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110

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OCS Study 

BOEM 2013-011110

Published by 

U.S. Department of the Interior 

Bureau of Ocean Energy Management 

Gulf of Mexico OCS Region

New Orleans, LA 

August 2013

Archaeological Analysis of Submerged 

Sites on the Gulf of Mexico 

Continental Shelf 

Authors 

Amanda M. Evans 

Matthew E. Keith 

Erin E. Voisin 

Patrick A. Hesp 

Gregory D. Cook 

Mead A. Allison 

Graziela M. de Silva 

Eric A. Swanson

Prepared under BOEM Contract 

M09PC00048 

by 

Tesla Offshore, LLC 

36499 Perkins Road 

Prairieville, LA 70769 
iii 

DISCLAIMER 

This report was prepared under contract between the Bureau of Ocean Energy Management 

(BOEM) and Tesla Offshore. This report has been technically reviewed by BOEM, and it has 

been approved for publication. Approval does not necessarily signify that the contents reflect the 

views and policies of BOEM, nor does mention of trade names or commercial products 

constitute endorsement or recommendation for use. 

REPORT AVAILABILITY 

To download a PDF file of this Gulf of Mexico OCS Region report, go to the U.S. 

Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies 

Program Information System website and search on OCS Study BOEM 2013-01110. 

This report can be viewed at select Federal Depository Libraries. It can also be obtained 

from the National Technical Information Service; the contact information is below. 

U.S. Department of Commerce 

National Technical Information Service 

5301 Shawnee Rd. 

Springfield, Virginia 22312 

Phone: (703) 605-6000, 1(800)553-6847 

Fax: (703) 605-6900 

Website: http://www.ntis.gov/

CITATION 

Evans, A.M., M.E. Keith, E.E. Voisin, P. Hesp, G. Cook, M. Allison, G. da Silva, and E. 

Swanson. 2013. Archaeological analysis of submerged sites on the Gulf of Mexico Outer 

Continental Shelf. U.S. Department of the Interior, Bureau of Ocean Energy Management, 

Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2013-01110. 432 p. 

COVER ART ACKNOWLEDGEMENTS 

Original cover art created by Matt Keith. 
v 

ACKNOWLEDGEMENTS 

The authors of this report thank the following personnel and institutions for support that 

proved invaluable to the completion of this study. First, we thank the Bureau of Ocean Energy 

Management (BOEM) for the opportunity to conduct this study. We are grateful for the direct 

assistance provided by BOEM personnel Chris Horrell, Dave Ball, Melanie Damour, Doug 

Jones, and Jack Irion. The geophysical acquisition could not have been possible without the crew 

of the M/V Nikola, particularly the diligence and expertise of party chiefs Steven Garrett and 

Bruce Carter. Operations managers Jerry Cook and George Loy supervised survey logistics and 

acquisition. Pete Henstridge provided his expertise with 3D Echoscope acquisition and 

processing and James Collier and Kyle Edmonds conducted acquisition and preliminary 

processing of multibeam data. Tesla Offshore office staff Stephen Kemp, Anthony Hidalgo, 

Michael Tripp, Bill Loggin, John Laiche, Kyle Ray, Ryan Newchurch, Randy Aucoin, Stuart 

Bledsoe, Donald Spicer, CD Schempf, Randy Bergeron, and Teresa Bowman provided direct 

support for various phases of the contract. 

Diving operations were productive, safe, and successful. The authors thank the crew of the 

M/V Spree: Captain Frank Wasson, Melanie Wasson, Captain John Camp, Colm O’Reilly, Ross 

Tague, and Butch Boggess. The field research could not have been conducted without support 

from the Archaeology Institute at the University of West Florida (UWF), specifically for the 

facilities, equipment, and administrative support crucial to the completion of the diving phase of 

this research. The authors recognize the cooperation and assistance of UWF’s Office of 

Sponsored Research. Thanks are extended to the staff members of the Archaeology Institute, 

particularly Dr. Elizabeth Benchley, Director, for her advice and support throughout the project, 

and Mrs. Karen Mims, Office Manager, for project administration. Finally, the assistance of 

UWF staff, students, and volunteers was crucial to the completion of the research. Special thanks 

to the entire UWF dive team: Project Dive Safety Officer Fritz Sharar, Norine Carroll, Aleks 

Adams, Danny Haddock, Mercedes Harrold, Sarah Linden, Andy Marr, Bill Neal, Jake Shidner, 

and Wes Perrine. In addition to providing diving support, Aleks Adams assisted with preparing 

the site map for Site 389. C. Lee McKenzie, UWF Archaeology Institute CAD specialist, 

provided his services preparing the final site plans. 

Thanks to the Florida Public Archeology Network for offering their services with the public 

outreach component of this project. Jason Kent provided his services in preparation of the project 

website (website forthcoming) and Della Scott-Ireton is assisting with an ongoing outreach 

component that will continue after report completion. 

Dan Duncan, under the direction of Dr. Mead Allison, assisted with the preparation and 

analysis of radioisotope samples. Special thanks are also due to Lynda Miller, Senior Grants and 

Contracts Specialist, Institute for Geophysics, Jackson School of Geosciences, University of 

Texas at Austin. Elizabeth “Cory” Sills of Louisiana State University assisted with core logging 

and splitting, and conducted grain size measurements under the direction of Dr. Patrick Hesp. 

William “Cappy” Bisso, President of Bisso Marine of Houston, Texas; C.J. Christ, President 

of the Regional Military Museum in Houma, Louisiana; and J. Avery Munson of Mamoet 
vi 

Salvage Americas, Inc., gave their time, shared research, and shared their wealth of knowledge 

during interviews with project team members. 

Personnel at numerous institutions, museums, and archives assisted greatly with both remote 

and on-site research. The authors would especially like to thank the following individuals for 

their time and assistance: Bill Barker, Archivist, and Erin Lopater, Photographic Services, 

Licensing & Publications, Mariner’s Museum, Newport News, Virginia; Marge McNinch, 

Reference Archivist, Hagley Museum & Library, Wilmington, Delaware; Scott Daniels, 

Reference Librarian, Oregon Historical Society, Portland, Oregon; Susan Abbott and Mark 

Mollan, Archivists, Navy/Maritime Reference, National Archives and Records Administration, 

Washington, D.C.; Bjorn Larsson, private collector, www.timetablesimages.com; Caitlin 

Donnelly, Archivist, Daughters of the Republic of Texas Library at the Alamo; David Pfeiffer, 

Archivist, Connie Beach and Nathaniel Patch, Archives Specialists, and Richard Peuser, 

Assistant Chief, NWCT2R-Reference Section, Textual Archives Services Division, National 

Archives, College Park, MD; Nora L. Chidlow, Archivist, U.S. Coast Guard, Historian’s Office; 

Elizabeth Pope, Archivist, National Archives at New York City; Frank Conahan, Curatorial 

Associate, and Kurt Hasselbach, Curator, MIT Museum, Hart Nautical and General Collections, 

Cambridge, Massachusetts; William Slatten, Bisso Towboat Company, Inc.; Paul F. Johnston, 

Curator of Maritime History, National Museum of American History Smithsonian Institution; 

Michele Ashmore, Picture Library Executive, National Museums Northern Ireland; Catherine 

Scott, Baltimore Museum of Industry; Gina Bardi, Reference Librarian, San Francisco Maritime 

National Historical Park, J. Porter Shaw Library, Fort Mason Center; Dr. Sheila Gallagher and 

Dr. Judith Bookbinder, Directors, Becker Collection, Boston College, Chestnut Hill, 

Massachusetts; Dr. Donald Keith, Ships of Discovery; Amy Borgens, State Marine 

Archaeologist, Texas Historical Commission; Ole Varmer, David W. Alberg, and Joseph C. 

Hoyt, National Oceanic and Atmospheric Administration; Ian Oxley and Chris Pater, English 

Heritage; Chris Amer, South Carolina Institute of Archaeology and Anthropology; Ashley 

Henderson and Elizabeth Martin at the Corpus Christi Museum of Science and History; Kate 

Morrand at the Naval History & Heritage Command, Underwater Archaeology Branch, 

Department of the Navy; and Amy Austin, IN Space, LLC. 

 
vii 

CONTENTS 

List of Figures ................................................................................................................................ xi

List of Tables ............................................................................................................................... xix

Abbreviations and Acronyms ...................................................................................................... xxi

1. Introduction ................................................................................................................................. 1

1.1 Background .............................................................................................................. 1

1.2 Current Management Strategies for OCS Shipwrecks ............................................. 4

1.3 Report Conventions .................................................................................................. 6

2. Research Design and Methodology ............................................................................................ 9

2.1 Background and Archival Research ......................................................................... 9

2.2 Geophysical Data ................................................................................................... 10

2.3 Data Acquisition ..................................................................................................... 12

2.4 Data Processing ...................................................................................................... 14

2.5 Diving Parameters .................................................................................................. 15

2.6 Coring and Environmental Analyses ...................................................................... 18

2.7 Oceanographic Analyses ........................................................................................ 21

2.8 Radioisotope Analysis ............................................................................................ 23

2.9 Standardization ....................................................................................................... 24

3. Site Results................................................................................................................................ 25

3.1 Site No. 380, South Pelto Area, Reported Wooden Wreck .............................................. 26

3.1.1 Site Background .................................................................................................. 26

3.1.2 Geophysical ......................................................................................................... 26

3.1.3 Diving .................................................................................................................. 32

3.1.4 Site Environment ................................................................................................. 35

3.2 Site No. 433, Ship Shoal Area, Probable R.W. Gallagher ................................................ 35

3.2.1 Site Background .................................................................................................. 35

3.2.2 Geophysical ......................................................................................................... 37

3.2.3 Diving .................................................................................................................. 47

3.2.4 Site Environment ................................................................................................. 50

3.3 Site No. 386, Ship Shoal Area, Probable Heredia ............................................................ 54

3.3.1 Site Background .................................................................................................. 54

3.3.2 Geophysical ......................................................................................................... 55

3.3.3 Diving .................................................................................................................. 62

3.3.4 Site Environment ................................................................................................. 63

3.4 Site No. 373, South Marsh Island Area, Probable Cities Service Toledo ......................... 64

3.4.1 Site Background .................................................................................................. 64

3.4.2 Geophysical ......................................................................................................... 65

3.4.3 Diving .................................................................................................................. 73

3.4.4 Site Environment ................................................................................................. 74

3.5 Site No. 15488, High Island Area, Unknown Modern Wreck .......................................... 76

3.5.1 Site Background .................................................................................................. 76
viii 

3.5.2 Geophysical ......................................................................................................... 77

3.5.3 Diving .................................................................................................................. 84

3.5.4 Site Environment ................................................................................................. 85

3.6 Site No. 15366, Galveston Area, Unknown Modern Wreck ............................................ 87

3.6.1 Site Background .................................................................................................. 87

3.6.2 Geophysical ......................................................................................................... 90

3.6.3 Diving .................................................................................................................. 96

3.6.4 Site Environment ................................................................................................. 97

3.7 Site No. 389, South Timbalier Area, Probable J.A. Bisso .............................................. 100

3.7.1. Site Background ............................................................................................... 100

3.7.2 Diving ................................................................................................................ 104

3.7.3 Geophysical ....................................................................................................... 105

3.7.4 Site Environment ............................................................................................... 112

3.8 Site No. 236, Galveston Area, USS Hatteras ................................................................. 114

3.8.1 Site Background ................................................................................................ 114

3.8.2 Diving ................................................................................................................ 115

3.8.3 Geophysical ....................................................................................................... 118

3.8.4 Site Environment ............................................................................................... 124

3.9 Site No. 15326, East Cameron Area, Unknown Barge ................................................... 127

3.9.1 Site Background ................................................................................................ 127

3.9.2 Diving ................................................................................................................ 130

3.9.3 Site Environment ............................................................................................... 131

3.10 Site No. 322, East Cameron Area, Unknown Modern Wreck ...................................... 132

3.10.1 Site Background .............................................................................................. 132

3.10.2 Diving .............................................................................................................. 133

3.10.3 Site Environment ............................................................................................. 134

3.11 Site No. Pending, West Cameron Area, Modern Debris .............................................. 135

3.11.1 Site Background .............................................................................................. 135

3.11.2 Diving .............................................................................................................. 138

3.11.3 Site Environment ............................................................................................. 139

4. Historical Significance ............................................................................................................ 141

4.1 Regional Expectations for the GOM ............................................................................... 141

4.1.1 Civil War Era ..................................................................................................... 143

4.1.2 World War II ..................................................................................................... 143

4.1.3 Industry and Commerce .................................................................................... 144

4.2 Archaeological and Historical Analysis of Study Sites .................................................. 146

4.2.1 Site No. 380, South Pelto Area, Reported Wooden Wreck ............................... 146

4.2.2 Site No. 433, Ship Shoal Area, Probable R.W. Gallagher ................................ 148

4.2.3 Site No. 386, Ship Shoal Area, Probable Heredia ............................................ 156

4.2.4 Site No. 373, South Marsh Island Area, Probable Cities Service Toledo ......... 163

4.2.5 Site No. 15488, High Island Area, Unknown Modern Wreck .......................... 169

4.2.6 Site No. 15366, Galveston Area, Unknown Modern Wreck ............................. 170

4.2.7 Site No. 389, South Timbalier Area, Probable J.A. Bisso ................................. 172

4.2.8 Site No. 236, Galveston Area, USS Hatteras .................................................... 179

4.2.9 Site No. 15326, East Cameron Area, Unknown Barge ..................................... 183

4.2.10 Site No. 322, East Cameron Area, Unknown Modern Wreck ........................ 184
ix 

4.2.11 Site No. Pending, West Cameron Area, Modern Debris ................................. 186

4.3 NRHP Eligibility ............................................................................................................. 187

4.3.1 Civil War ........................................................................................................... 188

4.3.2 World War II ..................................................................................................... 189

4.3.3 Modern Industry ................................................................................................ 189

4.4 Summary ......................................................................................................................... 190

5. Site Formation Processes ........................................................................................................ 193

5.1 Environmental Site Formation Processes ....................................................................... 193

5.1.1 Introduction ....................................................................................................... 193

5.1.2 Sediment Movement and Hydrodynamics ........................................................ 194

5.1.3 Water Quality .................................................................................................... 206

5.2 Anthropogenic Processes ................................................................................................ 211

5.3 Analysis of Shipwreck Site Formation Processes ........................................................... 215

5.3.1 Site No. 380, South Pelto Area, Reported Wooden Wreck ............................... 215

5.3.2 Site No. 433, Ship Shoal Area, Probable R. W. Gallagher ............................... 216

5.3.3 Site No. 386, Ship Shoal Area, Probable Heredia ............................................ 221

5.3.4 Site No. 373, South Marsh Island Area, Probable Cities Service Toledo ......... 224

5.3.5 Site No. 15488, High Island Area, Unknown Modern Wreck .......................... 228

5.3.6 Site No. 15366, Galveston Area, Unknown Modern Wreck ............................. 231

5.3.7 Site No. 389, South Timbalier Area, Probable J. A. Bisso ................................ 233

5.3.8 Site No. 236, Galveston Area, USS Hatteras .................................................... 237

5.3.9 Site No. 15326, East Cameron Area, Unknown Barge ..................................... 246

5.3.10 Site No. 322, East Cameron Area, Unknown Modern Wreck ........................ 246

5.3.11 Site No. Pending, West Cameron Area, Modern Debris ................................. 246

5.4 Comparison of Observed Site Formation Processes ....................................................... 247

6. Conclusions and Recommendations ....................................................................................... 251

6.1 Management Strategies ................................................................................................... 251

6.1.1. Regulatory Practice .......................................................................................... 251

6.1.2 Determining Avoidance Zones .......................................................................... 253

6.1.3 Evaluating Effectiveness of Avoidance Zones .................................................. 254

6.1.4 Observations and Recommendations ................................................................ 257

6.2 Further Research ............................................................................................................. 258

6.2.1 Historic Research .............................................................................................. 258

6.2.2 Long-term Monitoring ....................................................................................... 259

6.2.3 Core Analysis .................................................................................................... 259

6.2.4 Local Knowledge .............................................................................................. 260

6.2.5 The Future of Shipwrecks on the OCS .............................................................. 260

7. Literature Cited ....................................................................................................................... 261

Appendix A M/V Nikola Boat Diagram and Geophysical Equipment Specifications . 283

Appendix B Geophysical Survey Post-Plots ................................................................ 297

Appendix C Tabulated Magnetic Anomalies ............................................................... 307

Appendix D Supplemental Maps .................................................................................. 325

Appendix E Supplemental Documents ......................................................................... 331

Site 433 R. W. Gallagher .......................................................................... 333
x 

Site 386 Heredia ....................................................................................... 351

Site 373 Cities Service Toledo .................................................................. 363

Site 389 J. A. Bisso ................................................................................... 379

Site 236 USS Hatteras ............................................................................. 383

Appendix F Water Quality and Radioisotope Tables ................................................... 389

Appendix G Core Logs ................................................................................................. 399
xi 

LIST OF FIGURES 

Figure 1.1. Site distribution map. .................................................................................................. 3 

Figure 2.1. Geophysical survey vessel M/V Nikola. ................................................................... 12 

Figure 2.2. Project dive team and crew of M/V Spree. ............................................................... 16 

Figure 2.3. Viewing the Mesotech data.. .................................................................................... 17

Figure 2.4. Bill Neal and Amanda Evans remove a core sleeve from the 36” corer. ................. 19 

Figure 2.5. Distribution of study sites and location of the datums used in oceanographic 

modeling. .................................................................................................................. 22

Figure 3.1.1. Bathymetry map surrounding site 380 in 2-decimeter intervals. .......................... 27 

Figure 3.1.2. 410 kHz sonar mosaic of seafloor surrounding Site 380. ..................................... 29 

Figure 3.1.3. Sub-bottom profiles of survey lines 1, 11, and 22, Site 380. ............ ...............30 

Figure 3.1.4. Magnetic contours in 2 nT intervals at Site 380. .................................................. 31 

Figure 3.1.5. Photographs of metal band.................................................................................... 32 

Figure 3.1.6. Photograph of concretion (at top), copper tubing (at bottom), and objects 

recovered from inside concretion (middle). ......................................................... 33 

Figure 3.1.7. Site plan map showing relative distribution of objects identified at Site 380. ..... 34 

Figure 3.2.1. Sonar image of Site 433. ....................................................................................... 36 

Figure 3.2.2. Sonar image of Site 433 ........................................................................................ 37 

Figure 3.2.3. Bathymetry surrounding Site 433 in 5-decimeter intervals. ................................. 39 

Figure 3.2.4. 3-D multibeam renderings of Site 433. ................................................................. 40 

Figure 3.2.5. 410 kHz sonar image of vessel’s stern from survey Line 402. ............................. 41 

Figure 3.2.6. 100 kHz side scan sonar mosaic of Site 433. Inset is 410 kHz data. .................... 42 

Figure 3.2.7. Multibeam imagery of wreck at Site 433 showing internal structure. .................. 43 

Figure 3.2.8. Sub-bottom profiles of survey lines 302 and 307, Site 433.. ................................ 44 

Figure 3.2.9. Magnetic contours in 50-nT intervals at Site 433. ................................................ 46 

Figure 3.2.10. Image still highlighting bilge keel aft of midships. .............................................. 47 

Figure 3.2.11. Propeller blades. .................................................................................................... 48 

Figure 3.2.12. Image still showing oil seeping from the wreck site............................................. 49 

Figure 3.2.13. Sector scan highlighting the stern of the vessel. ................................................... 50 

Figure 3.2.14. Downcore 210Pbxs activity and linear sediment accumulation rate (LAR) 

calculations for Site T433. .................................................................................... 53 

Figure 3.3.1. Sonar image of Site 386. ....................................................................................... 55 
xii 

Figure 3.3.2. Bathymetry surrounding Site 386 in 2-decimeter intervals. ................................. 57 

Figure 3.3.3. 3-D multibeam renderings of Site 386. ................................................................. 58 

Figure 3.3.4. 120 and 410 kHz side scan sonar mosaic of Site 386. .......................................... 59 

Figure 3.3.5. Sub-bottom profile of survey line 509, Site 386.. ................................................. 60 

Figure 3.3.6. Magnetic contours in 50-nT intervals at Site 386. ................................................ 61 

Figure 3.3.7. Sector scanning sonar composite image oriented north up. .................................. 62 

Figure 3.4.1. Side scan sonar image of Site 373. ....................................................................... 65 

Figure 3.4.2. Bathymetry surrounding Site 373, in 2-decimeter intervals. ................................ 67 

Figure 3.4.3. 3-D multibeam renderings of Site 373. ................................................................. 68 

Figure 3.4.4. 120 and 410 kHz side scan sonar mosaic of Site 373.. ......................................... 69 

Figure 3.4.5. Echoscope still of Site 373, from CODA UIS software. ...................................... 70 

Figure 3.4.6. Sub-bottom profile of line 205, Site 373.. ............................................................ 71 

Figure 3.4.7. Magnetic contours in 50-nT intervals at Site 373. ................................................ 72 

Figure 3.4.8. Photograph of propeller shaft with descent line attached. .................................... 74 

Figure 3.4.9. Downcore 210Pbxs activity for Site T373. ........................................................... 75 

Figure 3.5.1. 410 kHz side scan sonar image of Site 15488 ...................................................... 77 

Figure 3.5.2. Bathymetry surrounding Site 15488, in 2-decimeter intervals. ............................ 79 

Figure 3.5.3. 120 and 410 kHz side scan sonar mosaic of Site 15488. ...................................... 80 

Figure 3.5.4. Echoscope still image of Site 15488, from CODA UIS software. ........................ 81 

Figure 3.5.5. Sub-bottom profile of line 305, Site 15488.. ........................................................ 82 

Figure 3.5.6. Magnetic contours at Site 15488, at 2-nT intervals. ............................................. 83 

Figure 3.5.7. Sector scanning sonar image of Site 15488. ......................................................... 84 

Figure 3.5.8. Downcore 210Pbxs activity and linear sediment accumulation rate (LAR) 

calculations for Site T15488. ................................................................................ 86 

Figure 3.6.1. Cochrane sonar image of Site 15366. ................................................................... 88 

Figure 3.6.2. Map showing Chance and Cochrane survey lines and magnetic anomalies in 

relation to reported shipwreck coordinates. .......................................................... 89 

Figure 3.6.3. Bathymetry surrounding site 15366, in 2-decimeter intervals. ............................. 91 

Figure 3.6.4. 120 and 410 kHz side scan sonar mosaic of Site 15366. ...................................... 92 

Figure 3.6.5. Echoscope still image of Site 15366, from CODA UIS software. ........................ 93 

Figure 3.6.6. Sub-bottom profile of survey Line 305, Site 15366. ............................................ 94 

Figure 3.6.7. Magnetic contours in 10-nT intervals at Site 15366. ............................................ 95 

Figure 3.6.8. Mesotech scan highlighting the stern at Site 15366. ............................................. 96 
xiii 

Figure 3.6.9. Longitudinal protrusion on hull of site 15366.. .................................................... 97 

Figure 3.6.10. Downcore 210Pbxs activity and linear sediment accumulation rate (LAR) 

calculations for Site T15366. ................................................................................ 99 

Figure 3.7.1. 100 kHz side scan sonar image set at 75-m range. ............................................. 101 

Figure 3.7.2. 410 kHz side scan sonar image set at 75-m range. ............................................. 103 

Figure 3.7.3. 500 kHz side scan sonar image set at 75-m range. ............................................. 103 

Figure 3.7.4. Sector scanning sonar image of Site 389. ........................................................... 104 

Figure 3.7.5. Porthole resting on deck. ..................................................................................... 105 

Figure 3.7.6. Bathymetry surrounding Site 389 in 2-decimeter intervals. ............................... 106 

Figure 3.7.7. 3-D multibeam renderings of Site 389. ............................................................... 107 

Figure 3.7.8. 120 and 410 kHz side scan sonar mosaic of Site 389. Inset at 410 kHz. ............ 109 

Figure 3.7.9. Shallow stratigraphy cube at intersection of sub-bottom profiler Lines 305 and 

209....................................................................................................................... 110 

Figure 3.7.10. Magnetic contours in 5-nT intervals at Site 389. ................................................ 111 

Figure 3.7.11. Downcore 210Pbxs activity and linear sediment accumulation rate (LAR) 

calculations for Site T389. .................................................................................. 113 

Figure 3.8.1. Divers Andy Marr and Jake Shidner mapping the starboard paddlewheel. ........ 116 

Figure 3.8.2. The starboard paddlewheel and shaft. ................................................................. 116 

Figure 3.8.3. Rectangular housing on paddlewheel shaft adjacent to the starboard 

paddlewheel. ....................................................................................................... 117 

Figure 3.8.4. Bathymetry surrounding site 236 in 2-decimeter intervals. ................................ 120 

Figure 3.8.5. 120 and 410 kHz side scan sonar mosaic of Site 236. ........................................ 121 

Figure 3.8.6. Sub-bottom profile of survey Line 307, Site 236. .............................................. 122 

Figure 3.8.7. Magnetic contours in 5-nT intervals over location of the USS Hatteras. .......... 123 

Figure 3.8.8. Downcore 210Pbxs activity and linear sediment accumulation rate (LAR) 

calculations for Site T236. .................................................................................. 126 

Figure 3.9.1. 500 kHz side scan sonar image of Site 15326. ................................................... 128 

Figure 3.9.2. 500 kHz side scan sonar image of Site 15326 from Survey Line 301. ............... 129 

Figure 3.9.3. Side scan sonar image of Site 15326, highlighting trawl scars........................... 129 

Figure 3.9.4. Sector scan of Site 15326 oriented north up. ...................................................... 130 

Figure 3.10.1. 410 kHz side scan sonar image of Site 322 from survey Line 305. .................... 133 

Figure 3.10.2. Mesotech scan of Site 322 oriented north up. ..................................................... 134 

Figure 3.11.1. 410 kHz side scan sonar image of target No. 7 from survey Line 88. ................ 136 

Figure 3.11.2. 410 kHz side scan sonar image of sonar target No. 7 from survey Line 89. ...... 136 
xiv 

Figure 3.11.3. 410 kHz sonar image of sonar target No. 9 from survey Line 20. ...................... 137 

Figure 3.11.4. Sector scan highlighting unidentified object. ...................................................... 138 

Figure 4.1. Photograph of R.W. Gallagher ca. 1938. ............................................................ 151 

Figure 4.2. Site plan of Site 433, based on diver investigation and remote sensing data. .... 153 

Figure 4.3. Stern assemblage of Sites 433 and 373, based on diver observation, compared 

with stern assemblage of R.W. Gallagher hull type and Cities Service Toledo

Plan. .................................................................................................................... 156 

Figure 4.4. The SS Heredia, date unknown. ......................................................................... 159 

Figure 4.5. Photograph ca. 1933 of General Pershing compared to the annotated site map of 

Site 386. .............................................................................................................. 162 

Figure 4.6. Photograph of Hamlet, date unknown. ............................................................... 163 

Figure 4.7. Cities Service Toledo, date unknown. ................................................................. 165 

Figure 4.8. Site plan of Site 373, based on diver investigation and remote sensing data. .... 168 

Figure 4.9. Detail of shrouded propeller. .............................................................................. 172 

Figure 4.10. Photograph of Alaska, date unknown. ................................................................ 174 

Figure 4.11. Site plan of Site 389. ........................................................................................... 176 

Figure 4.12. Comparison between last known photograph of J.A. Bisso and the site plan. .... 178 

Figure 4.13. “Destruction of the Gunboat Hatteras by a Rebel Cruiser off Galveston, Texas."

