of forms and decorations. Cups, pitchers, and 

bowls were decorated with a variety of multi-colored 

slip bands and elaborate slip designs. Other decorative 

methods employed on yellow ware vessels included 

molded relief, underglaze painted, finger trailing, and 

luster. One interesting attribute of yellow ware is that 

the type was produced in increasingly paler and brighter 

hues as the 19th century progressed (Leibowitz 1985; 

Richardson 2001; Sussman 1997).

Figure 15.28. Slip-banded American yellow ware bowl fragment (HL-0448). 

(Illustration by James W. Hunter III, courtesy of FOTH)
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Most of the kilns producing yellow ware in the 

United States were located in New Jersey, Pennsylvania, Ohio, Vermont, New York, and Maryland. The 

type peaked in popularity during the 1860s and 1870s, 

but declined shortly thereafter as whitewares began 

to dominate the ceramics market (Leibowitz 1985; 

Sussman 1997). Annular slip banding was the first 

decorative technique employed on yellow ware. The 

earliest versions were manufactured during the 1840s 

and produced until at least 1900. The most common 

forms of yellow ware recovered from the archaeological 

record are kitchen wares, storage jars, and other utilitarian vessels (Richardson 2001).

— SM

HL-0451 — Whiteware Dish or Bowl Fragment

Approximately one-half of a small, early 20th 

century white granite (whiteware) ceramic dish or 

bowl was recovered from the port OII perimeter trench, 

forward of the bow approximately 2.5 ft. (0.76 m) below 

the seabed (Figure 15.30). It has an estimated diameter 

of 14 cm (5.51 in.) and measures 3.8 cm (1.50 in.) (linear 

distance) from the bottom of the foot ring to the top of 

the rim. The sherd’s body thickness ranges from 0.35 

to 0.92 cm (0.14–0.36 in.). The rim is gently everted, 

scalloped, and decorated along its interior face with 

a simple molded relief design. No form of decoration 

is present along the exterior of the rim. At its widest 

point, the rim has a thickness of 0.4 cm (0.16 in.). The 

surviving base consists of a plain circular foot ring with 

beveled interior and exterior surfaces with an estimated 

diameter of approximately 6 cm (2.36 in.). Two small, 

concentric 0.05 cm (0.02 in.) thick decorative rings are 

present on the flat portion of the base. The foot ring 

has a maximum thickness of 0.75 cm (0.30 in.). Small 

dimples, perforations, chips, and other imperfections 

are present on the surface of the sherd. With the 

exception of the chips, most of these appear to have 

been introduced to the artifact during the glazing and 

firing processes, suggesting that the vessel was one of 

a number of mass-produced and cheaply manufactured 

wares. 

The sherd is composed of a partially vitrified white 

earthenware paste with no visible inclusions. Except 

where broken or chipped, the body is fully covered in 

clear, shiny glaze that shows no evidence of crazing. 

Although the vessel was undoubtedly wheel-thrown, no 

rill marks are evident on either the interior or exterior 

surface of the sherd. White graniteware evolved from 

earlier forms of Ironstone and stone china developed 

in England during the early 19th century. The type was 

first imported to the United States in the 1840s and, 

although still manufactured today, declined as a popular 

ceramic ware by the late 1920s. The classification 

“white graniteware” is derived from early 19th century 

shipping invoices, which typically labeled the ware as 

either “White Glaze” or “White Granite.” After 1850, 

the term white granite or “W.G.” became the common 

Figure 15.29. Annular decorative bands on the outer 

surface of HL-0448 show some manufacturing flaws. 

(Courtesy of FOTH)

Figure 15.30. White granite ceramic 

dish fragment (HL-0451). Note maker’s 

mark and distributor’s stamp on base 

of vessel. (Illustration by James W. 

Hunter III, courtesy of FOTH)
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designation for the type. According to Miller (1991:10), 

white graniteware was the dominant form of whiteware 

used in the United States between 1850 and 1900.

Two marks are present on the underside of the 

base and appear to denote both the maker and distributor of the vessel. The maker’s mark is impressed 

in the approximate center of the base. About one-third 

of the mark is missing and portions of the remainder 

are partially obscured by glaze. Although incomplete, 

enough of the mark remains to determine its original 

complete notation:

GREENWOOD C[HINA]

 TRENTON, N. [J.]

“Greenwood China” is a trademark of the 

Greenwood Pottery and China Company, a Trenton, 

New Jersey, pottery established in 1861 by William 

Tams. Tams was an experienced potter from Staffordshire, England who started the company with several 

investors from the Trenton area. During its heyday, the 

Greenwood pottery was one of the largest American 

producers of household and hotel china (Goldberg 

1998). It remained in business until 1933. For a short 

period of time in the 1880s, Greenwood produced 

famous, high-quality art porcelain known as Ne Plus 

Ultra. The “Greenwood China” trademark was first 

impressed on the company’s ceramic items in 1886 and 

used until 1910, after which time a different trademark 

was used (Lehner 1988:180). 

The other mark is stamped on the surface of the 

glaze in red ink. It is located near the inside edge of the 

foot ring and reads as follows:

JAMES M. SHAW & CO.

NEW YORK

1912

4

James M. Shaw and Company was a New Yorkbased selling agency that operated during the latter half 

of the 19th century and first few decades of the 20th 

century. It specialized in the sale and distribution of 

ceramic items produced by various potteries operating 

in the United States and England (Lehner 1988:417). 

Although the company dealt primarily with ceramic 

tableware, it also distributed a variety of other merchandise, including bedpans and mantel clocks. Interestingly, the year of distribution (1912) for this particular 

dish occurred two years after the Greenwood Pottery 

and China Company discontinued its “old” trademark 

(see above). The purpose of the Arabic numeral four 

(4) is unclear; it may represent a batch number or 

designate an individual item in a numbered dinner 

service or tableware set. 

— SM

HL-0506 — Condiment Bottle

 Five aqua-colored glass fragments were recovered 

from dredge spoil from the port OII perimeter trench, 

roughly in line with Hunley’s stern and approximately 

3.5 ft. (1.07 m) below the seabed. When reassembled, 

the pieces comprise approximately two-thirds of an 

eight-sided, Civil War-era United States Navy condiment 

bottle (Figure 15.31). The fragments include approximately one-half of the bottle body with a complete 

base; three miscellaneous body shards; and nearly all 

of the bottle’s neck and rim with an attached portion 

of shoulder. Glass fragments that would have linked 

the base, body, and neck portions together were not 

recovered from the Hunley site; however, enough of the 

bottle remains to ascertain its overall dimensions with 

a reasonable degree of accuracy. The reconstruction 

process was aided by comparing the Hunley specimen 

Figure 15.31. Reconstruction of fragmented U.S. Navy condiment bottle 

(HL-0506). (Illustration by James W. 

Hunter III, courtesy of FOTH)
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with U.S. Navy condiment bottles recovered from the 

Civil War shipwrecks CSS Florida and USS Cumberland. 

In its reassembled configuration, the bottle has 

an estimated overall length of 13.55 cm (5.33 in.), a 

maximum diameter (between flat sides) of 4.3 cm 

(1.69 in.), and maximum body thickness of 0.5 cm 

(0.20 in.). It is a relatively straight-sided vessel, tapering 

only slightly at the shoulder before the base of the 

neck. At its base, the bottle’s neck is 3.15 cm (1.24 in.) 

in diameter. This opening increases slightly at the rim, 

which has an exterior diameter of 3.3 cm (1.30 in.) and 

is 0.5 cm (0.20 in.) thick. The diameter of the mouth 

(interior) is 2.6 cm (1.0 in.). The base has a maximum 

diameter (between flat sides) of 3.8 cm (1.50 in.) and 

thickness of 0.4 cm (0.16 in.). A circular “push up” is 

located at the bottom center of the base. It is 2.5 cm 

(0.98 in.) in diameter and has a height of 0.1 centimeter (0.04 in.). Each of the eight panels comprising 

the sides of the bottle is 10.9 cm (4.29 in.) long and 

1.7 cm (0.67 in.) wide. 

Centrally located along one of the bottle’s eight 

side panels is the notation “U.S. NAVY” in 1 cm (0.39 in.) 

tall block letters. The word “PEPPER.” is embossed in 

block letters on the panel on the opposite side of the 

bottle. A very faint mold seam is visible across the 

center of the base. It continues upward along opposite 

sides of the bottle and terminates at the base of the 

neck. Based on these attributes, the bottle was most 

likely manufactured by a two-part process. Essentially, 

the body and base were blown together in a two-part 

mold, after which the neck was applied with hand tools 

and altered to conform to the desired bottle shape. Like 

most other glass bottles manufactured during the 19th 

century, HL-0506 developed numerous small bubbles in 

its body as molten glass surrounding pockets of gas in 

the metal cooled and solidified. While this object did 

not originate from Hunley, it appears to be contemporaneous and may have washed in from the wreckage 

of Housatonic.

— SM

HL-0661 — Bristol-style Stoneware Bottle

A completely intact, American-produced Bristolstyle glazed stoneware bottle was discovered near the 

port side of the submarine’s aft hatch (Figure 15.32). It 

has an overall height of 21 cm (8.27 in.) and a maximum 

diameter of 7.85 cm (3.09 in.). The base of the bottle 

is slightly concave and has a diameter of 7.45 cm (2.93 

in.). The diameter of the bottle’s mouth increases from 

0.8 cm (0.31 in.) at the neck to 1.1 cm (0.43 in.) at the 

rim. The bottle has a double-ring style finish, with a 

“doughnut-shaped” ring at the lip, which has a diameter 

of 3.5 cm (1.38 in.) and thickness of 0.9 cm (0.35 in.). 

Immediately below the rim is a second, smaller ring, or 

collar, forming a groove with the upper ring that was 

used to secure a length of wire or string that held the 

bottle’s cork stopper in place.

The bottom portion of the bottle is white-to-buff 

colored for approximately one-half to two-thirds of 

its height. The remaining upper portion is caramel 

colored—the result of being dipped in a ferruginous 

(iron oxide) solution prior to final glazing. The entire 

bottle is covered in a clear, glossy glaze. Portions of the 

bottle’s upper half exhibit areas where the glaze pooled 

or ran during the manufacturing process. A small 

(0.6 cm [0.24 in.] diameter) mark in the form of a zero 

or letter “O” is located near the base of the bottle. Its 

meaning remains unclear; however, it most likely represents a manufacturer’s mark.

William Powell of Bristol, England, invented the 

Bristol-style glazing process in 1835. It was developed 

as a substitute for toxic lead glaze and rapidly replaced 

salt-glazed stoneware and brown slip-glazed pottery. 

Because of its “clean” white look the type soon became 

Figure 15.32. Intact American-made 

Bristol-style glazed bottle (HL-0661). 

(Illustration by James W. Hunter III, 

courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

204

popular with the British public, who at the time were 

deeply concerned about sanitation. Within a decade, 

Bristol-style glazed bottles were being manufactured 

in North America, where they remained in production 

until at least 1900 (Noël Hume 2001:324, Richardson 

2001, Zug 1986).

According to Noël Hume (1969:80), most American 

ceramic bottle makers closely emulated the wares 

produced by their British counterparts in almost every 

way but overall form. Unlike British bottles, which 

have a very distinct shape, American versions typically 

resemble glass beer bottles. British bottles are also 

usually adorned with the names and trademarks of 

either their manufacturers or producers—or both. 

These marks were often stamped in the body of the 

vessel and then highlighted with dark ink or slip. By 

contrast, few American wares were marked; those 

that are exhibit little more than a plain maker’s stamp 

(Noël Hume 1969:80). The most common vessel 

forms decorated with Bristol-style glaze are preserve/

condiment jars or beverage bottles. Most Americanproduced bottles contained ginger beer, a sweetened 

carbonated non-alcoholic beverage heavily flavored 

with ginger, capsicum, or both.

— SM

HL-0662 — Glass Bottle Basal Fragments

Two basal shards from a cylindrical olive green 

glass bottle (Figure 15.33) were recovered from spoil 

dredged from around the bottom of the hull on the 

port side, aft of the aft hatch. The largest specimen 

comprises approximately 90 percent of the bottle base, 

as well as a small portion of the bottle’s side. It has 

a maximum preserved height of 2.7 cm (1.06 in.) and 

diameter of 7.6 cm (3.0 in.). A shallow circular depression or “push up” is located at the bottom center of 

the base. It is 6.5 cm (2.56 in.) in diameter, exhibits 

a maximum height of 1 cm (0.39 in.) and is 0.9 cm 

(0.35 in.) thick. The preserved remnant of the bottle’s 

side has a maximum thickness of 0.6 cm (0.24 in.) and 

curves slightly to conform to the cylindrical shape of the 

bottle. Numerous gas inclusions are present throughout 

the bottle base, and a faint mold seam traverses its 

bottom exterior surface.

A small, conical 1 cm (0.39 in.) diameter dimple 

is centrally located on the underside of the push up. 

Immediately adjacent to the dimple is an embossed 

symbol that most closely resembles a backwards letter 

L with a stylized arrowhead at the end of the short 

stroke. The meaning of the symbol is unclear, but 

could represent a batch number or other production 

mark. The presence of the embossed symbol, dimple, 

mold seam, and relatively smooth uniform push up all 

indicate that the bottle was manufactured in either an 

open-and-shut mold or a foot-operated, three-part 

mold. Both types of molds were extremely popular 

worldwide and were used to mass-produce cylindrical 

bottles from c. 1821 until the early 20th century (Van 

den Bossche 2001:58).

The other glass shard mends with the bottle base 

and forms part of the interface between the rim of 

the base and the side of the bottle. It has a maximum 

preserved length of 3.65 cm (1.44 in.), maximum 

preserved width of 1.6 cm (0.63 in.), and maximum 

thickness of 0.35 cm (0.14 in.). Based on their size, 

color, and diagnostic attributes, both glass fragments 

probably originated from a beer or spirit bottle manufactured during the early 20th century.

— SM

HL-0675 — Glass Bottle Body Fragment

An olive green glass fragment, most likely from the 

body of a cylindrical bottle, was found while dredging 

on the port side of the submarine around the disarticulated rudder (HL-0686). It has a maximum preserved 

length of 3.4 cm (1.34 in.) and width of 1.4 cm (0.55 

in.). Its maximum thickness is 3 cm (1.18 in.). The 

shard exhibits a slight curve for its entire length and is 

heavily riddled with numerous gas inclusions. Its color, 

thickness, curved shape, and seeded appearance is 

very similar to attributes exhibited by two glass bottle 

fragments grouped under artifact number HL-0662 

(see above). Additionally, the body fragment was 

recovered from the same general location as the two 

base fragments, suggesting that they may have originated from the same bottle.

— SM

Figure 15.33. Olive green bottle base 

fragments (HL-0662). (Illustration by 

James W. Hunter, III, courtesy of FOTH)
205

16. Conclusions

R o b e r t S . N e y l a n d

H. L. Hunley was successfully raised from the 

seafloor on 8 August 2000. After 136 years and 6 months, 

Lt. Dixon and his crew, who had left Battery Marshall, 

Sullivan’s Island, on the evening of 17 February 1864, 

returned to Charleston, passing Forts Sumter and 

Moultrie. The submarine and its recovery entourage 

traveled up the Cooper River to the former Navy shipyard’s Pier Juliet, located adjacent to the Warren Lasch 

Conservation Center in North Charleston (Figure 16.1). 

Hunley was welcomed with public fanfare from the 

moment it broke the surface, which continued until it 

completed its voyage. Hunley was disembarked from 

the barge and suspended from the dockyard crane that 

slowly rolled on rails to the rear of the conservation 

laboratory, preceded by an honor guard of Civil War 

reenactors. The recovery was thus part archaeology, 

part engineering, and part spectacle. Perhaps this is an 

inevitable mix for the realization of a myth. Hunley had 

reached iconic status in South Carolina since its loss, 

but also had obtained a global reputation, for anyone 

studying submarine development learns about the first 

such craft to successfully be used as a weapon.

Much of the success of the project can be tied to 

the level of initial planning. Detailed recovery, stabilization, and conservation plans were all drafted and thoroughly vetted in order for the project to go forward. This 

allowed for realistic cost estimates and was critical to 

fundraising. Without first targeting the cost for recovery 

and conservation it was impossible to implement the 

fundraising strategy. Even though seed funding was 

necessary for the planning phase, this initial outlay of 

money was worth the investment in the long run. 

Figure 16.1. H. L. Hunley begins its journey up the Cooper River to the Warren Lasch 

Conservation Center, accompanied by a flotilla of local boaters and cheered on by 

enthusiastic spectators on shore. (Photo by Cramer Gallimore, courtesy of FOTH)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

206

the time-consuming 

process of generating 

detailed design studies 

to put out for bid. The 

use of RFPs for recovery 

and conservation were 

therefore abandoned in 

favor of moving forward 

with a sole source 

contract for recovery 

to ensure meeting the 

2000 recovery goal. This 

work could have been 

done under an RFP, but it 

would have been tied into 

a tightly itemized contract 

that would leave little flexibility in case of sudden 

changes to processes or 

equipment, a common 

occurrence in large scale 

maritime projects. In the 

case of Hunley, the change 

in recovery platform from 

Marks Tide to KarlissaB would have resulted 

in potentially expensive 

modifications to the 

original contract. The construction and staffing of a 

dedicated conservation laboratory for Hunley made the 

conservation RFP unnecessary. Overall, the flexibility to 

assemble a diverse team of experts was an enormous 

benefit to the project (Figure 16.2). 

The method selected for raising Hunley proved to 

be optimal, resulting in a seamless and intact recovery. 

It provided opportunities for examining the boat 

and its contents that would have not been available 

through other recovery methods. Given the extent 

of the artifacts surrounding the site, as well as the 

unexpected presence of the spar, which increased the 

vessel’s effective length from 40 ft. (12.19 m) to 56 ft. 

(17.07 m), the proposed method of encapsulating the 

submarine with its exterior sediment in a box would 

have been entirely inappropriate. The loss of context 

in the perimeter of the site would have been significant. By excavating the surrounding area prior to rigging 

and lifting the vessel, all artifacts adjacent to the hull 

were recovered without damage and carefully mapped, 

allowing for important insights into site formation 

processes. The care taken to transport the vessel to the 

laboratory sealed and in its original orientation allowed 

for the methodical excavation of the interior that has 

facilitated collection of data shedding light not only how 

the men of the crew died, but also how they performed 

their duties in such a difficult environment. 

One of the recommendations from the 

initial 1996 survey was 

to have all financing for 

the recovery, conservation, and curation in 

hand before the recovery 

commenced. However, 

since the project was 

heavily “front end loaded,” 

with the concurrent 

demands of the recovery 

itself and the outfitting 

of a conservation laboratory, this expectation was 

found to be unrealistic. 

Full conservation would 

take more than a decade, 

and curation would be 

ongoing after that. State 

and federal fiscal laws 

do not allow agencies to 

commit to funding for 

future fiscal years. For the 

most part they require 

moneys to be expended in 

the year in which they are 

appropriated. In addition, 

private donors tend to 

be reluctant to give large 

sums of money unless they are assured the project will 

go through and do not want to give money before it 

will be expended. Thus financing was in place for the 

recovery itself and the conservation facility, primarily 

through public money from federal and state sources, 

supplemented by donations from private companies, 

usually in the form of equipment and services, which 

they found was easier to give than cash. It was impossible, however, to establish a curation endowment, as 

the recovery and conservation laboratory consumed 

all of the initial private and public donations. Although 

the submarine had been initially committed to the 

Charleston Museum, its final exhibition and curatorial facility was not contractually committed. Without 

this final decision, it would be difficult to raise funds 

for the curatorial endowment. Nevertheless, with the 

high public interest in the project and a long-term fundraising organization in place in the form of the Friends 

of the Hunley, it was believed that future donations 

would be enough to finance the ongoing conservation and curation efforts, and the threat to the site was 

deemed urgent enough that the project move forward 

with some projected costs initially unmet.

RFPs as a means to resource recovery and conservation assets were not used. They were initially considered, but were impossible to implement without 

Figure 16.2. Members of the Hunley recovery team with 

the submarine in its tank at the WLCC. (Courtesy of FOTH)
C O N C L U S I O N S

207

One lesson taught by Hunley’s recovery and the 

subsequent research is that during archaeological 

discovery there will also be discoveries made in the 

historical records. Interest in Hunley led researchers to 

unearth previously unidentified documents pertaining 

to the vessel, the crews and designers, and submarine 

development during the Civil War. Letters from Housatonic officer John K. Crosby and even correspondence 

from Dixon himself were found, as well as other records. 

Genealogical and forensic research identified the crewmembers, giving them not only names but faces as 

well. Historical misinformation was corrected, such as 

the proper position and length of the spar and the total 

number of crewmen, which proved to be eight, not nine 

as recorded in eyewitness accounts. 

Theories on the Loss of Hunley

The chief historical question that is as yet unresolved is why Hunley sank. Speculation began immediately after the reported loss, with the two most 

common early theories being that it was sucked into the 

hole blown in Housatonic’s hull or that currents were 

too strong for the crew to make it back to shore and it 

was carried further out to sea. In regards to the former 

theory there was a rumor that during the salvage 

of Housatonic, the submarine was discovered and 

scrapped with the ship’s boilers. All these were categorically proven false by the discovery of the submarine 

roughly 900 ft. (275 m) east of its victim. 