............................................................................................................................. 180 

Figure 4.14 Site plan of exposed portions of the USS Hatteras. ........................................... 182 

Figure 4.15. Plan and profile of exposed portion of site. ........................................................ 187 

Figure 5.1. Shear strength measurements across the Northern GOM, in relation to study sites.

............................................................................................................................. 199 

Figure 5.2. Significant wave height and mean wave-period during Hurricane Rita ............. 201 

Figure 5.3. Significant wave height and mean wave period during Hurricane Ike ............... 202 

Figure 5.4. Seasonal average salinity measurements of surface water. ................................ 207 

Figure 5.5. Seasonal average salinity measurements at a depth of 15 m BSL. ..................... 208 

Figure 5.6. Seasonal average salinity measurements at a depth of 20 m BSL. ..................... 208 

Figure 5.7. Seasonal average salinity measurements at a depth of 30 m BSL. ..................... 209 

Figure 5.8. Dissolved oxygen content of bottom-water, as sampled July 25–31, 2010. ....... 210 

Figures 5.9 and 5.10. Left: Model of a mat-supported jack-up rig at Ocean Star Offshore Drilling 

Rig & Museum, Galveston, Texas. ..................................................................... 212 

Figure 5.11. Pipeline lay-barge with anchors deployed. ......................................................... 214 

Figure 5.12. Individual tracks for all tropical systems centered within 37 km (20 nautical 

miles) of Site 433 between 1912 and 1932. ........................................................ 217 
xv 

Figure 5.13. Multibeam bathymetry rendering at Site 433, highlighting seafloor scour. ....... 218 

Figure 5.14. Profiles of seafloor surrounding Site 433. .......................................................... 219 

Figure 5.15. Multibeam rendering of the seafloor at Site 386. ............................................... 222 

Figure 5.16. Profiles of the seafloor surrounding Site 386. .................................................... 223 

Figure 5.17. Individual tracks for tropical systems centered within 37 km (20 nautical miles) of 

Site 373 since 1942. ............................................................................................ 225 

Figure 5.18. Multibeam bathymetry rendering at Site 373, highlighting seafloor scour. ....... 226 

Figure 5.19. Profiles of the seafloor surrounding Site 373. .................................................... 227 

Figure 5.20. Individual tracks for tropical systems centered within 37 km (20 nautical miles) of 

Site 15488 between 1947 and 1965. .................................................................. 229 

Figure 5.21. Individual tracks for tropical systems centered within 37 km (20 nautical miles) of 

Site 15366 between 1925 and 1987. ................................................................... 231 

Figure 5.22. Individual tracks for tropical systems centered within 37 km (20 nautical miles) of 

Site 389 between 1842 and 1960. ....................................................................... 234 

Figure 5.23. Multibeam rendering of Site 389, highlighting scour. ........................................ 235 

Figure 5.24 and 5.25. Left: Preliminary site plan, rotated and oriented north up.. .................... 238 

Figure 5.26. Composite of multiple Mesotech scans of the USS Hatteras site ...................... 239 

Figure 5.27. Individual tracks for all tropical systems centered within 37 km (20 nautical 

miles) of Site 236, between 1932 and 1949. ....................................................... 240 

Figure 5.28. Sonar backscatter data highlighting changes in sediment grain size. ................. 242 

Figure 5.29. Sub-bottom scour contours. ................................................................................ 243 

Figure 5.30. Multibeam rendering at Site 236. ........................................................................ 244 

Map B-1. Survey post-plot. Site 380, reported wooden wreck, South Pelto area. .............. 298 

Map B-2. Survey post-plot. Site 433, probable R.W. Gallagher, Ship Shoal area. ............ 299 

Map B-3. Survey post-plot. Site 386, probable Heredia, Ship Shoal area. ......................... 300 

Map B-4. Survey post-plot. Site 373, probable Cities Service Toledo, Ship Shoal area. ... 301 

Map B-5. Survey post-plot. Site 15488, unidentified wreck, High Island area. ................. 302 

Map B-6. Survey post-plot. Site 15366, unidentified wreck, Galveston, Texas, area. ....... 303 

Map B-7. Survey post-plot, Site 389, probable J.A. Bisso, South Timbalier area. ............. 304 

Map B-8. Survey post-plot. Site 369, the USS Hatteras, Galveston area. .......................... 305 

Map D-1. Reported location of U-boat victims in the north central GOM. ........................ 326 

Map D-2. Comparison of reported locations of designated study sites and World War II-era 

tankers. ................................................................................................................ 327 
xvi 

Map D-3. German grid system map showing reported locations of World War-II-era study 

sites, based on German U-boat accounts (Rowher 1983). A. R.W. Gallagher, B. 

Heredia, C. Cities Service Toledo. ...................................................................... 328 

Map D-4. Locations of study sites and datums in relation to 2005 hurricanes. .................. 329 

Map D-5. Locations of study sites and datums in relation to 2008 hurricanes. .................. 330 

Figure E-1. General arrangement and outboard profile plans for Hull 4306 (duplicate plans 

were made for Hull 4307-R.W. Gallagher) 1936 (last revised 1938), Bethlehem 

Shipbuilding Corp. Ltd. ...................................................................................... 335 

Figure E-2. Engineering plans for Hulls 4306-4309 (R.W. Gallagher–Hull No. 4307) 1936.

............................................................................................................................. 336 

Figure E-3. List of Hull Nos. 4305-4312 specifications, built at Bethlehem Sparrow’s Point, 

Maryland Shipyard.............................................................................................. 337 

Figure E-4. War shipping administration requisition time charter for R.W. Gallagher 1942, p.1

............................................................................................................................. 338 

Figure E-5. War Shipping Administration requisition time charter for R.W. Gallagher 1942, 

p.2........................................................................................................................ 339

Figure E-6. War Shipping Administration requisition time charter for R.W. Gallagher 1942, 

p.3........................................................................................................................ 340

Figure E-7. Degaussing installation report for R.W. Gallagher 1942, p.1 ............................ 341 

Figure E-8. Degaussing installation report for R.W. Gallagher 1942, p.2. ............................ 342 

Figure E-9. Degaussing installation report for R.W. Gallagher 1942, p.3 ............................. 343 

Figure E-10. Degaussing installation report for R.W. Gallagher 1942, p.4. ............................ 344 

Figure E-11. Port director’s report arming merchant vessels for R.W. Gallagher 1942, p.2. .. 345 

Figure E-12. Port director’s report arming merchant vessels for R.W. Gallagher 1942, p.3. .. 346 

Figure E-13. Port director’s material report for Armed Guard Unit for R.W. Gallagher 1942, 

p.4........................................................................................................................ 347

Figure E-14. R.W. Gallagher (Tk), Wreck No. 628, Determination of depth of water above the 

wreck of, pg. 1. ................................................................................................... 348 

Figure E-15. R.W. Gallagher (Tk), Wreck No. 628, Determination of depth of water above the 

wreck of, pg. 2. ................................................................................................... 349 

Figure E-16. Timetable cover from States Steamship Company highlighting General Pershing 

and her sister ships, 1932.. .................................................................................. 352 

Figure E-17. Timetable pages from States Steamship Company, showing drawing of General 

Pershing, 1932. ................................................................................................... 353 

Figure E-18. Pages of timetable from States Steamship Company, illustrating cabin plans for 

the General Liners, 1934. .................................................................................... 354 
xvii 

Figure E-19. Page of timetable from States Steamship Company, illustrating cabin plans for 

the General Liners, 1934. .................................................................................. 355 

Figure E-20. Image of Heredia in Portland, Oregon, December 23, 1932, upon 

commencement of the charter to States Steamship Service.. ............................ 356 

Figure E-21. Port director’s report arming merchant vessels for Heredia 1942, p.2 (OCNO 

1942a). ............................................................................................................... 357 

Figure E-22. Port director’s material report for Armed Guard Unit for Heredia 1942, p.1. .. 358 

Figure E-23. Armed Guard Center report of materials furnished to Armed Guard Units for 

Heredia 1942, p.2 .............................................................................................. 359 

Figure E-24. Letter to the Chief of Naval Operations, Hydrographic Office, regarding the 

removal of menaces to navigation, p.1... ........................................................... 360 

Figure E-25. Letter to the Chief of Naval Operations, Hydrographic Office, regarding the 

removal of menaces to navigation, p.2.. ............................................................ 361 

Figure E-26. Letter to the Chief of the Bureau of Ships, Navy Department, regarding the 

removal of menaces to navigation, p.2. ............................................................. 362 

Figure E-27. J. A. Bostwick outboard profile plan, Hull No. 445, Harlan and Hollingsworth 

Corp., Wilmington, Delaware, 1916.. ............................................................... 365 

Figure E-28. J. A. Bostwick profile and deck plans, Hull No. 445, Harlan and Hollingsworth 

Corp., Wilmington, Delaware, 1916. ................................................................ 367 

Figure E-29. J. A. Bostwick stern frame and rudder plans, Hull No. 445, Harlan and 

Hollingsworth Corp., Wilmington, Delaware, 1916. ........................................ 369 

Figure E-30. War Shipping Administration requisition time charter for Cities Service Toledo

1942, p.1.............................................................................................................. 371 

Figure E-31. War Shipping Administration requisition time charter for Cities Service Toledo

1942, p.2.............................................................................................................. 372 

Figure E-32. War Shipping Administration requisition time charter for Cities Service Toledo 

1942, p.3.............................................................................................................. 373 

Figure E-33. Port director’s report arming merchant vessels for Cities Service Toledo 1942, p.2.

............................................................................................................................. 374 

Figure E-34. Port director’s report arming merchant vessels for Cities Service Toledo 1942, p.3.

............................................................................................................................. 375 

Figure E-35. Port director’s material report for Armed Guard Unit for Cities Service Toledo

1942, p.1.............................................................................................................. 376 

Figure E-36. Port director’s material report for Armed Guard Unit for Cities Service Toledo

1942, p.2.............................................................................................................. 377 

Figure E-37. Photograph of J. A. Bisso, date unknown. .......................................................... 381 

Figure E-38. Photograph of J. A. Bisso, far right, reportedly on the job it was on when it sank

............................................................................................................................. 382 
xviii 

Figure E-39. Drawing of the engine for St. Mary’s, Hull No. 41, date unknown. ....... ........ .385 

Figure E-40. Paul A. Cloutier and Frank E. Vandiver shown with artifacts recovered from the 

Hatteras site. ....................................................................................................... 386 

Figure E-41. Iron ball, shown from above, recovered from the USS Hatteras site, housed at the 

Corpus Christi Museum of Science and History. ................................................ 387 

Figure E-42. Iron ball, side view, recovered from the USS Hatteras site, housed at the Corpus 

Christi Museum of Science and History. ............................................................ 388 

Figure F-1. Salinity measurements compared by depth of sample. ....................................... 391 

Figure F-2. Salinity measurements displayed west (left, Site 236) to east (right, Site 380). . 391 

Figure F-3. Salinity measurements displayed by distance offshore. ..................................... 392 

Figure F-4. Averaged pH values compared by depth of sample. ........................................... 392 

Figure F-5. Averaged pH values displayed by longitude west (Site 236) to east (Site 380). 393 

Figure F-6. Averaged pH values displayed by distance offshore. ......................................... 393 

Figure F-7. Averaged DO measurements compared by depth of sample. ............................. 394 

Figure F-8. Averaged DO values displayed west (left, Site 236) to east (right, Site 380). ... 394 

Figure F-9. Averaged DO measurements displayed by distance offshore. ............................ 395 
xix 

LIST OF TABLES 

Table 1.1 Study Sites ................................................................................................................. 2

Table 3.1 Sites Investigated ...................................................................................................... 25

Table 3.2 Water Sample Results for Site 380 .......................................................................... 35

Table 3.3 Water Sample Results for Site 433 .......................................................................... 51

Table 3.4 Averaged Shear Strength Measurements from Core No. 2, Site 433 ...................... 52

Table 3.5 Water Sample Results for Site 386 .......................................................................... 63

Table 3.6 Water Sample Results for Site 373 .......................................................................... 74

Table 3.7 Water Sample Results for Site 15488 ...................................................................... 85

Table 3.8 Water Sample Results for Site 15366 ...................................................................... 97

Table 3.9 Water Sample Results for Site 389 ........................................................................ 112

Table 3.10 Water Sample Results for Site 236 ........................................................................ 124

Table 3.11 Water Sample Results for Site 15326 .................................................................... 131

Table 3.12 Water Sample Results for Site 322 ........................................................................ 135

Table 4.1 Reported Shipwrecks in the Vicinity of Site 380 with Similar Dimensions ......... 147

Table 4.2 Reported U-boat Casualties in the Vicinity of Site 433 ........................................ 149

Table 4.3 Reported U-boat Casualties in the Vicinity of Site 386 ........................................ 157

Table 4.4 Reported U-Boat Casualties in the Vicinity of Site 373 ........................................ 164

Table 4.5 Reported Shipwrecks in the Vicinity of Site 15488 with Similar Dimensions ..... 169

Table 4.6. Reported Shipwrecks in the Vicinity of Site 15366 with Similar Dimensions ..... 170

Table 4.7 Reported Shipwrecks in the Vicinity of Site 389 with Similar Dimensions ......... 173

Table 4.8 Reported Shipwrecks in the Vicinity of Site 15326 with Similar Dimensions ..... 184

Table 4.9 Reported Shipwrecks in the Vicinity of Site 322 with Similar Dimensions ......... 185

Table 5.1 Measured Surficial Grain Sizes for Study Sites .................................................... 200

Table 5.2 Characteristics of Surface Sediments at Oceanographic Modeling Datums ......... 201

Table 5.3 Scour Estimates Based on Oceanographic Modeling ............................................ 203

Table 5.4 Sites Analyzed for Radioisotopes and the Number of Data Points Sampled from 

Each Site ................................................................................................................. 204

Table 5.5 Linear Accumulation Rates (LAR) and Disturbance Event Date Ranges 

Indicated from Radioisotope Data .......................................................................... 205

Table 5.6 Averaged Results of Water Quality Testing .......................................................... 210
xx 

Table F-1 Radiochemical and Porosity Data for Site 433 ......................................................... 396

Table F-2 Radiochemical and Porosity Data for Site 373 ......................................................... 396

Table F-3 Radiochemical and Porosity Data for Site 15488 ..................................................... 397

Table F-4 Radiochemical and Porosity Data for Site 15366 ..................................................... 397

Table F-5 Radiochemical and Porosity Data for Site 389 ......................................................... 398

Table F-6 Radiochemical and Porosity Data for Site 236 ......................................................... 398
xxi 

ABBREVIATIONS AND ACRONYMS 

BLM Dept. of the Interior, Bureau of Land Management 

BML Below mud line 

BOEM Dept. of the Interior, Bureau of Ocean Energy Management 

BOEMRE Dept. of the Interior, Bureau of Ocean Energy Management, 

Regulation, and Enforcement 

BSL Below sea level 

COTR Contracting Officer’s Technical Representative 

DO Dissolved oxygen 

DSO Dive Safety Officer 

ft feet 

ft/sec feet per second 

GOM Gulf of Mexico 

INC Incident of non-compliance 

kHz kilohertz 

LAR Linear accumulation rate 

LOA Length overall 

m meter 

m/sec meters per second 

mg/L Milligrams per liter 

M/V Motor vessel 

MMS Dept. of the Interior, Minerals Management Service 

MVUS Merchant Vessels of the U.S. 

ms millisecond 

NIMA National Imaging and Mapping Agency 

NOAA AWOIS National Oceanic and Atmospheric Administration 

Automated Wreck and Obstruction Information System 

NOAA NHC National Oceanic and Atmospheric Administration National 

Hurricane Center 

NRHP National Register of Historic Places 

nT nanotesla 

NTL Notice to Lessee 

OCS Outer Continental Shelf 

P&A Plugged and abandoned [well] 

ppT Parts per thousand 

SS Steamship 

μm micron 

USCG U.S. Coast Guard 

USGS U.S. Geological Survey 

UWF University of West Florida 
1 

1. INTRODUCTION 

1.1 BACKGROUND

Tesla Offshore, LLC, was awarded a contract in 2009 by the former Minerals Management 

Service (MMS) (then from May 2010 until October 201, the Bureau of Ocean Energy 

Management, Regulation and Enforcement, now the Bureau of Ocean Energy Management 

[BOEM]) to investigate six shipwreck sites on the Outer Continental Shelf (OCS), Gulf of 

Mexico (GOM). The sites were to be investigated through geophysical survey and a combination 

of diver observation and sediment core acquisition. The purpose of the study was to verify that 

the targets were shipwrecks, and, if possible, to provide identifications and assessments of 

potential eligibility for listing on the National Register of Historic Places (NRHP). A second aim 

of the study was to provide an assessment of site formation processes that impact the individual 

wreck sites. The six sites ranged in water depths from 11 to 36.5 m (36 to 120 ft) below sea-level 

(BSL) and were located across the north-central and northwestern GOM, from Morgan City, 

Louisiana to Galveston, Texas. 

The contract was awarded on September 27, 2009. Geophysical data was obtained at the six 

contracted study sites between March and August 2010. Diving operations were performed in 

August 2010. Before the fieldwork began, a contract modification was approved that would 

allow investigation of additional sites in case diving was restricted due to the Deepwater Horizon

oil spill that had occurred in April 2010. Though the oil spill did not adversely impact activities 

at any of the study sites, additional sites were added to the scope of work in the field with input 

and approval from the Contracting Officer’s Technical Representative, Dr. Christopher Horrell. 

A total of 11 sites were investigated during dive operations (Table 1.1). Following field work, it 

was decided that the study would benefit from geophysical data acquisition at two of the sites 

that had been added in the field. A second contract amendment was requested and approved to 

acquire additional geophysical data at the two supplemental sites and for including these wrecks 

in the overall analysis and modeling. 

 
2 

Table 1.1 

 

Study Sites 

Lease Protraction State BOEM Site 

Number 

Classification Tentative ID 

South Pelto LA 380 Wooden vessel Unknown wooden vessel 

Ship Shoal LA 433 Vessel R.W. Gallagher 

Ship Shoal LA 386 Vessel Heredia 

South Marsh Island LA 373 Vessel Cities Service Toledo 

High Island TX 15488 Vessel Unknown 

Galveston TX 15366 Vessel Unknown 

South Timbalier LA 389 Vessel J.A. Bisso 

Galveston TX 236 Vessel USS Hatteras (confirmed) 

East Cameron LA 15326 Barge Unknown 

East Cameron LA 322 Vessel Unknown 

West Cameron LA Pending Unknown Unknown 

Sediment core data was collected at eight of the 11 sites investigated during diving 

operations. As a time- and cost-saving measure, core data was not analyzed for sites where no 

shipwreck was identified. Sediment cores were not collected on Site 386, because unsafe 

conditions restricted diving operations (Chapter 3.3.3). Radioisotope analysis was performed on 

sediment samples for six of the study sites. The purpose of this analysis was to provide dates for 

sediment disturbances and estimates of sediment deposition rates at the sites. Oceanographic 

modeling was performed to provide baseline information on regional processes that affect 

sediment and water current movement in and around the study sites. Due to the complexity 

involved in the modeling, cost, the number of sites, and the large area of interest, three datums 

were selected across the study area and used as the basis for the modeling. These models were 

then extrapolated to address all of the primary study sites. 

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4 

1.2 CURRENT MANAGEMENT STRATEGIES FOR OCS SHIPWRECKS

The GOM has played an integral role in the nation’s cultural and historical heritage. 

Evidence of the nation’s maritime and economic history is represented by shipwreck sites 

covering approximately 500 years of exploration and exploitation across the region. Historically 

significant shipwreck sites documented throughout the GOM range from 16th-century ships of 

discovery to World War II-era U-boats. 

Archaeological sites can provide invaluable information that is missing from the historical 

record. Explicitly, the archaeological record consists of static evidence that can be scientifically 

examined to reveal information omitted from or misrepresented in the historical record. The 

archaeological record is unique in this regard; information that can be garnered from 

archaeological sites can contribute to a better understanding of the past. Shipwreck sites are 

tangible connections with history and, due to the often sudden or violent causes of their sinking, 

many have the added gravitas of being the final resting places of passengers and crews. For these 

reasons, federal laws such as the National Historic Preservation Act (1966), Executive Order 

11593, and the Sunken Military Craft Act (2005) were enacted to provide for the identification 

and protection of archaeological resources. 

BOEM, U.S. Department of the Interior, is tasked with regulating activities associated with 

mineral extraction on the OCS in the U.S. In accordance with Section 106 of the National 

Historic Preservation Act, the BOEM GOM OCS Region has issued multiple Notices to Lessees 

(NTLs) and other supporting documentation that provide rules and guidelines for investigating 

and protecting submerged archaeological sites on the OCS. Presently, NTL 2005-G07 designates 

survey requirements in leases that are considered archaeologically significant. Because all lease 

and pipeline surveys in the GOM already require geophysical hazard surveys (NTL 2008-G05), 

the hazard and archaeological surveys can often be performed in tandem. 

In brief, the archaeological NTL requires a geophysical survey using single beam 

bathymetry, side scan sonar, magnetometer, and sub-bottom profiler in water depths under 200 m 

(656 ft). In water depths over 200 m (656 ft), magnetometer and sub-bottom profiler are no 

longer required. The requirement for archaeological surveys was based on a predictive model 

that indicated either the occurrence and preservation of prehistoric sites, or the presence of 

historic shipwrecks. A maximum survey line spacing interval of 50 m (164 ft) is required in 

blocks that have been designated high probability for shipwreck occurrence in water depths 

under 200 m (656 ft). Leases that are considered high probability for prehistoric occurrence, or 

that are in water depths exceeding 200 m (656 ft), require a maximum line spacing interval of 

300 m (984 ft). The high probability model for requiring surveys in specific blocks was used 

from the first archaeological mitigation in 1973 until April 2011. However, the high probability 

model did not account for all shipwrecks, especially those occurring in deeper water. A 

mitigative document was prompted by documented cases of archaeological site damage and/or 

vandalism in blocks that were not originally identified as high probability areas for 

archaeological site occurrence; the document was issued in April 2011. The potential need for 

implementation of archaeological surveys or inspections is now considered in the National 

Environmental Policy Act (NEPA) analysis for permitted activities, regardless of their location, 

in the GOM. At the time of writing, survey parameters remain unchanged, but the mitigation 
5 

applies to all seafloor-disturbing, federally-permitted activities related to mineral extraction for 

which an Environmental Assessment (EA) is prepared. In the GOM, this concerns primarily well 

drilling, platform installation, pipeline installation, alternative energy projects, and less 

commonly, sediment or resource extraction. 

The sites presented in this report are located within a relatively low energy, micro-tidal 

environment of the GOM system (Curray 1960; Morton et al. 2004:21). Wave conditions, current 

movement, sediments, and other environmental variables affect shipwreck sites continuously, 

and these conditions can become exaggerated during extreme storm events. Currently, BOEM is 

responsible for managing cultural resources on the OCS, and specifically for balancing activities 

of the offshore oil and gas industry with the protection of cultural and natural resources. 

Avoidances are assigned to archaeological sites to protect them from anthropogenic (humaninduced) impacts and also to prevent the archaeological resource from posing a hazard to 

offshore development (Evans et al. 2009). A recent BOEM-funded study produced data useful 

for determining appropriate avoidances for deep-water shipwreck sites (Church et al. 2007); 

however, the biological and environmental processes documented at these sites are not 

applicable to shallower sites located on the continental shelf. A 2006 study discussed the 

relevance of avoidance criteria on shallow sites (Enright et al. 2006); a 2011 study assessed the 

impacts of recent hurricanes on shipwreck sites (Gearhart et al. 2011). Beyond these recent 

studies, there is limited data for modeling more accurate avoidance zones based on site formation 

and environmental processes for archaeological sites on the continental shelf. 

The data in this study is used to assess the long-term stability of the investigated shipwrecks 

on the OCS; it may assist BOEM as part of their mission to help better manage submerged 

cultural resources and guide regulations. An important aspect of this management strategy is to 

assess the effectiveness of prescribed avoidance zones to ensure that oil and gas development 

does not adversely impact shipwrecks. 

As discussed by Enright et al. (2006:141), “The goal of avoidance should be protection of 

shipwrecks and their associated debris fields from any kind of adverse effect by federally 

permitted activities on the OCS.” Most commonly, BOEM designates avoidance zones of 305 m 

(1,000 ft) to protect shipwrecks on the OCS; larger avoidance zones ranging from 457 to 609 m 

(1,500 to 2,000 ft) have been used for sites in deeper water and for sites that have established 

historic significance. Smaller avoidance zones, typically ranging from 61 to 152 m (200 to 500 

ft) are often prescribed to unidentified sonar targets and magnetic anomalies. The study sites 

discussed in this report have been assigned avoidance zones of 305 m (1,000 ft) by BOEM, with 

the exception of Hatteras, which has been assigned an avoidance zone of 609 m (2,000 ft). 

Avoidance zones are initially recommended by the archaeologist who is contracted to 

interpret the data and conduct the archaeological assessment, and are then evaluated and possibly 

revised by BOEM archaeologists as part of the plan or pipeline review process. Since BOEM 

maintains records of previous surveys, BOEM archaeologists often have additional data available 

that can be used to supplement a given survey. The coordinates of all targets to be avoided and 

their avoidance criteria are then provided to the operator as part of the BOEM approval 

notification. The supplied avoidance information is typically a single coordinate based on the 

centerpoint of a target or anomaly and a radius. 
6 

Following the completion of a permitted activity, operators are required to submit measured 

plats that show the location of all bottom disturbances associated with seafloor installations and 

pipeline installation. For pipelines, this includes the location of all anchors used during 

construction and the placements of associated anchor chain. These plats are analyzed during the 

post-installation review process to ensure that avoidance stipulations were met during the 

permitted activity. If anchors or chains impact an avoidance zone, BOEM may issue an Incident 

of Non-Compliance (INC) and require the operator to inspect the target or conduct other 

mitigative measures. 

1.3 REPORT CONVENTIONS

This report is structured to integrate the results of the geophysical survey, diver 

investigations, environmental sampling, and oceanographic modeling in such a way that the 

reader can focus solely on an individual site of interest, or read about the regional findings based 

on cross-site comparisons and modeling. Following this introduction, Chapter 2 discusses the 

research methodology and details the equipment, parameters, and specifications that were used 

for the study. Chapter 3 discusses each study site individually, presenting detailed results of 

analyses at each location. The original six study sites are discussed first, followed by the two 

contract modification sites, which are followed by the three sites that were investigated only 

during diving operations. Chapter 4 discusses the historical significance of the wreck sites as 

they pertain to regional chronologies and assesses their potential eligibility for placement on the 

NRHP. Chapter 5 discusses the natural and cultural site formation processes impacting the study 

sites, and focuses on a regional discussion and comparison of the individual data sets presented 

in Chapter 3. The final section, Chapter 6, summarizes the results and recommends avenues for 

future research. 

This contract was awarded by the Minerals Management Service, U.S. Department of the 

Interior (MMS). After the contract was awarded, the name of the agency was changed to the 

Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE). Effective in 

October 2011, a reorganization created the Bureau of Ocean Energy Management (BOEM). 

Before the 1982 passage of the Federal Oil and Gas Royalty Management Act, which placed 

offshore regulatory responsibility with the MMS, offshore resources in the GOM had been 

managed by the U.S. Department of the Interior’s Bureau of Land Management (BLM). 

Throughout this report, the bureau is referred to as BOEM, except when referring to a specific 

past action or regulation performed under the auspices of one of the previous agencies. 

Citations follow the format outlined by the Bureau of Ocean Energy Management. The 

locations of most of the study sites were obtained through geophysical surveys. Because 

geohazard and archaeological assessments performed in compliance with BOEM regulations are 

typically conducted using the same methodology, in most cases these assessments are combined 

into a single report. Most of these reports are prepared by an archaeologist and a geologist or 

geophysicist. When referencing these reports, the authors’ names are given with the 

archaeologist listed first because the archaeological portion of the report was typically the most 

relevant component for this study and in some cases was the only portion available for review. 
7 

Lease numbers and OCS designations have been redacted from the titles of these reports for 

confidentiality purposes. 

BOEM requires that surveys in the GOM use U.S. measurement units (feet and inches). 

Because of the prevalence of oil and gas industry-related research in the GOM, virtually all 

references, maps, and data were initially obtained and/or reported in feet. Also, most of the study 

sites are U.S. built and/or registered vessels that used U.S. measurement units. Formatting 

guidelines for BOEM studies require International or metric units as the primary convention. All 

measurements in this report, therefore, are given in metric with U.S. units (feet and inches) given 

in parentheses. In most cases, the original unit was feet; metric conversions were calculated 

specifically for this report. 
9 

2. RESEARCH DESIGN AND METHODOLOGY 

2.1 BACKGROUND AND ARCHIVAL RESEARCH

The majority of the sites investigated for this study were identified by geophysical surveys 

performed on behalf of oil and gas industry operators in compliance with BOEM regulations. 

Initial background research into the study sites started with the shipwreck database maintained 

by BOEM. This database was initially prepared under contract by Garrison et al. (1989) and was 

updated by Pearson et al. (2003); it contains a comprehensive listing of shipwrecks in the region, 

drawn from sources such as the U.S. Coast Guard, National Imaging and Mapping Agency 

(NIMA), National Oceanic and Atmospheric Administration Automated Wreck and Obstruction 

Information System (NOAA AWOIS), and Louisiana and Texas state site files. BOEM also 

maintains records of previous surveys that were conducted under their jurisdiction. Where 

possible, copies of pre-existing surveys that encompassed study sites were provided for inclusion 

in this study by COTRs Mr. Dave Ball and Dr. Christopher Horrell. In some cases, a full report 

of findings was available, including samples of geophysical data, tabulation of sonar targets and 

magnetic anomalies, and survey maps. In other cases, the complete report was not available, and 

only a single image of a wreck site or minimal text was available. Complete details of the 

discovery and subsequent investigation of each wreck site are given in Chapter 3, the Site 

Results section of this report. 

Three of the originally contracted shipwreck sites had been tentatively identified before this 

study; therefore, historical research at these locations focused on confirming or refuting the 

preliminary identifications. The remaining three study sites had been unidentified before this 

study. Research at every study site included an assessment of reported wrecks within, minimally, 

32 km (20 miles) of each site. Additional information on reported wrecks within the search radii 

for each site was obtained from publicly available sources, such as the Merchant Vessels of the 

U.S. (MVUS), and the USCG Port Information Exchange System. Published dimensions were 

not always directly comparable with overall measurements of wrecks observed in the field or 

ascertained from geophysical data. Lengths published in MVUS, for example, do not always 

represent length overall. MVUS publishes the length on tonnage deck for registered vessels, 

which is defined as the length along the tonnage deck from the fore part of the outer planking at 

the bow to the after part of the sternpost of screw steamers, or to the after part of the rudderpost 

on other vessels. For vessels with three or more decks, the tonnage deck is the second deck from 

the keel. The upper deck is considered the tonnage deck for all vessels with fewer than three 

decks (MVUS 1942:5). In the case of MVUS lengths used in the research of potentially 

identified shipwrecks, they were considered minimum lengths for an intact hull. Published 

dimensions and other criteria were used to eliminate reported losses as possible candidates for 

the wreck sites. Texas and Louisiana State Site File forms and the NOAA Automated Wrecks 

and Obstruction Information System (AWOIS) also provided additional information on wreck 

parameters and locations. 

Primary archival research was conducted in May 2011 at the National Archives in 

Washington D.C. and College Park, Maryland. Other archives and museums that were consulted 
10 

include: The Daughters of The Republic of Texas Library at the Alamo; The Baltimore Museum 

of Industry; the Mariner’s Museum; the Hagley Museum & Library; the Oregon Historical 

Society; U.S. Coast Guard, Historian’s Office; National Archives at New York City; MIT 

Museum, Hart Nautical and General Collections; National Museum of American History, 

Smithsonian Institution; National Museums Northern Ireland; San Francisco Maritime National 

Historical Park; the Becker Collection at Boston College; and the Regional Military Museum in 

Houma, Louisiana. Secondary sources pertaining to World War II vessels, convoys, and U-boat 

campaigns in the GOM were also consulted when attempting to refute or confirm the identities 

of tentatively identified study sites. 

2.2 GEOPHYSICAL DATA

A geophysical survey was conducted over each site in order to obtain site level information 

about each wreck, including the size, shape, and orientation of each wreck and any associated 

targets. Geophysical sensors also recorded information pertaining to each wreck site’s 

environment, including bathymetric contours, seafloor gradient, scour zones and depth, and 

subseafloor stratigraphy. Survey methodology included the use of both passive and active 

sensors deployed in a towed array at each site. The use of geophysics in archaeology, specifically 

in underwater archaeology, is a widely accepted practice because of the ability to accurately 

record large areas of the seafloor in greater detail than can be identified through visual survey 

alone. 

BOEM has previously funded studies to refine methodologies for the acquisition and 

interpretation of magnetometer data as it relates to submerged cultural resources (Garrison et al. 

1989; Pearson et al. 2003). Magnetometers are passive sensors that record the Earth’s ambient 

magnetic field, created by the interaction of the Earth’s “metallic nickel-iron core” and “viscous 

lower mantle” (Herz and Garrison 1998:165). The resulting magnetic field varies in intensity 

from approximately 35,000 to 70,000 nanoteslas (nT), depending on distance between the north 

and south poles (Herz and Garrison 1998:165). Local aberrations in the Earth’s magnetic field 

(anomalies) can result from the presence of a ferromagnetic object, or objects and sediments 

whose magnetization has been altered by human activity (Herz and Garrison 1998:167-169; 

Mussett and Khan 2000:162). It is important to note that all objects have the potential to become 

magnetized; therefore, recorded anomalies do not always represent human-made materials, let 

alone archaeological materials. Sediments, rocks, heated surfaces, and other naturally occurring 

features may become magnetized and produce anomalies sufficient to be recorded by 

magnetometers. Magnetic anomalies as interpreted for offshore survey reports were defined by 

Garrison et al. (1989) as a deviation in the ambient magnetic field measuring 5 nT (gammas) or 

more, and recorded across three or more consecutive data samples. Enright et al. (2006) restated 

this definition using the same intensity criteria, but using a distance measurement of 6 m (19.7 ft) 

or more rather than using a predefined duration of time. 

As discussed in Camidge et al. 2010, Enright et al. 2006, and Garrison et al. 1989, there are 

inherent limitations to contouring magnetic data. Magnetometer data for this study was acquired 

in order to identify any disarticulated components or artifacts within the overall site; however, 

virtually all of the study sites have significant quantities of metal. The process of contouring 
11 

magnetic data can make it difficult or impossible to identify smaller anomalies that are obscured 

by much larger, adjacent anomalies within the site. The result is that the smaller anomalies that 

may be caused by distinct targets away from the main body of a wreck are unidentifiable on the 

contour map. Also, contoured data is interpolated across survey lines, suggesting greater data 

density than is actually recorded (Camidge et al. 2010). For these reasons, magnetometer data 

interpretation for this study also included an analysis of individual anomaly characteristics and 

plotting of each individual anomaly. 

The remaining geophysical sensors used for this project are active acoustic sensors, including 

side scan sonar, single beam echosounder, multibeam echosounder, and sub-bottom profiler. 

Additional data was acquired at selected study sites using a 3-D scanning sonar system. Acoustic 

sensors are ubiquitous in underwater survey because of the superior ability of sound waves to 

propagate through water. Sound waves will travel at varying frequencies through the water 

column to depths of up to 10,000 km (Wille 2005). Generally, acoustic sensors operate by 

emitting a specific frequency signal and recording both the amount of time it takes the signal to 

return to the receiver and the strength of the returned signal (Wille 2005; Blondel 2009). 

Acoustic data collection depends on the actual speed of sound in two-way time travel through 

the water column; data can be acquired using the average speed of sound in salt water, 1,500 

meters/second (m/sec) (~5,000 ft/sec) or adjusted for the actual speed of sound recorded by 

velocity casts, or sound velocity profiles, conducted at each study site and specific to that data set 

(Wille 2005:27). The measured speed of sound can be applied directly to the data during 

acquisition or as a correction during data post-processing. Acoustic data, or imagery based on 

sound is produced when an object has a different acoustic impedance than its surroundings; 

acoustic impedance, also known as backscatter, is defined as “the product of the density and the 

speed of sound” (Wille 2005:29). A change in either density or speed of sound will produce an 

acoustic echo. Sound images of marine environments do not have a genuine color and generally 

are black and white, with a dynamic gray scale, although for ease of interpretation they can be 

changed to a false color scale (Wille 2005:30). Figures based on acoustic data in this report use 

both gray scale and false color scales. 

The side scan sonar, single beam echosounder, multibeam echosounder, and 3-D sonar are all 

acoustic devices designed to image or provide bathymetric data of the seafloor. The side scan 

sonar provides backscatter imagery to either side of the sensor; this highlights changes in object 

density, resulting in a picture that illustrates textural changes in the seafloor, or acoustic imagery 

of seabed objects such as a shipwreck. Lower sonar frequencies can travel further resulting in a 

wider coverage area, which allows surveys to be conducted much more rapidly using a wider 

survey grid; however, this is offset by decreased imaging resolution. Higher frequencies can 

provide much-improved imaging, but the area of seafloor that can be covered in a single pass is 

reduced. The single beam echosounder is used primarily to provide water depth values directly 

beneath the sensor. The disadvantage is that values are present only directly beneath the area 

traversed by the survey vessel, so data must be interpolated between survey lines. Wider survey 

line spacing intervals, coupled with complex seafloor conditions, will result in a less than 

accurate bathymetric map. Multibeam echosounders solve this problem by using multiple pings 

in a swath pattern similar to that of the side scan sonar. The result is that with proper survey 

design, more than 100% seabed coverage can be obtained, which results in very accurate 
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13 

Acquisition was typically timed to correspond with periods when Nikola was operating in the 

vicinity of one of the study sites. The contract called for only side scan sonar and magnetometer 

acquisition at each site. In addition to these sensors, a single beam echosounder, a multibeam 

echosounder, and a sub-bottom profiler were employed on all sites. Velocity probes were 

deployed at each site (typically at the commencement and termination of the survey) to measure 

the true speed of sound for calibration and processing of acoustic sensors. During data 

acquisition at three of the study sites, Tesla also deployed a CODA Echoscope© 3-D sonar 

mounted to Nikola’s hull. 

The geophysical systems used on all sites included a Marine Magnetics SeaSpy© total field 

magnetometer, an Edgetech 2400-FS© 120 & 410 kHz dual frequency side scan sonar, an Odom 

EchoTrac Mk III© 24 & 200 kHz dual frequency single beam echosounder, an Edgetech SB216© 2-16 kHz chirp sub-bottom profiler, and a R2 Sonic 2024© 200–400 kHz multibeam 

echosounder. A CODA Echoscope© 3D sonar was used during acquisition at three of the 

original contract sites. The sensor configuration for Nikola is shown in Appendix A. The single 

and multibeam echosounders and the Echoscope were pole-mounted to the hull of Nikola. All 

other sensors were towed behind the vessel. The hull-mounted sensors were positioned by the 

Veripos© augmented DGPS network and interfaced into a QINSy© hydrographic package by 

QPS©. The towed sensors were positioned using differential-enabled GPS receivers provided by 

the WAAS and USCG reference station networks interfaced to an EZ-Nav navigation package 

by Geonav Marine Systems©. 

All towed sensors are positioned relative to the vessel’s antennae. The sub-bottom profiler 

was towed at a constant distance behind the survey vessel. Cable changes were made for the 

sonar and magnetometer, as needed, to ensure that sensors were operated at the optimum height 

above the seabed. On occasion, sensors were towed beyond recommended specifications in order 

to avoid shipwrecks with significant relief above the seafloor. Sensor setbacks at each site are 

tabulated in Sensor Line Logs which have been provided to BOEM along with copies of the 

original data. To compensate for real-time cable changes, digital magnetometer and sonar data 

were set-back corrected by feeding cable counter data directly into the navigation system. An 

algorithm within the navigation software uses the height of the tow-fish above the seafloor 

subtracted from the water depth (to calculate the depth of the tow-fish), the cable counter value, 

and a cable catenary calculation to provide true-setback for each sensor in real-time. 

Specifications for all geophysical sensors and equipment are included in Appendix A. 

The geodetic datum for the survey was NAD 27, State Plane Coordinate System (Louisiana 

South or Texas South Central), Lambert Projection, in feet. Survey grids at each site were 

designed to parallel the orientation of each wreck, when known, based on available data. In most 

cases, two separate survey grids were employed and centered on the reported site coordinates. 

Both grids were typically oriented parallel and perpendicular to the orientation of the wreck site. 

The first survey grid covered a radius of 300 m (~1,000 ft) past the reported wreck coordinates. 

Survey lines were spaced at 100 m (328 ft) line spacing intervals. The side scan sonar was 

operated at 120 kHz and set at 100 m (328 ft) range to confirm the shipwreck position. The lower 

frequency spectrum allows the tow-fish to be flown higher in the water column, thereby reducing 

the risk of impacting the wreck site. The wider swath setting also provided maximum coverage 

of the seafloor while reducing time and costs. The second grid covered a 150-m (~500-ft) radius 
14 

around the wreck site and used a 30-m (98.4-ft) line spacing interval with the sonar operating at 

410 kHz and set at a 50-m (164-ft) range. The higher frequency spectrum provided increased 

resolution of the wreck and seafloor surrounding the wreck site while providing a tighter grid for 

magnetometer, multibeam, and sub-bottom profiler acquisition. The dual survey grid 

methodology also allowed for the comparison of magnetic contours using two different line 

spacing intervals over similar grids. 

Survey lines were numbered using separate numbering conventions according to line spacing 

interval and direction. For example, on Site 433, 100-m spaced lines that parallel the wreck are 

numbered consecutively, beginning with number 1, while the 100-m survey lines that are 

perpendicular to the wreck are consecutively numbered beginning with number 101. The 30-m 

spaced lines parallel to the wreck start with number 201 and the 30-m perpendicular lines start 

with number 301. Re-runs were deemed necessary in the field if sensor quality was 

compromised, the vessel was forced off-line, or sensors were out of specification. Each survey 

line re-run is appended with a letter designation. 

The grids described above were used on all sites except the shallowest site (Site No. 380), 

where the shallow water depths precluded the ability to achieve adequate sonar coverage using 

the 100-m line spacing interval. All lines at Site 380 were run at 30-m line spacing, covering the 

full 300-m radius. Sites Nos. 389 and 236 were added as part of a contract amendment and 

employed 30-m and supplemental 15-m survey lines directly over the shipwreck site, but fewer 

100-m survey lines. Navigation post-plot maps for each of the eight geophysical survey grids are 

included in Appendix B. 

 

2.4 DATA PROCESSING

Echoscope acquisition and preliminary data processing was performed by Pete Henstridge 

using CODA UIS©, QPS QINSy©, and QPS Qloud© software. Multibeam bathymetry 

acquisition and preliminary processing was performed by James Collier and Kyle Edmonds 

using QPS QINSy© and Qloud© software. Additional processing and preparation of final figures 

was performed by Matt Keith. All bathymetry maps and seafloor renderings were prepared using 

the multibeam bathymetry data. Depths are shown in meters on all maps included in this report. 

Bathymetric datum was the NGVD 29 vertical datum for mean sea-level with water depths 

adjusted for the measured velocity of sound in seawater during acquisition. All measurements 

were recorded in standard units and converted to metric for the final report. 

Sonar and sub-bottom profiler data interpretation was conducted using the latest CODA 

GeoSurvey Software. CODA Survey Engine Seismic+ software was also used for sub-bottom 

profiler interpretation. 

Magnetometer data was acquired in an ASCII format and interpreted using Tesla Offshore’s 

proprietary MagPick software. All magnetometer interpretation and tabulation was performed by 

Amanda Evans. All magnetic anomalies are tabulated in Appendix C, which details the anomaly 

characteristics and survey parameters in relation to the navigation post-plot for each site. Matt 

Keith prepared the magnetometer contours using proprietary Tesla software developed by Bill 
15 

Loggin. This software filters the data set by removing all data points that do not exceed 

specifications for gamma count increase over a specified distance. The remaining values are 

saved as a negative or positive value relative to the ambient background field. The result is the 

ambient background is removed and only anomalous readings remain, negating the need for a 

base station. This data was then contoured using Surfer© software. Excellent correlation was 

noted between individually mapped anomalies and contoured data. 

All maps and figures for this report based on the geophysical data were prepared by Matt 

Keith, with assistance from Tesla drafting staff. 

2.5 DIVING PARAMETERS

The diver investigation phase of the project involved Principal Investigator Amanda Evans 

(Tesla Offshore), Co-Principal Investigator Matt Keith (Tesla Offshore), Diving Field Director 

and Archaeologist Gregory Cook (UWF Archaeology Institute), Dive Safety Officer (DSO) Fritz 

Sharar (UWF Marine Services Department), Archaeologist Norine Carroll (UWF Archaeology 

Institute), and archaeological divers from the University of West Florida (UWF), including Aleks 

Adams, Daniel Haddock, Mercedes Harrold, Sarah Linden, Andy Marr, Bill Neal, Jake Shidner, 

Eric Swanson, and Wes Perrine. COTR Dr. Christopher Horrell and Marine Archaeologist 

Melanie Damour accompanied the field crew as observers for BOEMRE, and also participated in 

diving operations. 

It was recognized, from the initial planning stages that the field crew would benefit from 

preparatory dives conducted as a team and in water depths and conditions similar to those 

expected in the open GOM. Field equipment was tested before deployment and, where 

necessary, modifications were made to ensure optimum data quality during field operations. A 

dive in water depths equal to the deepest study site was conducted, involving field crew 

members, that simulated archaeological tasks that would be conducted during contracted field 

operations. Also, before field work began, all project divers went through supervised underwater 

entanglement exercises organized by UWF’s DSO Fritz Sharar. This was deemed necessary 

because many shipwrecks in the GOM are fouled by fishing line and netting which create 

entanglement hazards for divers in low to zero visibility conditions. The DSO had absolute 

authority to call dives for any reason in order to ensure the safety of all crew members. 
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18 

divers communicating their findings after completing their dive to those suited up and prepared 

to continue the investigation based on what had been completed or observed during previous 

dives. This resulted in an efficient dive rotation that often involved multiple dive teams working 

on different sections of the site, and clear communication between teams as to the status of the 

overall goals for the archaeological recording. After completing operations on each site, 

archaeologists transcribed their notes, cataloged video and still photographs, and made 

preparations for further investigations as the M/V Spree transited to the next site for 

investigation. 

 

Site maps based on diving and geophysical data were prepared by Greg Cook. Aleks Adams 

assisted with the preparation of the Site 389 site plan. C. Lee McKenzie prepared the final maps 

in Microsoft® Publisher which were entered into AutoCAD software and finalized by Tesla 

personnel. Measurements of diagnostic features taken in the field were recorded in standard U.S. 

units (feet and inches), and converted to metric for the final report. 