However, the true sequence of events that led 

to Hunley’s loss is not so obvious, and only a comprehensive forensic approach can hope to recreate what 

happened the night of its loss. The excavation and 

recovery method utilized on the project was designed to 

collect the most thorough dataset possible to aid in this 

effort. While the full range of studies has not yet been 

completed, preliminary evidence from the recovery 

have allowed us to narrow down the possibilities.

There are six theories that have been hypothesized 

since the submarine’s discovery. The first is that the 

submarine’s hull breached as a result of the explosion. 

Second is that the crew saw the USS Canandaigua

approach and decided to submerge and wait on the 

seafloor for Union forces to disperse but eventually 

succumbed to the lack of air. There was also speculation that Hunley was still at the surface after the attack, 

but was subsequently struck by Canandaigua when it 

arrived to aid the stranded crew of Housatonic. Fourth 

is that the damage to the forward conning tower was 

caused by small weapons fire from the deck of Housatonic, injuring Dixon and causing the submarine to 

flood as a result. Fifth, the grapnel anchor found after 

the recovery led some to suggest that Hunley’s crew 

attempted to hold position against the outgoing tide 

until the tide changed but were inadvertently pulled 

under due to the low freeboard of the submarine and 

lack of buoyancy. Finally, the sixth is that the crew was 

rendered unconscious after the torpedo explosion and 

unable to man the pumps or respond to any damage 

to the submarine. 

Evidence from the Recovery

In order to examine these theories more closely, it 

is important to review several salient details gleaned 

from the archaeological evidence. First, since Hunley

was found close to Housatonic, it is clear the submarine 

had to have taken on water and lost buoyancy sometime 

after the attack on Housatonic; otherwise it would likely 

have drifted far out to sea with the tide, as evidenced 

by the wind and tide conditions of the night in question 

(see Chapter 3). Even with only a 1 knot current Hunley

would have traveled 1 nautical mile in an hour, which 

is 6,076.12 ft. (1,852.00 m.). The report of Housatonic

Landsman Robert Flemming states that he saw a blue 

light, on the surface of the water at the time of Canandaigua’s approach, approximately 30 minutes after the 

explosion. It is possible he was referring to the bright 

chemical flares called by that name (see Chapter 2, 

Note 4), although it is strange that no one else reported 

seeing such a light. Perhaps he was mistaken and it 

came from Canandaigua or one of its boats to illuminate an area with the potential for debris or survivors in 

the water. However, the position at which he reported 

seeing the light was consistent with Hunley’s final 

location, lending more credence to his statement. If he 

did see just a small blue-colored light, and it did come 

from Hunley, then the submarine must still have been 

at the surface (DON 1864:0546–0547). Although one 

report to the Court of Inquiry put the current at 1 knot, 

Captain Pickering reported half ebb tide, which would 

have been about 0.5–0.6 knots according to data from 

the nearest tidal station. The same recording station 

puts 4th quarter ebb at 0.3 knots. Therefore, without 

calculating for wind, the submarine adrift at 1 knot 

of current would have traveled ca. 3,000 ft. (914 m), 

at 0.5 knots ca. 1,500 ft. (457 m), and at 0.3 knots ca. 

900 ft. (274 m) in the time between the explosion and 

the arrival of Canandaigua. 

Of the three significant hull breaches found during 

the excavation, only the missing viewport in the forward 

conning tower appears to have occurred close to the 

time of the sinking. Iron fragments and sediment 

inside and below the forward conning tower suggest 

the opening occurred while the submarine was still 

upright, before it settled into its starboard list on the 

seabed (Jacobsen et al. 2012). Empirical testing has 

shown that this damage could have been caused by 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

208

in Hunley’s hand indicates there was no interior light for 

himself and the crew to correct these mistakes. From these 

events, it is evident that conditions inside the submarine 

left little time or means to correct problems before they 

became irreversible.

Analysis of Loss

With these facts in mind, a review of the predominant theories shows that several are less likely than 

others. The least likely scenario is that Hunley was 

struck by Canandaigua as it came to render assistance. 

Had this been the case, the submarine would likely have 

suffered massive damage to the hull, possibly even 

been cut in half. With a draft of 15 ft. (4.57 m) and a 

propeller of similar diameter, it is unlikely the steamer 

would have inflicted only the relatively minor damage 

to Hunley’s propeller shroud and steering mechanism 

that was found upon excavation. 

The clearest sign of damage to the hull was the 

loss of the port viewport in the forward conning tower 

(Figure 16.3). Presuming it did occur prior to the sinking, 

either as a result of small arms fire or shrapnel, it is 

problematic because the conning tower was above the 

surface of the water and Dixon would have had time 

to block the hole to prevent water from flooding the 

submarine. However, weather and sea state could also 

have been a contributing factor. With the wind building 

from the northwest at the time of the attack and immediately afterwards, and the tide setting to the northeast, 

seas would have been building with waves that could 

have thus been lapping over the conning towers. The 

damage to the forward conning tower alone should not 

have been sufficient to sink the submarine, provided 

it stayed above the surface. The hole could have been 

plugged with a garment or rag to prevent water from 

weapons fire from the crew of Housatonic, particularly 

from rifle fire, and with the submarine running at the 

surface, the damage might even have been caused by 

flying debris from Housatonic; however, the possibility 

that it occurred after the sinking cannot yet be ruled 

out. The loss of the port propeller shroud and attachment bar, as well as the displacement of the starboard 

shroud attachment bar all appear to have been caused 

by snagging from a grapnel anchor or other surfacedeployed equipment, and this must remain under 

consideration for the conning tower damage as well. 

Further analysis of the area after deconcretion is 

complete may reveal the cause of the damage.

The forward conning tower hatch was found to 

be slightly ajar when first discovered. Excavation of 

the interior confirmed that this hatch was not bolted 

down, although the after hatch was firmly fastened. 

Since the mechanism used to secure the hatch would 

have blocked access to the viewing ports, it is currently 

believed the pilot conned the submarine with the hatch 

unfastened while operating on the surface so that he 

could see out. Further analysis of the artifacts found 

inside may reveal an alternative, temporary fastening 

method used when the pilot needed access to the 

conning tower. Another important observation from the 

interior of the vessel was that there was no evidence 

of attempting to release the keel weights, as occurred 

during the second sinking. The after hatch was found 

to be secured. Also, while the analysis of the pumps is 

not complete, there is no definitive evidence that the 

pumps’ valves were open to displace water from the 

ballast tanks. Finally, the presence of the spar, nearly 

intact with only a slight bend, seems to indicate that 

direct structural damage from the explosion itself was 

minimal. The bent bracket for the boom suggests that 

some external force was applied to it, but perhaps later, 

as with the damage at the stern, as a result of being 

snagged by an anchor.

When considering the possible sequence of events 

from the night of 17 February 1864, it is important to 

keep in mind the human factor. The causes of Hunley’s 

two previous losses have been reconstructed from historical testimony, with human error being a contributing 

factor in both instances (see Chapter 2). Accounts of 

the first sinking vary, but Hasker, who was aboard when 

it went down, stated that Payne became fouled in a 

line with the hatches still open while the submarine 

was getting underway and inadvertently depressed 

the diving plane lever (Fort 1918:459). In the case 

of the second sinking, in which Horace Hunley was 

in command, he appears to have failed to close the 

forward seacock, either prior to or during their planned 

dive, flooding the forward ballast tank. With the intake 

valve open, no amount of pumping from the aft pump 

would have been able to clear the water from the crew 

compartment. In addition, the presence of an unlit candle 

Figure 16.3. What caused the hole in Hunley’s conning 

tower, and when, remain critical questions in reconstructing the sinking event. (Photo by Brett Seymour, 

courtesy of FOTH)
C O N C L U S I O N S

209

slopping in while on the surface. If water did get in, it 

could have been removed with the pumps. Finally, no 

injuries were observed to Dixon’s skeletal remains that 

might indicate he was a casualty of weapons fire. 

In regard to taking the submarine down to wait out 

the Union rescue operation or for the tide to change, if 

the damage to the forward conning tower occurred at 

the time of the submaine’s attack, Dixon would not have 

been able to take the boat down to the bottom to wait 

or to run the submarine fully submerged. Although the 

damage might not be a serious problem on the surface 

it was too large for Dixon to have sealed it securely 

enough to prevent flooding when underwater. Any 

damage to the hull that resulted in leakage would likely 

have prevented him from submerging. Dixon should 

have anticipated that other ships in the Union fleet 

could be coming to assist in the rescue or that Housatonic would deploy its ship’s boats to rescue the crew. 

Hiding on the bottom until things quieted down on the 

surface or the tide changed might have been a shortterm strategy but an attempt to hide on the bottom 

could only have been a momentary escape. He had 

conditioned his crew to submerge until they ran low 

of oxygen and he knew the limits of their endurance, 

which would be only an hour or two at most. According 

to Alexander (1902c:89), they maxed out at two hours 

and thirty-five minutes on one test, although his figures 

are not always reliable. If Dixon submerged and everything was functioning normally, he would have had to 

surface amongst the enemy prior to depleting his crew’s 

air supply. In addition, one would anticipate that, if 

Dixon had seen the approach of Canandaigua, he might 

attempt to maneuver underwater out of harm’s way; 

however, Hunley’s final location, so close to Housatonic

seems to indicate that the submarine had not navigated 

away from the site under water.

The discovery of the grapnel anchor in 2002 relatively close to the submarine and oriented toward 

the starboard side led to speculation that the crew of 

Hunley might have attempted to anchor to wait out the 

Union forces and the ebb tide, but were pulled underneath the water instead. Hunley researcher and author 

Mark Ragan, who pilots small submersibles, related his 

own personal experience of nearly sinking his submersible by using an anchor. He found that when hoisting 

on the anchor line he was pulling his vessel under 

water (Ragan 2012, pers. comm.). In addition, none of 

the historic accounts of the submarine by Alexander 

or McClintock mention the deployment of an anchor. 

Alexander states:

During this time we went out on an average 

of four nights a week, but on account of 

the weather, and considering the physical 

condition of the men to propel the boat 

back again, often, after going out six or seven 

miles, we would have to return. This we 

always found a task, and many times it taxed 

our utmost exertions to keep from drifting 

out to sea, daylight often breaking while we 

were yet in range. (Alexander 1902a)

This account indicates that they cranked the propeller 

against the outgoing current, rather than resting at anchor.

In addition, the type of anchor found does not seem 

an appropriate choice for anchoring the submarine 

(see Chapter 15). It is of light weight and appears to 

have lacked any chain between the grapnel and rope. 

Grapnels anchor better in rocky bottoms and are not the 

best choice as anchors on a sandy or hard mud bottom, 

and they also are hard to free from the bottom once 

they have set. If the vessel was going to anchor, another 

type other than a grapnel would have been the better 

choice. The submarine Intelligent Whale, for example, 

used two 350 lb. (159 kg) iron ball anchors that could 

be dropped directly down and retrieved from inside 

the crew compartment (Hitchcock 2002:167). Likewise, 

Confederate torpedoes used mud anchors similar to the 

one found at a distance from the excavation site (see 

Chapter 11). In the face of this evidence, the reports 

that the U.S. Navy dragged for Hunley offers a more 

plausible reason for the grapnel having been lost near 

the wreck site.

The most obvious place to look for a cause of the 

sinking was damage from the explosion, in particular 

a hull breech. The recovery, however, did not reveal a 

large breech caused by the explosion that led to catastrophic flooding. As mentioned above, the damage to 

the forward conning tower could have been caused by 

gunfire or shrapnel from the explosion, but should not 

have been enough to sink the vessel. However, the concussion resulting from the detonation of the torpedo 

would have created an underwater shock wave and 

the force could have been severe enough to damage 

the hull or the crew. Dixon’s watch, which was found 

to have stopped at between 8:22 and 8:23 that night, 

suggests that it stopped at the time of the explosion 

and is evidence of an effect of the concussion. If the 

explosion stopped the watch it probably also put out 

the candle flame. It is possible this could have caused 

distortion or fracturing of the metal components of the 

hull, allowing water to enter around rivets or seams, 

and physical injuries to the crew. A slow leak would 

be consistent with the report that Hunley remained at 

the surface after the explosion. It seems likely the crew 

would have attempted to stop the leaks and man the 

pumps, and, if unable to do so, they would have had 

sufficient time to unfasten both hatches and abandon 

the submarine to escape. If, on the other hand, the 

crew was disoriented or disabled by the shockwave, 

there is a chance slow leaks went unchecked and the 

boat slowly sank without an attempt to stop it. Recently, 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

210

the copper-alloy fill pipe for the forward ballast tank 

was discovered to be broken at the flange and slightly 

displaced. If this happened due to the explosion it 

would have allowed water to enter the submarine. 

However, it is as yet to be determined if this occurred 

at the time of the explosion of after. If it occurred as a 

result of the explosion, why did the crew not attempt 

to plug the hole or man the pumps? 

Given the lack of a proverbial “smoking gun,” it is 

possible that several smaller problems occurred simultaneously that, when combined, could not be overcome. 

For example, the concussion from the explosion might 

have caused some leakage that could have been 

managed by the crew’s pumping, but additional factors 

worsened the situation, such as the wake of the Canandaigua or an increase in wave height causing additional 

water to flow through the open forward hatch. Another 

possibility is that the crew was sufficiently disoriented 

from the explosive shock wave that they were unable 

to respond efficiently to the danger of hull leakage. If 

they lost their interior light and were unable to relight 

the candle or lantern soon after the explosion, their 

situation would have been compounded. Longitudinal 

instability resulting from changes in the metacentric 

center of balance due to partial flooding could have 

accelerated the submarine’s journey to the bottom. 

Finally, if Hunley was leaking but submerged to the 

bottom, such leakage would have increased in response 

to increases in exterior water pressure on the hull. Once 

on the bottom no one would have been able to lift the 

hatches due to outside pressure unless the submarine 

was completely filled with water. If Dixon was the only 

one aware of what was happening he might perhaps 

have broken out the forward viewing port himself in an 

attempt to equalize pressure by allowing the conning 

tower to fill, but was unable to lift the hatch to escape. 

This last still does not explain why the after hatch is 

securely fastened, and there was no attempt to use the 

pumps or unfasten the keel weights. 

In summation, although it still cannot be definitively stated why Hunley was lost, some scenarios can 

be ruled out or appear to be unlikely. These discounted 

theories include Hunley being struck by the Canandaigua, anchoring with the grapnel, and damage alone 

to the forward conning tower. Submerging to the sea 

floor to wait out the enemy would have been futile and 

resulted in having to emerge a short time later among 

the enemy. Submerging would also not have been 

possible with the damaged conning tower and an unfastened hatch. If they became trapped on the bottom 

they would have certainly attempted to remove the keel 

weights and pump out the ballast. Dixon and the crew 

being completely incapacitated may be unlikely due to 

the distance and position of the submarine from the 

explosion, which suggests it might not have drifted as 

far as the half ebb current would naturally have carried 

it if Hunley was still at the surface when Canandaigua 

arrived; however, the unsubstantiated sighting by 

Flemming may never be proven conclusively. 

Future Work

There is still much research and analysis to be done, 

in particular regarding the pumps and the position 

of valves to confirm for certain what the crew was 

doing immediately after the attack and if the crew had 

attempted to man the pumps or make repairs. Studies 

are underway in collaboration with the Naval Surface 

Warfare Center and the University of Michigan to 

determine the theoretical effects of the explosion on the 

hull and its crew, as well as the rate of flooding, stability, 

and performance of Hunley under various conditions. 

With the completion of deconcretion, closer examination of the hull may reveal damage, such as microfractures or distorted rivets, that could shed further light 

on what forces had the most impact on the submarine. 

Future archaeological research at the wreck site 

might include returning to the site to survey for the piece 

of the propeller shroud, thus expanding on the 2002 

and 2003 surveys. If found, its location and condition 

might yield information to determine if it was removed 

by an anchor snag. Likewise, the mud anchor should 

be relocated, excavated, and recovered to determine 

if there is any connection to Hunley or the attempts to 

relocate it. Of course additional work could be done on 

USS Housatonic, particularly in regards to the areas of 

the explosion. The anchor that was located during the 

previous surveys should be reinvestigated to determine 

if it is indeed the anchor Housatonic was on at the time 

of the attack. 

Challenges still remain for the Hunley project. The 

conservation of the submarine and artifacts has to be 

completed, as well as funding, designing, and constructing a final exhibition facility that can maintain a 

stable curatorial environment. In order to answer the 

many questions concerning Hunley’s operation and 

demise, and bring a successful conclusion to the project 

as a whole, all of the analysis has to be completed and 

published in a series of detailed reports. These should 

be comprehensive explorations of the submarine’s 

interior excavation, artifacts, crew forensics, and hull 

architectural studies. These reports should be accessible to the public and scholars. Hunley, its science, and 

its story belong to the American public. 
211

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2000 The Louisiana State Museum Vessel: A Historical and Archaeological Analysis of an 

American Civil War-Era Submersible Boat. 

Master’s thesis, Department of Anthropology, 

Texas A&M University, College Station. 

Wilson, Robert

1875 A Treatise on Steam Boilers: Their Strength, 

Construction, and Economical Working. 3rd 

edition, revised. Lockwood, London, UK.

Wise, Henry A.

1863 Letter to Mary Wise, 1[1] November. Letters 

of Henry A. Wise to His Wife, Mss1 W7574 

b, Wise Family Papers, 1777–1973, Virginia 

Historical Society, Richmond, VA.

Zug, Charles

1986 The Folk Potters of North Carolina. University 

of North Carolina Press, Chapel Hill. 
225

APPENDIX A

Hunley Conservation 

Symposium

Summary of Proceedings
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

226

Hunley Conservation Symposium

In 1999 a symposium was held in Charleston, 

South Carolina to consider the proposed recovery of 

the submarine H. L. Hunley. The meeting, held from 

November 18 to 20, brought together an international 

group of authorities experienced in recovery and conservation of objects similar to Hunley. The purpose was 

to explore issues specific to Hunley and exchange ideas 

on methods of recovery, excavation, and conservation 

of the submarine. Ten experts were invited to present 

papers on their research, participate in discussions 

regarding Hunley, and critique methods for its recovery 

and conservation (Table A1). 

Hunley and other similar large iron objects 

recovered from marine environments pose unique 

retrieval and conservation problems that few experts 

have experienced. The group in attendance represented 

pioneers in the fields of corrosion of iron shipwrecks, 

in-situ preservation, and conservation. Invitees, their 

affiliations, and titles of their papers are provided below. 

Warren Lasch, Chairman of the Friends of the Hunley, 

welcomed the group and Senator Glenn McConnell, 

Chairman of SCHC, made the opening remarks.

Other archaeologists, conservators, and interested 

parties attended the symposium and participated in the 

question and answer sessions. These included Richard 

Lawrence, Underwater Archaeologist for the State of 

North Carolina, Dr. John Broadwater, Manager of the 

USS Monitor National Marine Sanctuary, Dr. Bradley 

Rodgers of East Carolina University, and Kate Singley, 

a conservator of waterlogged artifacts. Other participants included Maria Jacobsen and Paul Mardikian of 

the Hunley Recovery Team, Steve Wright and Leonard 

Whitlock both of OII, and Robert Adams, an underwater 

archaeologist representing IAL, a firm requesting an 

opportunity to submit a proposal for recovery of the 

vessel.

The opening presentations were made by Larry 

Murphy of the National Park Service and Dr. Robert 

Neyland of the Naval Historical Center. Mr. Murphy 

reported on data recovered from the Hunley archaeological site during a 1996 survey conducted by the 

National Park Service. The survey provided valuable 

data with which to make determinations about whether 

recovery was warranted and how it could be accomplished safely. While corrosion appeared to have been 

slowed by the stable anaerobic burial environment, 

their assessment was that corrosion would continue 

until all the metal in the submarine was eventually 

lost. None of the areas of the hull that they uncovered 

appeared to be excessively corroded and overall the hull 

and hatches appeared solid, sound, and strong. The only 

damage observed was a hole in the forward conning 

tower, originally noted by the NUMA team who found 

the vessel in 1995.

Table A1. Symposium Participants and Presentations

Participant Affiliation Presentation

Larry Murphy NPS Submerged Cultural 

Resources Unit

The 1996 Hunley Assessment

Dr. Jonathan Leader South Carolina Institute of 

Archaeology and Anthropology

Corrosion Measurements during 

the 1996 Assessment

Dr. Robert S. Neyland U.S. Navy Naval Historical Center Work on the Hunley Project, 1996-1999

Dr. Michael McCarthy Department of Maritime 

Archaeology, Western Australian Maritime Museum

The Submarine as a Class of 

Archaeological Site 

Martin Dean Archaeological Diving Unit, University of St. Andrews, ScotlandThe Second Loss of the Resurgam: 

Problems in Protecting One of the World’s 

First Steam Powered Submarines

Dr. Donny Hamilton Nautical Archaeology Program, 

Texas A&M University

Conservation of Large Iron Artifacts: 

The Sacred and Profane

Peter Lawton Treadgold Industrial Heritage 

Museum, Portsmouth, England

The Use of Electrolysis in the Conservation of HM Monitor M33 (Built 1915)

Dr. Ian MacLeod Department of Materials Conservation, Western Australian Maritime MuseumCase Management of the Conservation of the SS Xantho and How 

to Avoid Uncontrolled Decay

Paul Mardikian Hunley Research Center, 

College of Charleston

Conservation of the Blakely 

Cannon from CSS Alabama

Curtiss Peterson The Rescue Company, Virginia Conserving the Monitor

Drs. Donald Johnson and 

William Weins. (Co-author John 

D. Makinson not present)

Department of Mechanical Engineering, University of Nebraska.Corrosion, Metallurgy, and Biofoul 

Interactions on USS Arizona
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227

The Submarine as a Class of Archaeological Site

Dr. Michael McCarthy 

Department of Maritime Archaeology, Western Australian Maritime Museum

PROFESSIONAL PAPERS

The Second Loss of the Resurgam: Problems in Protecting One of the World’s First Steam Powered 

Submarines

Martin Dean

Archaeological Diving Unit, University of St. Andrews

Dr. McCarthy addressed the importance of the 

archaeological study of submarines. As the person in 

charge of the 1985 recovery of the SS Xantho steam 

engine and manager of the Japanese submarine I-124

recovery team, Dr. McCarthy had come to look at them 

as sites unique in their international character, technology, and culture. By studying factors such as the 

organization of interior space one can gain insights into 

how the crew structured their society, which developed 

within cramped living conditions and isolation. He 

stressed the universality of the submarine experience 

that transcends national boundaries and political affiliations. The broader social effects of submarine culture, 

such as the impact of base development on communities and the international sharing of technologies, 

provide new avenues of research. As an archaeological 

site submarines are unique because of the encapsulation of the site and the potential for preservation of 

human remains in these tomblike environments. The 

ethical challenges of how to treat human remains 

from excavated submarines can be precedent-setting 

for underwater archaeologists, who rarely encounter 

these materials at traditional shipwreck sites. McCarthy 

expressed his belief that the Hunley project would 

become a benchmark and “raise the bar” in maritime 

archaeology. 

Martin Dean presented a cautionary tale of what 

can happen to an historic submarine when left on the 

seabed. Resurgam was built in 1879, designed by the 

Reverend George Garrett Prasher, who was working on 

submarines as early as the 1860s, and fabricated by 

Cochran and Co., boilermakers in Birkenhead. It was 

lost in 1880 off the northern coast of Wales, just west 

of Liverpool, while under tow. The story was popular 

in the area and many had searched for the wreck over 

the years. Resurgam was finally located by chance in 

1995 after being snagged by fishermen. The discovery 

was publicized on television and in local newspapers. 

Upon Dean’s first visit to the site, the main body of the 

vessel was relatively intact, though it had at least one 

large hole and many of its exterior control surfaces were 

missing; a section of iron straps with wooden cladding 

lay approximately eight meters away. Within 10 days, 

a porthole had been stolen, along with several brass 

control rods, and the steering wheel smashed. An initial 

survey to record the site was conducted involving local 

volunteer divers, in hopes of educating divers about 

archaeological techniques and goals. During this period, 

some of the missing pieces were returned to the site, 

suggesting the educational program was having a 

positive effect.

An effort to obtain funding for the raising and 

preservation of Resurgam was unsuccessful. The site 

was designated under the Protection of Wrecks Act, 

a cathodic protection system was installed to inhibit 

corrosion, and it was monitored under by a local 

caretaker, who went out and checked on the site 

approximately once per month. It was this man who discovered one day that the submarine had been moved. 

Dean returned to the site and found the vessel now 

upright instead of canted at 45°, and lay perpendicular 

to the current instead of parallel; its wooden cladding 

was all gone, the conning tower caved in on one side, 

and there were remains of a crude lifting strap beneath 

the hull. Dean gleaned from this experience that you 

can never guarantee a wreck’s safety when left on 

the seabed, and, as he learned from a different site, 

even 24-hour monitoring could not prevent looting of 

artifacts. His recommendation was to move Hunley to 

a safe location as soon as possible. 
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Conservation of Large Iron Artifacts, the Sacred and the Profane

Dr. Donny Hamilton

Nautical Archaeology Program, Texas A&M University

Dr. Hamilton’s talk was aimed at ethical concerns 

involved in the selection of conservation methods for 

large metal artifacts recovered from underwater sites. 

He pointed out that archaeological conservators have 

ethical standards for treating fragile artifacts, which 

generally advocate caution and reversibility of the conservation process. In his experience, ethics have to be 

balanced with the need to take decisive action and risks; 

this is especially true with large iron artifacts such as 

Hunley. Electrolytic reduction (ER), in his opinion, was 

the only existing process that had a proven track record 

for conserving iron impregnated with salts. Nevertheless, some conservators still consider the use of ER as 

“profane” and too dangerous a process to use on significant historic artifacts. He stressed there were many 

misconceptions about ER, and that it could be employed 

safely as long as the conservator fully understood how 

it worked and how to customize the process for the 

artifact in question. By way of example, he presented 

the results of several large conservation projects he 

had undertaken using this technique, including a single 

4,000 lb. (1,814 kg) anchor and a 5,000 lb. (2,268 

kg) concretion containing two stacked wrought-iron 

anchors, a cannon, two blocks, and approximately 1,000 

smaller artifacts. Artifacts from the 1554 wreck he had 

previously treated by electrolysis were still stable 20 

years later. He has found that stainless steel vats are 

not necessary, but mild steel can be a workable and 

cheaper option, and that sodium hydroxide has the best 

reduction potential. 

He pointed out that some conservators advocate 

leaving a wreck on the seabed until a better technique 

was developed; however, based on his experience, and 

referencing the example presented by Martin Dean, the 

risk of looting is too great—“[o]nce something has been 

discovered, it’s extremely difficult to keep people off 

of it.”

Conserving Hunley would be on a “completely 

different level, a completely different magnitude, 

something that’s never been attempted in the United 

States.” Among the questions the team needed to 

consider in planning to apply ER would be: what kind 

of vat to use, would it be used as the anode, what 

kind of power supplies, can the vessel be conserved 

intact or must it be disassembled. With a careful plan 

in place, use of ER would be a safe and cost-effective 

conservation option. Hamilton’s final advice was “don’t 

over-design, don’t over-complicate, and like everything 

in archaeology and conservation, 95% of it is common 

sense—the other 5% is science.” 

Use of Electrolysis in the Conservation of HM Monitor M33

Peter Lawton 

Treadgold Industrial Heritage Museum

Peter Lawton presented another practical example 

of the use of electrolysis on a large-scale iron artifact. 

Lawton agreed with Hamilton “if you have artifacts, 

you probably need fairly robust solutions to problems.” 

Historic ships such as the SS Great Britain, he noted, 

were falling apart due to overly cautious preservation 

efforts. 

Built in 1915, M33 is one of only two surviving 

British World War I warships. It is a monitor-class vessel, 

177 ft. (53.95 m) in length and 32 ft. (9.75 m) in beam. 

After the war, it was converted to a mine layer known 

as HMS Minerva, and then in the 1940s converted 

again to Hulk C23 and used in a variety of roles over 

the ensuing decades. While never sunk, the ship had its 

engine removed when it became a hulk and remained 

floating in place for many years. It was acquired by the 

Hampshire County Council in the 1980s and there was 

one failed attempt at restoration. The vessel was then 

employed as a floating park with two bars and a disco 

on board. This activity was shut down by Mr. Lawton in 

1995 on his first day overseeing the vessel.

When M33 was placed in dry dock it was found 

that much of the original metal had completely deteriorated and was held together by rust and attached 

mussels. Lawton began by pressure washing the hull at 

4,000 p.s.i. (276 bar), which in some spots was strong 

enough to burn holes through badly deteriorated metal, 

although overall the vessel was found to be relatively 

sound. Eleven tons (9.98 t) of rust were removed from 

the bilge. To remove damaging chlorides, Lawton 

decided on electrolysis. They took metal samples from 

the ship and tested various anodes to find the best 

system. The area of the ship Lawton was treating at the 

time required 100 tn. (90.72 t) of electrolyte solution 

through which he passed 180 amps, equivalent to only 

350 milliamps per square meter. 
A P P E N D I X A

229

His success with M33 resulted in requests to treat 

other historic British vessels including the SS Great 

Britain and Cutty Sark. On both vessels, woven plastic 

mats developed for greenhouses were adapted to hold 

the electrolye, since the former vessel was too structurally unsound to support flooding compartments for 

treatment, and the latter was required iron frames to be 

treated without damaging the surrounding wooden hull. 

In the conservation of all three ships, bacterial attacks 

on the original anodes—316 grade steel mesh—were 

a problem, interfering with the process and eroding 

the anodes. They eventually switched to platinized 

titanium mesh with better results. Lawton stated that 

the potential problem of anode deterioration should be 

monitored closely in electrolytic treatments of Hunley. 

His recommended electrolyte was sodium carbonate, 

and he reported no problems with treating dissimilar 

metals together. 

Case Management of the Conservation of the SS Xantho and How to Avoid Uncontrolled Decay

Dr. Ian MacLeod 

Department of Materials Conservation, Western Australian Maritime Museum

Dr. MacLeod discussed his experience conserving 

the steam engine from SS Xantho, illustrating some of 

the pitfalls one can encounter dealing with large, multicomponent, iron artifacts. The engine is an example of 

the world’s first mass-produced high-pressure marine 

steam engine, built in 1861 and installed second-hand 

on Xantho in Scotland 1871. The vessel was purchased 

by Charles Broadhurst for pearling in Western Australia, 

where it eventually sank in 1872. The wreck was discovered in 1979 and the engine, weighing 7.5 tons, was 

recovered in 1985.

 Among the practical lessons gained from the 

process of conserving such a large piece, MacLeod 

emphasized the importance of teamwork between 

the archaeologists and conservators, pointing out the 

hardships of working many hours in a wet and cramped 

environment inside a conservation tank. There is a limit 

as to how many hours at a time an individual can do this 

work. His team also discovered that an oxy-acetylene 

torch could efficiently remove the rock-hard concretion 

without harm to the underlying metal and speed up the 

deconcretion process. 

The foremost lesson learned after a decade of conservation was that the engine must be disassembled in 

order to remove the chlorides located in sealed areas 

and between covered surfaces. After the removal of a 

flange on the steam pump that had been in electrolysis 

nine and a half years revealed the presence weeping 

iron corrosion products, it was decided that the entire 

engine needed to be disassembled. Some surfaces after 

disassembly still measured 2,500 ppm chlorides after 

ten years in electrolysis. MacLeod also warned of the 

danger of measuring the voltage only on the carbonized outer layer of an iron artifact and not securing 

direct measurements of the residual metal below the 

corrosion layers. This led to the development of overpotential and a strong evolution of hydrogen bubbles, 

which led to the loosening and loss of the graphitized 

outer layer. Further investigation revealed that this 

process was exacerbated by keeping the engine in 

fresh water in between rounds of electrolysis over the 

months of deconcretion. By doing this, they were inadvertently washing hydroxide ions out of the interface 

between the graphitized layer and residual metal, 

allowing it to become oxidized, thereby loosening the 

bond between the two zones. The fact that there was 

no longer a connection between the layers also contributed to the unreliable the surface voltage measurements. He advised avoiding a scenario that involves 

alternating caustic and fresh water environments on 

long-term projects. Additionally it was determined that 

right-angle edges or corners were subject to increased 

corrosion and therefore more easily damaged during 

deconcretion and conservation processes. 

Several interesting features were found on the 

interior of the engine that provided clues about the 

operational and post-depositional history of the vessel. 

One was the discovery of maghemite corrosion products 

on the interior surface of a sealed area, which does not 

normally form on marine iron. Researchers determined 

that this was a product of the engine’s normal operational use. Thus it is important to identify and document 

all corrosion products on the artifact. There were also 

two corrosion lines found that were related to water 

levels trapped inside the engine after the sinking—one 

attested the vessel’s initial position on the seabed, while 

the other reflected the position in which it settled after 

the collapse of the ship’s superstructure. MacLeod 

urged Hunley excavators to keep a close eye out for 

details like this, which might be easily overlooked but 

could actually provide important information. 
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Conservation of the Blakely Cannon from CSS Alabama

Paul Mardikian

Senior Conservator, Hunley project

The Blakely gun was recovered from the wreck of 

CSS Alabama in 60 m (200 ft.) of water off Cherbourg, 

France. He noted that much of the concretion layer was 

lost during recovery, which is not ideal from a conservation standpoint. He recommended for future cannon 

recoveries coating the surface with some sort of silicone 

prior to the lift and rigging it with a net to keep the concretions together. The cannon, similar to Hunley, was 

constructed of both wrought and cast iron. Its brass 

tangent sight was also present. 

The most difficult aspect of the conservation of the 

cannon was the removal of a munitions shell lodged 

inside the chamber. The unexpected discovery forced 

conservators to change their treatment plan, as no 

work, particularly no electrolytic reduction, could be 

performed with the barrel still loaded. A French military 

demolition team was brought in to help develop a plan 

to remove the brass fuse from the shell and flush out 

the gun powder. Conservators took a silicone mold of 

the fuse, and the demolitions team used the resulting 

cast to make a custom tool for removing the fuse. After 

one year of soaking, the gun was taken to a remote 

location, for safety purposes, and the fuse successfully 

removed. 

After the shell was made inert, it took several more 

years to remove sufficient concretion from inside the 

bore of the cannon to remove the shell and adjacent 

lead sabot. During this time the gun was put through 

a series of 2% sodium hydroxide electrolyte baths in 

order to remove chlorides. Electrolysis was first used 

to treat just the interior of the barrel, and then it was 

applied to the entire cannon. When chloride removal 

was complete, an infrared lamp was used to try the 

inside of the barrel, and then molecular sieves were 

applied to fully dehydrate the whole piece. After drying, 

specific surface areas of the cannon were coated with a 

surface consolidant (Paraloid B-48N) and then the entire 

piece received a coating of Owatrol, which can be easily 

removed with sodium hydroxide. This treatment was 

selected for its reversibility instead of using the more 

common method of submerging the artifact in hot 

microcrystalline wax. 

Conserving the USS Monitor: Adventures with Big Iron

Curtiss Peterson

The Rescue Company

Curtiss Peterson presented knowledge he and his 

team gained working with large iron artifacts and hull 

components from USS Monitor, a Civil War ironclad that 

sank off Cape Hatteras, North Carolina, at the end of 

1862. From a conservation standpoint, these types of 

artifacts make up a class Peterson termed “big iron,” 

which is more difficult to handle than most artifacts 

and requires industrial-sized equipment, larger working 

space, and special safety precautions to protect both 

the artifact and the conservators.

The anchors were the first large iron object from 

the site to be conserved, and served as a valuable 

learning opportunity prior to tackling the hull components. In order to disassemble one anchor, they used 

a combination of heat, penetrants, and physical force, 

a process resulting in the destruction of a come-along 

rated to 4,200 lb. (1,905 kg) and a bent 48 in. (122 cm) 

wrench. In the end 12 tn. (10.89 t) of press force to successfully separate the two pieces being held together by 

one bolt and one rivet. Upon disassembly, uncombined 

sodium chloride was found in abundance on the previously covered surfaces. This supported the comments 

from previous speakers that iron objects of multiple 

components must be disassembled to remove all the 

salts. 

Another example of working with big iron was 

Monitor’s propeller. At 9 ft. (2.74 m) in diameter, it 

was too large to be easily moved, requiring the conservators to constantly consider positioning themselves 

and not the object. The tank holding the propeller 

held 1,100 gal. (4,164 l), and was designed to accommodate conservators working inside. The propeller’s 

electrolysis arrangement consisted of a perforated 

plastic polyethylene pipe containing platinum-coated 

copper anodes. Current was provided by two cathodic 

protection power supplies of a type used to maintain 

pipelines. These power supplies had 12 special circuits 

for controlling current density thus allowing Peterson 

to select individual areas to reduce and control current 

flow. Electrolysis helped remove the concretion, which 
A P P E N D I X A

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came off in large sections of 20 to 50 lb. (9–23 kg). 

The team found it best to crack the concretion strategically with hammers to prevent it from coming off 

in pieces so large they might become unmanageable 

or injure someone. The tank also functioned as an 

ongoing museum exhibit, drawing several hundred 

visitors a day, and even thousands on days when the 

tank was drained. Peterson highly recommended incorporating Hunley’s conservation into a public outreach 

environment.

Highlighting his experience with riveted structures, 

Peterson discussed his working with several hull and 

deck plates from Monitor. In some cases he found that 

the plate was intact but the rivets had been entirely lost; 

in other cases, rivet heads survived, but their shanks 

were gone; and occasionally the hole in the plate around 

the rivet had enlarged, leaving a rivet in place that was 

no longer holding the plate. The variation in corrosion 

was highlighted, Peterson pointing a case where “on the 

same piece, the rivets were both anodic and cathodic 

to the structural membrane.” He also noted there was 

sometimes more significant corrosion along plate edges 

where plate compression had stressed the metal. 

An unexpected surprise was that the propeller’s 

wrought-iron shaft had apparently corroded preferentially to the cast-iron propeller itself, the exact opposite 

of how wrought iron usually behaves. This unique sacrificial corrosion was evidenced by the build-up of carbonates on the surface of the propeller, which only 

occurs when the cast iron is in a cathodic relationship to 

another metal. Research into the manufacture of 19th 

century wrought iron showed that foundry methods 

changed during the 1850s and 1860s from sponge manufacturing, in which the metal never becomes a liquid, 

to puddling. In the latter case, impurities were put into 

the liquid iron so that it would resemble the traditional 

wrought iron derived from sponge manufacture. Peterson’s assessment is that the propeller shaft consisted of 

relatively purer iron than is usually expected under the 

term wrought iron.

In closing, Peterson noted some difficulties in 

reading electrode potential measurements through 

encrustation. Measurements were more reliable when 

the encrustation had been removed. He cautioned the 

Hunley team to pay very close attention to the condition 

of the rivets. 

Corrosion, Metallurgy and Biofoul Interaction on USS Arizona.

Dr. Donald Johnson and Dr. William Weins

Department of Mechanical Engineering, University of Nebraska, Lincoln

Drs. Johnson and Weins presented data on the 

corrosion studies that have been conducted on USS 

Arizona, a 608 ft. (185.3 m) U.S. Navy battleship sunk 

during the Japanese attack on Pearl Harbor in 1941. It 

has been preserved in situ as one of the best known 

World War II Navy war memorials, but is also a potential 

environmental problem because of the hundreds of 

thousands of gallons of oil trapped within its hull. Hull 

failure due to corrosion is therefore of major concern 

and research was initiated to determine steel hull thicknesses, materials composition, signs of delamination, 

biofouling (hard concretion), and the effects of the Pearl 

Harbor environment on corrosion. 

In order to understand the corrosion processes 

acting on the hull, it was first necessary to assess the 

metal itself, analyzing its chemical composition and 

microstructure. Johnson, Weins, and co-author John 

Makinson examined metal samples from Arizona’s 

superstructure, taken from materials salvaged from the 

wreck immediately following the war, in storage at the 

Pearl Harbor Naval Base. Arizona’s hull was confirmed 

to be plain carbonate steel with a low carbon content of 

about 0.2%. The metal was also low in sulfur and phosphorous. The steel had been manufactured by the basic 

open hearth process sometime between 1913, when 

the ship was built, and the 1929-1931 ship refitting. 

Dr. Weins noted that, as with Monitor, corrosion was 

prevalent around the rivet holes of the sample metal.

The team also measured the ductile-brittle transition temperature, which was found to be high compared 

to modern standards, but significantly better than 

some early steel ship plate, such as that from Titanic. 

They then took samples from the submerged hull of 

Arizona. Samples demonstrating significant biofouling 

were vacuum encapsulated in epoxy and sectioned. 

The microstructure of the metal was examined and the 

cross section of the sample characterized using X-ray 

diffraction (XRD). This allowed them to understand what 

materials were present all the way from the base metal 

to the seawater interface.

Dr. Johnson reviewed the main avenues of 

corrosion and detailed some of the cases encountered 

with Arizona that may have a bearing on Hunley. The 

basic corrosion process has three components: an electrolyte, a metallic circuit, and an anode and cathode. 

The most obvious source of a difference in potential 

is galvanic action resulting from different metals, for 

example copper being cathodic to steel. However, other 
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232

factors can result in broad or localized potential differences. On a microstructural level, grain within a metal 

can act as a cathode, while the grain boundary itself 

acts as an anode, the principle behind etching metal. 

Iron carbide (cementite) tends to act as a cathode 

because it will allow ready evolution of hydrogen, while 

iron ferrite holds on to hydrogen and will act as an 

anode. The state of the metal surface is another factor, 

where clean or smooth areas can be a cathode, while 

rough areas might act as an anode. Where the metal 

has been under high stress will be anodic to areas of 

low stress. In instances where there is only partial or 

uneven oxygen coverage, contrary to expectation, the 

high oxygen areas act as cathodes, while low oxygen 

areas act as anodes. 