2.6 CORING AND ENVIRONMENTAL ANALYSES

In addition to the historical significance and archaeological aspects of this study, 

environmental factors were analyzed to determine site formation processes impacting the wreck 

sites. The majority of analyses used in long-term environmental monitoring require repeated site 

visits for long-term data collection; however, due to time and budget constraints, this was not an 

option for the present study. Core acquisition was required as part of the contracted scope of 

work, and the research design and sampling strategy was constructed to maximize the amount of 

information that could be produced from a single visit to the site, effectively collecting a 

snapshot of site conditions and applying the data in more detailed long-term scenarios. Cores 

were collected by divers, rather than from the vessel, for two reasons: first, to avoid incidental 

damage to the site caused by remote coring, and, second, to allow divers to position the core 

barrel so that sediments were collected as close to the hull as possible. Water samples were 

added to the research design as a cost effective way to provide additional information, and were 

sampled at the actual wreck site depths. Core lithology and environmental samples are illustrated 

in Appendix G; water sampling results are tabulated in Appendix F. Analyses of sediments 

captured stratigraphically within the cores were used to measure conditions at the time of 

sampling and applied to estimates of long-term processes, while water sample test results were 

compared with known values and ranges across the GOM. 
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Diver-co

gravity c

disturban

advance 

during re

Matt 

physical 

visibility

Followin

were coll

Core slee

stored up

ng devices a

l bottom sed

ely types of

nd Louisiana

ds. The latte

and hurrican

nantly relict 

ttributed to 

silts and clay

ildco 2” diam

was chosen b

t profile of 

could be c

llected core

orer (Mudro

nce in the se

of the samp

etrieval to the

Keith and A

requiremen

y conditions

ng acquisitio

lected by Am

eves were se

pright on the

Figure 2.4.

are generally

diment samp

f sediment t

a, and the m

er are mode

nes, and pre

and deposit

and/or rewo

y were antici

meter, 36” l

because it w

sediments 

conducted, h

es have been

och and Azcu

ediment strat

pler; tilting o

e sampling p

Amanda Evan

nts of handli

 on site, c

on, each cor

manda Evan

ealed, labele

 vessel to av

. Bill Neal a

sleeve from

y designed f

pler, the cor

to be encou

most likely se

ern, suspend

eferentially d

ted near the 

orked by stor

ipated with v

ength coring

was managea

for use in p

however, on

n shown to 

ue 1995:54).

tigraphy. So

or skewed pe

platform” (M

ns were resp

ing the cori

cores were 

e sleeve wa

ns during cor

ed, and catal

void unneces

19 

and Amanda 

m the 36” core

for either sa

ring device 

untered. The

ediments to b

ded and tran

deposited du

coastline by

rms or hurri

varying amo

g device was

able by dive

planned grai

nly if the co

retain great

. It was not p

ources of dis

enetration of

Mudroch and

ponsible for 

ing unit and

usually acq

as capped at

ring dives u

loged on the

ssary mixing

Evans remo

er. 

and or silt an

chosen for 

e sites inves

be analyzed

nsported dur

uring calm 

y transgress

icanes. Base

ounts of sand

s selected fo

ers in the op

in size and 

ores capture

ter integrity

possible, how

sturbance in

f the sample

d Azcue 1995

collecting th

d sampling 

quired with 

t depth befo

sing sterile 

e boat imme

g of strata wi

ove a core 

nd clay. Bec

this study w

stigated are 

d are princip

uring river h

conditions. 

ive events (

ed on region

d. 

or use in this

pen GOM a

radioisotop

ed the upper

y than those

wever, to ex

nclude, “the 

er; and wash

5:56). 

he sediment 

tubes, and 

a three-pe

ore surfacing

8 oz. water 

ediately after

ithin the core

cause there 

was based o

located off

pally quartz s

high flow st

Sand layer

(Curray 1960

nal environm

s study. The

and it provi

pic analyses.

rmost sedim

e sampled w

xclude all typ

pressure wa

hout or other

cores. Due t

the low to 

erson dive t

g. Water sam

sampling bo

r acquisition

e sleeve. 

is no 

n the 

fshore 

sands 

tages, 

rs are 

0), or 

mental 

e core 

des a 

. The 

ments. 

with a 

pes of 

ave in 

r loss 

to the 

zero 

team. 

mples 

ottles. 

n, and 
20 

Sediment cores were opened immediately after the conclusion of field operations by Amanda 

Evans and Matt Keith in Baton Rouge, Louisiana. Cores were split, catalogued and logged; core 

logs were prepared using LogPlot 7 software. Sediment samples were immediately obtained and 

shipped to Dr. Mead Allison at the University of Texas for radioisotope analysis (Section 2.8). 

The remaining cores were measured for sediment shear strength (where possible) and samples 

were taken for grain size analysis. Grain size samples were collected from units identified during 

core logging in order to refine the final core log. Samples were collected and placed into labeled 

Whirl-Pak bags and weighed. Grain size measurements were conducted by Cory Sills, under the 

direction of Dr. Patrick Hesp, using a laser particle counter at the Louisiana Universities Marine 

Consortium (LUMCON). Results were exported into a Microsoft® Excel® spreadsheet; grain 

size S-curves were created, and plotted. Amanda Evans calculated median and graphic mean 

grain sizes for each sample following methods published by Folk (1980). Median is the most 

commonly used definition due to its simplicity; median represents the grain size diameter found 

at 50% on the cumulative S-curve (Folk 1980:41). Graphic mean is a more accurate 

representation of grain size within a given sample and is calculated by averaging the diameters of 

grains at three places along the cumulative S-curve; (Φ16 + Φ50 + Φ84)/3 (Folk 1980:41). A 

Pocket Penetrometer and mini-torvane were used for down-core shear strength measurements. 

According to Lee (1985:215), both the Torvane and Pocket Penetrometer are quick and 

efficient tools, which, depending upon the operator, can produce data that is good for creating a 

“rough comparative index of strength.” Shear strength measurements were obtained where 

possible, or when sediment cohesion and water content resulted in reliable measurements. Down 

core sediment content in open ocean samples increases as the water content decreases; according 

to Mudroch and Azcue (1995:66), “in fine-grained material, the water content is about 80% at 

the 10 cm sediment depth, 70% at the 20 cm sediment depth, and about 50–60% at the 30–40 cm 

sediment depth. Below 50 cm, the sediment usually becomes more compacted and there is little 

change in water content.” 

 

Water samples were tested by Amanda Evans for pH, salinity, and dissolved oxygen content. 

An Amprobe WT-30 salinity pen-style meter was used for salinity measurements and calibrated 

using a 30g/L NaCl solution. Remaining instruments included an Extech Instruments ExStik 

DO600 dissolved oxygen meter and ExStik EC500 pH/Conductivity/TDS/salinity meter. Water 

sampling measurement accuracy for dissolved oxygen, salinity, and pH were +/- 2% of the Full 

Scale. The EC500 did not have the range necessary to measure the higher salinity levels found in 

the open GOM, and therefore could be used only for pH readings; conductivity and TDS are 

related to salinity readings and therefore were not recorded from the EC500 meter. 

Measurements for pH were made after completion of a one-step calibration using 7.0 pH 

solution. Handling of collected water samples followed USGS standards for water quality testing 

(USGS 2010). While it is acknowledged that long-term monitoring with repeat visits to a site 

throughout the year are necessary to understand site chemistry and seasonal fluctuations, it was 

felt that this information could provide valuable baseline data and a useful comparison between 

site specific measurements and published data sets for the GOM. 

 
21 

2.7 OCEANOGRAPHIC ANALYSES

Long-term site formation processes are an integral component of shipwreck site research and 

management. Oceanographic processes contribute to observable changes to the vessel from its 

pre-wrecking event appearance to the documented wreck site investigated on the seafloor. 

Numerous post-depositional site formation investigations address the roles of seafloor scour, 

bioturbation, chemical processes, and mechanical processes, such as currents, waves, and storm 

surge (Robinson 1981; Gifford 1982; MacLeod 1989; Henderson 1990; Lenihan 1990; Quinn et 

al.1997; Cullimore and Johnston 2003; McNinch et al. 2006, Quinn 2006, Quinn et al. 2007). 

One of the principal mechanisms for preserving both wooden and metal-hulled shipwrecks 

identified from these studies is the degree of sediment cover that protects the site from chemical, 

physical, and biological degradation. Oceanographic research for this study focused on the 

potential for sediment transport and mobility at the site, including accretion and scour, as it 

relates to site exposure. Grain sizes and shear strengths measured from core samples can provide 

information concerning the sediments impacted by modeled oceanographic patterns (Keith and 

Evans 2009; Rego et al. 2011). 

 

Due to the prevalence of oil and gas industry exploration, the GOM’s near surface geology 

has been extensively studied (e.g., Bernard 1970; Curray 1960; McClelland 1979). Sediment 

distribution on the continental shelf of the GOM indicates that the sediments between the 

Mississippi Delta and the Mexican border can be divided into two basic units: (1) transgressive 

nearshore sands and (2) shelf muds (Curray 1960; Balsam & Beeson 2003). Major portions of 

the Texas and Louisiana shelf are covered with clay and varying amounts of sand, silt, and 

organics (Allison et al. 2000; Gordon et al. 2001; Balsam & Beeson 2003; Ellwood et al. 2006). 

Sediment deposition, erosion, and scouring are most accurately measured by long-term 

monitoring using such devices as current meters or profilers, sediment traps, and erosion pins. 

Because of the contract’s relatively short duration and the inability to make repeated site visits, 

site-specific data was compared with established data sets to determine maximum potentials for 

scour and ranges of active sediment deposition. Maximum potentials are defined as those 

resulting from extreme storm events, including recent hurricanes, such as Katrina, Rita, and Ike. 

Estimates of sediment transport under combined wave-current conditions are used to infer the 

impact of hydrodynamic processes on the shipwrecks, particularly with regard to site exposure. 

Sediment transport occurs in three different ways: by rolling, saltation, and suspension, any of 

which can occur after individual grains are moved by fluid drag (Dyer 1986). As the flow 

intensity increases, individual grains moving along the bottom take off due to impact with 

stationary grains. In this case, the mode of sediment transport changes from rolling and sliding to 

jumping (saltation) along the bottom (U.S. Army 2002). When the vertical components of the 

turbulent velocity are approximately equal to the setting velocity of the grain, these jumps are 

higher and the grain can return to the bed and saltate again or be taken into suspension (Dyer 

1986). 

Computer modeling of sediment transport was conducted by Deltares, under contract to Dr. 

Patrick Hesp, for three datum points in the GOM (Rego et al. 2011). Because of the complexity 
of the co

Instead, t

31.0 m (

373 and u

correspon

sampling

water dep

2.7). Sed

shipwrec

hydrodyn

GOM ba

curviline

and Del

represent

wind spe

cyclone 

hydrodyn

shelf. De

short-cre

Figure

Resu

given wa

potential

shipwrec

estimates

published

omputer mod

three separa

50.8, 85.3, a

used water d

nd with site

g and analysi

pths and gra

diment types 

ck sites. The

namics and w

asin using a 

ar models o

ft3D-WAVE

ting model r

eed data wa

surface w

namic mode

elft3D-WAV

sted, wind-g

e 2.5. Distri

mode

lts of the c

ater depths 

s for sedim

ck site’s wat

s provided 

d studies of 

deling, creat

ate datum po

and 101.7 ft

depths and g

es analyzed a

is. Datums 2

in sizes for m

at the select

e modeling i

waves using

rectangular

f 50 m (164

E to simula

results for b

as prepared 

ind observ

el that simul

VE is design

generated wa

bution of stu

eling. 

omputer mo

and sedimen

ment transpor

ter depth and

by radiosio

GOM ocean

ting models 

oints were se

t) below sea

grain sizes ac

as part of a 

2 and 3 were

many of the 

ted datums a

incorporated

g proprietary

r model of 

 ft) maximu

ate localized

both loose a

by NOAA 

ations (H*W

ates horizon

ned to simula

aves in coast

udy sites and

odeling prod

nt types in 

rt calculated

d location w

otopic analy

nography an

22 

for each sh

elected, repr

a level (BSL

cquired as p

separately-f

e specifically

sites include

also represen

d H*WIND d

y Delft3D-FL

10km resolu

um resolution

d condition

and consolid

and is ava

WIND). D

ntal and vert

ate the trans

tal waters” (R

d location of 

duced estim

the GOM d

d for the da

were compar

ysis (Section

nd sediment 

hipwreck stu

resenting wa

L). The first 

art of this st

funded study

y chosen sinc

ed in the cur

nted typical g

data for rece

LOW and D

ution around

n were also 

ns. Curves 

dated sedime

ailable as re

elft3D-FLO

tical water m

sformation a

Rego et al. 2

the datums 

ates of pote

during extrem

atum point m

red with site

n 2.8) and 

transport. G

udy site was 

ater depths o

datum corre

tudy. The se

y, which inc

ce they corre

rrent shipwre

grain sizes f

ent hurrican

elft3D-WAV

d the datum

created with

for each si

ent types. H

eal-time ana

W is a th

movement o

and propaga

2011). 

used in oce

ential sedim

me storm ev

most approp

e specific se

were also 

Geophysical 

cost-prohib

of 15.5, 26.0

esponds with

cond two da

cluded grain

elate closely

eck study (F

found at the 

nes and simu

VE models i

m points. Sm

h Delft3D-FL

ite were cr

Hurricane su

alyses of tro

hree-dimens

on the contin

ation of “ran

eanographic 

ment transpor

vents. Maxi

priate to a g

ediment accr

compared 

data, specifi

bitive. 

0, and 

h Site 

atums 

n size 

y with 

Figure 

study 

ulated 

in the 

maller, 

LOW 

reated 

urface 

opical 

sional 

nental 

ndom, 

rt for 

imum 

given 

retion 

with 

fically 
23 

multibeam bathymetry, side scan sonar, and sub-bottom profiler were then used to attempt to 

quantify or qualify sediment mobility at each of the shipwreck sites given the rates of accretion 

and potential for sediment transport. Computer modeling also resulted in wave height, period, 

and directional data for recent hurricanes in the GOM, and also scour patterns, which are 

summarized and correlated with the shipwreck study sites in Chapter 5. 

2.8 RADIOISOTOPE ANALYSIS

A primary objective of the coring was to determine site formation processes; this information 

would result in recommendations related to long-term site management. Sediment accumulation 

rates and scour are typically monitored as part of long-term projects, requiring multiple site visits 

and measurements over an extended period (Masselink and Hughes 2003). It was determined that 

reaching the goals of the study would be aided by the inclusion of radioisotope analysis as a 

proxy indicator of sedimentation and possible scour (Allison and Lee 2004; Allison et al. 2005; 

Neill and Allison 2005). Radioisotope tracers, particularly Lead-210 (210Pb) and Cesium-137 

(

137Cs), may provide an indication of recent processes, due to their short half-life duration. A 

variety of particle-reactive radioisotopes have been applied to the study of seabed mixing and 

accumulation in coastal environments. For this study, the use of multiple tracers (210Pb and 137Cs) 

allowed for examination of seabed processes on several time scales, given that the characteristic 

time scale of each tracer is about 4 to 5 half-lives. 210Pb (t1/2 = 22.3 yr) is a naturally occurring 

daughter product of the Uranium-238 (238U) decay series. 

Radiochemical samples were collected from cores acquired at six of the shipwreck sites: 389, 

433, 373, 15488, 15366, and 236. All samples were prepared on August 29, 2010, immediately 

after the completion of diving operations. Sampling methodology included preparation of 

continuous 1 cm sediment slices to a depth of 5 cm down the core. For sites 433, 373, and 236, 

additional near-surface samples were prepared, consisting of continuous 2 cm slices between 5 

and 11 cm downcore. For all cores, near-surface samples were followed by 2 cm slices collected 

every 10 cm downcore from the last near-surface sample. Samples were weighed individually, 

and packed in sterile Whirl-Pak bags, labeled with the site number, date of acquisition, water 

depth, distance from shore, and sample depth. 

Samples were shipped immediately to the University of Texas Institute for Geophysics and 

analyzed for downcore activities of the particle-reactive radiotracers 210Pb (naturally occurring, 

22.3-year half-life) and 137Cs (atmospheric thermonuclear testing in 1954–72, 30-year half-life). 

These tracers have been widely used in marine sediments to calculate sediment accumulation 

rates extending back ~100 years as tracers in sediment dynamics. During analysis, it became 

apparent that, in the present application to marine archaeological research, it would be possible 

to address two questions. The first was to determine post-disturbance sediment accumulation 

rates or erosion signatures that would contribute to an understanding of the likelihood and rates 

of shipwreck burial or scour, both of which are related to site preservation. The second was 

whether the sediments in the immediate vicinity of the wreck site preserve a disturbance “time 

marker” in the steady state sediment deposition record that can provide an independent estimate 

of the date of the wrecking event, which would be particularly useful for unidentified wrecks. 

The second question became apparent during lab analysis, during which it was observed to have 
24 

merit. Data collection and sampling strategies conducted before the lab work, however, were not 

designed specifically for this task. Results presented in the following chapters suggest that this 

method may have merit in future applications. 

Sediment samples from the cores arrived wet at the University of Texas Institute for 

Geophysics laboratory. Activities of the particle-reactive radiotracers 210Pb and 137Cs were 

measured for sediment intervals that were initially freeze-dried and finely ground. Wet and dry 

weights of each sample were recorded and used to calculate sediment porosity. Radiochemical 

samples were packed in either 50 mm diameter Petri dishes (planar geometry) or 60 mm long test 

tubes (well geometry), sealed to prevent Radon-222 (222Rn) loss, and allowed to ingrow to 

secular equilibrium for 210Pb for at least three weeks. Samples were then counted for 1–2 days 

using both coaxial planar and well-type, low-energy germanium (LEGE) γ-spectrometers; 

detector type was dependent on sample size (all samples from a single core were counted by one 

detector type). 137Cs activities were determined using the 661.6 keV photopeak. Total 210Pb 

activity was determined from the 46 keV photopeak and supported 210Pb activities were 

determined by using averaged activities of the Radium-226 (226Ra) daughters 214Pb (295 and 352 

keV) and Bismuth-214 (214Bi) (609 keV). Detector efficiencies for this geometry were calculated 

using a natural sediment standard (IAEA-300 Baltic Sea sediment) and detector backgrounds at 

each energy of interest were determined using sample container blanks (Cutshall et al. 1983). A 

best-fit linear regression of the natural log of excess 210Pb (210Pbxs) with depth below any surface 

mixed layer of homogenous activity was used to determine the sediment accumulation for the 

past ~100 years (Nittrouer and Sternberg 1981). 137Cs (T1⁄2 = 30 years) is the product of fallout 

from atmospheric testing of thermonuclear weapons that began in 1954. Two time markers for 

137Cs with depth can be used: the depth of maximum 137Cs penetration (1954), and the depth of 

maximum 137Cs fallout in the northern hemisphere, which, according to Chmura and Kosters 

(1994), occurred in 1963. 137Cs rates can be calculated by dividing the depth of the 1954 or 1963 

peak occurrence in the core by the number of years passed; errors are derived by extrapolating 

across the core interval represented by that particular year. Final accumulation rates were depthcorrected to a standard core porosity (75%) to expand or contract interval depths (to allow for 

inter-comparison of sites in linear terms) and can be converted from linear accumulation rates 

(LAR; consolidation-corrected cm/y) to mass accumulation rates (MAR; g/cm2

/y) (Allison et al. 

2007). Radioisotope sample locations are shown on individual core logs in Appendix G and 

sampling results are tabulated in Appendix F. 

2.9 STANDARDIZATION

The above-mentioned methodologies are to be considered the standard procedures followed 

at all sites. Protocols and conventions are detailed in this chapter to avoid redundancy in the 

following report sections. Chapter 3 details the individual results for each study site. Alterations 

to the above stated methodologies were required at some sites or for specific analyses; those 

alterations are described in detail in the relevant section. 
25 

3. SITE RESULTS 

The original contract stipulated investigation of six shipwreck sites located in federal lease 

areas offshore Louisiana and Texas, between South Pelto to the east, and Galveston to the west 

(Sites 380, 433, 386, 373, 15488, and 15366). A geophysical survey was conducted over each 

survey site before diving operations, to allow divers to use the most recent geophysical data at 

each site to target areas for further investigation. Due to the Deepwater Horizon incident, which 

occurred less than four months before dive operations, the project team planned alternate sites 

for the diving phase of the project in case oil or other on-site conditions prevented safe diving on 

any of the contracted sites. Alternate sites included numbers 389, 15326, 322, and a target in the 

West Cameron lease area (site number pending). The site of the USS Hatteras (Site 236) was 

also included as an alternate to allow documentation of site conditions, and add to existing site 

data based on sporadic monitoring visits. None of the contracted sites had to be skipped due to 

impacts from Deepwater Horizon, but additional time was available to investigate the prepared 

alternates. Following conclusion of dive operations, and in consultation with the COTR, the 

contract was amended to include geophysical survey over two of the alternate sites (Sites 389 

and 236). All sites investigated are detailed in the following sections. 

Table 3.1 

Sites Investigated 

BOEM Site 

Number Hull Type Tentative ID Propulsion Function 

380 

Wooden 

vessel 

Unknown wooden 

vessel Unknown Unknown 

433 Vessel R.W. Gallagher Oil-screw Tanker 

386 Vessel Heredia Oil-screw 

Passenger & 

freighter 

373 Vessel Cities Service Toledo Oil-screw Tanker 

15488 Vessel Unknown Unknown Unknown 

15366 Vessel Unknown Unknown Unknown 

389 Vessel J.A. Bisso Oil-screw Tow vessel 

236 Vessel 

USS Hatteras

(confirmed) Steam-screw Military 

15326 Barge Unknown Unknown Unknown 

322 Vessel Unknown Unknown Unknown 

Pending Unknown Unknown n/a Unknown 

 
26 

3.1 SITE NO. 380, SOUTH PELTO AREA, REPORTED WOODEN WRECK 

3.1.1 Site Background 

Site number 380 is located in the South Pelto Area south of the Cat Island Pass Shipping 

Channel, between Isles Dernieres and Timbalier Island, which serves as the entrance into 

Terrebonne Bay. The only known account of this wreck comes from the NOAA AWOIS 

database (Record 9003), where it is identified as both “Unknown Wooden wreck” and 

“Dangerous Wreck.” The AWOIS entry, dated August 2, 1994, reports that the wreck was 

investigated by divers who observed wooden vessel remains consisting of “ribs, keel and rudder 

post.” The wreck was reportedly located on a sandy bottom and oriented NE by SW. The vessel 

location is defined as highly reliable. The wreck reportedly measured approximately 35.59 m 

(120 ft) long by 5.49 m (18 ft) wide and was described as a wooden vessel. No imagery or site 

plans were available. The wreck condition listed in the BOEM database was identified as 2 

(partially intact, 25–50%) and exposure was listed as 2 (hull partially buried by sediment, less 

than 50%). Seafloor sediments were reported as sand and the water depth was reported as 7 m 

(23 ft). NOAA archaeological personnel Dave Alberg and Joe Hoyt were consulted for additional 

information pertaining to this record, but no additional information was identified. 

BOEM records indicate that no known geophysical surveys had been conducted over the area 

of the reported wreck. In 1978, a 10” pipeline was installed that crosses within 62.5 m (205 ft) of 

the putative wreck site. In 1974, the Bureau of Land Management issued the first NTL requiring 

archaeological surveys for oil and gas development (NTL 74-10). This NTL was followed by 

NTL 75-03, which required archaeological surveys before drilling operations, the installation of 

any structure, or the installation of pipelines. Based on the chronology of NTLs, it can be 

concluded that a geophysical survey should have been conducted for the 10” pipeline, in 

compliance with NTL 75-03. The BOEM archaeology division had no records of any such 

survey; therefore, it was not possible to determine if a survey had taken place or if the wreck was 

identified before the pipeline was installed. The 10” pipeline is listed as active, and ongoing 

maintenance associated with the pipeline could potentially disturb the seafloor in the vicinity of 

the site. No other infrastructure is located within 1,525 m (5,000 ft) of the site. 

3.1.2 Geophysical 

Geophysical data acquisition was conducted at Site 380 on June 1 and 2, 2010, aboard the 

M/V Nikola. The survey grid was centered on the reported wreck position and extended out in a 

300-m (1,000 ft) radius surrounding the wreck site, and consisted of 22 east-west survey lines 

(numbered 1–22) and 22 north/south survey lines (numbered 101–121) spaced 30 m apart (see 

Navigation Post-Plot Map, Appendix B; Figure B-1). Sonar data was acquired at 410 kHz, using 

a 50-m (164-ft) range (see Chapter 2 and Appendix A for complete sensor specifications and 

survey vessel configuration). 
Bathy

survey g

zones or 

 

Figure

ymetry data 

rid. Water d

other macro

e 3.1.1. Ba

indicates th

depth at the 

o-bathymetri

athymetry ma

hat water dep

reported sh

c irregulariti

p surrounding

27 

pths range fr

hipwreck site

ies were obs

g site 380 in 2

rom 10 to 12

e is 11.1 m 

served (Figu

2-decimeter in

2.4 m (33 to

(36 ft). No 

ure 3.1.1). 

ntervals.

 41 ft) withi

significant 

n the 

scour 
28 

Sonar data highlighted a medium reflective seafloor, indicative of course-grained sandy 

sediments with some clay and or silt content (Figure 3.1.2). Although some minor divots and 

irregularities were evident, no trawl scars or other seafloor disturbances were observed; this 

indicates that either sediments lack sufficient cohesion to retain the imprint of drag scars or a 

combination of sediment transport/accretion rates and scour act to neutralize microbathymetric 

features. 

Sub-bottom profiler data penetration in the southern portion of Site 380 ranged from 6 to 7.6 

m (20 to 25 ft) before the data was attenuated completely by a strong, somewhat irregular gas 

front. The seafloor in the south consists of a strong reflector followed by a thin zone of parallel 

strata. This, in turn, overlies a zone of mostly acoustically transparent sediments, followed by 

parallel bedded laminated strata. Sub-bottom attenuation increases as the survey grid progresses 

to the north, likely due to the increased presence of surficial sand deposits associated with the 

flanks of Ship Shoal, which is located west of the site. In the extreme northern portion of the 

survey grid, sub-bottom penetration was reduced to the upper 1.2 m (4 ft) of surficial strata 

(Figure 3.1.3). Diffractions were occasionally resolved over the 10” pipeline. No other 

irregularities or disturbances that could be attributed to a shipwreck site were evident on the subbottom profiler data. 