A sample of steel from Arizona showed 

pearlite, a eutectoid mixture of iron carbide and ferrite 

placements, in which the carbide tended to act cathodically to the ferrite, resulting in a differential in corrosion 

rate. Corrosion due to oxygen differential was shown 

on an iron bolt, where the deterioration began inside 

a crevice that was anaerobic. In addition to lack of 

oxygen, crevices and other areas isolated by such things 

as biofouling or pitting can trap chloride ions, therefore 

becoming acidic, resulting in an increased corrosion 

rate. An example of stress corrosion was shown, demonstrating its characteristic branching pattern. This was 

contrasted to the more linear cracking patterns of both 

corrosion fatigue and hydrogen embrittlement.

Johnson addressed the issue of biological effects 

on the corrosion environment, particularly in relation 

to bacteria. He noted that in aerobic conditions where 

bacteria consume oxygen, corrosion rates are independent of the microstructure of the metal. On the 

other hand, in anaerobic conditions where hydrogen 

is consumed, corrosion rates become somewhat 

dependent on the microstructure of the metal and the 

amount volume of hydrogen evolving from it. After 

observing that diving activity at the site led to increased 

evolution of bacteria products, such as H2

S, he hypothesized that the gas volume developed has proportionality to the corrosion rate.

Incorporating the organic materials into their 

research, Drs. Johnson and Weins took biofoul samples, 

collected the Fe3

O4 from the samples from 8 ft. (2.44 

m) down to 28 ft. (8.53 m), and using, the weight of 

iron recovered, calculated an annual corrosion rate in 

relation to depth. After compensating for corrosion 

before the attack and for periods out of water while 

in dry dock, they calculated a total penetration rate 

incurred between 1913 to 1999 to be 0.2 to 0.25 mils 

(0.005–0.006 mm) per year. Johnson acknowledged 

that this method involved a number of assumptions, 

including that the all of the iron converted to iron oxide 

was preserved in the biofoul layer.

Conclusion

The papers delivered at the symposium raised many important issues to be considered by the archaeologists, 

conservators, and engineers who planned and implemented the recovery of H. L. Hunley. Since a full-scale symposium 

may not be feasible for all recovery projects, it is hoped that the inclusion of these papers here will allow future 

project planners to benefit from their advice and expertise. Many of the projects discussed have been written up in 

more detail since the conference, and a selection of publications is included below.
A P P E N D I X A

233

Further Reading

Cook, Desmond C. and Curtiss E. Peterson

2005 Corrosion of Submerged Artifacts and 

the Conservation of the USS Monitor. In 

Industrial Applications of the Mössbauer 

Effect: International Symposium, Madrid, 

Spain, 4–8 October 2004, edited by 

Mercedes Gracia, José F. Marco, and 

Fernando Plazaola. pp. 91–96. AIP 

Conference Proceedings, Vol. 765. 

American Institute of Physics, Melville, NY.

Gregory, David

2000 In Situ Corrosion Studies on the Submarine 

Resurgam: A Preliminary Assessment of 

Her State of Preservation. Conservation 

and Management of Archaeological Sites 

4:93–100.

Johnson, Donald, William N. Weins, John D. Makinson, 

and D. Martinez

2000 Metallographic Studies of the U. S. S. 

Arizona. In Understanding Processing, 

Structure, Property, 31 October–3 

November 1999. Conference Proceedings, 

pp. 85-91. Microstructural Science, Vol. 27. 

ASM International.

Johnson, Donald L., B. M. Wilson, James D. Carr, 

Matthew A. Russell, Larry E. Murphy, David L. Conlin

2006a Corrosion of Steel Shipwreck in the Marine 

Environment: USS Arizona–Part 1 Materials 

Performance 45(10):40–44.

2006b Corrosion of Steel Shipwrecks in the Marine 

Environment: USS Arizona–Part 2 Materials 

Performance 45(11):54–57.

Johnson, Donald L., Robert J. DeAngelis, Dana J. 

Medlin, James D. Carr, David L. Conlin

2014 Advances in Chemical and Structural 

Characterization of Concretion with 

Implications for Modeling Marine 

Corrosion. JOM 66:817–22.

Krop, David and Eric Nordgren

2011 Disassembly of USS Monitor’s Complex 

Mechanical Components. In Metals 2010: 

Proceedings of the Interim Meeting of the 

ICOM-CC Metal Working Group, Octover 

11-15, 2010, Charleston, South Carolina, 

USA, edited by Paul Mardikian, Claudia 

Chemello, Christopher Watters, and Peter 

Hull, pp. 70–78. Clemson University, SC.

MacLeod, Ian D.

1999 Conservation of the SS Xantho Engine: 

Lessons Learnt. AICCM Bulletin 24:10–19.

Mardikian, Paul

1997 The Conservation of Two Composite 

Objects from the Confederate Raider 

Alabama (1864). In Underwater 

Archaeology: Proceedings of the Society for 

Historical Archaeology Conference, edited 

by Denise A. Lakey, pp. 128–34.

McCarthy, Michael

1998 The Submarine as a Class of Archaeological 

Site. Bulletin of Australian Institute for 

Maritime Archaeology 22:61–70.

2002 Iron and Steamship Archaeology: Success 

and Failure on the SS Xantho. Kluwer 

Academic, New York, NY.
234

APPENDIX B

Recovery Operations 

Personnel
A P P E N D I X B

235

HAT (Hunley Archaeological Team )

Dive Team:

Dr. Robert Neyland Project Director and Chief Archaeologist NHC, SCAH

Leonard Whitlock Senior Project Manager IC

David Conlin Field Manager NPS

Matt Russell Asst. Field Manager - Diving & Logistics NPS-SCRU

Claire Peachey Asst. Field Manager - Data Recovery NPS, NHC

Harry Pecorelli III Archaeologist/Diver/Dive Safety Officer College of Charleston

Paul Mardikian Senior Conservator College of Charleston

Chris Amer Archaeologist SCIAA

Joe Beatty Archaeologist SCIAA

Dan Davis Archaeologist IC

William Gotts Archaeologist IC

Wes Hall Archaeologist IC

Shea McLean Archaeologist IC

Mark Ragan Project Historian IC

Drew Ruddy Archaeologist IC

Brett Seymour Photographer NPS-SCRU

James Spirek Archaeologist SCIAA

David Whall Archaeologist IC

Ralph Wilbanks Archaeologist IC

Surface Team:

Maria Jacobsen Senior Archaeologist College of Charleston

Michael Scafuri Archaeologist IC 

Jason Burns Archaeologist IC

Steve Howard Crew Boat Jeremy Captain IC

Darlene Russo Office Administrator FOTH

Samantha Omoresemi Administrative Support FOTH

Cindy Elgenberger Administrative Support FOTH

Tristan Amer Intern FOTH

Terri Henderson Intern FOTH

Jennings Woods Intern FOTH

FOTH – Friends of the Hunley

IC – Independent Contractor

NHC – Naval Historical Center (now Naval History and Heritage Command)

NPS-SCRU – National Park Service Submerged Cultural Resources Unit (now Submerged Resources Center)

SCIAA – South Carolina Institute of Archaeology and Anthropology

SCAH – South Carolina Archives and History
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

236

Oceaneering Team: 

Steve Wright Project Manager

Doug Dawson Asst. Project Manager/Diver

Perry Smith Lead Project Engineer/Diver

Ken Edwards Dive Supervisor

Clint Allison Diver

Josh Brown Diver

Mike Crago Diver

Todd Groseclose Diver/Shift Supervisor

Chris Hanson Diver

Marcus Harper Diver/Shift Supervisor

Eric Howard Diver

Jeff Ledda Engineer

Benni Martin Diver

Jon Sears Diver

Mark Van Emmerik Engineer/Diver

David Fontaine Captain, Marks Tide

Titan Maritime Industries, Inc. (Karlissa-B)

Dan Schwall Project Manager

Colin Trepte Barge Captain

Hank Bergman Chief Engineer

Jenkins Montgomery Crane Operator

Ken Bradford Crane Operator

Oscar Lopez Jacking Engineer
237

APPENDIX C

Companies Providing 

Essential Services to 

Hunley Recovery Operation
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

238

3M of Austin

Body Glove International 

Bultman/Bell (Greenville, SC)

Carolina Flag & Banner (Charleston, SC)

Celanese Corp

Charleston Museum (Charleston, SC)

Charleston Rigging & Marine Hardware (Charleston, SC)

City of Charleston

Coastal Carolina University

Coastal Inspection Services

College of Charleston

Cortland Cable

Cottage Industry Models

Detyens Shipyards (North Charleston, SC)

Diver Alert Network (Durham, NC)

DuLux Paints (Mount Pleasant, SC)

Fisher Scientific

Froth Pak / Dow Chemical

Ft. Sumter National Monument

Fuji Film

Fuji NDT Systems of Roselle, IA

Krautkramer Branson

Larry Raney (Charleston, SC)

Lou Edens (Mount Pleasant, SC)

Magic Brush (Deland, FL)

Marketing Solutions (Marietta, GA)

Medical University of South Carolina

National Geographic 

National Park Service

National PrintFast (Indianapolis, IN)

NCS Supply Inc. (Philadelphia, PA)

Nederman

Newco, Inc. (Florence, SC)

NuVan Technologies (Dallas, TX)

Nycom

Orion Research, Inc.

Phillips Industrial Services (Mt. Pleasant, SC)

Progressive Integrations (Charleston, SC)

Rick Guobaitis

South Carolina Department of Natural Resources

South Carolina Educational Television

Sirisky Marine

Soil Consultants

Stephen Leonard

Suncom

Teleco

Tidewater Marine

Thompson Pump (Summerville, SC)

Turner Network Television (Atlanta, GA)

US Army Corps of Engineers, Savannah

The Wet Shop (North Charleston, SC)

Williams Scotsman

YSI Inc. (Indian Trail, NC)
239

APPENDIX D

Engineering Drawings
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

240A. Building 255 - First Floor Plan
A P P E N D I X D

241

B. Chiller Tank (Elevation)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

242C. Suction Pile
A P P E N D I X D

243

D. Suction Pile and Truss (Elevation and Plan)
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

244E. Truss Chord Plans
A P P E N D I X D

245

F. Truss Steel Details
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

246G. Rigging Plan (Elevation)
A P P E N D I X D

247

H. Marks Tide Deck Plan
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

248I. Karlissa B (Elevation)
A P P E N D I X D

249

J. Sluice Box
250

APPENDIX E

Summary of Environmental Data 

Collected at the Hunley Site 

over a Period of 48 Hours
A P P E N D I X E

251
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

252
A P P E N D I X E

253
254

APPENDIX F

Analysis of Oxygen Reduction Potential 

of 

Hunley Iron Hull Plates In-Situ

Steve West

Orion Research, Inc.

Beverly, MA
A P P E N D I X F

255

May 17, 2000

Hunley Recovery Site

Offshore, Charleston, SC

Equipment Description

1. Combination Platinum ORP (Oxidation-Reduction Potential) Probes (Qty. 3)

Standard features:

• Orion Model 9179BN ORP Probes

• 6.25 mm dia. platinum pellet sensing half-cell

• Sealed, internal Ag/AgCl reference element with gelled, sat’d AgCl, sat’d KCL electrolyte

• 2 fiber liquid junctions at probe perimeter, 180 degrees apart

• Reference half-cell potential +200mV vs NHE

Modifications

• The 1-meter cables with BNC connectors were replaced with 100-foot cables with waterproof DIN connectors

• The temperature sensor was not installed.

• A chamfer was machined into the epoxy surrounding the platinum element such that the platinum protruded 

several thousandths of an inch from probe end to ensure contact with the hull of the Hunley.

2. High-Input-Impedance pH/mV Meters (Qty. 2)

Standard Features:

• Orion Model 265A

• pH and direct mV modes

• Waterproof case with DIN waterproof probe connection

3. Fluke Model 833 Multimeter

4. Miscellaneous

• Orion ORP standard solution, Cat. No. 967901

• Banana plug adapters to connect ORP probes to multimeter

Procedures, Results, and Discussion

1. The ORP probe cables were strain-relieved along their entire lengths using 3/16-in. polypropylene line and 

duct tape.

2. All three probes were tested in Orion ORP Standard (420 mV vs NHE); all read 220 mV, indicating a reference 

electrode potential of +200 mV vs NHE as expected for sat’d KCL (reference is connected to negative meter 

terminal, necessitating reversal of sign).

3. Meters and probes were set up on the port-side gunwale walkway.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

256

4. While connected to 265A meters, Probe 1 and Probe 2 were handed to divers Claire and Matt respectively. 

Coiling and uncoiling of cables was handled by Pam and Leonard topside; communication with divers was 

relayed by Dave.

5. As divers descended and moved into position, ORP in the ocean water from Probe 1 varied between 184 and 

195 (-16 and -5 vs NHE) while ORP from Probe 2 was between 193 and 199 (-7 and -1 vs NHE).

6. Both probes were contacted initially with the bow region of the sub and became immediately stable at -578 

and -579 respectively for Probes 1 and 2 (-378 and -379 vs NHE).

7. Probe 2 was relocated to the stern where a noisy reading -530 ±10mV was obtained while Probe 1 maintained 

a steady reading of -579 ±1mV at the bow (-330 and -379 mV vs NHE).

8. The positions of Probes 1 and 2 were reversed. Probe 1, now at the stern, read -530 ±10mV while Probe 2 read 

a steady -579 ±2mV at the bow. Thus the difference in readings [was] a function of the location on the hull, not 

of the individual probes.

9. Positions were reversed again and the original readings recovered. Then, after a minute or so of scraping the 

probe against the hull, quite a stable reading, -561 ±2mV (-361 vs NHE) was obtained from Probve 2 at the 

stern. This seemed to suggest that making good contact with the hull was more difficult at the stern location 

and the quality of the contact was varying.

10. To summarize the corrosion potential measurements:

• Corrosion potential at the bow of the Hunley was determined to be -379 ±2mV vs NHE.

• Corrosion potential at the stern of the Hunley was determined to be between -320 and -363 mV vs NHE.

11. Next the probes were disconnected from the 265A pH/mV meters and connected to the Fluke multimeter for 

continuity tests. When the probes were in the water near the bow and stern, readings fluctuated around 20-30 

kohm. (This is not an absurd number. The resistance of a 1-cm cube of typical seawater at 20-25 C is ~20 ohm. 

If the area of each electrode is about 0.25 sq. cm. and the electrodes are about 500 cm apart, the expected 

resistance would be in the range of, but less than, 20×500/0.25=40,000 ohm.)

12. Placing the probes in contact with the sub at the bow and stern caused the readings to drop intermittently 

to the 0.8 kohm or less range, but only briefly. If conduction through the hull were occurring, poor surface 

contact was resulting in unreliable readings. When readings were attempted from amidships to the bow and 

stern respectively, the readings didn’t add up. Between the bow and amidships, readings over 1 Mohm were 

obtained, and between amidships and the stern the readings intermittently dropped to the 0.6 kohm range, 

but again only briefly.

13. To summarize the continuity measurements:

• Either poor continuity exists between different sections of the Hunley’s hull, or poor contact was being made 

between the probes and hull.

• It might be advisable, either while the sub is still on site or when it is in the tank, to try some continuity 

measurements between spots close together on the hull (a few centimeterscm apart or less) in order to help 

diagnose whether poor continuity or poor contact resulted in the unstable, inconclusive readings.
257

APPENDIX G

Catalog of Artifacts 

Recovered from the Seabed 

Surrounding the Submarine 

H. L. Hunley
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

258Artifact #† Date Mat. Description Provenience

HL-0342 5/8/2000 ME Iron scale – 38 fragments, modern. All exhibit uniform thickness and appear cylindrical-shaped. Anomaly 2000-1.

HL-0346 5/14/2000 ME/ CC Metal flakes, thin, probably modern, and metal concretions. Total amount fills 1⁄4 of a 4 × 6 in. plastic bag. Starboard perimeter zone (10 × 130 ft., 0–5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0347 5/14/2000 SL Boiler slag – ca. 900 pieces; 3.58 kg Starboard perimeter zone (10 × 130 ft., 0–5 ft. deep). Found in sluice box while sieving dredge outflow.

HL-0348 5/14/2000 WO Wood fragments. Total amount fills a large plastic bag (9 × 12 in.). Starboard perimeter zone (10 × 130 ft., 0–5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0349 5/14/2000 CO Coal – ca. 300 pieces; 1.54 kg Starboard perimeter zone (10 × 130 ft., 0–5 ft. deep). Found in sluice box while sieving dredge outflow.

HL-0350 5/14/2000 CC

Unidentified concretion, possibly natural. Total amount 

fills a 4 × 6 in. plastic bag. Saved for reference and 

identification.

Starboard perimeter zone (10 × 130 ft., 0–5 ft. deep). Found in sluice 

box while sieving dredge outflow.

HL-0351 5/14/2000 WO Wood fragment with remnants of flat faces 2 ft. from grid, Starboard bow perimeter area.

HL-0352 5/14/2000 WO Wood sliver and four indeterminate wood fragments In sediment above forwardmost section of bow.

HL-0353 5/14/2000 SL Boiler slag, yellow and red-brown color, iridescent – 4 pieces; 0.02 kg. In sediment above forwardmost section of bow.

HL-0354 5/14/2000 CO Small fragments of coal – 9 pieces. In sediment above forwardmost section of bow.

HL-0355 5/14/2000 CC Unidentified concretion. Resembles slag, but possibly natural. Retained for future inspection and identification. Recovered from sediment at forward section of the bow.

HL-0356 5/14/2000 WO Burned wood fragments, resembling charcoal. Total amount fills 1⁄3 of a plastic bag (4 × 6 in.). Starboard perimeter zone (10 × 130 ft., 0–5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0357 5/15/2000 CO Coal, good condition – 1 large piece; 0.115 kg Stern, 2 mm abaft aftermost hatch, 0.5 m starboard of vessel centerline, and 0.5 m below mud line.

HL-0358 5/15/2000 BO Bone – 5 individual specimens; one example is broken into 3 fragments and may be an animal pelvic bone. Starboard perimeter zone (10 × 130 ft., 0–5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0364 5/15/2000 CO Coal – 30 pieces; 0.12 kg Stern area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.

HL-0365 5/15/2000 SL Boiler slag – 145 pieces; 0.53 kg Stern area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.HL-0366 5/15/2000 WO Wood fragments – 13 pieces, largest 5 cm long Stern area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.HL-0367 5/15/2000 ST Stones. Retained for reference and identification. Discovered throughout excavation area at depths ranging from 0 to 5 ft. below datum.

HL-0368 5/15/2000 ME Iron flakes (2), possibly modern Stern area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.
A P P E N D I X G

259

Artifact #† Date Mat. Description Provenience

HL-0370 5/16/2000 CC Concretion, flat with raised circular section, 4 × 2.5 × 2 cm Port bow, in sediment between hatch and bow; 0–50 cm below grade.

HL-0371 5/16/2000 WO Wood fragments. Largest piece 8 cm long. Bow area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.

HL-0372 5/16/2000 SL Boiler slag – 182 pieces; 0.54 kg Bow area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.HL-0373 5/16/2000 BO Bone – 6 fragments, likely fish Bow area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.HL-0374 5/16/2000 CO Coal – 50 pieces; 0.225 kg Bow area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.

HL-0377 5/16/2000 CC Metal concretion – 16 pieces, largest one 5.8 × 4 × 2.6 cm Bow area, surface of seabed to 3 ft. below datum. Recovered from mesh bag on dredge outflow.

HL-0378 5/16/2000 CC

Metal concretion, preserves mold of 5.7 cm length of 

cylindrical metal object, 5–6 mm diameter. Likely part of 

HL-0381.*

Bow area, surface of seabed to 3 ft. below datum. Recovered from 

mesh bag on dredge outflow.

HL-0379 5/17/2000 CC Hull concretion fragments (11), max. thickness 0.8 cm Bow area, below forward end of cutwater, 20 cm to port side.

HL-0380 5/17/2000 CC Hull concretion fragments (7), max. thickness 1.6 cm Amidships, along centerline, between 2nd and 3rd deadlight aft.

HL-0381 5/17/2000 ME/ CC Iron rod (partial) and concretion preserving mold of rod – 4 pieces. Combined length 40.6 cm. Likely also includes HL-0378, HL-0386, HL-411, HL-0428 and HL-0432.* Bow area, starboard side of hull.

HL-0382 5/18/2000 CC Concretion – 13 pieces, possible can fragments Bow area, to starboard of hull, approximately level with end of bow.

HL-0383 5/18/2000 CC Concretion – 2 pieces, possible can fragments Stern area, abaft end of submarine, moving towards datum stakes.

HL-0384 5/18/2000 ME Unidentified iron fragment, cylindrical, 10.8 cm long. Possible modern welding rod. Bent at one end. Stern area, abaft end of submarine, moving towards datum stakes.

HL-0385 5/18/2000 PA Paint fragment, red-grey, modern. Stern area, abaft end of submarine, moving towards datum stakes.HL-0386 5/19/2000 CC Iron concretion – preserves mold of 4.0 cm length of cylindrical object, 6 mm diameter. Likely part of HL-0381.* Bow area. Recovered from mesh bag on dredge outflow.

HL-0387 5/19/2000 CC Concretion, possibly natural Bow area. Recovered from mesh bag on dredge outflow.