Magnetometer data produced numerous large dipolar anomalies that verified the published 

coordinates for the 10” pipeline. A total of 34 additional anomalies were observed that cannot be 

attributed directly to the pipeline. These individual anomalies are detailed in the Magnetic 

Anomaly Table for Site 380 (Appendix C). A cluster of five magnetic anomalies was identified 

at the reported shipwreck position, including anomaly nos. 16, 19, 20, 40, and 44. Anomaly no. 

16 is a 37 nT dipolar anomaly with a 72-m (237-ft) duration, no. 19 is a 9 nT negative monopole 

with an 18.5-m (61-ft) duration, no. 20 is a 252 nT dipole with a 42-m (137-ft) duration, no. 40 is 

a 89 nT complex anomaly with a 47-m (154-ft) duration, and no. 44 is a 6 nT dipole with a 17-m 

(57-ft) duration. These anomalies are tabulated in Appendix C and can be correlated with their 

positions on the survey post-plot map for Site 380 (Appendix B; Figure B-1). The magnetic 

contour map clearly shows these anomalies extending beyond the pipeline and over the reported 

wreck site (Figure 3.1.4). Although interference from the nearby pipeline reduces the ability to 

provide a comprehensive prediction of the amount of ferromagnetic mass present at the reported 

shipwreck site, the size and distribution of these anomalies indicates that a significant quantity of 

buried ferromagnetic material is present at this location. 

Although the combined geophysical data did not provide any indication of a clearly resolved 

intact shipwreck within the survey grid, magnetometer data at the location of the reported 

shipwreck site indicated that diver investigation was warranted. 
29 

Figure 3.1.2. 410 kHz sonar mosaic of seafloor surrounding Site 380. 
Figure 3.1.3. Sub-b

Headi

penetr

Vertica

2 millis

ottom profile

ng for all thr

ration decrea

al scale lines

second interv

30 

es of survey 

ree lines was

ases from no

s in 150-m inc

vals. 

lines 1, 11

s 270 degree

orth (Line 22

crements. Ho

, and 22, S

es (right to le

2) to south (

orizontal scale

Site 380. 

eft). Data 

(Line 1). 

e lines in 
Figure 3.1.4. Magnetic contours in

31 

 2 nT intervals at Site 380.
3.1.3 Div

Durin

point of 

August 1

 A

 T

 V

A bu

operation

extensive

from the 

width, an

band, but

ving 

ng the divin

embarkation

3, 2010, fro

Average reco

Total bottom 

Visibility: 1.5

uoy was dro

ns commenc

e circle sear

sediment fo

nd 1.25 cm 

t found no d

Fi

g field cruis

n in Morgan

m the M/V S

orded water d

time on site

5–1.8 m (5–6

opped at th

ced from this

ches. The m

or a distance 

(0.5 in) in th

distinctive fea

igure 3.1.5. 

se, Site 380 

n City, Lou

Spree. 

depth on bot

e: 18.37 hour

6 ft). 

e spot of th

s point. Usin

most signific

of approxim

hickness (Fi

atures (i.e., r

Photographs

intervals. 

32 

was the firs

isiana. Divin

ttom: 10.67 m

rs. Average d

he reported 

ng a handhe

ant object e

mately 5 m (

igure 3.1.5).

rivets, fasten

 of metal ban

st site visite

ng operation

m (35 ft). 

dive time: 39

coordinates

eld metal det

ncountered 

16 ft), and m

. Archaeolog

ners, etc.) or 

nd. 10 cm sc

d due to its 

ns at this si

9.26 minute

s for the w

tector, dive 

was an iron

measuring 3.

gists hand-fa

other associ

cale bar in 2 

proximity t

ite took plac

s. 

wreck and d

teams condu

n band protru

.2 cm (1.25 

anned aroun

iations. 

cm 

to the 

ce on 

diving 

ducted 

uding 

in) in 

nd the 
A bas

using the

band. Th

to be ran

metal/she

by 2.5 cm

appeared

recovered

Objects w

seline was e

e hand-held 

he metal dete

ndom modern

ell concretio

m (1 inch). 

d to be a deb

d after its lo

within the co

stablished al

metal detect

ector searche

n wire nails

ons, and a fra

There was 

bris field of

ocation was 

oncretion inc

Figure 3.1.6.

long the ban

tor. These s

es produced 

, beer cans, 

agment of a 

no indicatio

f random, di

noted. The 

cluded a plas

. Photograp

(at bottom

concretion

intervals.

33 

nd to facilita

earches wer

a few weak 

copper tubin

modern woo

on of any in

scarded mat

concretion w

stic housing 

ph of concreti

m), and object

n (middle). 10

ate additiona

re extended 

targets whic

ng, fragmen

oden board m

ntact woode

terial. One o

was carefully

and a moder

ion (at top), co

ts recovered f

0 cm scale ba

l circle searc

in each dire

ch, after inve

nts of fiber-o

measuring 10

en structure;

of the small

y opened on

rn wire nail 

opper tubing 

from inside 

ar in 2cm 

ches at eithe

ection beyon

estigation, pr

optic cable, 

0.2 cm (4 in

 instead, the

l concretions

n the dive ve

(Figure 3.1.

er end 

nd the 

roved 

small 

nches) 

e site 

s was 

essel. 

6). 
Figure 3.1.7. Site p

at Sit

lan map sho

e 380. 

34 

wing relative distribution of objects identified 
35 

No evidence of an intact shipwreck was identified in the vicinity of Site 380. The objects 

identified on site did not appear to be historically significant, or associated with a shipwreck. The 

relative distribution of these objects is shown in Figure 3.1.7. 

3.1.4 Site Environment 

Sediment cores were not collected at this site due to the absence of any archaeological 

materials. Therefore, no information is available for sediment stratigraphy, grain size, 

radioisotopes, or shear strength at Site 380. It was decided in the field that the resources required 

to analyze cores from this site would be better used on additional cores from subsequent sites. 

3.1.4.1 Water Sampling 

One 8-ounce water sample was collected from Site 380 on August 13, 2010 at a depth of 11.2 

m (37 ft) below sea level (BSL). Water temperature at the time and depth of acquisition was 86° 

F. Repeat measurements were taken for pH, salinity, and dissolved oxygen content and averaged 

(Table 3.2). Salinity was measured in parts per thousand (ppT). Dissolved oxygen (DO) is 

reported in milligrams per liter (mg/L). 

Table 3.2 

 

Water Sample Results for Site 380 

Type Average 

Salinity (ppT) 31.60 

pH 7.24 

Dissolved oxygen (mg/L) 6.75 

3.2 SITE NO. 433, SHIP SHOAL AREA, PROBABLE R.W. GALLAGHER

3.2.1 Site Background 

Site number 433 is located in the Ship Shoal Federal Lease Area south of Isles Dernieres, 

Terrebonne Parish, Louisiana. The first known contemporary visit to the site was by Avery 

Munson and Gary Hebert, who located the wreck based on coordinates supplied by local 

fishermen and shrimpers. They conducted a diver investigation of the site on August 2, 1984. 

The MMS appears to have first been notified of the site’s location as the result of a geophysical 

lease survey conducted in 1989 by John E. Chance and Associates. The resulting interpretation 

and report were performed by Marine Archaeologist Dr. Robert J. Floyd and Geophysicist 

Robert Callahan (Floyd and Callahan 1989). The slant range corrected sonar image in the report 

does not clearly resolve the wreck (Figure 3.2.1). The wreck is identified in the report as the 

Steam Ship (SS) Heredia. 
In 19

U.S. Coa

recovered

published

as the so

is believe

leaking (

depth wh

The w

by Coch

contract 

and El D

the struct

features 

were als

assessme

Heredia.

victims o

poor, but

at least 7

Figure 3

992, an oil s

ast Guard (T

d and diver

d in the New

urce of the o

ed that the w

(R.W. Gallag

hich correspo

wreck was s

hrane Techn

Archaeologi

Darragi 1996

ture is about

appear to be

so verified 

ent prepared

 Both vessel

of German s

t a sub-botto

 m (23 ft) ab

3.2.1. Sona

slick over th

Treadway 1

rs attempted

w Orleans Ti

oil (see Sect

wreck in qu

gher was a t

onds with th

subsequently

nologies, Inc

ist Allen Sa

6; Figure 3.2

t 450 ft long 

e present.” T

by the mag

d in 1996 su

ls were repo

ubmarines in

om profiler i

bove the seaf

ar image of Si

he site was in

992; Christ 

d to patch t

imes Picayu

tion 3.3). Al

estion is act

tanker and H

e depth at Si

y verified thr

c. The resul

altus, Jr., and

2.2). The Co

and some si

The report in

gnetometer, 

uggested tha

orted to have

n 1942. Son

image over t

floor. 

36 

te 433 (Floyd

nvestigated 

2005:93). C

the leak (C

ne (Treadwa

lthough coor

tually Site 4

Heredia was 

ite 433. 

rough a geop

lting interpr

d contract G

chrane repo

ixty to seven

ndicates that

echosounde

at the featur

e gone down

nar imagery 

the wreck sit

d and Callaha

by commer

Christ repor

Christ 2005:9

ay 1992) ide

rdinates are 

433; this is b

a freighter) 

physical lea

retation and

Geophysicist

rt reads, “Th

nty-five ft w

t the presenc

er, and sub

re was likely

n in the same

of the wreck

te indicated

an 1989). 

rcial divers c

rts that a sa

93). An art

entifies the w

not provided

because of t

 and the rep

ase survey pe

d report wer

t S. Dean E

he sonar im

wide. Deck ra

ce and posit

b-bottom pr

y either R. 

e general are

k in the Coc

that the ship

contracted b

ample of oil

ticle on the 

wreck of He

d in the artic

the amount o

ported 80-ft w

erformed in 

re performe

El Darragi (S

age suggests

ail and other

tion of the w

ofiler. The 

W. Gallagh

ea, and both 

chrane repor

pwreck proj

by the 

l was 

leak 

eredia

cle, it 

of oil 

water 

1996 

ed by 

Saltus 

s that 

r deck 

wreck 

final 

her or 

were 

rt was 

ected
The N

the BOEM

single sid

divers int

the divin

point ide

Guard in

indicated

No k

abandone

abandone

3.2.2 Ge

Geop

M/V Nik

parallel a

Plot Map

multibeam

Appendix

All h

states pre

Figur

NOAA AWO

M position f

de scan sona

tended to inv

ng are unkno

entified as H

nspections. A

d that the ves

known infra

ed (P&A) w

ed line and a

eophysical

physical data

kola. Thirtyand perpend

p Appendix

m, and sing

x A for a ful

high-frequen

ecluded fini

re 3.2.2. S

OIS databas

for Site 433.

ar image was

vestigate the

own. Accord

Heredia, pos

Avery Muns

ssel was, in f

structure is 

well is locat

a 30” active 

l 

a for Site 43

- and 100-m

dicular to the

x B; Figure

gle beam ba

ll description

ncy survey li

shing the ac

Sonar image o

se reports an

 The record 

s available. 

e wreck, but 

ding to the 

sibly based 

son subsequ

fact, R.W. G

located wit

ted 655 m (

line, are loca

33 was acqu

m grids were

e published 

e B-1). Side

athymetry d

n of geophys

ines were fi

cquisition of

37 

of Site 433 (S

n unknown w

indicates th

The databas

no subseque

BOEM data

on the 1989

uently notifi

allagher (BO

thin 300 m 

(2,150 ft) S

ated 1,535 m

uired on July

centered ov

orientation 

e scan sona

data were ac

sical sensor s

nished at Si

f low freque

Saltus and El 

wreck with c

hat the wreck

se record ind

ent entry wa

abase, the ve

9 geophysic

ied MMS th

OEM Datab

(1,000 ft) 

SE of the si

m (5,035 ft) t

y 17, 2010 a

ver the repo

of the wrec

ar, sub-bott

cquired at t

suite and nav

ite 433 on J

ency sonar l

Darragi 1996

coordinates 

k was reporte

dicates that U

as available a

essel at Site

cal survey or

hat his earli

ase 2011). 

of the site.

ite and two 

to the SW. 

and June 3, 

orted wreck 

ck site (see 

tom profiler

the site (see

vigation par

July 17, 201

lines. The s

6). 

in the vicini

ed to MMS 

U.S. Coast G

and any resu

e 433 was a

r the 1992 C

ier investiga

. A plugged

pipelines, a

2011 aboar

site and ori

Navigation 

r, magnetom

e Chapter 2

rameters). 

10, but roug

onar needs 

ity of 

and a 

Guard 

ults of 

at one 

Coast 

ations 

d and 

a 16” 

rd the 

ented 

Postmeter, 

2 and 

h sea 

to be 
38 

towed much higher off of the bottom for lower frequency data acquisition, making it more 

susceptible to rough seas. To maximize vessel time, the vessel moved to Site 386 to run highfrequency sonar lines until sea state allowed for acquisition of higher quality, low frequency data 

at Site 433. During operations and before finishing the low frequency survey lines at both sites, 

Nikola was diverted at the request of MMS and BP to perform seismic operations at the 

Macondo well in support of relief well operations; because of this, data acquisition on site was 

not finished. A return trip was made to both sites in June 2011, and the low frequency (100 kHz) 

survey lines were finished. During interpretation of the 2010 geophysical data it was noted that 

the actual orientation of the vessel differed from published information; therefore, the survey 

grid was reoriented for use during the June 2011 survey work to provide better image quality 

over the wreck site. 

Ambient water depths are 26–27 m (85–88.5 ft) throughout the survey grid (Figure 3.2.3). 

The multibeam data illustrates that the wreck is upside down, with a large break towards the 

south (Figure 3.2.4). The vessel is oriented with the bow facing 204 degrees SSW and the stern 

facing 23 degrees NNE. An additional hole in the hull appears to be located on the NE portion of 

the wreck (towards the starboard stern). Significant, broad scour zones are evident around the 

shipwreck extending to the west and SW. Deeper, more concentrated scour zones are evident on 

the west side of the wreck near the break in the hull and toward the stern reaching as deep as 

29.6 m (97 ft). Multibeam data appears to provide an indication of some stern assemblage (such 

as running gear and/or propeller) as well as the lower portion of a transom stern, the upper 

portion of which is buried in the seafloor (Figure 3.2.4). 

 

 
Figure 3.2.3. Bathymetry surrou

39 

nding Site 433 in 5-decimeter intervals. 
Figure 3.2.4. 3-D multibeam render

40 

ings of Site 433. 
The 

sufficient

The 410 

hull, and 

size was 

seafloor, 

clearly s

identified

(300 ft) 

length of

magnetic

2.4 m (8

mosaic c

the wreck

100 kHz so

t resolution 

kHz survey

increased re

evident on t

with the b

seen on the

d away from

SSW of the 

f cable or p

c anomalies. 

 ft) wide, w

created using

k at 410 kHz

Figure 3.

onar data cl

to identify s

y grid clearl

esolution at t

the high freq

ow oriented

 high frequ

m the wreck 

wreck, situ

ipe located 

An anchor 

was observed

g only the 10

z from Surve

.2.5. 410 kH

learly image

specific com

ly outlined t

the stern of t

quency sona

d towards th

uency sonar

site. The fi

ated along t

NNE of the

drag scar, m

d 284 m (93

00 kHz surv

ey Line 402.

z sonar imag

41 

ed the wrec

mponents of t

the wreck, p

the vessel. N

ar. As noted 

he SSW. Th

r imagery (F

rst is a sma

the same axi

e wreck and

measuring 53

30 ft) SW of

vey lines tha

 

ge of vessel’s

ck site in its

the vessel or

provided det

No significan

previously, 

he vessel’s r

Figure 3.2.5

all, irregular 

is as the wr

d associated 

3 m (173 ft) 

f the wreck.

at parallel th

stern from su

s entirety, b

r changes in

tails around 

nt variation i

 the wreck i

rudder and 

5). Two son

feature app

reck itself. T

with a sign

in length an

. Figure 3.2

he wreck site

urvey Line 40

but did not 

n seafloor tex

the break i

in sediment 

is inverted o

propeller ca

nar targets 

proximately 

The second w

nificant clust

nd approxim

.6 shows a 

e; an inset s

02. 

have 

xture. 

in the 

grain 

on the 

an be 

were 

91 m 

was a 

ter of 

mately 

sonar 

shows 
42

Figure 3.2.6. 100 kHz side scan sonar mosaic of Site 433. Inset is 410 kHz data. 
Acou

(72 ft). T

The wrec

the curva

Figur

Sub-b

stratigrap

acoustica

are the on

the scour

stratigrap

deepest, 

further w

ustic imaging

The large bre

ck sits appro

ature of the i

re 3.2.7. Mu

bottom prof

phic profile 

ally transpar

nly significa

r zones and 

phic profiles

sharpest, sc

where the sco

g indicates th

eak in the ve

oximately 7.3

inverted hull

ltibeam image

filer data pe

consists of 

rent zones of

ant irregulari

no apparen

s; Survey Li

cour zones a

our is broade

hat the shipw

essel’s hull m

3 m (24 ft) a

l and some in

ery of wreck a

enetrated 14–

alternating b

f fine silts o

ity in the sub

nt infill of re

ine 307 runs

are evident.

er and shallo

43 

wreck measu

measures app

above the se

nternal struc

at Site 433 sh

–18 m (45–

bands of pa

r sands. The

b-bottom dat

elict scour h

s close to th

Survey Lin

wer. 

ures 140 m (

proximately 

eabed. Acou

cture (Figure

howing intern

–60 ft) throu

arallel strata,

e scour zone

ta set. Sedim

has taken pl

he wreck sit

ne 302 is SW

(458 ft) by a

12 m (40 ft)

stic multibea

e 3.2.7). 

al structure. 

ughout the 

, occasional

es surroundin

ments appear

ace. Figure 

te, just to th

W of the wr

an estimated 

) by 10 m (3

am data reco

survey grid.

ly interrupte

ng the wreck

r truncated w

3.2.8 shows

he NE wher

reck, but sli

22 m 

33 ft). 

orded 

. The 

ed by 

k site 

within 

s two 

re the 

ightly 
Figure 3.2.8. Sub-bottom

located SE

NW of the w

increments

 profiles of 

 of the wreck

wreck with a 

. Horizontal s

44 

survey lines

k, with a head

heading of 13

scale lines in 2

s 302 and 3

ding of 310 d

30 degrees. V

2-ms intervals

307, Site 433

egrees. Line 

Vertical scale 

s. 

3. Line 302 

307 is locate

lines in 150 

is 

d 

m 
45 

Magnetometer data produced massive anomalies over the hull of the large metal-hulled 

shipwreck. A total of 19 magnetic anomalies were identified that could not be directly attributed 

to the hull of the shipwreck. All individual magnetic anomalies have been tabulated and are 

included in Appendix C. A contour map was also prepared that highlights changes to the ambient 

field using contours shown in a 4 nT interval (Figure 3.2.9). Anomaly nos. 3, 9, 14, 15, 16, and 

37 were located in relative proximity to the wreck and may represent small quantities of debris 

related to the wrecking event. It should be noted that these anomalies are not discernible within 

the contour maps due to the massive signature produced by the wreck. They were instead 

identified by analyzing the individual trace plot for each survey line. Two significant anomaly 

clusters were identified further from the wreck site, both of which lie approximately 240 m (787 

ft) from the site, one to the east and the other to the NE. The eastern cluster is the smaller of the 

two and is comprised of Anomaly nos. 8 and 10. Anomaly no. 8 is a 10 nT positive monopole 

with a 19.5-m (64-ft) duration and Anomaly no. 10 is a 51 nT negative monopole with a 34-m 

(111-ft) duration. No seafloor features or debris were evident on the correlating geophysical data 

that correspond with this anomaly cluster; therefore, it is unknown if the anomalies are related to 

the shipwreck or are intrusive. The larger anomaly cluster is located to the NE and includes 

Anomaly no. 2, a 315 nT negative monopole with a 62.5-m (205-ft) duration, no. 6, a 28 nT 

dipole with a 45-m (148-ft) duration, no. 11, a 153 nT dipole with a 46.6-m (153-ft) duration, no. 

12, a 157 nT negative monopole with a 67-m (220-ft) duration, and no. 13 a 10 nT positive 

monopole with a 30-m (99-ft) duration. This cluster is associated with a length of cable or pipe 

measuring 12 m (40 ft) in length and spanning 15 cm (0.5 ft) above the seafloor. 
Figure 3.2.9. Magnetic contours in 50

46 

-nT intervals at Site 433. 
3.2.3 Div

Divin

 M

 T

 V

se

Dive 

dive team

diagnosti

operation

aspects, i

Near 

to 45 cm

were obs

post-depo

be the re

vessel. B

establish 

ving 

ng operation

Maximum rec

Total bottom 

Visibility: 3–

eabed. 

teams were

m was assig

ic features t

ns managed 

including the

Figure 3.

midships, th

m (18 in) at th

served on the

ositional det

esult of exte

Because of t

the descent 

s at Site 433

corded water

time on site

–9 m (10–30 

e limited in t

gned a specif

that would 

to examine 

e rudder, the

.2.10. Imag

Cap

he I-beam sh

he base of th

e remote sen

terioration. O

ensive torpe

the relativel

line for the 

3 took place 

r depth durin

e: 10.32 hour

ft) on wreck

their bottom

fic task whi

aid in the i

the entirety

e propeller, h

ge still highlig

ptain John Ca

haped bilge 

he keel. Dive

nsing data, b

Only one of 

edo damage 

ly featureles

site. The da

47 

on August 1

ng dives: 29

rs. Average d

k, 1.5 m (5 ft

m time due to

ile on the ve

identification

y of the wre

hull plating, 

ghting bilge k

mp). 

keel measur

ers also attem

believed to b

the breache

approximat

ss hull, this

amage at this

15, 2010 from

.5 m (97 ft).

dive time: 25

ft) near area o

o the vessel’

essel, measu

n and asses

eck, but focu

and the bilg

keel aft of m

res 36 cm (1

mpted to ins

be caused eit

s was access

tely 46 m (1

s area also 

s point is ext

m the M/V S

.

5.79 minute

of hull dama

’s sheer size

uring and ph

sment of th

used primar

ge keel (Figu

midships. (Cou

14 in) in heig

spect breache

ther by the t

sible to dive

150 ft) from

served as a

tensive, and 

Spree. 

s. 

age, zero on 

e and depth.

hotographing

he vessel. D

rily on diagn

ure 3.2.10). 

urtesy of 

ght and incr

es in the hul

torpedo strik

ers; it appear

m the bow o

a secure poi

suggests tha

Each 

g key 

Diving 

nostic 

reases 

ll that 

kes or 

red to 

of the 

int to 

at the 
torpedo b

surround

On th

point, wh

larger as 

through, 

to bend i

damage w

deteriora

the keel 

ft). The p

long and 

blast nearly 

ding hull plat

he starboard 

hile the port 

the hull ext

from the po

inward on th

was, in fact

ation. The sh

of the vesse

propeller co

1.34 m wide

broke the sh

ting connect

side, the hu

side breach 

ended down

rt side to the

he port side

, caused by 

hip’s rudder 

el down into 

ontained a fo

e (8.2 by 4.4

Figure 3.2.1

hip into two 

s the bow to

ull breach me

measured 8.

nward into th

e starboard s

e, and outwa

a powerful 

and propell

the seafloor

our-blade co

4 ft) (Figure 

11. Propeller

of Colm O

48 

pieces, as o

o the remaind

easures near

.4 m (28 ft) a

he sediment.

side of the hu

ard on the st

explosion, 

ler were map

r and measu

onfiguration 

3.2.11) 

r blades. (P

O’Reilly.) 

only a small 

der of the ve

rly 4.3 m (15

at the turn o

. Divers note

hull, at this b

tarboard sid

and not mer

pped in deta

ures 3 m lon

with individ

hotograph co

portion of th

essel. 

5 ft) at the la

f the bilge, a

ed that they 

breach. The h

de, lending c

rely due to p

ail. The rudd

ng by 3 m de

dual blades 

ourtesy 

he bilge kee

argest observ

and actually 

could see cl

hull plates ap

credence tha

post deposit

der extends 

eep (9.84 by

measuring 2

el and 

vable 

grew 

learly 

ppear 

at this 

tional 

from 

y 9.84 

2.5 m 
Diver

topside c

Secto

Although

the stern 

rs noted sma

crew on the r

Figure 3.2

or scanning 

h the size of

assemblage 

all droplets o

research vess

2.12. Image 

of Capt

sonar data

f the vessel 

was obtaine

of oil rising 

sel (Figures 

still showing 

tain John Cam

a over the 

precluded im

ed (Figure 3.

49 

from the wr

3.2.12). 

oil seeping fr

mp.) 

wreck site 

magery of m

.2.13). 

reck, and an

rom the wrec

was obtain

much of the 

n oil sheen w

k site. (Video

ned after di

wreck, exce

was visible b

o courtesy 

iving operat

ellent image

by the 

tions. 

ry of 
 

3.2.4 Sit

3.2.4.1 W

Two 

29.5 m (

depths of

Repe

sample a

(DO) is r

Figu

te Environ

Water Sam

8-ounce wa

97 ft; sampl

f acquisition

at measurem

and averaged

reported in m

ure 3.2.13. S

ment 

mpling

ater samples 

le 1) and 27

n was 77° F. 

ments were 

d (Table 3.3)

mg/L. 