HL-0388 5/19/2000 SL Boiler slag fragments of varying sizes – ca. 650 pieces, 3.23 kg Port perimeter zone (10 × 130 ft., 0–3.5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0389 5/19/2000 SL Boiler slag – 170 pieces; 1.25 kg Port perimeter zone (10 × 130 ft., 0–3.5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0390 5/19/2000 WO Wood fragments. Total amount fills 1⁄2 plastic bag (9 × 12 in.). Port perimeter zone (10 × 130 ft., 0–3.5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0391 5/19/2000 CC Concretion, possibly natural, and stone. Total amount fills 20% of plastic bag (9 × 12 in.) Port perimeter zone (1 0x 130 ft., 0–3.5 ft. deep). Found in sluice box while sieving dredge outflow.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

260Artifact #† Date Mat. Description Provenience

HL-0392 5/19/2000 ME Iron flake, 1.5 × 1.1 × 0.2 cm Port perimeter zone (10 × 130 ft., 0–3.5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0393 5/19/2000 ME Modern brass screw with slotted head Sediment along port side of stern cutback.

HL-0394 5/19/2000 SL Boiler slag – 121 pieces; 0.55 kg Stern area of hull around and to starboard of propeller.HL-0395 5/19/2000 CO Coal – 25 pieces; 0.145 kg Stern area of hull around and to starboard of propeller.

HL-0396 5/19/2000 WO Wood fragments – 13 pieces, largest 4.6 cm in length Stern area of hull around and to starboard of propeller.HL-0397 5/19/2000 CC Concretion – 2 pieces, largest 7.9 × 5 × 2.7 cm Stern area of hull around and to starboard of propeller.

HL-0398 5/20/2000 CO Coal – 1 piece; 1.4 kg Port cutback, stern quarter.

HL-0399 5/20/2000 RU Rubber fragments (2), 1 a partial gasket Cutback area at starboard amidships.HL-0400 5/20/2000 CC Concretion – 2 small, roughly circular pieces Bow area.

HL-0401 5/20/2000 CO Coal – 46 pieces; 0.285 kg Bow area, starboard side between bow and hatch, excavating forward and to starboard.

HL-0402 5/20/2000 SL Boiler slag – 125 pieces, 0.4 kg Bow area, starboard side between bow and hatch, excavating forward and to starboard.HL-0403 5/20/2000 CC Iron concretions (2), largest 3.9 × 2.6 × 1.7 cm Bow area, excavating to starboard of the hull between the tip of the bow and the forward hatch.

HL-0404 5/20/2000 ME Iron object, cylindrical, 5.4 cm long, .25 cm diameter. No diagnostic features. Possible modern welding rod. Bow area.

HL-0405 5/20/2000 CC Unidentified concretion, possibly natural Bow area, starboard side between bow and hatch, excavating forward and to starboard.

HL-0406 5/20/2000 SL Boiler slag – 231 pieces, 0.96 kg Starboard side of stern, from forward of aft hatch to hole abaft hatch and out to starboard; coming down on iron rod forward of aft hatch.HL-0407 5/20/2000 CO Coal – 50 pieces, 0.17 kg Starboard side of stern, from forward of aft hatch to hole abaft hatch and out to starboard; coming down on iron rod forward of aft hatch.

HL-0408 5/20/2000 WO Wood – 23 small pieces Starboard side of stern, from forward of aft hatch to hole abaft hatch and out to starboard; coming down on iron rod forward of aft hatch.HL-0409 5/20/2000 CC Concretion, possibly contains an iron nail. Rectangular- shaped object is visible in radiograph. Starboard side of stern, from forward of aft hatch to hole abaft hatch and out to starboard; coming down on iron rod forward of aft hatch.

HL-0410 5/20/2000 CC Concretion – ca. 50 pieces, from hull surface tests Around entire periphery of hull within the two inner cutback lines.

HL-0411 5/20/2000 CC Concretion, 5 cm in length, with hollow mold openings at each end. Possibly related to HL-0381. Stern area from forward of aft hatch, abaft hole aft of hatch, and along starboard side.

HL-0412 5/20/2000 ME Steel spring, modern Starboard side of stern, excavating down to rod on starboard side.HL-0413 5/22/2000 CC Iron concretions – 22 pieces. At least one from hole-and- cap can. Starboard side of stern, excavating down to rod near aft hatch.
A P P E N D I X G

261

Artifact #† Date Mat. Description Provenience

HL-0414 5/22/2000 ME Iron, amorphous chunk Starboard perimeter zone.

HL-0415 5/22/2000 GL Glass bottle fragment, brown Starboard perimeter zone.HL-0416 5/22/2000 CL Clay – 3 pieces; compact mass Starboard perimeter zone.

HL-0417 5/22/2000 CC Metal concretions – 36 pieces; possible can Port perimeter strip, 0–3 ft. deep.

HL-0418 5/22/2000 SL Boiler slag – 45 small fragments; 0.115 kg Starboard side of stern, around rod and concretion. Recovered from mesh bag on dredge outflow.HL-0419 5/22/2000 CO Coal – 19 pieces; 0.095 kg Starboard side of stern, around rod and concretion.

HL-0420 5/22/2000 WO Wood fragments – 6 small pieces Starboard side of stern, around rod and concretion.HL-0421 5/22/2000 BO Bones – 2 specimens, likely fish Starboard side of stern, around rod and concretion.

HL-0422 5/22/2000 CC Metal concretion with rectangular void (0.2 × 04 cm × 3 cm). Possible nail shaft. Starboard side of stern, around rod and concretion.

HL-0423 5/22/2000 WO Wood fragments – 9 small pieces Starboard side of bow above diving plane.HL-0424 5/22/2000 WO Iron concretions – 3 small pieces Starboard side of bow above diving plane.

HL-0425 5/23/2000 CC Concretions from hull surface – 10 pieces Port perimeter zone (10 × 130 ft., 0–3.5 ft. deep). Found in sluice box while sieving dredge outflow.

HL-0426 5/23/2000 BO Bones – 3 specimens, at least one vertebra Port perimeter zone (10 × 130 ft., 0–3.5 ft. deep). Found in sluice box while sieving dredge outflow.HL-0427 5/23/2000 ME Iron can – base and partial wall, heavily concreted, and 8 additional fragments. Maximum diameter 16 cm. Stern area, immediately starboard of propeller at propeller's lower level

HL-0428 5/23/2000 CC

Iron concretion – curved with roughly cylindrical cross 

section; length 31.5 cm, diameter 0.5 cm. May be part of 

HL-0381 and related pieces.*

Bow area, just to starboard of forwardmost end of bow casting.

HL-0429 5/23/2000 CC Iron concretion, cylindrical, 4.4 cm long, 2.7 cm diam. Bow area, to starboard of bow near artifact HL-0428

HL-0430 7/19/2000 SL Boiler slag – 2 pieces; 0.305 kg Bow area, close to stem. 2 –2.5 ft. beneath upper tip of bow casting.

HL-0431 5/23/2000 SL Boiler slag – 1 piece; 0.045 kg Recovered from within mud matrix inside artifact HL-0427.

HL-0432 5/23/2000 CC Concretion, 6 cm in length, with hollow mold openings at each end, 6 mm diam. Possibly related to HL-0381.* Port side of hull at the stern and excavating aft from aft hatch.

HL-0433 5/23/2000 WO Wood fragments – ca. 25 pieces; largest 7 cm long Portside of hull, excavating to port cutback line, bringing down level (approximately to the submarine’s expansion strake), bow to stern.HL-0434 5/23/2000 SL Boiler slag – 249 pieces; 0.81 kg

Portside of hull, excavating to port cutback line, bringing down level 

(approximately to the submarine’s expansion strake), bow to stern. 

Recovered from mesh bag on dredge outflow.

HL-0435 5/23/2000 SL Boiler slag – 30 pieces; 0.14 kg Portside of hull, excavating to port cutback line, bringing down level (approximately to the submarine’s expansion strake), bow to stern.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

262Artifact #† Date Mat. Description Provenience

HL-0436 5/24/2000 SL Boiler slag – 72 pieces; 0.345 kg Starboard side of stern area, immediately around large hole.

HL-0437 5/24/2000 CO Coal – 10 pieces; 0.09 kg Starboard side of stern area, immediately around large hole.

HL-0438 5/24/2000 WO Wood fragments – 6 pieces Starboard side of stern area, immediately around large hole.HL-0439 5/24/2000 BO Bone, possibly tortoise, very hard (fossilized?) Starboard side of stern area, immediately around large hole.HL-0440 5/24/2000 SL Boiler slag – 442 pieces; 1.165 kg Bow area around spar from top of mud to spar surface. Dredge spoil recovered from mesh bag on dredge outflow.HL-0441 5/24/2000 WO Wood fragments – ca. 15 small pieces Bow area around spar from top of mud to spar surface. Dredge spoil recovered from mesh bag on dredge outflow.HL-0442 5/24/2000 CO Coal – 129 pieces; 0.315 kg Bow area around spar from top of mud to spar surface. Dredge spoil recovered from mesh bag on dredge outflow.

HL-0443 5/24/2000 BO Bone – 2 specimens of unidentified fish species, 1 is a vertebra Bow area around spar from top of mud to spar surface. Dredge spoil recovered from mesh bag on dredge outflow.HL-0444 5/24/2000 CC Iron concretion – 2 pieces, largest 6.1 × 3.2 × 1.3 cm Bow area, above spar, excavating through sediment down to it.

HL-0445 5/26/2000 OR Nut husk fragment (approximately half of entire husk) Starboard side of stern, between hatch and end (approximately 3–5 ft. along starboard hull), 1–3 ft. deep.

HL-0446 5/26/2000 ME Metal disk-shaped object, possibly lead or zinc alloy. Ext. diam. 3.2 cm; int. diam. 0.8 cm. Heavily mineralized. Port cutback strip.

HL-0447 5/27/2000 GL Glass shard, clear; 1 thin raised ridge on exterior surface. Curved, possibly from a bottle wall.* Starboard cutback strip.HL-0448 5/27/2000 CM Ceramic sherd, large, comprising approximately one-third of a slip-banded American yellow ware bowl* Starboard perimeter zone, adjacent to forward end of submarine (approximately 1.5 ft. deep in mud).

HL-0451 5/28/2000 CM

Ceramic sherd comprising approximately one-half of a 

small, early 20th century white granite (whiteware) dish or 

bowl; retains two maker’s marks, which read as follows: 

“GREENWOOD CHINA TRENTON, N. J.” and “JAMES M. 

SHAW & CO. NEW YORK, 1912 4.”*

Port perimeter strip, forward, approximately 2.5 ft. down in mud. May 

have fallen into hole from above.

HL-0452 5/28/2000 SL Boiler slag – 630 pieces; 2.7 kg

Forward suction pile area, to port and starboard of spar; additional 

fragments recovered after spar removal. Dredge spoil recovered from 

mesh bag (HAT) or sluice box (OI) at the end of dredge hoses.

HL-0453 5/28/2000 CO Coal – 81 pieces; 0.76 Forward suction pile area, to port and starboard of spar; additional fragments recovered during excavation after spar removal.

HL-0454 5/28/2000 WO Wood fragments. Total amount fills about 1⁄3 of a large (9 × 12 in.) plastic bag. Forward suction pile area, to port and starboard of spar; additional fragments recovered during excavation after spar removal.HL-0455 5/28/2000 BO Bones – 4 small specimens, fish; 2 larger specimens, likely mammal: 1 rib, 1 vertebra with possible cut marks. Forward suction pile area, to port and starboard of spar; additional fragments recovered during excavation after spar removal.
A P P E N D I X G

263

Artifact #† Date Mat. Description Provenience

HL-0456 5/28/2000 CC Metal concretions – 9 fragments, thin, some slightly curves; likely from can Forward suction pile area, to port and starboard of spar; additional fragments recovered during excavation after spar removal.

HL-0457 5/28/2000 CC Metal concretions – 6 small fragments, as least 2 from can Port side of hull moving out to port, bow to stern. Dredge spoil.

HL-0458 5/29/2000 SL Boiler slag – 176 pieces; 0.97 kg Excavation area directly around propeller. Recovered from mesh bag on dredge outflow.

HL-0459 5/29/2000 CO Coal – 19 pieces; 0.235 kg Excavation area directly around propeller.

HL-0460 5/29/2000 WO Wood fragments – 6 small pieces. Excavation area directly around propeller. Dredge spoil.HL-0461 5/29/2000 OR Walnut, 1⁄2 of shell, heavily abraded Excavation area directly around propeller. Dredge spoil.

HL-0462 5/29/2000 CC Metal concretion – 1 large piece, possibly from hull tests Excavation area directly around propeller. Dredge spoil.

HL-0463 5/29/2000 ME

Long (5.07 m), cylindrical, metal object possibly 

associated with the spar torpedo assembly, or intrusive 

to the site. Fluorescent x-ray analysis revealed that its 

metallic composition is approximately 2% lead, 4% iron, 

and 94% zinc, indicating it is made from galvanized steel.*

Discovered just off submarine’s port bow in close proximity to the 

torpedo spar, 1.5 m to port and 25 cm higher than the spar. Aft/large 

end positioned 1.9 m aft of the bow.

HL-0464 5/30/2000 SL Boiler slag – 603 pieces; 2.49 kg Stern suction pile area, perimeter line to subdatums, 0–5 ft. depth. Found in sluice box while sieving dredge outflow.HL-0465 5/30/2000 WO Wood fragments – ca. 60 pieces Stern suction pile area, perimeter line to subdatums, 0–5 ft. depth.HL-0466 5/30/2000 CO Coal – 68 pieces; 0.475 kg Stern suction pile area, perimeter line to subdatums, 0–5 ft. depth.

HL-0467 5/30/2000 CC Metal concretions (6), largest 4.3 × 4.3 × 1.4 cm Stern suction pile area, perimeter line to subdatums, 0–5 ft. depth.

HL-0468 5/31/2000 CC/ ME Metal concretions – 29 pieces, with thin lead strips on a least five. Likely from soldered can or cans. Starboard side of stern suction pile area.

HL-0469 5/31/2000 BO Bone – 4 specimens; largest is possible femur from a large animal (pig?), one end cut flat, the other broken. Stern suction pile area, close to datum array, starboard side; largest fragment recovered approximately 1 ft. below mud line.

HL-0470 5/31/2000 CR Macrofaunal specimen; coral fragment originally misidentified as concretion. Starboard side of stern suction pile area.

HL-0471 5/30/2000 SL Boiler slag – 43 pieces; 0.185 kg Port side of stern, around rudder at level of bottom of hull.

HL-0472 5/30/2000 CO Coal – 5 pieces; 0.05 kg Port side of stern, around rudder at level of bottom of hull.

HL-0473 5/30/2000 WO Wood fragments – 4 small pieces Port side of stern, around rudder at level of bottom of hull.HL-0474 5/30/2000 CC Concretion – ca. 40 pieces chiseled from torpedo spar Spar Y-assembly and nut; all sides.

HL-0475 5/30/2000 OT Three dental putty molds of spar surface and hex-nut Spar Y-assembly and nut; all sides.

HL-0476 5/30/2000 SL Boiler slag – 64 pieces; 0.53 kg Stern area, aft and to starboard of propeller. Recovered from mesh bag on dredge outflow.HL-0477 5/30/2000 CO Coal – 5 pieces; 0.0555 kg Stern area, aft and to starboard of propeller. Dredge spoil.

HL-0478 5/30/2000 WO Wood fragment Stern area, aft and to starboard of propeller. Dredge spoil.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

264Artifact #† Date Mat. Description Provenience

HL-0479 6/1/2000 SL Boiler slag – 144 pieces; 0.755 kg Stern area, port datum S4 to hatch. Found in sluice box while sieving dredge outflow.HL-0480 6/1/2000 WO Wood fragments – 13 small pieces Stern area, port side, datum S4 to hatch. Dredge spoil.HL-0481 6/1/2000 CO Coal – 15 pieces; 0.055 kg Stern area, port side, datum S4 to hatch. Dredge spoil.

HL-0482 5/31/2000 SL Boiler slag – 60 pieces; 0.595 kg Stern suction pile area, starboard side, around datums. Spoil recovered from sluice box (OI) or mesh bag (HAT) on dredge outflow

HL-0483 5/31/2000 CO Coal – 7 pieces; 0.11 kg Stern suction pile area, starboard side, around datums. Dredge spoil.

HL-0484 5/31/2000 WO Wood fragments – 5 small pieces Stern suction pile area, starboard side, around datums. Dredge spoil.HL-0485 5/31/2000 CC/ ME Metal concretion – 19 pieces, at least one with lead thin lead strip. Likely from soldered can or cans. Stern suction pile area, starboard side, near subdatum array, 0–3.5 ft. depth.HL-0486 5/31/2000 CC Metal concretion from hull surface, 5.8 × 2.8 × 1 cm Stern suction pile area, starboard side, around datums. Dredge spoil.

HL-0487 6/1/2000 OT Dental putty mold of spar Y-assembly, upper surface Spar Y-assembly; upper surface.

HL-0488 5/29/2000 OT

Unidentified material; black exterior, interior red and 

black; likely caulking, possible red lead component. 4 

joining pieces (28.5 cm), triangular cross section. 

Port perimeter strip, 0–3.5 ft. depth

HL-0502 6/4/2000 ME Iron hex-nut removed from spar assembly Spar Y-assembly, port side.

HL-0503 6/3/2000 OT Dental putty mold of hex-nut from spar assembly Hex-nut located on port side of spar Y-assembly.

HL-0504 6/3/2000 SL Boiler slag – 1 large piece; 2.115 kg 1.96 m to port of hull, 35 cm forward of hatch collar center, 1.13 m below top of hull.

HL-0505 6/4/2000 WO Wood, plank-like piece, appears to be cut along two or more sides, 68 × 10 × 6 cm.* Adjacent to starboard hull at bow. Wood intersected stem 52 cm from top measured diagonally down stern; 42 cm plumb from bow top to wood. Wood extends 27 cm forward of stem

HL-0506 6/3/2000 GL

Five aqua-colored glass fragments that, when 

reassembled, comprise approximately two-thirds of an 

eight-sided, Civil War-era United States Navy condiment 

bottle; the fragments include approximately onehalf of the bottle body with a complete base; three miscellaneous body shards; and nearly all of the bottle’s neck and rim with an attached portion of shoulder.*

Port perimeter strip; 23 ft. forward of the port stern perimeter line, 3 

ft. in from port perimeter, approx. 3.5 ft. deep.

HL-0507 6/2/2000 ST Stones (5) Stern, suction pile area. Dredge spoil.

HL-0508 6/2/2000 ME Iron and brass – 2 fragments, apparently from the Marks Tide fire pump impellor. Stern, port side, excavating from the propeller to aft hatch along the cutback line.

HL-0509 6/1/2000 OR Unidentified material, sticky and black, possibly tar; 2.9 × 2.9 × 1.7 cm Stern suction pile area, starboard side, aft of datum array, 0–3.5 ft. deep.
A P P E N D I X G

265

Artifact #† Date Mat. Description Provenience

HL-0510 6/4/2000 OT Dental putty mold of bolt head from spar assembly Bolt head located on starboard side of spar Y-assembly.

HL-0511 6/5/2000 ME Iron bolt removed from spar assembly Spar Y-assembly, starboard side.

HL-0512 6/5/2000 SL Boiler slag – 411 pieces; 1.65 kg Stern suction pile area, 20 ft. diameter and 5–8 ft. deep. Found in sluice box while sieving dredge outflow.

HL-0513 6/5/2000 CO Coal – 47 pieces; 0.18 kg Stern suction pile area, 20 ft. diameter and 5–8 ft. deep. Dredge spoil.

HL-0514 6/5/2000 WO Wood fragments. Total amount fills a large (9 × 12 in.) plastic bag approximately 1⁄3 full. Stern suction pile area, 20 ft. diameter and 5–8 ft. deep. Dredge spoil.HL-0515 6/5/2000 BO Bone – 7 small pieces; primarily fish, but one appears to be a small mammalian rib. Stern suction pile area, 20 ft. diameter and 5–8 ft. deep. Dredge spoil.

HL-0516 6/5/2000 CC/ ME Metal concretions and lead, likely fragments from soldered can Stern suction pile area, 20 ft. diameter and 5–8 ft. deep. Dredge spoil.

HL-0517 6/5/2000 ST Stone – piece of limestone, 14.4 × 5.7 × 5.1 cm Concreted to port side of hull, aft of aft hatch, about half way down. 

HL-0518 6/4/2000 CC Concretion – 3 pieces, removed from spar assembly. Spar, Y-assembly, near starboard bolt head.

HL-0519 6/6/2000 PL/ ME Miscellaneous modern materials (vinyl sticker, plastic, and beer can fragments) Stern suction pile area, 20 ft. diameter and 5–8 ft. deep. Dredge spoil.

HL-0520 6/6/2000 CC Concretion – 1 pieces, curved, possibly from spar Forward suction pile area.

HL-0521 6/8/2000 WO Wood – uncut tree limb fragment, 34.4 × 2.39 cm Discovered floating in aft suction pile hole.HL-0522 6/9/2000 OR Nut husk, possibly walnut Forward suction pile area, 20 ft. diameter and 5–8 ft. deep.