Sector scan h

were collec

7.4 m (90 ft;

taken for p

). Salinity wa

50 

ighlighting the

cted from Si

 sample 2) B

H, salinity, 

as measured

e stern of the

ite 433 on A

BSL. Water

and dissolv

d in parts per

e vessel. 

August 15, 2

r temperatur

ved oxygen 

r thousand. D

2010 at dept

e at the time

content for 

Dissolved ox

ths of 

e and 

each 

xygen 
51 

Table 3.3 

 

Water Sample Results for Site 433 

Type Sample Average 

Salinity (ppT) 1 32.70

Salinity (ppT) 2 32.10

pH 1 7.767

pH 2 7.837

DO (mg/L) 1 6.79

DO (mg/L) 2 6.98

3.2.4.2 Core Lithology and Grain Size 

Two cores were collected from Site 433 on August 15, 2010. The first was collected from the 

west side of the vessel at approximately midships at a depth of 29.5 m (97 ft). Visibility at the 

seafloor was zero. During sampling, the core barrel encountered significant resistance; divers 

noted the presence of metal in the immediate area. It is very probable that the first attempt at core 

collection was conducted on sediments overlying a piece of hull debris; however, blackwater 

conditions and limited bottom time made this difficult to confirm. Due to the lack of visibility, 

even with primary and secondary lights, divers were unable to read their gauges. Once core 

refusal was noted and no immediate area was identified for re-sampling, the coring attempt was 

aborted. Core no. 1 resulted in a maximum of 22 cm of sediment. A second core was collected 

from the east side of the vessel at midships from a depth of 27 m (90 ft). This coring attempt was 

successful and resulted in a 75 cm stratigraphic sample. Core no. 2 was used for all subsequent 

sampling, while Core no. 1 was only used to correlate near surface lithology. 

From each of the three units observed within Core no. 2, samples were gathered and 

measured for grain size. Median and graphic mean calculations demonstrate that sediments from 

Site 433 are cohesive-clay dominant. The measured sediments became increasingly fine 

downcore, transitioning from coarse silt at the seafloor to either fine silt (graphic mean) or very 

fine silt (median). 

Shear strength measurements were taken using both a pocket penetrometer and a minitorvane. The pocket penetrometer was used with an adapter specifically for use in sediments with 

low shear strengths; however, the penetrometer measurements were deemed inaccurate due to 

their proximity to areas disturbed through radioisotope sampling downcore. The 2” diameter core 

sleeve did not capture sufficient mass to allow for accurate shear strength measurements at the 

same depths as grain size and radioisotope samples, which were taken from corresponding 

depths on opposite halves of the core to allow for direct comparisons. Mini-torvane 

measurements were offset 2.5 cm from previous radioisotope samples and taken at 5 cm intervals 

down each half of the split core; they were deemed more accurate. The averaged measurements 

are provided in Table 3.4. 

Salinity, pH, and DO measurements were also obtained from pore water trapped in Sediment 

Core no. 2, and pH measurements were taken of sediments within the core. The pore water 
52 

analysis resulted in higher salinity and lower pH and DO values than measured from samples 

collected in the water column. Average pore water salinity was 36 ppT; average pore water pH 

was 7.5; average DO was 6.097 mg/L. Downcore measurements of pH values in Core no. 2 

sediments were higher than any of the measurements obtained from water samples; the average 

sediment pH was 7.9. 

Table 3.4 

 

Averaged Shear Strength Measurements from Core No. 2, Site 433 

Depth (cm) ksf 

5 0.032

10 0.032

15 0.128 

20 0.192

25 0.218

30 0.230

35 0.256

40 0.282

45 0.256

50 0.256

55 0.243

60 0.281

65 0.289

70 0.256

75 0.218 

3.2.4.3 Radioisotope Analysis 

Radioisotope analysis of sediments sampled from Core no. 2 reveals a post-disturbance linear 

accumulation rate (LAR) of 0.17 cm/yr (Figure 3.2.14). Based on the sampling interval, it 

appears that a disturbance had occurred 78 to 98 years before the 2010 core collection. Predisturbance sediments show a trend of downcore decay in the two points shown in Figure 3.2.15, 

but this is insufficient data to ascribe an LAR for pre-disturbance accretion. 
3.2.4.4 O

The p

conducte

shipwrec

with coh

located e

hurricane

of hurric

hurricane

F-2). Site

at Datum

and plast

are there

2011). Sc

the mode

depositio

Datum 1 

ranged fr

Figure 

Oceanogra

potential imp

ed at three d

ck site (Rego

esive-clay d

east of the ey

e force wind

cane force w

e force wind

e 433 is ther

m 1 during Ik

ticity were n

efore unknow

cour estimat

eled hurrica

on of sedime

resulted in m

rom 21 cm (l

3.2.14. Dow

rate 

aphic Analy

pact of hurri

datum sites 

o et al. 2011)

dominated se

ye of the two

ds associated

winds associa

ds associated

efore expect

ke and Rita.

not. The deg

wn and sco

tes were gen

anes. In all c

ents, resultin

maximum sc

loose) to 0.0

wncore 210Pbx

(LAR) calcul

ysis 

canes on sea

in the GOM

). Datum 1 s

ediments, sim

o modeled hu

d with both s

ated with bo

d with Hurric

ted to have e

 Although g

ree of sedim

ur estimates

nerated for b

cases, maxim

ng in smaller

cour of betw

03 cm (conso

53 

xs activity an

ations for Site

afloor scour 

M as a prox

imulated hu

milar to the c

urricanes, Ik

storms. Site 

oth storms a

canes Gustav

experienced 

grain sizes w

ment consolid

s are based 

oth loose an

mum hurric

r net scour es

ween 1.5 m (l

olidated) (Re

nd linear sedi

e T433. 

is suggested

xy for seaflo

urricane impa

conditions f

ke and Rita, 

433 lies just

and just wes

v and Katrin

lower poten

were measur

dation and p

solely on f

nd consolida

cane-induced

stimates. Sto

loose) and 3

ego et al. 20

iment accum

d by oceanog

oor conditio

acts at a site

found at Site

but still with

t east of the 

st of the ma

na (Appendi

ntial scour ra

ed for Site 4

potential for 

flow conditi

ated bed scen

d scour was 

orm-related 

 cm (consoli

11). 

ulation 

graphic mod

ns at the cu

 in 26 m of w

e 433. Datum

hin the exten

maximum e

aximum exte

ix F; Maps F

ates than mo

433, bulk de

mud fluidiz

ions (Rego 

narios for ea

 followed b

scour model

idated); net 

deling 

urrent 

water 

m 1 is 

nts of 

extent 

ent of 

F-1 & 

deled 

ensity 

zation 

et al. 

ach of 

by reled at 

scour 
54 

3.3 SITE NO. 386, SHIP SHOAL AREA, PROBABLE HEREDIA

3.3.1 Site Background 

Site 386 is located in the Ship Shoal Federal Lease Area south of Isles Dernieres, Terrebonne 

Parish, Louisiana. C.J. Christ reports diving on the site in the early 1970s (2011, pers. comm.) 

and Avery Munson and Gary Hebert investigated the site through diving on August 5, 1982 

(Munson 2011, pers. comm.). Both Christ and Munson appear to have independently identified 

the wreck based on the condition of the site and examination of several diagnostic artifacts. The 

wreck was subsequently located through a geophysical survey conducted in 2004 by the 

Louisiana State University Coastal Fisheries Institute in partnership with the Louisiana 

Department of Wildlife and Fisheries (Figure 3.3.1). The shipwreck was reported to MMS, who, 

in turn, consulted wreck coordinates provided by Munson and determined that the unidentified 

vessel was likely the steam freighter Heredia. The LSU report reads: 

We located one uncharted wreck within the SSARPA. The object is 

approximately 100m in length and 25m in breadth . . . . The location of this 

wreck was not indicated on the RNCs or on the updated Electronic Navigation 

Charts (ENCs). Conversations with MMS archaeologists indicated that this 

wreck may be the US “Heredia”, a steam freighter that was sunk on 19 May 

1942 by a German U-boat. MMS did not previously have a side scan image or 

accurate location on this vessel. Other sources have indicated that this may not 

be the Heredia (Wilson et. al. 2004:18-19). 

Based on coordinates and descriptions reported to the U.S. Navy (Henderson 1942; Powers 

1942a), it appears that both Heredia and R.W. Gallagher sank within close proximity to one 

another. Conflicting coordinates for Heredia and R.W. Gallagher have been published by various 

sources (Rohwer 1983; Wiggins 1995). These irregularities, coupled with incidental sonar 

imagery, likely led to the one-time misidentification of Site 433 as Heredia (see Section 3.2). 

The results of the geophysical and diver investigations at Site 386 were compared with available 

records in an attempt to either refute or confirm that Site 386 is in fact the wreck of Heredia. 

 
No kn

to the no

ft) respec

The site 

Departm

3.3.2 Ge

Geop

the M/V 

oriented 

Post-Plot

multibeam

Appendix

The g

their pro

operation

and befor

Nikola w

operation

was mad

Wate

The mult

and 3.3.3

to the no

Figure 

nown infras

rth, ESE, an

ctively. A lar

is also loca

ent of Wildl

eophysical

physical data

Nikola. Th

parallel and 

t Map Appe

m, and sing

x A for a ful

geophysical 

oximity. On

ns moved to 

re finishing 

was diverted 

ns. Due to th

e to both site

er depths are

tibeam data 

3). Broad sco

orth. Deeper,

3.3.1. Son

tructure is lo

nd south of th

rge platform

ated within t

life and Fish

l 

a was acquir

irty- and 10

perpendicul

endix B; Fig

gle beam ba

ll description

survey at Si

nce all high

Site 386 (be

the low freq

to perform s

he diversion 

es in June 20

e 32.8 to 36

illustrates th

ouring was e

, more conc

ar image of S

ocated withi

he site: 838 

m complex is

the Ship Sho

eries (LDWF

red at Site 3

00-m survey

lar to the pu

gure B-3). S

athymetry d

n of geophys

ite 386 was r

h frequency 

efore finishin

quency surve

seismic oper

of Nikola, d

011 at which

 m (107.5 to

hat the wrec

evident surro

entrated sco

55 

Site 386 (Wils

in 300 m (1,

m (2,750 ft)

 located app

oal reef plan

F 2011). 

86 on July 

y grids were 

ublished orie

Side scan son

data were ac

sical sensor s

run in tande

survey lin

ng the low fr

ey lines at bo

rations at the

data acquisit

h point the 1

o 118 ft) thr

ck is right si

ounding the 

our zones are

son et al. 2004

000 ft) of Si

), 1,250 m (4

proximately 2

nning area m

18, 2010 an

 centered on

ntation of th

nar, sub-bot

cquired at t

suite and nav

m with the a

nes were fin

requency sur

oth sites, at 

e Macondo 

tion on site w

00 kHz lines

roughout th

de up, listin

shipwreck,

e evident alo

4:30). 

ite 386. Pipe

4,100 ft), an

2,455 m (8,0

maintained b

d June 3 an

n the wreck

he wreck site

ttom profiler

the site (see

vigation par

acquisition a

nished on S

rvey grid). D

the request 

well in supp

was suspend

s were finish

e survey gri

ng to starboa

extending m

ong the nort

elines are lo

d 1,473 m (4

050 ft) to the

by the Loui

d 4, 2011 ab

k coordinates

e (see Navig

r, magnetom

e Chapter 2

rameters). 

at Site 433 d

Site 433, su

During opera

of MMS and

port of relief

ded. A return

hed. 

id (Figure 3

ard (Figures

more promin

th side (port

ocated 

4,830 

e NE. 

isiana 

board 

s and 

gation 

meter, 

2 and 

due to 

urvey 

ations 

d BP, 

f well 

n trip 

.3.2). 

3.3.2 

nently 

t) and 
56 

stern of the wreck and most significantly at the port bow where water depths may reach over 37 

m (121 ft) (Figures 3.3.2 and 3.3.3). 

Sonar data corresponds with multibeam data, indicating that the wreck site is oriented with 

the bow facing 95 degrees ESE. The 100 kHz survey grid clearly imaged the wreck site in its 

entirety, but did not have sufficient resolution to detail specific components of the vessel or 

changes in seafloor texture. The 410 kHz survey grid clearly outlined the wreck, providing 

details of the numerous components that sit atop the hull and on the surrounding seafloor. 

Ancillary wreck components are scattered across the seafloor close to the wreck, with smaller 

amorphous quantities of debris identified as far as 91 m (300 ft) south and 46 m (150 ft) east of 

the wreck. It is unknown if these targets are associated with the wreck site. No significant 

variation in sediment grain size was evident on the high frequency sonar. A sonar mosaic was 

created using only the survey lines that parallel the wreck site. An inset image shows a 

composite of various high frequency sonar lines providing uninterrupted imagery of the entire 

wreck (Figure 3.3.4). 

The main component of the wreck site measures 112 m (367 ft) by 19 m (62 ft). A debris 

field is scattered at the stern of the vessel; when this field is included in the overall length 

measurements, the wreck measures 119 m (390 ft). Ancillary components of the wreck site were 

resolved both within the hull and on the surrounding seafloor. The most significant such 

component is a large box-like structure located on the starboard side of the vessel, aft of 

midships. This object measures approximately 4.3 m (14 ft) by 7.6 m (25 ft). The geophysical 

data indicates that although much of the vessel’s hull appears relatively intact, the superstructure 

appears to be heavily disturbed and disarticulated. 

Sub-bottom profiler data penetrated 7.6–9 m (25–30 ft) throughout the survey grid. The subbottom data is similar to Site 433, which is not surprising considering the proximity of the two 

sites. The stratigraphic profile consists of alternating bands of parallel strata, occasionally 

interrupted by acoustically transparent zones of fine silts or sands. Scour zones surrounding Site 

386 are less significant than those surrounding Site 433. Sediments appear truncated within the 

scour zones and no apparent infill of relict scour has taken place. Figure 3.3.5 shows a 

stratigraphic profile close to the wreck site (Survey Line 509) where the deepest, sharpest scour 

zone is evident. 
Figure 3.3.2. Bathymetry surrounding

57 

 Site 386 in 2-decimeter intervals. 
Figure 3.3.3. 3-D multibeam rendering

58 

s of Site 386. 
59 

Figure 3.3.4. 120 

surve

and 410 kHz side

y lines. 

 scan sonar mosaic of Site 386. Inset is a composite of 410kHz. Data 
Figur

Magn

along the

which co

are detail

4, 12, 13

anomalie

multibeam

anomalie

individua

Smal

of these 

nos. 9, 10

23.4-m (

area surr

the seaflo

evident t

related to

re 3.3.5. Su

wr

Ho

netometer da

e axis of the

ould not be d

led in the M

3, 14, 17, 1

es appear to 

m data scatt

es are not d

al trace plot 

ll clusters of

clusters is lo

0, and 50. A

77-ft) negat

ounding this

oor was only

that correspo

o the shipwre

ub-bottom pro

reck, with a 

orizontal scale

ata produced

e reported s

directly attrib

Magnetic Ano

8, 20, and 5

be related t

tered on the 

discernible w

for each surv

f anomalies w

ocated 265 m

Anomaly no. 

ive monopo

s anomaly cl

y imaged by

ond with thi

eck or are in

ofile of surve

heading of 1

e lines in 2-m

d very high i

shipwreck si

buted to the

omaly Table

52 were ide

o smaller qu

seabed surro

within the c

vey line (Fig

were also ide

m (870 ft) N

9 is a 62 nT

le; and no. 5

luster was b

y low freque

s anomaly c

ntrusive. 

60 

ey line 509, S

0 degrees. V

ms intervals. 

ntensity, lon

ite. A total o

 main hull o

 for Site 386

entified in cl

uantities of d

ounding the 

ontour map

gure 3.3.6). 

entified furth

NW of the w

T, 44-m (145

50 is a 9 nT

beyond the e

ency sonar d

cluster; there

Site 386. Lin

Vertical scale

ng duration a

of 55 magne

of the wreck

6 (Appendix

lose proxim

debris that c

wreck site.

s and were 

her from the

wreck site. Th

5-ft) negative

T, 44-m (145

extent of the

data. No sea

efore, it is u

e 509 is loca

e lines in 15

anomalies st

etic anomal

k. These indi

x C). Magnet

mity to the w

can be seen 

It should be

identified b

e wreck. The

his cluster in

e monopole;

5-ft) negativ

30-m surve

afloor feature

unknown if t

ated east of 

0-m increme

tretched east

ies was reco

ividual anom

tic Anomaly

wreck site. T

on the sona

e noted that 

by analyzin

e most signif

ncludes Ano

; no. 10 is a 

ve monopole

ey grid; there

es or debris 

the anomalie

the 

ents. 

t/west 

orded 

malies 

y nos. 

These 

ar and 

these 

g the 

ficant 

omaly 

9 nT, 

e. The 

efore, 

were 

es are 
Figure 3.3.6. Magnetic contours in 50-nT 

61 

intervals at Site 386. 
3.3.3 Div

Divin

sector sc

in its enti

 M

 T

 V

ft

The w

team. Th

approxim

black wa

visibility

surround

visible re

dive team

possible 

condition

searches 

accessibl

could be 

Imme

deteriora

ving 

ng operation

anning sona

irety, it prov

Figure 3.3

Maximum rec

Total bottom 

Visibility: 30

t) in water de

wreck site lo

he wreck site

mately 25 m

ater diving e

y, as well as 

ding the wrec

emains exten

m extending 

since they 

ns were dee

at approxim

le to divers. 

seen rising t

ediately aft

ated and Spr

ns on Site 3

r was deploy

vided details 

3.7. Sector 

corded water

time: 3 hour

 m (100 ft) i

epths greater

ocation was v

e was obscu

(80 ft) BSL

environment.

uncertainty 

ck site, the D

nding above 

above the f

extended in

emed unsafe

mately 25 m 

Divers noted

to the surfac

er the seco

ree returned 

386 took pla

yed before d

of various s

scanning son

r depth durin

rs. Average 

in water dept

r than 25 m 

verified from

ured by a thi

L. Visibility

. Due to the

about the m

DSO decided

the floccule

flocculence.

nto the flocc

e by the DS

(80 ft) of w

d that throug

ce, verifying 

ond dive te

to the dock

62 

ace on Augu

diving began

site compone

nar composite

ng diving: 25

dive time: 2

ths less than

(80 ft) BSL.

m the Mesot

ick layer of 

y below the 

e risk of an e

maximum wat

d to limit ope

nce. Possibl

Detailed inv

culent layer,

SO. Despite

water depth, 

ghout the du

that they we

eam returne

k at Morgan 

ust 16, 2010

n and, althou

ents (Figure 

e image orien

5 m (80 ft).

22.5 minutes

n 25 m (80 ft

.

tech scans an

suspended s

floc layer d

entanglemen

ater depth wi

erations to c

le steel frame

vestigation o

, where visi

e conducting

no other po

uration of the

ere over a w

ed to the s

City, Louis

0 from the 

ugh it could n

3.3.7). 

nted north up.

. 

t) BSL. 0 to 

nd verified b

sediment (fl

decreased qu

nt/impalemen

ithin some o

circle searche

es were iden

of these com

ibility was 

g large 60-m

ortions of hu

e search, sm

wreck-site. 

surface, we

siana. While

M/V Spree.

not image th

0.5 m (0 to 

by the initial

oc) that beg

uickly, creat

nt hazard in

of the scour z

es to identify

ntified by the

mponents wa

zero, and d

m (200-ft) c

ull structure 

mall droplets 

eather condi

e the team w

. The 

he site 

1.5 

l dive 

gan at 

ting a 

n zero 

zones 

fy any 

e first 

as not 

diving 

circle 

were 

of oil 

itions 

waited 
63 

out the storm, Spree was refueled and additional equipment and supplies were obtained from 

Tesla Offshore’s office and local hardware stores. Due to the conditions encountered on site, the 

DSO decided that further dive operations were unsafe, and that no further investigation would be 

conducted on Site 386; dive operations proceeded to the next site. 

3.3.4 Site Environment 

3.3.4.1 Water Sampling 

One 8-ounce water sample was collected from Site 386 on August 16, 2010 at a depth of 21.3 

m (70 ft) BSL; divers did not descend below a maximum depth of 25 m (80 ft) at this site since 

visibility and probable entanglements created an unsafe diving environment. The water sample 

was collected by the first dive team and is assumed to be representative of conditions impacting 

the wreck site at deeper depths. Water temperature at the time of acquisition was 83° F. Repeat 

measurements were taken for pH, salinity, and dissolved oxygen content and averaged (Table 

3.5). Salinity was measured in parts per thousand. Dissolved oxygen (DO) is reported in mg/L. 

Table 3.5 

 

Water Sample Results for Site 386 

Type Average 

Salinity (ppT) 33.60

pH 7.563

Dissolved oxygen (mg/L) 6.78

3.3.4.2 Core Lithology and Grain Size 

Due to the poor visibility and dangerous conditions observed in the field, the DSO restricted 

divers to a maximum depth of 25 m (80 ft); therefore, no sediment cores were obtained from the 

seafloor at approximately 32.8–36 m (107.5–118 ft). 

3.3.4.3 Oceanographic Analysis 

The potential impact of hurricanes on seafloor scour is suggested by oceanographic modeling 

conducted at datum sites in the GOM as a proxy for seafloor conditions at the current site (Rego 

et al. 2011). Datum 1 is located east of the eye of the two modeled hurricanes, Ike and Rita, but 

still within the extents of their associated hurricane force winds. Site 386 lies just east of the 

maximum extent of hurricane force winds associated with both storms and just west of the 

maximum extent of hurricane force winds associated with Hurricanes Gustav and Katrina 

(Appendix F; Maps F-1 & F-2). Site 386 is therefore expected to have experienced lower 

potential scour rates than modeled at Datum 1 during Ike and Rita. 

Since core data was not obtained at this site, comparisons are made between potential scour 

zones and observed sub-bottom profiler data. Storm-related scour modeled at Datum 1 resulted 

in maximum scour between 1.5 m (loose) and 3 cm (consolidated); net scour ranged from 21 cm 
64 

(loose) to 0.03 cm (consolidated) (Rego et al. 2011). Datum 3 models represent scour estimates 

for a site located in 31 m of water, similar to the current site; sediments are likely coarser at 

Datum 3 than would be expected from samples at Site 386. Using the loose bed scenario, 

maximum scour ranged from 1.3 m (Ike) to 60 cm (Rita); consolidated bed scenarios resulted in 

net scour of 30 cm (Ike), but a net sediment accretion of 5 cm from Hurricane Rita (Rego et al. 

2011). The sub-bottom profiles recorded closest to the hull at Site 386 depict scour zones that 

lack any evidence of sediment infill or re-deposition. 

3.4 SITE NO. 373, SOUTH MARSH ISLAND AREA, PROBABLE CITIES SERVICE 

TOLEDO

3.4.1 Site Background 

Site 373 is located in the South Marsh Island Federal Lease Area, south of Marsh Island, 

Vermilion Parish, Louisiana. The site was reported to MMS as the result of a geophysical lease 

survey performed by John E. Chance and Associates, Inc., on October 19 and 20, 1992 (Figure 

3.4.1). The October 1992 report was written by Marine Archaeologist Laura Landry and Senior 

Geophysicist Jeffrey Thomas. The hazard section of the report reads: 

Sonar data revealed a significant contact that is interpreted to be a sunken 

ship. This ship appears to be lying hull up, measures approximately 65 x 420 

feet, and protrudes up from the seafloor about 28 feet. The ship also appears to 

have broken into two major pieces. There are two linear contacts extending out 

from the ship approximately 80 feet to the north and 225 feet to the south. These 

linear features could represent either seafloor dragmarks or lengths of cable or 

chain. Other scattered pieces of debris are also observed in the vicinity of the 

shipwreck. The 40 gamma, 1,500-foot duration magnetic anomaly detected on 

line 10, 1,130 gamma, 2,000-foot duration anomaly on line 11, and the 30 

gamma, 1,300-foot anomaly on line 22 are directly related to the sunken vessel. 

The 1,000+, 650-foot anomaly detected on line 11 is probably associated with a 

piece of scattered ferrous debris associated with the shipwreck. A number of 

other targets which remain unidentified are scattered about the wreck which do 

not correlate with magnetic anomalies (Landry and Thomas 1992: 20). 

In the hazard and archaeological sections of the report, the dimensions of the wreck site 

differ. The hazard section reports that the wreck is 128 m (420 ft) by 20 m (65 ft); the 

archaeological section reports that the wreck is 137 m (450 ft) by 20 m (65 ft). The report does 

not postulate a possible identity for the wreck, but it does point out that German U-boats 

operated in this area during World War II and this wreck could represent one of the victims. 