HL-0523 6/8/2000 SL Boiler slag – 15 pieces; 0.065 kg Excavating between hatches and along starboard berm between OI trench and submarine, 0–3 ft. deep. Dredge spoil.

HL-0524 6/8/2000 WO Wood – 9 small pieces, very worn Excavating between hatches and along starboard berm between OI trench and submarine, 0–3 ft. deep. Dredge spoil.

HL-0525 6/8/2000 PL Plastic action figure; spaceman. Bottom of stern suction pile area; artifact very likely washed into site.

HL-0526 6/10/2000 ME Wrought-iron shackle or bracket associated with spar torpedo assembly; nearly complete.* Approximately 2.7 cm forward and to starboard of bow. Artifact located within forward suction pile excavation area.HL-0534 6/11/2000 WO Wood – 1 unworked piece, possible root, 42 × 7 × 9 cm Forward suction pile area.

HL-0535 6/10/2000 SL Boiler slag – 126 pieces; 1.365 kg. Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Found in sluice box while sieving dredge outflow.

HL-0536 6/10/2000 CO Coal – 51 pieces, 0.97 kg Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Found in sluice box while sieving dredge outflow.

HL-0537 6/10/2000 WO Wood fragments. Total amount fills a large (9 × 12 in.) plastic bag approximately 1⁄4 full. Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Found in sluice box while sieving dredge outflow.

HL-0538 6/10/2000 BO Bone – 9 fragments; colors vary, possibly due to presence of calcareous marine deposits Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Dredge spoil.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

266Artifact #† Date Mat. Description Provenience

HL-0539 6/10/2000 CC Metal concretion with broken end revealing a thin, flat iron object. Likely fragment of a can. Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Dredge spoil.HL-0540 6/11/2000 OR Organic object, roughly spherical (1.4 cm diameter); possibly a nut or seedpod Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Dredge spoil.

HL-0541 6/11/2000 PA/ FI Miscellaneous modern materials (paint chip; woven fragment, plant fiber, 15 × 1.8 × 0.1 cm) Starboard berm between OI trench and submarine, 0–3 ft. deep. Dredge spoil.HL-0542 6/11/2000 OT Unidentified object, calcareous mineral, possibly fossilized wood Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Dredge spoil.

HL-0543 6/11/2000 ME Miscellaneous modern materials (thin wire; lead/zinc “plug” with the word CANADA molded on side) Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Dredge spoil.

HL-0544 6/11/2000 CO Coal – 1 pieces; 0.345 kg Forward suction pile hole, 20 ft. diameter and approximately 5–8 ft. deep. Dredge spoil.HL-0545 6/12/2000 OT Dental putty molds (2) of thin, flat concretion sticking out of side of hull Port side, just forward of diving plane.

HL-0546 6/13/2000 ME Custom-made steel wrench used to remove torpedo spar bolt during excavation Located within torpedo spar trench approximately 1 m from end of bow.

HL-0547 6/12/2000 SL Boiler slag – 52 pieces; 0.195 kg Starboard side of hull; cleaning silt, some excavation to concretions, exposing rod along hull.HL-0548 6/12/2000 CO Coal – 18 pieces; 0.065 kg Starboard side of hull; cleaning silt, some excavation to concretions, exposing rod along hull.

HL-0549 6/12/2000 WO Wood fragments – ca. 16 pieces Starboard side of hull; cleaning silt, some excavation to concretions, exposing rod along hull.HL-0550 6/12/2000 CC Iron concretions – 10 pieces, from hull surface tests Starboard side of hull; cleaning silt, some excavation to concretions.

HL-0551 6/12/2000 SL Boiler slag – 28 pieces; 0.155 kg Stern suction pile hole, cleanup plus additional excavation approximately 1 ft. below floor of hole.HL-0552 6/12/2000 CO Coal – 8 pieces; 0.06 kg Stern suction pile hole, cleanup plus additional excavation approximately 1 ft. below floor of hole.

HL-0553 6/12/2000 WO Wood fragments, primarily intrusive Stern suction pile hole, cleanup plus additional excavation approximately 1 ft. below floor of hole.HL-0554 6/14/2000 CC Metal concretion, thin, curved. Possible fragment of can body. Port side of hull near aft end of diving plane, discovered lying loose in sediment.

HL-0555 6/20/2000 CC Iron concretion containing stern cutwater* Starboard side of hull, forward of aft hatch, 100 cm below deck level.

HL-0556 6/13/2000 ME Iron torpedo spar (concreted)* Attached to bottom tip of bow casting; removed from submarine for recovery.

HL-0557 6/19/2000 CC Concretion – 34 pieces, removed from hull in order to take gas sample Port side of hull, forward of third deadlight.
A P P E N D I X G

267

Artifact #† Date Mat. Description Provenience

HL-0558 6/15/2000 SL Boiler slag – 21 pieces; 0.145 kg. Intrusive, washed in from surrounding area. Starboard trench; recovered from spoil during maintenance dredging. HL-0559 6/15/2000 CO Coal – 5 pieces; 0.13 kg. Intrusive, washed in from surrounding area. Starboard trench; recovered from spoil during maintenance dredging. 

HL-0560 6/15/2000 CC Metal concretion, one flat surface, 3.8 × 2.3 × 2.5 cm Starboard trench; maintenance dredging of infilled mud. Dredge spoil.

HL-0561 6/16/2000 WO Wood fragments – 6 pieces, one with extensive teredo damage Starboard trench; recovered during maintenance dredging. Dredge spoil.

HL-0562 6/16/2000 SL Boiler slag – 1 large piece, 14.5 × 11.5 × 8.5 cm; 0.625 kg Bow, port side, just aft of suction pile hole.

HL-0563 6/16/2000 SL Boiler slag – 9 pieces, medium-small; 0.305 kg. Likely intrusive, washed in from surrounding area. Port perimeter trench; maintenance dredging of infilled mud. Dredge spoil.HL-0564 6/15/2000 SL Boiler slag – 217 pieces; 1.27 kg Starboard side of hull, aft end, near hatch, around concretion HL-0555.HL-0565 6/15/2000 CO Coal – 198 pieces; 0.34 kg Starboard side of hull, aft end, near hatch, around concretion HL-0555.

HL-0566 6/15/2000 WO Wood fragments – 23 small fragments Starboard side of hull, aft end, near hatch, around concretion HL-0555.HL-0567 6/15/2000 OR Nut husk fragment, species unidentified Starboard side of hull, aft end, near hatch, around concretion HL-0555.

HL-0568 6/16/2000 BO Bone, possible vertebra fragment from marine organism Starboard side of hull, aft end, near hatch, around concretion HL-0555.HL-0569 6/19/2000 CC Concretion – 2 pieces, 2 cm and 2.5 cm Starboard side of hull, aft end, around concretions below hatch.

HL-0570 7/26/2000 WO Wood fragments – 9 pieces, largest 7.5 cm long Hole excavated for bow end truss legs.HL-0571 7/26/2000 BO Bone, possible rib, broken at one end Hole excavated for bow end truss legs.HL-0572 7/26/2000 CO Coal – 3 pieces; 0.06 kg Hole excavated for bow end truss legs.

HL-0573 7/26/2000 SL Boiler slag – 6 pieces; 0.085 kg Hole excavated for bow end truss legs.HL-0574 7/26/2000 CO Coal – 3 pieces; 0.015 kg Hole excavated for bow end truss legs.

HL-0575 7/26/2000 CC Metal concretion, amorphous, 3.8 × 3.2 × 2.2 cm Bow area, hole excavated for truss legs, between pile & bow, 3 ft. × 10 ft.

HL-0576 7/26/2000 CO Coal – 3 pieces; 0.02 kg Deepening of hole for truss legs at stern end.

HL-0577 7/26/2000 SL Boiler slag – 1 piece; 0.001 kg Deepening of hole for truss legs at stern end.

HL-0578 7/27/2000 CO Coal – 68 pieces; 0.24 kg. Intrusive. Recovered after sandbag removal, after excavation hiatus.

HL-0579 7/27/2000 SL Boiler slag – 24 pieces; 0.075 kg. Intrusive. Recovered after sandbag removal, after excavation hiatus.HL-0580 7/27/2000 WO Wood fragments – 9 pieces. Intrusive. Recovered after sandbag removal, after excavation hiatus.HL-0581 7/27/2000 FI

Rope fragment comprised of three strands of fibrous plant 

material (likely hemp or sisal). The fragment measures 

ca. 21.5 cm in overall length and is 1 cm in diameter. Each 

strand measures ca. 6 mm in diameter.*

The forward end of the rope was located 60 cm below the tip of the 

bow and 43 cm aft of the bow’s upper surface.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

268Artifact #† Date Mat. Description Provenience

HL-0582 7/27/2000 ME

Conglomerate containing a wrought-iron shackle or 

bracket associated with spar torpedo assembly and 2 

additional artifacts (HL-3288 and HL-3289).*

Located 35 cm to starboard, 5 cm forward, and 57 cm below the 

forwardmost end of the submarine’s bow.

HL-0583 7/27/2000 WO Wood, cylindrical piece, unworked, with areas of bark intact, 13.2 × 3.5 cm Located 15 cm forward, 45 cm to starboard, and 85 cm beneath the forwardmost end of the submarine’s bow (atop spar yoke).

HL-0584 7/27/2000 SL Boiler slag – 2 pieces; 0.145 kg Located immediately to starboard of the forwardmost end of the submarine’s bow, in close proximity to concretion HL-0582.HL-0585 7/27/2000 FI

U-shaped rope fragment comprised of three strands of 

fibrous plant material (likely hemp or sisal). The fragment 

measures ca. 27 cm in overall length (if straightened) and 

is 1 cm in diameter. Each strand comprising the main rope 

body measures approx. 6 mm in diameter.*

Located 60 cm beneath the forwardmost end of the submarine’s bow, 

and to starboard of the bow, below breach in the hull.

HL-0586 7/27/2000 CC

Iron concretion, likely partial base and wall of can. Very 

thin (ca. 0.25 mm) layer of metal survives. May also 

include HL-0590, HL-0591, HL-0592, HL-0593, & HL-0595.

Starboard bow, below breach in hull.

HL-0587 7/27/2000 WO Wooden barrel cant* Starboard bow, below breach in hull.HL-0588 7/27/2000 CO Coal – 1 large piece; 2.05 kg Starboard bow.

HL-0589 7/27/2000 CO/ SL Coal with slag adhesions – 1 piece; 0.305 kg Starboard bow, below breach in hull.

HL-0590 7/27/2000 CC Iron concretion; thin, curved plate; possible can or container wall. May be part of HL-0586. Starboard bow, below breach in hull.

HL-0591 7/27/2000 CC Iron concretion; flat surface with remains of rim and possible small rivet head. May be part of HL-0586. Starboard bow, below breach in hull.

HL-0592 7/27/2000 CC Iron concretion; thin plate, curved in center with flatter edges; possible can fragment. May be part of HL-0586. Starboard bow, below breach in hull.

HL-0593 7/27/2000 CC Iron concretion; thin, curved plate, with remains of rim and base. May be part of HL-0586. Starboard bow, below breach in hull.

HL-0594 7/27/2000 WO Wooden plank with chamfered end, curved or warped along 82 cm length. Parallel saw marks on both surfaces.* Starboard bow, 92 cm below top of hull, 77 cm aft of bow.HL-0595 7/27/2000 CC Iron concretion; thin, curved plate; bent at one end as if crushed. May be part of HL-0586. Starboard bow, immediately adjacent to the breach in the hull.

HL-0596 7/27/2000 CO Coal – 199 pieces: 0.865 kg Starboard bow, near breach in hull.

HL-0597 7/27/2000 SL Boiler slag – 70 pieces; 0.415 kg Starboard bow near breach, at and below level of rope.

HL-0598 7/27/2000 WO Wood fragments – 10 small pieces Starboard bow near breach, at and below level of rope.HL-0599 7/27/2000 CC Iron concretion – 4 pieces; two preserving folded rim Starboard bow near breach, at and below level of rope.

HL-0600 7/27/2000 SL Boiler slag – 4 pieces; 0.02 kg Starboard bow near breach in hull.
A P P E N D I X G

269

Artifact #† Date Mat. Description Provenience

HL-0601 7/27/2000 CO Coal – 4 pieces; 0.2 kg Starboard bow.

HL-0602 7/27/2000 WO Wood – 3 pieces of bark; longest piece 32 cm Starboard bow near breach in hull, beneath the breach.HL-0603 7/27/2000 CO Coal – 28 pieces; 0.17 kg Recovered during dredging along port side of bow.

HL-0604 7/27/2000 SL Boiler Slag – 6 pieces; 0.06 kg Recovered during dredging along port side of bow.

HL-0605 7/28/2000 CO Coal – 6 pieces; 0.285 kg Starboard and port bow, aft of and beneath Slings 0 and 1.

HL-0606 7/28/2000 SL Boiler slag – 3 pieces; 0.035 kg Aft of and below first two slings, starboard and port bow.

HL-0607 7/28/2000 CO Coal – 188 pieces; 0.66 kg Starboard bow, dredging for Slings 2 and 3.

HL-0608 7/28/2000 SL Boiler slag – 53 pieces; 0.155 kg Starboard bow, dredging for Slings 2 and 3.

HL-0609 7/28/2000 WO Wood fragments – 16 small pieces; largest 4.3 × 2.0 cm Starboard bow, dredging for Slings 2 and 3.HL-0610 7/28/2000 CO Coal – 6 pieces; 0.105 pieces Dredging below shell layer in bow for Slings 3 and 6.

HL-0611 7/28/2000 WO Wood fragments – 2 rounded, worn pieces; largest 3.9 × 4.5 × 2.9 cm Preparing for Slings 3 and 4, dredging starboard and port side, and underneath hull.

HL-0612 7/28/2000 SL Boiler slag – 1 piece; 0.05 kg Preparing for Slings 3 and 4, dredging starboard and port side, and underneath hull.HL-0613 7/27/2000 CC Concretion – 3 pieces; one with folded or lapped seam. Starboard bow, near hole, around level of rope HL-0581 & below.

HL-0614 7/29/2000 ME Iron snorkel tube, Fragment A, 67 cm long* Starboard bow, below cutwater, clearing for Slings 4 and 5.

HL-0615 7/29/2000 ME Iron snorkel tube, Fragment B, 85 cm long* Starboard bow, below cutwater and forward hatch.HL-0616 7/29/2000 ME Iron snorkel tube, 142 cm long* Starboard side of hull, below forward hatch and snorkel box.HL-0617 7/29/2000 CC/ ME Iron concretion, gently curving flat plate with loosely connected lead strip. Likely soldered can fragment. Starboard bow aft of Sling 5, excavating around snorkel tubes HL-0615 and HL-0616.

HL-0618 7/29/2000 SL Boiler slag – 31 pieces; 0.53 kg Starboard bow, aft of Sling 5, excavating around snorkel tubes HL-0614 and HL-0616.HL-0619 7/29/2000 CO Coal – 36 pieces; 0.43 kg Starboard bow, aft of Sling 5, excavating around snorkel tubes HL-0614 and HL-0616.

HL-0620 7/29/2000 CO Coal – 41 pieces; 0.24 kg Port side of hull beneath diving plane, excavating in preparation for installation of Slings 6 and 7.

HL-0621 7/29/2000 SL Boiler slag – 29 pieces; 0.08 kg Port side of hull beneath diving plane, excavating in preparation for installation of Slings 6 and 7.HL-0622 7/29/2000 CC Iron concretion – thin, flat, curved plate, thickly concreted; 13.4 × 11.9 × 5.0 cm Starboard bow, attached to hull, forward of diving plane.

HL-0623 8/4/2000 BO Bone – 1 specimen, animal, partial long bone Dredging under forward section of keel.

HL-0624 7/29/2000 CO Coal – 7 pieces; 0.01 kg Dredging under forward section of keel.

HL-0625 7/29/2000 ME Lead, possible nail, broken; circular head with rectangular shaft; 2 cm long Dredging along forward section of keel.
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

270Artifact #† Date Mat. Description Provenience

HL-0626 7/29/2000 SL Boiler slag – 9 pieces; 0.03 kg Dredging along forward section of keel.

HL-0627 7/30/2000 CC/ ME Iron concretion – thin, flat, curved plate; strip of lead solder preserved along edge Dredging beneath hull for Slings 6 and 7. Likely fell in from higher strata.

HL-0628 7/30/2000 CO Coal – 2 pieces; 0.13 kg Excavating beneath hull for Slings 6 and 7, after jetting through marl. Probably fell in from above.

HL-0629 7/30/2000 SL Boiler slag – 1 piece; 0.25 kg Excavating beneath hull for Slings 6 and 7, after jetting through marl. Probably fell in from above.HL-0630 7/30/2000 CO Coal – 1 piece; 0.03 kg Dredging starboard side of hull in preparation for Slings 8 and 9.

HL-0631 7/30/2000 CO Coal – 7 pieces; 0.07 kg Beneath hull, in area between Slings 8 and 9.

HL-0632 7/30/2000 SL Boiler slag – 1 piece; 0.035 kg Beneath hull, in area between Slings 8 and 9.HL-0633 7/31/2000 CO Coal – 45 pieces; 0.195 Below and aft of port diving plane, excavating in preparation for Slings 11 and 12.

HL-0634 7/31/2000 WO Wood fragments – 19 pieces, 2 of which are cylindrical Below and aft of port diving plane, excavating along port side of hull in preparation for Slings 11 and 12.HL-0635 7/31/2000 SL Boiler slag – 19 pieces; 0.05 kg Below and aft of port diving plane, excavating along port side of hull between Slings 11 and 13 in preparation for Slings 11 and 12.HL-0636 7/31/2000 WO/ CC Wood piece, natural, knee-like, 35 × 10.7 × 9 cm, with patch of iron concretion, 14.2 × 4.6 cm, adhered to side Excavating in preparation for Slings 11 and 12, beneath sub, 3.5 ft. aft of port diving plane.HL-0637 8/1/2000 CC Concretion – small sample (4.8 × 1.6 × 1.1 cm) of large encrustation on hull surface. No metal visible. Starboard side of hull, beneath second deadlight aft, approx. 40 cm above keel.

HL-0638 8/1/2000 OT Dental putty mold of hull surface Starboard, between and beneath first and second deadlights aft.

HL-0639 7/31/2000 CC Concretion – amorphous lump, no void or metal Port side of hull, beneath diving plane, clearing for Slings 11 and 12.

HL-0640 8/1/2000 SL Boiler slag – 38 pieces; 0.125 kg Dredging port side of hull in preparation for Slings 15 thru 19.

HL-0641 8/1/2000 WO Wood fragments – 6 small pieces, longest 6.9 cm Dredging port side of hull in preparation for Slings 15 thru 19.HL-0642 8/1/2000 CC Iron concretions – 22 pieces, from hull surface tests Dredging port side of hull in preparation for Slings 15 thru 19.

HL-0643 8/1/2000 CO Coal – 94 pieces; 0.32 kg Dredging port side of hull in preparation for Slings 15 thru 19.

HL-0644 8/1/2000 CC/ ME Iron concretions – 4 flat, curved pieces, one with lead strip, one preserving a rim or seam. Likely from a can. Excavating port side of hull, close to centerline; beneath the hull; and in area between Slings 18 and 19.

HL-0645 8/1/2000 CO Coal – 10 pieces; 0.96 kg Excavating starboard side of hull, close to centerline; beneath the hull; and in area between Slings 18 and 19.

HL-0646 8/1/2000 CC Iron concretions – 5 small, flat pieces. Likely from a can. Port side of hull, dredging for Slings 15 thru 19 (midships to forward hatch).

HL-0647 8/1/2000 CC Iron concretion – 1 amorphous piece, no diagnostic features Port side of hull, dredging for Slings 15 thru 19 (midships to forward hatch).
A P P E N D I X G

271

Artifact #† Date Mat. Description Provenience

HL-0648 8/1/2000 SL Boiler slag – 1 piece; 0.001 kg Starboard side of hull, dredging for Slings 18 thru 20.

HL-0649 8/1/2000 CC Iron concretion – one related to HL-0637, one natural Starboard side of hull, dredging for Slings 18 thru 20.

HL-0650 8/1/2000 CO Coal – 14 pieces; 0.21 kg Port side of hull, dredging for Slings 18 thru 20.

HL-0651 8/1/2000 SL Boiler slag – 6 pieces; 0.065 kg Port side of hull, dredging for Slings 18 thru 20.

HL-0652 8/1/2000 CC Iron concretions – 2 small pieces from hull surface tests Port side of hull, dredging for Slings 18 thru 20.

HL-0653 8/1/2000 CC/ ME Iron cylinder, fragile, heavily concreted, with lead strip adjoining two pieces. Partial soldered can. Concreted to underside of keel in midships area.

HL-0654 8/1/2000 CC/ ME Iron object, roughly cylindrical; lead strip visible within concretion. Partial soldered can. Concreted to port side of keel, directly on side/bottom junction.

HL-0655 8/1/2000 CC Iron concretions – 3 curved, flat pieces. Likely can fragments. Port side of hull, amidships near distinct joint in keel.

HL-0656 8/2/2000 ME Iron concretions – one thin, flat, with slaggy surface; one small, amorphous piece Dredging beneath port and starboard sides of hull for installation of Slings 21 thru 23.