The BOEM database identifies this wreck as the tanker Cities Service Toledo. It is unclear 

from the database when the vessel at Site 373 was first identified as Cities Service Toledo, but it 

is possible that this first identification was made by avocational divers. C.J. Christ was part of a 

group that dived on the site on June 19, 1971 (Christ 2006; 2011, pers. comm.). They found the 

site based on coordinates supplied to their boat captain by a local fisherman. While on the site, 
they note

see the ru

A 10

and lies 

abandone

approxim

3.4.2 Ge

Geop

additiona

extended

were run

survey l

reconnais

kHz sona

bottom p

B-4). Si

ed that the v

udder, but th

” abandoned

approximate

ed wells and

mately 680 m

Figu

eophysical

physical dat

al data was o

d out in a 30

n over the s

ines were r

ssance and t

ar data and s

profiling, and

ide scan so

vessel was up

he propeller w

d pipeline ru

ely 438 m (1

d removed p

m (2,230 ft) t

ure 3.4.1. S

1

l

a acquisitio

obtained on 

0-m (1,000-

ite, both co

run using 1

to maximize

spaced 30 m

d magnetic 

onar, sub-bo

pside down 

was missing

uns WNW o

1,435 ft) WN

platforms are

to the north.

Side scan son

992). 

on was cond

May 30 and

ft) radius su

ontaining sur

100 kHz so

e sonar cove

m apart for in

contouring 

ottom profi

65 

and had a s

g (2006). 

of the wreck

NW of the w

e located no

nar image of S

ducted at th

d 31, 2010 a

urrounding th

rvey lines p

onar data a

erage. A tota

ncreased son

(see Naviga

iler, magnet

ingle screw.

k site. The pi

wreck at its 

orth of the s

Site 373 (Lan

his site on 

aboard the M

he wreck sit

paralleling th

and spaced 

al of 23 surv

nar resolutio

ation Post-Pl

tometer, mu

. Christ note

ipeline was 

closest poin

site, the clos

dry and Thom

March 5 a

M/V Nikola.

te. Two sepa

he wreck sit

100 and 2

vey lines we

on, multibeam

lot Map App

ultibeam, a

es that they c

installed in 

nt. A groupin

sest of which

mas 

and 6, 2010

. The survey

arate survey 

te. A total o

200 m apar

ere run using

m coverage,

pendix B; F

and single b

could 

1972 

ng of 

h lies 

0 and 

y grid 

grids 

of 12 

rt for 

g 410 

, subFigure 

beam 
66 

bathymetry data were acquired at the site during both the March and May field operations. A 

CODA 3-D Echoscope was also used during the March operations (see Chapter 2 Methodology 

and Appendix A for a full description of geophysical sensor suite and navigation parameters). 

The seafloor throughout the survey area is a fairly constant 27 m (88.5 ft), with undulations 

ranging from 26.8 to 27.2 m (88 to 89 ft) (Figure 3.4.2). The multibeam data illustrates that the 

wreck is hull up with a major break just south of midships. The wreck sits approximately 6.7 m 

(22 ft) above the surrounding seafloor. The vessel appears to be listing slightly to the eastern side 

(Figure 3.4.3). Scouring was evident surrounding the shipwreck and extended primarily to the 

western side with deeper, more concentrated zones to the north, south, and at the break in the 

hull south of midships. Water depths within these scour zones reach a maximum of 28 m (92 ft). 

Sonar data corresponds with multibeam data, indicating that the wreck site is oriented along a 

roughly north-south axis with the north end oriented at 17 degrees and the south end oriented at 

197 degrees. The 100 kHz survey grid clearly imaged the wreck site in its entirety, but did not 

have sufficient resolution to detail specific components of the vessel or changes in seafloor 

texture. The 410 kHz survey grid clearly outlined the wreck and provided details of some 

seafloor mottling surrounding the wreck as well as an increase in reflectivity extending SE of the 

hull. This reflectivity change may be the result of an increase in sediment grain size, or may be 

related to very small quantities of debris associated with deterioration of the wreck site. A 

possible ancillary component of the wreck site was resolved just north of the hull; this may 

represent a small length of cable or line. Figure 3.4.4 shows a sonar mosaic created using the low 

frequency sonar lines that run perpendicular to the wreck site and the high frequency lines that 

parallel the wreck site. An inset shows a composite of two high frequency sonar lines, providing 

uninterrupted imagery of the entire wreck. 
Figure 3.4.2. Bathymetry surrounding Sit

67 

e 373, in 2-decimeter intervals. 
Figure 3.4.3. 3-D multibeam renderings

68 

 of Site 373.
69 

Figure 3.4.4. 120 and 410 kHz side scan sonar mosaic of Site 373. Insert is a composite of two 410 kHz l
In ad

employed

detail of 

believed 

 

The c

the wreck

sits 6.7 m

ft) by 6 m

stern. No

Sub-b

stratigrap

acoustica

6.1 m (20

that over

evident t

zones are

following

demonstr

(Figure 3

ddition to th

d at this sit

a second ho

to be the res

Figure 3.

combined so

k is nearly s

m (22 ft) abo

m (20 ft). It i

o evidence of

bottom prof

phic profile 

ally amorpho

0 ft) of well

rlies acoustic

to the wester

e not very p

g figure sh

rating minor

3.4.6). 

he multibeam

te during th

ole in the hu

sult of a torp

.4.5. Echos

onar, multibe

split in half.

ove the seafl

is not clear f

f running ge

filer data p

consists of

ous zone app

l-laminated, 

cally amorph

rn and south

prominent; i

ows a strat

r seafloor de

m and side 

e March op

ull of the ve

pedo impact 

scope still of S

eam, and ech

The wreck 

floor. The br

from the geo

ear or rudder 

penetrated 1

f a moderat

proximately 

parallel-bed

hous, foreset

hern portion

instead, they

tigraphic pr

epression w

70 

scan sonar

perations. Th

ssel that lies

(Figure 3.4.5

Site 373, from

hoscope data

site measur

each in the h

ophysical dat

was observe

10.7 m (35

te to strong

1.5 m (5 ft) 

dded strata. T

t deltaic dep

s of the wre

y have been 

rofile close

with in-filled 

r data, the C

he resulting 

s along the 

5). 

m CODA UIS s

a supports th

res 141 m (4

hull measur

ata which end

ed. 

 ft) throug

gly reflectiv

thick. This i

The base of 

posits. Signif

eck. Unlike 

in-filled to 

to the wre

scour appro

CODA 3-D

real-time im

SE side of t

software. 

he original i

463 ft) by 19

res approxim

d is the bow

ghout the su

ve seafloor, 

is followed b

this zone is 

ficant, broad

Sites 433 an

depths of 1

eck site (Su

oximately 1

D Echoscope

magery prov

the wreck; th

nterpretation

9.8 m (65 ft

mately 18.2 m

w and which 

urvey grid.

followed b

by approxim

an unconfor

d scour zone

nd 386, the 

1.5 m (5 ft)

urvey Line

.5 m (5 ft) 

e was 

vided 

his is 

n that 

t) and 

m (60 

is the 

The 

by an 

mately 

rmity 

es are 

scour 

. The 

205) 

thick 
Magn

directly o

recorded 

8, 11, 16

appear to

surround

contour m

to the ma

debris dir

Conto

the surve

identified

(1,215 ft

no. 13 is

monopol

consisten

of the rep

was not e

separate 

position, 

surround

seafloor 

evident th

Figure 3.4.6

netometer d

over and adj

which could

6, 17, 18, an

o be related 

ding the wrec

maps and we

assive signa

rectly adjace

oured magne

ey grid withi

d further fro

) NW of the

s a 404 nT, 

le, and no. 

nt with a pip

ported pipel

enough evid

ferromagne

it is likely

ding this ano

was imaged

hat correspo

6. Sub-bott

the wrec

150-m in

data produce

jacent to the

d not be dire

nd 20 were i

to smaller q

ck site. It sho

ere identified

ature of the m

ent to the wr

etometer dat

n the run-ou

om the wrec

e wreck site

46-m (153-

15 is a 15 n

peline crossin

line. Since th

dence to dete

etic source. 

y that it is

maly cluster

d by only lo

ond to this an

tom profile of

ck site with a

ncrements. H

ed a numbe

e hull of the

ectly attribut

identified in 

quantities of

ould be note

d by analyzin

metal hull, i

reck site (Fig

ta identified 

ut of survey l

ck site. The 

e. This cluste

ft) positive 

nT, 15.5-m 

ng; however

he pipeline 

ermine if the

Because of

s related to

r was beyon

ow frequenc

nomaly clust

71 

f line 205, Si

a heading of

orizontal scal

er of very h

e shipwreck.

ted to the ma

close proxi

f debris that 

ed that these

ng the indiv

it is not poss

gure 3.4.7). 

the abandon

line 103. Som

most signif

er includes A

monopole, n

(51-ft) dipo

r, the source

was just bey

e pipeline is 

f this cluste

o pipeline c

nd the extent

cy sonar dat

ter. 

ite 373. Line 

f 10 degrees.

le lines in 2-m

high intensit

 A total of 2

ain hull of th

imity to the 

may be buri

e anomalies a

vidual trace p

sible to iden

ned 10” pipe

me small clu

ficant of the

Anomalies n

no. 14 is a 6

ole. Anomal

e of the anom

yond the ext

displaced o

er’s proxim

construction 

ts of the 30-

ata. No seafl

205 is locate

. Vertical sca

ms Intervals. 

ty, long du

20 magnetic

he wreck. An

wreck site. 

ied in the su

are not disce

plot for each

ntify all sma

eline at the w

usters of ano

ese clusters i

no. 13, 14, a

69 nT, 22-m

ly no. 13 ha

maly lies 12

tent of the s

or if the anom

mity to the 

or mainten

-m survey gr

floor feature

ed west of 

ale lines in 

uration anom

c anomalies 

nomalies no.

These anom

urficial sedim

ernible withi

h survey line

aller quantiti

western exte

omalies were

is located 3

and 15. Ano

m (72-ft) po

as character

28 m (420 ft)

survey grid, 

maly represe

pipeline as

nance. The 

rid; therefore

s or debris 

malies 

were 

. 2, 6, 

malies 

ments 

in the 

. Due 

ies of 

ent of 

e also 

70 m 

omaly 

sitive 

ristics 

) east 

there 

ents a 

-built 

area 

e, the 

were 
Figure 3.4.7. Magnetic contours in 50-n

72 

T intervals at Site 373. 
73 

3.4.3 Diving 

Diving operations on Site 373 took place on August 18 and 19, 2010 from the M/V Spree. 

 Maximum recorded water depth on bottom: 26 m (85 ft). 

 Total bottom time: 6.63 hours. Average dive time: 23.41 minutes. 

 Visibility: 1.8–6 m (6–20 ft) on wreck, 0–0.9 m (0–3 ft) on seafloor. 

Like Site 433, the wreck at Site 373 is upside down on the seafloor, reducing the number of 

accessible diagnostic features. Before diving operations, dive teams reviewed plans of the tanker 

J.A. Bostwick (the former name of Cities Service Toledo) that had been obtained from the Hagley 

Museum (Appendix E; Figures E-27-29). These plans contained extensive design and 

construction details, including the vessel’s propeller and rudder assembly. Based on these 

drawings, the project team decided to concentrate initial diving operations on the stern of the 

vessel in an attempt to obtain potentially diagnostic data that could be compared to the plans. 

The first dive team established a descent line at the southern end of the shipwreck. 

Geophysical data was unable to distinguish the bow from the stern at Site 373, and it was quickly 

determined that the southern end was in fact the bow of the vessel. The descent line was 

subsequently moved to the stern of the vessel, where it was secured to the propeller shaft (Figure 

3.4.8). Teams that investigated features on this vessel developed drawings, measurements, and 

photographs for the propeller shaft and hull plating. It immediately became apparent during 

diving operations that salvage had likely occurred on the vessel after sinking, as the rudder, 

sternpost, and propeller had been removed. Attempts to clean and record hull plating details met 

with marginal success because of the heavy marine growth on the hull and the limited time 

divers had on the site. Other activities on this site included looking for the remains of any draft 

marks on the stern, and searches off of the stern to verify that the rudder/propeller were not 

disarticulated and subsequently obscured by near-seafloor sediments. Despite conducting these 

searches at 24 m (80 ft) water depth and investigating a deep scour off of the stern at 27 m (90 

ft), no indication of the missing stern features were found. 
The M

made, du

3.4.4 Sit

3.4.4.1 W

One 8

m (81 ft)

were take

measured

Figur

Mesotech w

ue to the size

te Environ

Water Sam

8-ounce wat

) BSL. Wate

en for pH, sa

d in parts per

re 3.4.8. Ph

as deployed

e, shape, and

ment 

mpling

ter sample w

er temperatu

alinity, and d

r thousand. D

W

Salinity

pH 

Dissolv

hotograph of 

d the evening

d height of th

was collected

ure at the tim

dissolved ox

Dissolved ox

T

Water Sample

Type 

y (ppT) 

ved oxygen (m

74 

propeller sha

g of August 

he vessel, no

d from Site 3

me of acqui

xygen conten

xygen (DO) 

Table 3.6 

 

e Results fo

mg/L) 

aft with descen

18, 2010. A

o useful imag

73 on Augu

isition was 8

nt and avera

is reported i

r Site 373 

Average 

30.80 

8.013 

7.45 

nt line attache

Although mu

gery was obt

ust 19, 2010 a

83° F. Repe

aged (Table 3

in mg/L. 

ed. 

ultiple drops 

tained. 

at a depth of

eat measurem

3.6). Salinity

were 

f 24.7 

ments 

y was 
3.4.4.2 C

A sin

approxim

east; wat

Water de

The core

Samp

lithology

that sedim

mean). B

to mediu

radioisot

or the mi

3.4.4.3 R

Sedim

that can b

changes 

them. No

the over

fraction p

Core Litho

ngle core wa

mately 15 m 

ter depth at t

epth at the co

 resulted in a

ples were su

y and measur

ments from 

Based on me

um silt down

ope samplin

ini-torvane in

Radioisoto

ments from S

be used to a

in activity d

o sharp dow

all absence 

percentage. 

Fi

logy and G

as collected 

(49 ft) sout

the core site 

oring locatio

a 58 cm stra

ubsequently

red for grain

Site 373 ar

dian grain s

ncore. Shear

ng did not le

n the 2” diam

ope Analys

Site 373 do 

arrive at a lin

downcore (li

ncore differ

of downco

igure 3.4.9. 

Grain Size

from Site 3

th of the nor

was approxi

on was recor

tigraphic sam

y collected f

n size. Medi

re cohesive-c

ize, the near

r strength m

eave sufficie

meter core sl

sis 

not show an

near accumu

ines at 3 an

ences in por

re decay in

Downcore 

75 

373 on Augu

rthernmost e

imately 27 m

rded using th

mple. 

from each o

ian and grap

clay domina

r seafloor se

easurements

ent material 

leeve. 

ny evidence 

ulation rate (

d 42 cm on

rosity or gra

n Pb activity

210Pbxs activ

ust 19, 2010

end of the w

m (89 ft), sim

he divers’ wr

of two unit

phic mean c

ant, and con

ediments are

s were not o

to measure 

of a downco

(LAR). Alth

n Fig. 3.4.11

ain size were

y cannot be

ity for Site T3

0. Divers po

wreck and 25

milar to the a

rist mounted

ts observed 

alculations b

nsist of med

e fine silt and

obtained for 

with either 

ore decay tre

hough there 

), no age ca

e observed d

e linked to 

373. 

ositioned the

5 m (82 ft) t

ambient seaf

d dive compu

within the 

both demon

dium silt (gr

d increase in

this site bec

the penetrom

end in Pb ac

are several 

an be ascrib

downcore; h

changing c

e core 

to the 

floor. 

uters. 

core 

strate 

aphic 

n size 

cause 

meter 

ctivity 

sharp 

bed to 

hence, 

coarse 
76 

3.4.4.4 Oceanographic Analysis 

Oceanographic modeling of flow conditions was conducted using recorded wave and current 

patterns during Hurricanes Ike and Rita as applied to measured grain sizes for seafloor sediments 

at Site 373 (Datum 1; Rego et al. 2011). Site 373 is located east of the eye, but within the swath 

of hurricane force winds associated with both storms modeled in this exercise (Appendix F; 

Maps F-1 & F-2) Datum 1 was based on coordinates very close to Site 373 with the same water 

depths and sediment types. Scour estimates were generated for both loose and consolidated bed 

scenarios for each of the modeled hurricanes. In all cases, maximum hurricane-induced scour 

was followed by re-deposition of sediments, resulting in smaller net scour estimates. Stormrelated scour modeled at Site 373 resulted in maximum estimates of between 1.5 m (loose) and 3 

cm (consolidated); net scour ranged from 21 cm (loose) to 0.03 cm (consolidated) (Rego et al. 

2011). 

3.5 SITE NO. 15488, HIGH ISLAND AREA, UNKNOWN MODERN WRECK 

3.5.1 Site Background 

Site number 15488 is located in the High Island Federal Lease Area, south of Jefferson 

County, Texas. The site is approximately 13 km (8 miles) SE of a modern shipping fairway that 

connects Sabine, Port Arthur, and Galveston. 

The site was originally identified during a geophysical survey performed by Thales 

Geosolutions, Inc., in December 2001. The geophysical data analysis and resulting report were 

prepared in 2002 by Marine Archaeologist, Robert J. Floyd and Marine Geologist, John L. 

Rietman. The archaeological report states: 

Available references on shipwrecks in the general vicinity... include the Doris

(1915), Shamrock (1939), Frances H. (1909), the Lydia (1909), and the Emma 

Harvey (1916). The magnetometer and side scan sonar records... were examined 

for wrecks, and the wreck located 700 feet southeast of the... 6-inch pipeline 

appears to be a modern work boat approximately 75 feet long and 20 feet wide. 

The magnetic readings (#4 and #16) indicate a vessel slightly under 100-ton class. 

The coordinate for the sonar image should be used as the center of avoidance 

rather than the magnetic readings in this specific case. (Floyd and Rietman 

2002:19) 

This wreck was not entered into the MMS shipwreck database; it was again “discovered” 

during a geophysical survey performed by Tesla Offshore in May of 2008. The geophysical data 

analysis and resulting report were prepared by Marine Archaeologist Amanda Evans, and 

Geoscience Manager Matt Keith (Evans and Keith 2008). The hull of the vessel measured 21 m 

(69 ft) in length with a beam of approximately 7 m (22 ft). The wreck was determined to rest 

upside down with the bow facing NE. The sonar data indicated that debris was present on the 

port side, including a linear projection extending out and away from the hull (Figure 3.5.1). The 

2008 report also concluded that the vessel was likely a modern workboat, “It is unlikely based on 
the initia

distance 

vessel’s p

A 6” 

660 m (2

(4,590 ft)

3.5.2 Ge

Geop

16 and 1

multibeam

August f

(see Cha

and navig

Due t

return tri

The surv

on the ve

lines para

kHz son

coverage

frequency

bottom p

B-5). 

al survey dat

of approxim

potential his

abandoned 

2,165 ft) NE

) to the SSE

Figure 3.5.1. 

eophysical

physical data

17, 2010 abo

m, and singl

field operatio

apter 2 Meth

gation param

to rough sea

p was made 

vey grid exte

essel’s positi

allel and per

ar data and 

e. A total of 

y and space

profiling, and

ta that the v

mately 300 m

torical signi

pipeline lies

. A few P&A

. 

410 kHz sid

l

a acquisition

oard the M/V

le beam bath

ons. A COD

hodology and

meters). 

as, data quali

to the site a

ended out in

ion. Two sep

rpendicular 

spaced 100

23 survey l

ed 30-m ap

d magnetic 

vessel is a h

m (1,000 ft

ficance” (Ev

s 190 m (625

A wells are l

de scan sona

n was conduc

V Nikola. S

hymetry data

DA 3-D Ech

d Appendix 

ity was sever

and all senso

n a 300-m (1

parate survey

to the wreck

0 and 200 m

lines were ru

part for incr

contouring 

77 

istoric resou

) until a de

vans and Kei

5 ft) NW of 

located in th

r image of Sit

cted at Site 1

Side scan son

a were acqui

hoscope was

A for a full

rely compro

rs (with the 

1,000-ft) rad

y grids were 

k site. A tota

m apart for 

un directly o

reased sonar

(see Naviga

urce, howev

efinitive asse

ith 2008). 

the site and 

he area, the c

te 15488 (Eva

15488 on M

nar, sub-bot

ired at the sit

s also used d

l description

mised durin

exception of

dius surround

 run over the

al of 12 surv

reconnaissa

over the wre

r resolution

ation Post-Pl

ver it should 

essment can

a 4” abando

closest of wh

ans and Keith

arch 17, 201

ttom profile

te during bo

during the M

n of geophy

ng initial surv

f the echosc

ding the wre

e site, both c

vey lines we

ance and to 

eck site usin

n, multibeam

lot Map App

be avoided

n be made o

oned pipelin

hich lies 1,4

h 2008). 

10 and on Au

r, magnetom

oth the March

March opera

sical sensor 

vey operatio

ope) were re

eck site, cen

containing su

ere run using

maximize 

ng 410 kHz 

m coverage, 

pendix B; F

d by a 

of the 

ne lies 

400 m 

ugust 

meter, 

h and 

ations 

suite 

ons. A 

e-run. 

ntered 

urvey 

g 100 

sonar 

sonar 

subFigure 
78 

Water depths throughout the survey area range from 13.4 to 13.8 m (44 to 45 ft) (Figure 

3.5.2). The multibeam data illustrates that the wreck is upside down and the bow is oriented 65 

degrees NE. The wreck sits approximately 2.1 m (7 ft) above the surrounding seafloor and 

appears to be listing to the NW side (starboard). Scour appears to be limited to the area 

immediately surrounding the wreck site with maximum depth reaching 14 m (46 ft). 

Sonar data corresponds with multibeam data, indicating that the wreck site is oriented with 

the bow facing NE. The 100 kHz survey grid clearly imaged the wreck site in its entirety, but did 

not have sufficient resolution to detail specific components of the vessel or changes in seafloor 

texture. The 410 kHz survey grid clearly outlined the wreck and provided details of some 

seafloor mottling surrounding the site. Debris associated with the wreck site was identified off of 

the SE side, just fore of midships. Seafloor scars caused by trawling activities are also evident on 

the sonar data. 

Figure 3.5.3 shows a sonar mosaic created using the low frequency and high frequency sonar 

lines that were run parallel to the wreck site. An inset shows the wreck as imaged from survey 

line 307. Sonar data did not produce high quality imagery over the wreck site, likely due to the 

difficulty in imaging the wreck with acoustics because of the angular hull and the angle at which 

the wreck site has settled into the seafloor. 

 
Figure 3.5.2. Bathymetry surrounding

79 

 Site 15488, in 2-decimeter intervals. 
80 

Figure 3.5.3. 120 and 410 kHz side scan sonar mosaic of Site 15488. Inset at 410 kHz. 
In ad

employed

the listin

wreck is 

Figure

The c

the wreck

side. The

Sub-b

course-gr

of weakl

paleo-cha

seafloor. 

shipwrec

are restri

further fr

immediat

ddition to th

d at this site 

ng hull and r

buried in the

e 3.5.4. Ech

combined so

k is upside 

e wreck site m

bottom profi

rained, sand

ly reflective

annels are ev

Sediments 

ck lies direct

icted to the 

from the wre

tely SW of t

he multibeam

during Mar

running gear

e seafloor se

hoscope still i

onar, multibe

down with i

measures ap

iler data is u

y deposits. T

e surficial de

vident throug

within the 

tly over an o

area immed

eck. The fol

the wreck sit

m and side 

ch operation

r (Figure 3.5

ediments and

mage of Site 

eam, and ec

intact runnin

pproximately

unstratified, 

The seafloor

eposits is o

ghout the ar

channel de

observed pal

diately adjac

llowing figu

te where the 

81 

scan sonar

ns. The resul

5.4). The da

d the port ch

15488, from

choscope dat

ng gear, and

y 21 m (70 ft

indicative o

r is typically 

ccasionally 

ea with marg

eposits exhib

leo-channel.

cent to the h

ure shows a 

typical scou

r data, the C

lting imagery

ata indicate t

hine is the hig

CODA UIS s

ta support th

d a field of d

t) by 6 m (20

f sediments 

y strongly ref

present (Fig

gins extendi

bit sag into

 Scour zone

hull. In-filled

stratigraphi

ur sequence 

CODA 3-D

y provided e

that the starb

ghest point o

software. 

he original in

debris locate

0 ft). 

with a high

flective, alth

gure 3.5.5). 

ing to within

o the underl

es surroundin

d scour is e

ic profile (S

is evident. 

D Echoscope

excellent det

board side o

on the wreck

nterpretation

ed off of the

h concentrati

hough a thin 

Poorly reso

n a few feet o

lying strata.

ng the wreck

evident exten

Survey Line 

e was 

tail of 

of the 

k site. 

n that 

e port 

on of 

layer 

olved 

of the 

. The 

k site 

nding 

305) 
F

Magn

NNW of

smaller m

anomalie

most wer

Figure 3.5.5. 

netometer d

f the wreck

magnetic ano

es not attribu

re small and 

Sub-bottom

wreck site

increments

ata very cle

k (Figure 3.5

omalies than

uted to the m

none was id

m profile of l

e, with a hea

s. Horizontal 

early highlig

5.6). The w

n had the larg

main body of

dentified on m

82 

line 305, Site

ading of 330

scale lines in

ghted the w

wreck at Site

ger shipwrec

f the wreck 

multiple sur

e 15488. Line

0 degrees. Ve

n 2-ms interva

wreck site an

e 15488 pro

cks discussed

were identif

rvey lines. 

e 305 is loca

ertical scale 

als. 

nd the 6” p

oduced few

d previously

fied further f

ated SW of t

lines in 150

pipeline that 

wer and gene

y. A few scat

from the site

the 

0-m 

runs 

erally 

ttered 

e, but 
Figure 3.5.6. Magnetic contours at Sit

83 

e 15488, at 2-nT intervals. 
3.5.3 Div

Site 1

 W

 T

 V

The 

multibeam

gear (Fig

Dive 

features, 

vessel). T

in) in le

observed

and no le

noted ne

fouling p

was note

effectiven

ving 

15488 was in

Water depth: 

Total dive tim

Visibility: 0–

sector scann

m, and echo

gure 3.5.7). 