HL-0657 8/2/2000 CO Coal – 3 pieces; 0.02 kg Dredging beneath and alongside port and starboard sides of hull for installation of Slings 21 thru 23.

HL-0658 8/2/2000 SL Boiler slag – 3 pieces; 0.035 kg Dredging beneath and alongside port and starboard sides of hull for installation of Slings 21 thru 23.

HL-0659 8/2/2000 WO Wood fragments – 6 small pieces, longest 10.7 × 4.6 × 2.9 cm Dredging beneath and alongside port and starboard sides of hull for installation of Slings 21 thru 23.HL-0660 8/2/2000 ME Iron strap 1.77 cm long, possibly part of propeller shroud attachment* Dredging along starboard side from aft hatch to hole in starboard side of stern. Originally attached to hull.

HL-0661 8/3/2000 CM Completely intact American-produced Bristol-style glazed bottle* Port side of hull, 45 cm below and 40 cm abaft aft hatch, 10 cm below bottom of sub.

HL-0662 8/2/2000 GL Two basal shards from a cylindrical olive green glass bottle dating from c. 1821 until the early 20th century.* Dredging along port side of hull for installation of Slings 23 thru 26.

HL-0663 8/2/2000 BO Bone – 1 specimen, animal vertebra Dredging along port side of hull for installation of Slings 23 thru 26.

HL-0664 8/2/2000 CO Coal – 24 pieces; 0.2 kg Dredging along port side of hull for installation of Slings 23 thru 26.

HL-0665 8/2/2000 SL Boiler slag – 11 pieces; 0.07 kg Dredging along port side of hull for installation of Slings 23 thru 26.

HL-0666 8/2/2000 CC Concretion, amorphous, roughly cylindrical, 3.4 × 1.8 cm Dredging along port side of hull for installation of Slings 23 thru 26.

HL-0667 8/2/2000 CO Coal – 2 pieces; 0.035 kg Dredging beneath starboard side of hull in preparation for installation of Slings 24 and 25.

HL-0668 8/2/2000 BO Bone – 1 specimen, animal scapula, cut by sharp tool Dredging starboard side of hull between Slings 23 and 26.

HL-0669 8/2/2000 WO Wood fragment, dense, almost coal-like Dredging starboard side of hull between Slings 23 and 26.

HL-0670 8/2/2000 CO Coal – 27 pieces; 0.16 kg Dredging starboard side of hull between Slings 23 and 26.
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272Artifact #† Date Mat. Description Provenience

HL-0671 8/2/2000 SL Boiler slag – 16 pieces; 0.21 kg Dredging starboard side of hull between Slings 23 and 26.

HL-0672 8/2/2000 WO Wood fragments – 2 small pieces Dredging starboard side of hull between Slings 23 and 26.

HL-0673 8/2/2000 CC Iron concretions – 3 small pieces, one possibly from can Dredging starboard side of hull between Slings 23 and 26.

HL-0674 8/3/2000 WO Wood fragments – 17 fragments, one oblong with a square notch Dredging abaft aft hatch to port side of rudder.

HL-0675 8/3/2000 GL Olive green glass fragment, likely from a cylindrical bottle; may be associated with artifact HL-0662.* Dredging abaft aft hatch to port side of rudder.

HL-0676 8/3/2000 CO Coal – 46 pieces; 0.14 kg Dredging abaft aft hatch to port side of rudder.

HL-0677 8/3/2000 SL Boiler slag – 9 pieces; 0.04 kg Dredging abaft aft hatch to port side of rudder.

HL-0678 8/3/2000 CC Iron concretions – 15 pieces; most flat, curved plate; one with lead strip, 2 with seams. Likely can fragments. Dredging along the starboard side of the stern abaft Sling 25.

HL-0679 8/3/2000 SL Boiler slag – 43 pieces; 0.135 kg Dredging along the starboard side of the stern abaft Sling 25.

HL-0680 8/3/2000 CO Coal – 31 pieces; 0.9 kg Dredging along the starboard side of the stern abaft Sling 25.

HL-0681 8/3/2000 ME Lead (or lead-alloy) ring, triangular cross section. Likely solder from hole-and-cap can. Dredging along the starboard side of the stern abaft Sling 25.

HL-0682 8/3/2000 ME Lead (or lead-alloy) curved strip, with fragments of iron concretion attached. Likely solder from can. Dredging along the starboard side of the stern abaft Sling 25.

HL-0683 8/3/2000 CC Iron concretion containing mold of flat metal strap* Excavating around and below rudder, 3 cm of concretion beneath rudder.

HL-0684 8/4/2000 CC Concretion containing remains of iron rivet, likely lost from hull during formation of stern hole.* Starboard side of hull, in the shell layer forward of propeller and propeller shroud.HL-0685 8/4/2000 CC Iron concretion containing mold of iron spike* Starboard side of hull in shell layer. 10 cm forward of propeller and propeller shroud.

HL-0686 8/4/2000 ME Submarine’s iron rudder. Approx. measurements: 51 cm wide × 78 cm long. Heavily shell encrustation.* Directly beneath stern end of submarine, at slings 28 and 29. Rudder positioned diagonally across keel line.

HL-0687 8/3/2000 SL Boiler slag – 25 pieces; 0.135 kg Dredging starboard side of stern in preparation for Slings 28 and 29.

HL-0688 8/3/2000 CO Coal – 82 pieces; 0.195 kg Dredging starboard side of stern in preparation for Slings 28 and 29.

HL-0689 8/3/2000 WO Wood fragments – 16 small pieces Dredging starboard side of stern in preparation for Slings 28 and 29.HL-0690 8/3/2000 SL Boiler slag – 1 piece, associated with Rivet #3 on the northern side of CT4; 0.01 kg Dredging starboard side of stern in preparation for Slings 28 and 29.

HL-0691 8/3/2000 CO Coal – 16 pieces; 0.07 kg Dredging on and around the upper surface of rudder; resting on clay.

HL-0692 8/3/2000 WO Wood – 1 small piece, flat with rounded edges Dredging starboard side of stern in preparation for Slings 28 and 29.HL-0693 8/3/2000 BO Bone – 1 piece from edge of turtle carapace Dredging on and around the upper surface of rudder; resting on clay.

HL-0694 8/3/2000 SL Boiler slag – 3 pieces; 0.005 kg Dredging on and around the upper surface of rudder; resting on clay.
A P P E N D I X G

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Artifact #† Date Mat. Description Provenience

HL-0695 8/4/2000 CO Coal – 31 pieces; 0.17 kg Starboard side of stern, just forward of propeller.

HL-0696 8/4/2000 SL Boiler slag – 21 pieces; 0.155 kg Starboard side of stern, just forward of propeller.

HL-0697 8/4/2000 CC Concretions – 1 small, flat, possibly can; 1 slag-like Starboard side of stern, just forward of propeller.

HL-0698 8/4/2000 WO Wood fragments – 4 small pieces Starboard side of stern, just forward of propeller.HL-0699 8/4/2000 CO Coal – 105 pieces; 0.62 kg Starboard side of stern, just forward of propeller.

HL-0700 8/4/2000 CC Iron concretion, cylindrical; a nearly complete can Starboard side of extreme stern edge.

HL-0701 8/4/2000 SL Boiler slag – 39 pieces; 0.205 kg Dredging starboard side of stern to area abaft propeller.

HL-0702 8/4/2000 CC Iron concretion – 1 small, flat piece; likely from a can Dredging starboard side of stern to area abaft propeller.

HL-0703 8/4/2000 CO Coal – 52 pieces; 0.14 kg Dredging beneath aft edge of stern.

HL-0704 8/4/2000 SL Boiler slag – 8 pieces; 0.075 kg Dredging beneath aft edge of stern.

HL-0705 8/3/2000 CC Concretion containing remains of iron rivet, likely lost from hull during formation of stern hole.* Dredging starboard stern area abaft Sling 25.HL-0706 8/6/2000 CO Coal – 1 piece, 14.4 × 5.7 × 3.8 cm; 0.29 kg Lying loose on upper surface of port diving plane.

HL-0708 8/8/2000 ME H. L. Hunley submarine In Charleston Harbor, South Carolina, approx. 4 miles offshore in 40 ft. of water.

HL-2917 ME Grapnel anchor with 5 tines

HL-2918 ME Iron ring originally attached to grapnel anchor (HL-2917)HL-3288 5/11/2004 CC/ ME Iron food can, heavily concreted, metal layer thin and fragile. Removed from conglomerate HL-0582.* Recovered from within ferrous concretion (HL-0582) containing iron shackle.

HL-3289 5/11/2004 ME Wooden handle(?), possibly for a tool such as an awl or file.* Recovered from within ferrous concretion (HL-0582) containing iron shackle.

† Numbers were assigned from the same pool to both artifacts and environmental samples in order of recovery. Any gaps in numbering sequence in this catalog represent samples 

taken for analysis, which have been omitted for brevity.

* See full entry in Chapter 15.

Material Codes: BO – bone; CC – concretion; CM – ceramic; CO – coal; CR – coral; FI – fiber; GL – glass; ME – metal; OR – organic; OT – other; PA – paint; PL – plastic; RU – rubber; SL – slag; ST – stone; WO – wood.
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APPENDIX H

Cumulative Frequency Diagrams 

of 

Sediment Cores Taken at the H. L. 

Hunley Site
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APPENDIX I

Trends for Mean Grain Size, 

Standard Deviation, and 

Skewness

of Sediment Samples Taken 

at the H. L. Hunley Site
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

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Mean Grain Size Plots (mm)

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Standard Deviation (Sorting) Plots

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Skewness Plots

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APPENDIX J

Benthic Infaunal Samples 

Identified from Cores Taken 

at the H. L. Hunley Site
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APPENDIX K

Profiling of Iron-Reducing Microbial Populations 

Associated with the H. L. Hunley by Denaturing 

Gel Electrophoresis Analysis of Polymerase Chain 

Reaction-Amplified Genes Coding for 16S rDNA

Jeremy Goldbogen

Department of Biology

Grice Marine Laboratory

College of Charleston, S.C.

Charleston, South Carolina 29412

Monday, August 13th, 2001
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ABSTRACT

Anaerobic goethite media enriched with sediments 

associated with the sunken confederate submersible, 

the H. L. Hunley, was examined by denaturing gradient 

gel electrophoresis (DGGE) of PCR-amplified 16S 

rDNA fragments. DGGE analysis shows that microbial 

community structure is dissimilar between interior and 

exterior sediments. This distinction suggests that the 

environment within the Hunley is significantly different 

than the surrounding benthos. Analysis also implies a 

substantial impact of the Hunley on inhabitant microorganisms. This study presents the first molecular analysis 

of microbial communities associated with shipwrecks.

INTRODUCTION

During the American Civil War, the Confederacy 

was under an economic blockade by the Union Naval 

Fleet. Consequently, there was pressure to produce 

submersibles to attack Federal ironclads that guarded 

southern ports. The H. L. Hunley was the first successful 

submarine of such innovations by sinking the USS Housatonic on February 17, 1864. However, on its return to 

port it disappeared without a trace. Almost 131 years 

later, the Hunley was discovered approximately 4 miles 

off the coast of Sullivan’s Island, Charleston County, 

South Carolina. The vessel was successfully excavated 

and transported to the Warren Lasch Conservation 

Center on August 8th, 2000. 

Representing a significant breakthrough in technology and an important piece of United States history, 

the conservation of the Hunley is of particular concern. 

More interestingly, the knowledge of the environment 

within and surrounding the sub that has existed for the 

duration of its burial may be better understood through 

microbiological techniques. The most critical component 

influencing the relationship between the Hunley and 

marine microorganisms is the sub’s wrought-iron hull. 

In addition to normal corrosion rates in seawater, iron is 

also susceptible to the biochemical effects of microbial 

communities. Through the formation of biofilms, microorganisms are able to augment metal chemistry into 

microenvironments where corrosion is more thermodynamically favorable (Videla 1996).

Iron-reducing bacteria (FeRB) posses the ability 

to couple the dissimilatory reduction of Fe (III) to the 

oxidation of organic compounds, yielding energy for 

microbial growth (Lovely 1993). Under anaerobic conditions, FeRB have been shown to utilize Fe3+ as the 

sole electron acceptor during oxidative phosphorylation (Lovely and Phillips 1988). This metabolic characteristic directly affects the integrity of the iron hull by 

the causing the dissolution of the protective iron oxide 

layer, thus creating pits and other forms of localized 

attack on the substrate. Other microorganisms, such 

as sulfate-reducing bacteria (SRB), can indirectly affect 

the iron hull by producing the highly corrosive agent 

hydrogen sulfide (Edyvean 1991, Lee et al. 1995). In a 

similar mechanism to FeRB, SRB couple the dissimilatory reduction of sulfate to the oxidation of organic 

compounds (Postage 1979). Both FeRB and SRB have 

the ability to form comensal biofilms and synergistically 

promote the corrosion of iron surfaces.

The Hunley may have an impact on resident marine 

microorganisms. Through its burial by anoxic sediment 

and iron constitution, unique environments may exist 

to promote the proliferation of specific microorganisms 

that can out-compete other microorganisms. Through 

molecular techniques microbial communities from 

sediment associated with the Hunley may be analyzed 

to predict environments that have existed during its 

burial. The relationship between shipwrecks and microorganisms has never been studied in terms of microbial 

community structure. Previous studies involving microorganisms and shipwrecks solely include a bacterial 

growth assay on the Porcupine-class frigate Pandora 

(Guthrie et al. 1994).

The aim of this project is to investigate ironreducing microbial community structure representative 

of sediments associated with the H. L. Hunley. Samples 

of sediment will be obtained from two opposable 

transects leading away from the bow and stern, as well 

as from within the ship. Sediments and concretions will 

be sub-sampled introduced into anaerobic geothite 

enrichment media to select for iron reducing microorganisms. Geothite (a-FeOOH) is an amorphous iron 

oxyhydroxide used to mimic naturally occurring iron 

oxides in marine sediment as well as the oxide layer 

on the Hunley hull. After incubation of geothite enrichments, DNA will be extracted using a modified bead 

beating protocol. Extracted DNA will be amplified by 

polymerase chain reaction (PCR) specific for the highly 

variable 323-bp V9 region on the 16S ribosomal DNA 

of prokaryotes. Successful PCR fractions will be subject 

to denaturing gradient gel electrophoresis (DGGE) to 

determine microbial community structure. DGGE, first 

introduced by Fischer and Lerman (1983), denatures 

double stranded DNA fragments based on guaninecytosine content. An increasing gradient of denaturant 

immobilizes the melted DNA fragment at a specific 

location on the gel which is representative of its genetic 

sequence. While DGGE was first used to detect point 

mutations, it is now increasingly being used in studies 

involving microbial community structure (Muyzer et al. 

1993, Ferris et al. 1996, Teske et al. 1996, Rolleke et al. 

1996, MacNaughton et al. 1999). 

MATERIALS AND METHODS

Sample Acquisition. Divers from the National 

Park Service obtained core sediment samples from 
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two opposable transects leading away from the bow 

and stern of the H. L. Hunley prior to its excavation. 

Transects displayed intervals of 1, 3, 5, 10 and 20 m 

distances at which sediment samples were taken with 

aluminum core barrels (3 in. in diameter and 1.3 m 

in length). The core barrels were capped, brought 

to the surface, flushed with nitrogen, anaerobically 

sealed, and placed on ice for transport the Ft. Johnson 

campus. Samples were placed in 4°C and sub-sampled 

for storage in –80°C for microbial community analysis.

Enrichment of FeRB. To select for FeRB, goethite 

media (Schwertmann and Cornell 1991) was made 

through the combination of hydrolyzed Fe (NO3

)

3

• 

9H2

O and 5M KOH. In a 2L-polyethylene flask 180 mL 

of 5M KOH is added and stirred quickly into 100 mL of 

1M Fe(NO3

)

3

. Without delay, the chimera is diluted to 

2L with distilled water, stupider and placed in 70°C for 

60 hrs. After incubation, the flask is centrifuged and 

the precipitate is washed and dried. Under anaerobic 

conditions, sediment sub-samples were introduced into 

the goethite enrichments and incubated for 8 months.

DNA Extraction. A 1.5 mL aliquot was transferred 

from the goethite enrichments and transferred to a 

‘bead beating vial’ containing 2.0 g of silica/zirconia 

beads. From the moment of transfer, the samples 

were placed on ice through the entire DNA extraction 

process. The remaining volume of the vial is filled with 

250 ml of 10% SDS solution (J. T. Baker, Phillipsburg, 

NJ) and an equal amount of TE Buffer (10mM Tris-HCl, 

pH7.5; 1mM EDTA, pH 8.0). Vials were then placed on 

bead mills and processed for two 2.5 minute cycles at 

2,500 rpm. After milling, the vials are centrifuged for 

5 minutes at 14,000 rpm at 4°C. The supernatant was 

removed from the vials after centrifugation and placed 

into a sterile 1.5 mL microcentrifuge tube. As a rinse, 

250 ml of TE buffer is added to the bead vial and a 30 

second milling cycle follows at 2500 rpm. The supernatant from this process is combined with the supernatant from the previous step and treated with 100 ml 

of 5M NaCl and 80 ml of CTAB (10% in 0.7 M NaCl, J. 

T. Baker, Phillipburg, NJ). Following this addition, the 

samples are placed in a hot water bath for 10 minutes 

at 65°C. After incubation, an equal amount of Tris-buffered phenol was added to the microcentrifuge tube. 

The tubes were centrifuged for 10 minutes at 14,000 

rpm at 4°C. The resulting supernatant was transferred 

to a sterile 1.5 mL microcentrifuge tube. The phenol 

wash procedure is repeated on this transferred supernatant. A 0.6 volume of ice cold isopropanol was added to 

the suspension and the samples were stored overnight 

at -20°C. The following day, samples were allowed to 

thaw then centrifuged for 10 minutes at 4°C. The isoporpanol was then poured off of the pelleted DNA. 

The remaining pellets were rinsed with 500 ml of 70% 

ethanol and stored at -20°C for 30 minutes. After incubation, the samples were centrifuged for 10 minutes 

at 4°C. The supernatant formed in the previous step 

was removed and the remaining ethanol droplets surrounding the pellet were evaporated in a fume hood 

for one hour. Next, the DNA pellet was resuspended in 

50 ml of TE buffer. Extractions were confirmed with a 

1% agrarose gel infused with ethidium bromide which 

was run in 1xTAE buffer (20 mM Tris acetate [pH 7.4], 

10 mM sodium acetate, 1 mM Na2

EDTA). The resultant 

DNA extraction-gel complex was analyzed and photographed using an ultraviolet transilluminater. 

DNA Amplification. Successful DNA extracts were 

amplified using PCR with a set of universal eubactierial 

primers that target the V9 323-bpregion of the 16S rDNA 

(Ferris et al. 1996). The conserved sequences targeted 

by these primers are shown in Figure 1. A GeneMATE 

Thermal Cycler (ISC BioExpress, Kaysville, UT) was 

used to control the ambient temperature changes 

involved in the amplification reactions. The method of 

Muyzer et al. (1993) was used for the PCR reactions. 

Figure 1. The forward primer and reverse primer, E. coli positions 

1055 to 1070 and 1392 to 1406 respectively, used in the PCR amplifications. The reverse primer includes a 40bp GC clamp to improve 

DNA stabilization and sequence differentiation. 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

304

Template DNA strands were 

initially denatured for 5 minutes 

at 94°C. Next, 10 annealing cycles 

of 30 sec intervals, decreasing 1°C 

from 53°C to 43°C, each followed 

by a 2 min primer extension. 

Next, 20 annealing cycles took 

place at 43°C, followed by final 

primer extension at 72°C for a 

duration of 6 mins. To determine 

PCR effectiveness, products were 

confirmed under ultraviolet light 

with a 1% agarose gel stained 

with ethidium bromide in 1xTAE 

buffer. 

DGGE Analysis. Successful 

PCR products were analyzed 

following the methodology of 

Muyzer et al. (1993) of denaturing 

gradient gel electrophoresis. 

A D-code Universal Mutation 

Detection system (Bio-Rad Laboratories, Richmond, VA) was used 

to run the amplified 16S rDNA 

fragments through an 8% (wt:vol) 

polyacrylamide gel in 0.5xTAE 

(20mM Tris acetate [pH 7.4], 

10 mM sodium acetate, 1mM Na2-EDTA) buffer at 60°C 

for 18 hours. The gels were processed with 40% (vol:vol) 

formamide deionized with AG501-X8 mixed bed resin 

(Bio-Rad Laboratories, Richmond, VA) and a denaturing 

gradient (7M urea) which would subject the PCR product 

to an initial 40% denaturant that increases linearly with 

propagation to a final 60% denaturant. Completed gels 

were stained with SYBR Green I (Molecular Probes, 

Eugene, OR) for one hour in preparation for analysis. 

Visualization of the prepared gels involved a model 595 

laser Flourimager 

with ImageQuant 

software (Molecular 

Dynamics, Sunnyvale, 

CA).

RESULTS

The reduction 

of goethite enrichments was observed 

after 8 months incubation by the volumetric decrease of 

the Fe (III) matrix to 

the more compact 

Fe (II) structure. The 

observed transformation is shown in Figure 2 compared 

to the control enrichment.

Nucleic acids were successfully extracted and amplified 

from goethite enrichments from 

interior and exterior sediments of 

all distances except for 3m. Denaturing gradient gel electrophoresis 

analysis of these amplified 16S 

rDNA fragments is shown in Figure 

3, displaying the inherit banding 

pattern and its respective location.

DISCUSSION

DGGE analysis of PCRamplified extracts indicates a 

distinct difference in microbial 

community structure between 

interior sediments and exterior 

sediments. In terms of exterior 

sediments, no substantial difference in banding patterns can 

be observed among different 

distances, depths, or transects. 

Note that the decrease in band 

number in samples from 1 m and 20 m distances may 

be due to weak amplification of DNA fragments rather 

than a representation of fewer microorganisms. The 

ubiquitous community structure observed from exterior 

sediments may emulate the benthic environment characteristic of estuarine sediments of this area.

The observed distinction between interior and 

exterior sediments may reflect the difference between 

the Hunley’s interior environment and the environment 

surrounding the submersible. Considering the limited 

amount of oxygen 

within the sub 

upon sinking, the 

anoxic sediments 

that aided in its 

burial, decomposition of Confederate 

soldiers, restricted 

ocean current flow 

and oxygenation by 

benthic organisms, 

the interior environment of the 

Hunley may have 

been anaerobic for 

a number of years. 

With the Hunley

now excavated, 

there is now no 

Figure 2. The reduction of 

goethite enrichments after 8 

months incubation. A) Un-enoculated goethite media. Iron 

(III) oxyhydroxide. B) Goethite 

media enoculated with Hunley 

sediment. Reduced Iron (II).

Figure 3. DGGE Analysis of PCR-amplified 16S rDNA fragments 

extracted from goethite media enriched with interior sediments 

and exterior sediments of 1m, 5m, 10m, and 20m distances from 

H. L. Hunley.
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A P P E N D I X K

way to determine interior environmental conditions 

except though inferences through microbial community 

structure. This study provides the first multiparameter 

proxy data regarding the past environmental conditions 

within the H. L. Hunley. Continuing studies to identify 

specific microorganisms within these communities will 

further our understanding of the relationship between 

the submersible and its associated microorganisms. 

AKNOWELDGMENTS

Dr. Pam Morris

NSF Research Experiences for Undergraduates Grant # 

DBI-9876926

Drs. Karen and Louis Burnett

The Morris Lab: Amanda, Chris, Dan, Jeff, Jessica, Joy, 

and Sean

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mat community. Appl. Environ. Microbiol. 62:340–46.

Fischer, S. G. and L. S. Lerman. 1983. DNA fragments 

differing by single-base-pair substitutions are separated 

in denaturing gradient gel: Correspondence with 

melting theory. Proc. Natl. Acad. Sci. 80:1579–83.

Guthrie, J. N., L. L. Blackall, D. J. W. Moriarty, and 

P. Gesner. 1994. Wrecks and marine microbiology: case 

study from the Pandora. Bull. Australian Institute for 

Marine Archaeology 18(2):19–24.

Lee, W., Z. Lewandowski, P. Nielsen, and W. A. 

Hamilton. 1995. Role of sulfate-reducing bacteria in 

corrosion of mild steel: A review. Biofouling 8:165–94.

Lovely, D. R. 1993. Dissimilatory metal reduction. 

Ann. Rev. Microbiol. 47:263–90.

Lovely, D. R. and E. J. P. Phillips. 1988. Novel Mode 

of microbial energy metabolism: Organic carbon 

oxidation coupled to dissimilatory reduction of iron or 

manganese. Appl. Environ. Microbiol. 54:1472–80.

MacNaughton, S. J., J. R. Stephen, A. D. Venosa, 

G. A. Davis, Chang Yun-Juan, and D. C. White. 1999. 

Microbial population changes during bioremediation 

of an experimental oil spill. Applied & Environmental 

Microbiology 65(8):3566–74.

Murphy, L. E. 1998. H. L. Hunley Site Assessment. 

Submerged Cultural Resources Unit, Cultural Resources 

Management, National Park Service, Santa Fe, NM.

Moore, W. S. 1998 Age Determination in the 

Sediment at the Hunley Site using 210 Pb in Murphy, 

L. E. 1998. H. L. Hunley Site Assessment. Submerged 

Cultural Resources Unit, National Park Service, Santa 

Fe, NM.

Muyzer, G, E. C. DeWaal, and A. G. Uitterlinder. 

1993. Profiling of complex microbial populations by 

denaturing gel electrophoresis analysis of polymerase 

chain reaction-amplified genes coding for 16S rRNA. 

Appl. Environ. Microbiol. 59:695–700.

Postgate, J. R. 1979. The Sulphate-Reducing 

Bacteria. Cambridge University Press, Cambridge, MA. 

Rolleke, S., C. Gurtner, J. Heyrman, G. Pinar, W. 

Lubitz, and J. Swings. 2000. Comparative analyses of 

the bacterial diversity on two different biodeteriorated wall paintings by DGGE and 16S rDNA sequence 

analysis. International Biodeterioration & Biodegradation 46(3):229–39.

Schwertmann, U. and R. M. Cornell. 1991. Iron 

Oxides in the Laboratory. VCH, Weinheim, Germany.

Teske, A., C. Wawer, G. Muyzer, and N. B. Ramsing. 

1996. Distribution of sulfate-reducing bacteria in a stratified Fjord (Mariager Fjord, Denmark) as evaluated by 

most-probable-number counts and denaturing gradient 

gel electrophoresis of PCR-amplified ribosomal DNA 

fragments. Applied & Environmental Microbiology

62(4):1405–15.

Videla, H. A. Manual of Biocorrosion. CRC Press, 

Boca Raton, FL.
306

APPENDIX L

Analytical Characterization of Coal Artifacts 

Recovered from H. L. Hunley and USS 

Housatonic

Rod Hatt

Coal Combustion, Inc.
A P P E N D I X L

307
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

308
A P P E N D I X L

309

* Images submitted with this report were not reproduced due to the low resolution of archived files.
310

APPENDIX M

South Atlantic Blockading 

Squadron Ships

Stationed off Charleston, 

South Carolina

24 December 1861– 

1 July 1865
311

A P P E N D I X M

B On Station off Bull’s Bay

S On Station off Stono Inlet

X On Station off Charleston

MS Mortar Schooner

 † Reports do not include ships off Stono; Stono ships from prior report presumed to have been still on station

Class Vessel 24 Dec. 1861 18 Mar. 1862 23 Apr. 1862 14 May 1862 30 May 1862 3 June 1862† 25 June 1862† 23 July 1862 26 Sept. 1862 12 Oct. 1862 27 Oct. 1862 16 Nov. 1862 1 Dec. 1862 16 Dec. 1862

1 Powhatan X X X X X X

2 Bienville X X X X X X X X X

2 Canandaigua X X X X X

2 Housatonic X X X X

2 Pawnee S

2 Quaker City X X X X

3 Alabama X X X X

3 Augusta X X X X X

3 Conemaugh S S

3 Flag X X X X X

3 Flambeau X S X X X X X X X X X X

3 Florida X X

3 James Adger X X X* X X X

3 Keystone State X X X X X X X X

3 Memphis X X X X

3 Mercedita X X X X X

3 Mohican X

3 Pocahantas S X X X X X

3 South Carolina X X X X X

4 Crusader X

4 Ellen S S† S† S S

4 Gemsbok B

4 Henry Andrew S

4 Huron X X X X

4 Isaac Smith S S S S

4 Madgie X

4 Marblehead X X X X

4 Norwich X X X

4 Ottawa S S S† S† S S S

4 Pembina S S† S† S X

4 Potomska

4 Seneca X X X S S

4 Stettin X X

4 Sumpter X X X X X

4 Unadilla X S S† S†

Sail America X X X

Sail Fernandina X

Sail G. W. Blunt X X X X X X X X X

Sail Onward X B X X X

Sail Para (MS) X X X

Sail Restless X B X B B B B B B B B

Sail Roebuck X X X X X X

Sail Shepherd Knapp X X X X

Sail Vandalia X

Total Ships on Station 4 5 10 12 18 15 16 17 13 11 15 17 19 17

 (Source: ORN 1.12:427, 635, 773, 814–15; ORN 1.13:59, 72, 138, 206, 348–49, 387, 419–20, 451–52, 465–66, 480–81)

24 December 1861 – 16 December 1862
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

312

Class Vessel Jan. 15, 1863 Feb. 1, 1863 Feb. 15, 1863 Mar. 1, 1863 Mar. 15, 1863 Apr. 15, 1863 May 1, 1863 May 15, 1863 June 1, 1863 June 15, 1863 July 1, 1863 July 15, 1863 July 24, 1864*  Oct. 23, 1863** Nov. 15, 1863** Dec. 1, 1863 Dec. 15, 1863

1 New Ironsides (I)XXXXXXXXXXXXXXXX

1 PowhatanXXXXXX

XXXXX

1 WabashXXXXXX

2 Canandaigua

XXXXXXXXXXXX

2 HousatonicXXX

XXXXXXXXXXX

2 Lehigh (I)XX

2 PawneeSSSSSSSSSSSSS

2 Quaker CityXXXX

3 AugustaXXXXXXXXX

3 Catskill (I)XX

3 ConemaughX

3 FlagXXXXXXXXXXX

3 FlambeauX

3 James AdgerXXXXX

3 Keystone StateX

3 LodonaXXXXX

3 Mary SanfordXXX

3 MemphisXXXXXB

3 MerceditaX

3 Montauk (I)XXXXX

3 Nahant (I)XXXXX

3 Nantucket (I)SX

3 Passaic (I)XXX

3 Patapsco (I)X

3 Paul JonesXXXXX

3 SebagoXX

3 SonomaXXX

3 South Carolina

XXXBBBX

3 Weehawken (I)

XXXXX

4 Cdre. McDonoughS

SSSSSSSXXXX

4 Chippewa

XXX

4 Dai ChingX

4 E. B. HaleS

4 HuronXXXXXXXXXSS

4 Isaac SmithS

4 MadgieX

4 MarbleheadXXXSSSSSS

4 NipsicXXX

4 NorwichX

4 OttawaXXXXXX

4 PhiladelphiaXXXX

4 SenecaXX

4 StettinXXXXXXX

4 UnadillaXXSXXXXX

1863
313

A P P E N D I X M

Class Vessel Jan. 15, 1863 Feb. 1, 1863 Feb. 15, 1863 Mar. 1, 1863 Mar. 15, 1863 Apr. 15, 1863 May 1, 1863 May 15, 1863 June 1, 1863 June 15, 1863 July 1, 1863 July 15, 1863 July 24, 1864*  Oct. 23, 1863** Nov. 15, 1863** Dec. 1, 1863 Dec. 15, 1863

4 Wamsutta X X

4 Wissahickon X X X

4 Clover (T) X

4 Columbine (T) X

4 Daffodil (T) X X X

4 Dandelion (T) X X X X X X X X

4 Geranium (T) X

4 Home (T) X X X

4 Iris (T) X X X

4 Jonquil (T) X X

4 Oleander (T) X X X X

4 O. M. Petit (T) X

Sail America X X X X X X X

Sail C. P. Williams (MS) S S S S S S S S S S

Sail Dan Smith X

Sail Ethan Allen X

Sail G. W. Blunt X X X X X X X X X X X B B B B

Sail Hope X X X X

Sail Norfolk Packet X X X X X

Sail Para (MS) X X

Sail Racer (MS) X X X X

Sail Restless B

Sail Supply X X X

Sail T. A. Ward X X X

Total Ships on Station 18 14 12 13 15 15 14 17 19 16 20 28 16 21 24 27 30

(Sources: ORN 1.13:511–12, 625, 663–64, 709, 755–56; ORN 1.14:135–36, 167, 195, 224–25, 305–6, 343–44, 390; ORN 1.15:69, 113, 144, 176)

X On Station off Charleston

B On Station off Bull’s Bay

S On Station off Stono Inlet

MS Mortar Schooner

T Tug

* This report does not include ships already in Stono, only those on the way; there is no reference to Bull’s Bay

** Also listed was the storeship Hannibal, not on the Navy roster; it is not clear whether this was a steam powered or sailing vessel. 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

314

Class Vessel

 Jan. 1, 1864 Jan. 15, 1864 Feb. 1, 1864 Feb. 15, 1864 Mar. 1, 1864 Mar. 15, 1864 Apr. 1, 1864 Apr. 15, 1864 May 15, 1864 June 1, 1864 June 15, 1864 July 1, 1864 July 16, 1864 Aug. 1, 1864 Aug. 16, 1864 Sept. 1, 1864 Sept. 15, 1864 Oct. 1, 1864 Oct. 15, 1864 Oct. 22, 1864 Nov. 1, 1864 Nov. 15, 1864 Dec. 12, 1864

1 New 

Ironsides (I)

XXXXXXXXXX

1 WabashXXXXXXXXX

2 CanandaiguaXXXXXXXXXXXXXX

2 HousatonicXXXXX

2 Lehigh (I)XXXXXXXXXXSXXXXXXXX

2 PawneeSSSXXXXXXX

3 AugustaX

3 Catskill (I)XXXXXXXXXXXXXXXXXX

R

3 CimarronSSSSSXX

3 FlagXXXXXXXXX

3 FlambeauXXXXXX

3 James AdgerXBXXXX

3 Mary 

Sanford

XXXXXXXXXXXXXX

3 MemphisX

3 MingoeXXXXX

3 Montauk (I)XXXXXXSXXXSXX

R

X

R

X

R

X

R

XX

3 Nahant (I)XXXXXXXXXXXXX

3 Nantucket (I)XXXXXXXXXXXXX

3 Passaic (I)XXXXXXX

3 Patapsco (I)XXX

XX

3 Paul JonesSS

3 PocahantasX

3 PontiacXXXX

3 Sangamon (I)XXXXXXXXXXXXXXXX

R

3 SonomaSSSSSSSSSXXX

3 South 

Carolina

XXX

3 Weehawken 

(I)

XXXXX

4 AcaciaXXXXXXXXXXXXXXXX

4 Cdre. 

McDonough

XXXXXXXSSSSSSSSSSSSS

4 Dai ChingX

4 NipsicXXXXXXXXXXXXX

4 OttawaX

4 PhiladelphiaXXXXXXX

SB

4 PotomskaXXXXX

4 SenecaSSS

4 WamsuttaXXXXXXXXXXXXX

4 WinonaXXXXXXXXXXXX

4 Amaranthus 

(T)

XXXXXXXX

4 Azalea (T)XXXXXXXXXXXX

4 Camelia (T)XXXXXXXXXX

4 Catalpa (T)XXXXXXXX

4 Clover (T)XXXXXXXXXXXXXXX

1864
315

A P P E N D I X M

Class Vessel

 Jan. 1, 1864 Jan. 15, 1864 Feb. 1, 1864 Feb. 15, 1864 Mar. 1, 1864 Mar. 15, 1864 Apr. 1, 1864 Apr. 15, 1864 May 15, 1864 June 1, 1864 June 15, 1864 July 1, 1864 July 16, 1864 Aug. 1, 1864 Aug. 16, 1864 Sept. 1, 1864 Sept. 15, 1864 Oct. 1, 1864 Oct. 15, 1864 Oct. 22, 1864 Nov. 1, 1864 Nov. 15, 1864 Dec. 12, 1864

4 Daffodil (T) X X X X X X X X X S X X X X X

4 Dandelion (T) X X X X X X X X X X X X X

4 Geranium (T) X X X X X X X X S X X X X X

4 Gladiolus (T) X X X X X X X X X X

4 Home (T) X X X X X X X X X X X X X X X X X X

4 Hydrangea 

(T) X X X X

4 Iris (T) X X X X X X X X X X X X X X X

4 Jonquil (T) X X X X X X

4 Laburnum (T) X X X X X X X X X

4 Oleander (T) S

4 Sweet Brier 

(T) X X X X X X X X X X S

Sail C. P. Williams 

(MS) S S S S S S

Sail Dan Smith S S S S S S S S

Sail Ethan Allen X X

Sail G. W. Blunt B B B B X X X X X X X X X X

Sail George 

Mangham B B B B B B

Sail Hope X X X X B X B B B B B B B B B B B

Sail John Adams X X X X X X X X X X X X X X X X X X X X X X X

Sail Orvetta (MS) X X

Sail Perry X

Sail Racer (MS) X S S X S S S S S S S S S S S

Sail Sarah Bruen X X X X X X X

Sail Supply X X X X X X X X X X X X X X

Sail T. A. Ward X X X X

Total Ships on Station 31 29 28 25 28 29 27 26 26 27 22 27 24 25 24 26 26 23 24 26 31 31 29

(Sources: ORN 1.15:217, 242, 258, 324, 347, 365, 390, 400, 433, 465, 524, 550, 570, 588, 628, 656, 676; ORN 1.16:3, 17, 27, 39, 54, 125) 

B On Station off Bull’s Bay

S On Station off Stono Inlet

X On Station off Charleston

I Ironclad

MS Mortar Schooner

T Tug

R Repairing 
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

316

1 January – 1 July 1865

Class Date Jan. 1, 1865 Jan. 15, 1865 Feb. 1, 1865 Feb. 15, 1865 Mar. 1, 1865 Mar. 15, 1865 Apr. 1, 1865 Apr. 15, 1865 May 1, 1865 May 15, 1865†† June 1, 1865†† June 15, 1865†† July 1, 1865

2 Canandaigua X

2 Juniata X X

2 Lehigh (I) X X X S S

2 Pawnee X X X X X X X

2 Shenandoah X B X

3 Cambridge X X

3 Canonicus (I) X X

3 Catskill (I) XR X X X X XR X X X X X X X

3 Chenango X

3 Cimarron X X X X X

3 Conemaugh X

3 Flambeau X X X X

3 James Adger X X X

3 Mary Sanford X X X X

3 Memphis X

3 Mohican X

3 Monadnock X X

3 Montauk (I) X X

3 Nahant (I) X X X X S SR S

3 Nantucket (I) X X X X X R X

3 Passaic (I) X X X X X X X

3 Patapsco (I) X X

3 Sangamon (I) X X

3 Sonoma B X X X X

3 South Carolina X X X X X

3 State of Georgia B X X

4 Acacia X X X XR

4 Calypso X

4 Commodore McDonough S S S S S S S S S S S

4 Donegal X X X

4 Ellen X

4 Fahkee X

4 Gemsbok X

4 Harvest Moon S

4 Mahopac (I) X X

4 Nipsic X X XR

4 Ottawa B
317

A P P E N D I X M

4 Philadelphia S S X X X X X X X X

4 Potomska X X X X X X

4 Tuscarora X X X

4 Wamsutta X X X X X X

4 Wando X X X X X

4 Winona X

4 Wissahickon S S S S S S S S X

4 Amaranthus X X X X X X X

4 Azalea (T) X X X X X

4 Camelia (T) X X X X XR X X X

4 Catalpa (T) X X X X X

4 Clover (T) X X X X X XR X X X X

4 Daffodil (T) X X

4 Dandelion (T) X X X X

4 Geranium (T) X X X B X X X X X

4 Gladiolus (T) X X X X X X X X

4 Home (T) X X X X X X X X X X X X X

4 Hydrangea (T) X X X X X X

4 Iris (T) S X XR X XR X X

4 Jonquil (T) X X X X X X X X XR X X X X

4 Laburnum (T) X X X X X X X X X X

4 Larkspur (T) X X

4 Oleander (T) X X

4 Sweet Brier (T) X X X

Sail C. P. Williams (MS) S S S S S S S X X X

Sail Dan Smith S S S S S X X X X

Sail G. W. Blunt X X X X X X X

Sail George Mangham B

Sail Hope X X XR X X X X

Sail John Adams X X X X X X X X X X X X

Sail James S. Chambers X B B B B B

Sail Orvetta (MS) X X X X X X X X X X

Sail Sarah Bruen X X X X X X X X X X X

Sail Sea Foam X

Sail Sophronia (MS) X

Sail Supply X

Sail T. A. Ward X X X X X X X X X X

Total Ships on Station 36 35 39 43 35 24 25 29 23 23 27 17 10

(Sources: ORN 1.16:154, 169–70, 210–12, 244–46, 281–82, 292–93, 303–4, 317–18, 326–28, 331–33, 340–42)

B On Station off Bull's Bay

S On Station off Stono Inlet

X On Station off Charleston

I Ironclad

MS Mortar Schooner

T Tug

R Repairing 

†† Also listed were the lightship Lady Davis and tug Transport, not on the official Navy roster, as well as captured ships Mab and, on 15 May only, Columbia.
318

APPENDIX N

Oral Account of H. L. Hunley by William G. Mazyck,

Taken Down and Summarized by Robert Lunz 

(1957)
A P P E N D I X N

319
H . L . H U N L E Y : R E C O V E R Y O P E R A T I O N S

320

Editor’s note: Mazyck is most likely William Gaillard Mazyck, of Charleston, S.C., listed in the 1921 edition of Who’s Who in South Carolina (Crawford 

1921) with a birth date of 12 October 1846.
A P P E N D I X N

321