Figure 3.5.7

teams enco

and an ass

The ship wa

ngth, with 

d intact, with

etters or othe

ear the bow 

paint was pre

ed on the hu

ness of mapp

nvestigated o

14 m (46 ft)

me: 7.77 hou

–0.3 m (0–1 f

ning sonar p

oscope image

7. Sector sca

untered an u

sociated deb

s powered w

a maximum

h horizontal 

er markings 

and stern. C

eserved unde

ull bottom a

ping. 

on August 2

). 

urs. Average 

ft). 

produced im

es indicating

anning sonar 

upside-down

bris field of 

with a single

m width of 4

vanes near 

could be see

Close exami

er a thin laye

as well. Poo

84 

1, 2010 from

dive time: 2

magery that 

g that the ves

image of Site

n, metal-hull

net-covered

e, 4-bladed p

40 cm (16 

its bottom a

en or felt by

ination of th

er of growth

or visibility p

m the M/V Sp

25.89 minute

correlated w

ssel was ups

e 15488. 

led vessel w

d iron objec

propeller; the

in). A sing

and top. The

y divers. Rai

he hull indi

h. A through

precluded p

Spree. 

es. 

with the pre

side down w

with relativel

cts (presuma

e blades mea

le central m

e vessel has

ised sections

icated that b

h-hull speedo

photography 

evious side 

ith intact run

ly few diagn

ably parts o

asured 60 cm

metal rudder

 a transom s

s or “vanes”

blue bottom 

ometer transd

and reduce

scan, 

nning 

nostic 

of the 

m (24 

r was 

stern, 

were 

antiducer 

ed the 
85 

3.5.4 Site Environment 

3.5.4.1 Water Sampling 

Two 8-ounce water samples were collected from Site 15488 on August 21, 2010 at a depth of 

14 m (46 ft) BSL. Water temperature at the time of acquisition was 88° F. Repeat measurements 

were taken for pH, salinity, and dissolved oxygen content and averaged (Table 3.7). Salinity was 

measured in parts per thousand. Dissolved oxygen (DO) is reported in mg/L. 

Table 3.7 

 

Water Sample Results for Site 15488 

Type Sample Average 

Salinity (ppT) 1 31.5 

Salinity (ppT) 2 31.80 

pH 1 8.02 

pH 2 7.837 

DO (mg/L) 1 6.915 

DO (mg/L) 2 6.87 

3.5.4.2 Core Lithology and Grain Size 

Two cores were attempted at Site 15488 on August 21, 2010. The first core was attempted 

south of the wreck, but divers experienced core refusal at a depth of approximately 10 cm (4 in). 

Sediments were observed to be sandy and exhibited a lack of cohesion resulting in the core 

falling out of the core barrel before it could be capped. A second attempt was made at the wreck 

site, to the east of midships less than 1 m south of the hull; water depth at the successful core site 

was approximately 14 m (46 ft), similar to the ambient seafloor. The core resulted in a 67 cm 

stratigraphic sample. 

Samples were collected from each of four units observed within the core lithology and 

measured for grain size. Median and graphic mean calculations demonstrate different patterns 

downcore. Median grain size indicates fining downcore, from medium silt in the upper two 

samples to medium/fine silt, and fine silt. Graphic mean calculations indicate a more complex 

grain size pattern with alternating layers of coarse and medium silt downcore. Shear strength 

measurements were not obtained for this site due to disturbance caused by sampling for 

radioisotopes, which did not leave sufficient material for the penetrometer or the mini-torvane to 

produce accurate measurements in the 2” diameter core sleeve. 

3.5.4.3 Radioisotope Analysis 

Radioisotope analysis at Site 15488 indicates a post-disturbance linear accumulation rate 

(LAR) of 0.06 cm/yr. Based on the sampling interval, a disturbance occurred 45 to 63 years prior 

to the 2010 core collection. No sharp downcore differences in porosity or grain size are observed 

in the pre-disturbance zone; hence, the overall absence of downcore decay in Pb activity cannot 
be ascrib

event dis

3.5.4.4 O

The p

conducte

shipwrec

water, sim

the eyes 

Ike, whic

hurricane

analyzed

medium, 

measured

consolida

based so

loose and

hurricane

scour est

1.0 m (l

(consolid

cm (loos

bed to chang

sturbed (mix

Fig

Oceanogra

potential imp

ed at three d

ck site (Rego

milar to the 

of Hurrican

ch passed thi

e (NOAA N

d as part of 

and very fi

d for Site 

ation and po

olely on flow

d consolidate

e-induced sc

timates. Ikeloose) and 0

dated) (Rego

e) and a net 

ging coarse f

ed) in situ se

gure 3.5.8. 

aphic Analy

pact of hurri

datum sites 

o et al. 2011

conditions fo

nes Rita and 

is area as a c

NHC; Append

a separate s

fine silt, with

15488, bulk

otential for m

w conditions

ed bed scena

cour was fo

-related scou

0.2 cm (con

o et al. 2011)

scour of 10

fraction perc

ediments.

Downcore 2

accumulation

ysis 

canes on sea

in the GOM

1). Datum 2

found at Site 

Ike; Site 15

category 2 st

dix F; Maps

study and in

h small amo

k density a

mud fluidiza

s (Rego et a

arios for eac

llowed by r

ur modeled 

nsolidated); 

). Less scour

0 cm (loose);

86 

centage. The

210Pbxs activ

n rate (LAR) c

afloor scour 

M as a prox

2 simulated h

15488. Datu

5488 and Da

torm, and w

s F-1 & F-2)

ndicate that t

ounts of ver

and plasticit

ation are the

al. 2011). S

ch of the mo

re-deposition

at Datum 2 

net scour r

r was calcul

; under the c

e most likely

vity and lin

calculations fo

is suggested

xy for seaflo

hurricane im

um 2 and Sit

atum 2 were 

west of Rita, w

). Sediment 

the surficial

ry fine sand

ty were no

erefore unkn

Scour estima

odeled hurric

n of sedime

resulted in 

ranged from

lated during 

consolidated

y scenario is

near sedime

or Site T1548

d by oceanog

oor conditio

mpacts at a s

te 15488 are

east of the 

which passe

samples fro

l seafloor co

d. Although 

ot. The deg

nown and sc

ates were ge

canes. In all 

ents, resultin

maximum s

m 30 cm (lo

Rita, with a

d bed scenari

s that the sea

ent 

88. 

graphic mod

ns at the cu

site in 15.5 

e located bet

eye of Hurr

ed as a categ

m Datum 2 

onsists of co

grain sizes 

gree of sedi

our estimate

enerated for 

cases, maxi

ng in smalle

scour of bet

oose) to 0.0

a maximum 

io there was

afloor 

deling 

urrent 

m of 

tween 

ricane 

gory 3 

were 

oarse, 

were 

iment 

es are 

both 

imum 

er net 

tween 

3 cm 

of 84 

s little 
87 

to no net scour resulting from Rita. Results may vary slightly at Site 15488, but should be 

comparable. 

3.6 SITE NO. 15366, GALVESTON AREA, UNKNOWN MODERN WRECK 

3.6.1 Site Background 

Site 15366 is centered on the east Texas inner continental shelf SSE of the mouth of 

Galveston Bay. The wreck is located in an Anchorage area associated with the safety fairway out 

of Galveston Bay. A reported “Dumping ground, discontinued” is located SE of the site 

(Mississippi River to Galveston, C.&G.S. Coastal Chart #12116A. 1971; Saltus and El Darragi 

2005). 

The site was identified by a geophysical lease survey performed by Cochrane Technologies, 

Inc., in March, April, and May of 2004. The survey used a 50-m by 900-m survey grid with the 

primary survey lines oriented north-south. The geophysical data analysis and resulting report 

were prepared by Marine Archaeologist, Allen R. Saltus, Jr. and Marine Geophysicist, S. Dean 

El Darragi (Saltus and El Darragi 2005). The report reads, “A shipwreck was captured on the 

sonar image . . . . The sonar feature, Side Scan Contact No. 3, was also covered by two additional 

survey lines, Lines 105 and 106, and provided additional data and verification of the target 

location. The vessel measures 66 ft long and 13 ft wide. This sonar feature is associated with a 

magnetic anomaly.” In addition to the shipwreck, the Cochrane report identified Side Scan 

Contact No. 1, approximately 389 m (1,275 ft) SW of the wreck. Sonar target No. 1 measured 

4.88 by 0.6 m (16 x 2 ft) and was associated with four magnetic anomalies, the largest of which 

was an 8,327 nT dipole with a duration of 63 m (207 ft). 

 
An e

Associate

Floyd, an

were iden

may indi

a terminu

simply n

sonar dat

100 m. It

included 

Based

interval w

coverage

fish. Giv

missed b

of the so

location 

appears t

further su

sonar. 

Figure 3.

earlier study

es (Floyd an

nd Geophys

ntified on th

icate that the

us ante que

not identified

ta in the Ch

t is assumed

and no othe

d on the Ch

was 150 m. I

e, but limited

en these par

eneath the n

onar signal. 

of the wrec

to be oriente

upports the 

.6.1. Coch

y had been 

nd Savarino 

sicist Mark S

he sonar data

e shipwreck 

m of 2004. 

d during the

hance report.

d that this re

er indication 

hance naviga

If the range 

d redundant 

rameters, it i

nadir of the to

Coordinate

ck, which is

ed north-sout

possibility t

hrane sonar im

conducted 

1985). The 

Savarino, in

a. The fact t

is modern a

It is also p

 Chance geo

. Appendix 

fers to the r

of the sonar

ation post-pl

had been se

coverage an

is not difficu

ow-fish, or n

es for the w

s in close pr

th, which is 

that the wrec

88 

mage of Site 1

over this a

report prep

ndicates that 

that the wre

and would pr

possible that 

ophysical su

B of the rep

ange setting

r range settin

lots, it was 

et at 100 m, 

nd no cover

ult to imagin

not identified

wreck suppli

roximity to 

the same ori

ck could hav

15366. 

area in 198

pared by Ma

t no sonar ta

eck was not 

rovide a term

t the shipwr

urvey. There

port indicate

g of the sona

ng is mention

determined 

this would h

rage beneath

ne that a sma

d on the son

ied by Coch

a Chance s

ientation as 

ve been mis

85 by John 

arine Archae

argets, debri

observed in

minus post q

reck pre-date

e is limited 

es that the s

ar. No sonar 

ned in the re

that the sur

have provide

h the nadir o

all shipwrec

nar due to no

hrane were 

survey line. 

the Chance 

ssed beneath

E. Chance

eologist Rob

is, or shipw

n the 1985 su

quem of 1985

es 1985 and

discussion o

onar “scale”

data sample

eport. 

rvey line sp

ed 100% sea

of the sonar 

ck may have 

ise or attenu

used to plo

Since the w

survey lines

h the nadir o

e and 

bert J. 

wrecks 

urvey 

5 and 

d was 

of the 

” was 

e was 

acing 

afloor 

towbeen 

uation 

ot the 

wreck 

s, this 

of the 
The C

almost d

survey li

nearly 15

Altho

was iden

and Coch

The 

anomalie

Contact N

The C

type of m

not made

survey li

the magn

the fact t

supports 

not ident

event pre

sometime

Chance surv

directly over 

ine; howeve

50 m (492 ft)

ough in 200

ntified more 

hrane survey

1985 Chanc

es (247 and 

No. 1 was ap

Chance surv

magnetomete

e available f

ne cannot b

netometer wa

that the shipw

a deposition

tified due to

e-dates 1985

e after 1985

F

vey did not i

the shipwre

er, the chara

) east of the 

4 Cochrane 

than 120 m

y lines in rela

ce survey id

248) identi

pparently ide

vey used a G

er used durin

for review). 

e attributed 

as malfuncti

wreck had n

n date post-1

o faulty data 

, but post-de

. 

Figure 3.6.2. 

identify any 

eck. A smal

acteristics of

wreck, sugg

identified f

m (~400 ft) f

ation to the s

dentified a m

ified from th

entified on th

Geometrics 8

ng the Coch

The lack of

to differenc

ioning, incor

not been iden

1985, there i

acquisition

epositional p

Map show

lines and 

reported sh

89 

magnetic a

ll magnetic 

f the anoma

gest that it is 

four anomal

from the wre

shipwreck an

magnetic ano

he Cochrane

heir sonar da

801/03 proto

hrane survey

f significant m

ces in sensor

rrectly recor

ntified in 19

s still a remo

. There is al

processes int

wing Chance

magnetic a

hipwreck coor

anomalies on

anomaly wa

aly and the f

 unlikely tha

ies associate

eck site. Fig

nd associate

omaly in clo

e survey bu

ata. 

on procession

y is unknown

magnetic an

r technology

rded, or inco

85 by either

ote possibili

lso a slight 

troduced the

e and Cochr

anomalies in 

rdinates. 

n the survey

as identified

fact that the

at these are r

ed with the 

gure 3.6.2 sh

d magnetic a

ose associati

ut no eviden

n marine ma

n (the full s

nomalies on 

y; however, i

orrectly inter

r sonar or m

ity that the w

possibility t

e wreck to its

rane survey 

relation to 

y line that cr

d on the adj

e survey line

related. 

shipwreck, 

hows the Ch

anomalies. 

ion with the

nce of Side 

agnetometer

urvey report

Chance’s cl

it is possible

rpreted. Alth

magnetometer

wreck was si

that the wrec

s present loc

rosses 

acent 

e lies 

none 

hance 

e two 

Scan 

r. The 

t was 

losest 

e that 

hough 

r data 

imply 

cking 

cation 
90 

A minimal amount of infrastructure reportedly exists in the vicinity of Site 15366. An 8” 

active pipeline is reportedly located approximately 780 m (2,560 ft) west of the shipwreck and a 

P&A Well is located approximately 670 m (2,200 ft) to the SW. 

3.6.2 Geophysical 

Geophysical data acquisition was conducted at Site 15366 on March 20, 2010 and on August 

17, 18, and 19, 2010, aboard the M/V Nikola. A CODA 3-D Echoscope was used during the 

March operations, but weather conditions negated the ability to acquire suitable data with the 

remaining sensors at this time. Side scan sonar, sub-bottom profiler, magnetometer, multibeam, 

and single beam bathymetry were acquired at the site during the August field operations (see 

Chapter 2 Methodology and Appendix A for a full description of geophysical sensor suite and 

navigation parameters). 

The survey grid extended out in a 300-m (1,000-ft) radius centered on the wreck site. Two 

separate survey grids were run over the site, both containing survey lines paralleling the wreck 

site. A total of 12 survey lines was run using 100 kHz sonar data and spaced 100 and 200 m apart 

for reconnaissance and to maximize sonar coverage. A total of 23 survey lines was run directly 

over the wreck site using 410 kHz sonar frequency and spaced 30 m apart for increased sonar 

resolution, multibeam coverage, sub-bottom profiling, and magnetic contouring (see Navigation 

Post-Plot Map Appendix B; Figure B-6). An additional two survey lines were run over the 

reported location of Cochrane’s Sonar Contact No. 1. 

The seafloor throughout the survey area is a constant 18 m (59 ft). The only identifiable 

bathymetric irregularities can be directly attributed to the wreck site (Figure 3.6.3). A scour zone 

surrounds the wreck site, with a significant expression extending SW of the site. Water depths 

within the deepest portion of scour, just SW of the wreck, reach a maximum of 18.8 m (62 ft). 

The multibeam illustrates that the wreck is upside down with the bow facing almost directly 

south. The wreck sits approximately 1.8–3.4 m (6–11 ft) above the surrounding seafloor. 

Sonar data indicates that the wreck is oriented along a 180-degree axis, with the bow directly 

to the south. The 100-kHz survey grid clearly imaged the wreck site in its entirety, but did not 

have sufficient resolution to detail specific components of the vessel or changes in seafloor 

texture. The 410-kHz survey grid clearly outlined the wreck and provided details of some 

seafloor mottling and possible scour zones surrounding the wreck. Debris associated with the 

wreck site is identified off of the eastern side, just fore of midships. Trawl scars were also 

observed on the seafloor within the survey grid. Figure 3.6.4 shows a sonar mosaic that was 

created using the low frequency and high frequency sonar lines that run parallel to the wreck site. 

An inset shows a composite image of the wreck. Sonar data did not produce high quality imagery 

over the wreck site, likely due to the relatively small size of the site and the difficulty in acoustic 

imaging of the wreck due to the angle of the vessel’s hull. Lines 201 and 202 were run in an 

attempt to investigate a reported sonar target and associated magnetic anomalies located SW of 

the shipwreck but did not result in an identified source of the target or anomalies. 

 
Figure 3.6.3. Bathymetry surround

91 

ing site 15366, in 2-decimeter intervals. 
92 

Figure 3.6.4. 12

site

0 and 410 kHz s

 produced from 

ide scan sonar m

410 kHz data. 

osaic of Site 15366. Inset shows a composite image o
In ad

employed

other aco

3.6.5). 

Figur

 

The 

upside d

appears t

width is 

although 

Sub-b

attenuate

are mode

some int

deposits 

of poorl

surround

Some m

stratigrap

is eviden

ddition to th

d at this sit

oustic senso

re 3.6.5. Ech

combined s

own on the 

to be the ste

approximat

an unusuall

bottom profi

ed by an irre

erately to hig

ternal stratif

approximate

ly resolved,

ding the wrec

minor infill m

phic profile 

nt (Figure 3.6

he multibeam

e during the

ors and prov

hoscope still i

sonar, multib

seafloor. T

ern of the ve

tely 7 m (2

ly large runn

filer data pen

egular gas fro

ghly reflectiv

fication. Thi

ely 3.7 m (12

 weakly to

ck site were

may be pre

(Survey Lin

6.6). 

m and side 

e March op

vided additi

mage of Site 

beam, and 

The wreck si

essel, and 2

23 ft). The 

ning gear ass

netrated to a

ont. Surficia

ve, and repre

is unit is fo

2 ft) thick. T

o moderately

e broad and 

sent within 

ne 305) close

93 

scan sonar

erations. Th

onal imager

15366, from 

echoscope d

ite measures

4.7 m (81 ft

stern of the

semblage app

an average d

al sediments 

esent genera

ollowed by 

This zone in 

y reflective

shallow and

the closest

e to the wrec

r data, the C

he resulting 

ry of the ve

CODA UIS s

data demon

s approxima

ft) to the end

e wreck app

pears to be p

depth of 14.

are approxi

ally acoustica

a zone of p

turn overlies

e, parallel l

d do not exte

t zones. Th

ck site wher

CODA 3-D

imagery co

essel’s runn

software. 

nstrate that t

ately 23.5 m

d of the pro

pears to be 

present. 

.4 m (47 ft)

imately 3 m 

ally amorpho

poorly resol

s approxima

layered stra

end very far

e following

re the typica

D Echoscope

orrelated wit

ning gear (F

the shipwre

m (77 ft) to 

opeller. Mea

partially bu

) before data

(10 ft) thick

ous deposits

lved, unstra

ately 7.6 m (2

ata. Scour z

r from the ve

g figure sho

al scour sequ

e was 

th the 

Figure 

eck is 

what 

sured 

uried, 

a was 

k and 

s with 

atified 

25 ft) 

zones 

essel. 

ows a 

uence 
F

Magn

magnetic

durations

not direc

Lines 20

magnetic

either of

approxim

Anomaly

estimated

4 from th

the most 

As discu

anomaly,

Figure 3.6.6. 

netometer d

c anomalies 

s between 14

ctly correlate

1 and 202 w

c anomalies 

f these lines

mately 30 m 

y nos. 247 a

d 30 m (98 f

he 2010 data

significant a

ussed in the

, and Sonar T

Sub-bottom

of the wrec

150-m incre

data very cl

attributed 

45.4 m and 

e to the wre

were run in 

located SW

s; however, 

(98 ft) north

and 248, wh

ft) NW of an

a was a 243 n

anomaly ide

e previous s

Target No. 1

m profile of su

ck site, with 

ements. Horiz

learly highli

to the wrec

196 m (477–

ck. Most of

an attempt t

W of the ship

Anomaly n

h of Line 202

hich were id

n anomaly id

nT negative 

ntified in the

sonar text, n

1 from the C

94 

rvey Line 305

a heading of

zontal scale li

ighted the 

ck measure

–642 ft). On

f these anom

to investigat

pwreck. No 

no. 4 was id

2. Anomaly n

dentified from

dentified from

monopole w

e survey grid

no targets w

Cochrane surv

5, Site 15366

f 360 degree

ines in 2-ms i

wreck site

d between 

nly six anom

malies were r

te a reported

magnetic a

dentified at 

no. 4 from th

m the 2004 

m the 1985 C

with a duratio

d not directly

were identif

vey was not 

. Line 305 is 

es. Vertical s

intervals. 

(Figure 3.6

2,687 and 

malies were 

relatively sm

d sonar targe

anomalies w

the beginn

he 2010 data

Cochrane s

Chance surv

on of 48 m (

y attributed 

fied in asso

re-located. 

located west 

cale lines in 

6.7). The la

28,115 nT

recorded tha

mall and isol

et and assoc

were identifie

ning of Line

a falls in bet

survey, and 

vey. Anomal

(158 ft). This

to the shipw

ciation with

argest 

with 

at did 

lated. 

ciated 

ed on 

e 101 

tween 

is an 

ly no. 

s was 

wreck. 

h this 
Figure 3.6.7. Magnetic contours in 10-nT

95 

 intervals at Site 15366. 
3.6.3 Div

Divin

 A

 T

 V

The M

wreck lo

and the s

as is wha

This 

oriented 

Immedia

runs mos

47 cm ta

beam.” L

ving 

ng operation

Average reco

Total bottom 

Visibility: 0–

Mesotech S

cation and p

stern of the v

at appears to 

Figure 3.6.8

site was ver

with its bow

ately aft of th

st of the leng

ll, 16 cm wi

Longitudinal

s on Site 153

orded water d

time: 6 hour

–0.3 m (0–1 f

ector Scann

provide supp

vessel (3.6.8

be a shroud

8. Mesotech

rified by div

w facing sout

he nozzle an

gth of the hul

ide at its bas

l protrusion

366 took pla

depth on site

rs. Average 

ft). 

ning Sonar w

plemental im

8). The rudde

ded propeller

h scan highlig

vers as a me

th. The sing

nd propeller 

ll and extend

se and 3 cm 

s, likely for

96 

ace on Augu

e: 18.25 m (6

dive time: 2

was deployed

magery. The s

er is evident

r. 

ghting the ster

etal-hulled w

le four-blade

assembly di

ds across the

wide along 

r engine co

ust 22 and 23

60 ft). 

22.5 minutes

d before div

sector scans 

t, protruding

rn at Site 153

wreck lying 

ed propeller

ivers noted a

e nozzle to th

its length, an

oling, run a

3, 2010, from

. 

ving operati

detailed the

g from the st

366. Oriented 

upside down

r is shrouded

a single met

he rudder. T

nd is shaped

along the le

m the M/V Sp

ons to verif

e mottled sea

tern of the ve

 north up. 

n on the sea

d within a no

tal rudder. A

The keel mea

d similar to a

ength of the

pree. 

fy the 

afloor 

essel, 

afloor 

ozzle. 

A keel 

asures 

an “Ie hull 
(Figure 3

and diver

3.6.4 Sit

3.6.4.1 W

Two 

of 18 m

measurem

3.8). Sali

3.6.9). The v

rs discovered

Figure 3

te Environ

Water Sam

8-ounce wa

m (59 ft) B

ments were 

inity was me

Ty

Sa

Sa

pH

pH

DO

DO

vessel exhibi

d distinctive

3.6.9. Lon

2 c

ment 

mpling 

ater samples 

BSL. Water 

taken for pH

easured in pa

Wa

ype 

alinity (ppT) 

alinity (ppT) 

H

H

O (mg/L) 

O (mg/L) 

its black bot

e marks of tw

ngitudinal pro

cm intervals. 

were collec

temperatur

H, salinity, 

arts per thou

T

ater Sample 

97 

ttom paint pr

wo diagonal 

otrusion on h

cted from Sit

e at the tim

and dissolv

usand. Dissol

Table 3.8 

 

Results for 

Sample 

1 

2 

1 

2 

1 

2 

reserved und

white stripe

ull of site 153

te 15366 on

me of acqu

ved oxygen c

lved oxygen

Site 15366

Av

33.

33.

8.0

8.1

7.4

7.4

der a layer o

s on the port

366. 10 cm s

n August 23,

uisition was

content and 

n (DO) is rep

verage 

.2 

.1 

097 

6 

455 

48 

of marine gro

t bow. 

scale in 

 2010, at a d

s 88° F. R

averaged (T

ported in mg/

owth, 

depth 

Repeat 

Table 

/L. 
98 

3.6.4.2 Core Lithology and Grain Size 

Two cores were attempted at Site 15366. On August 22, 2010, the first core was attempted 

approximately 8 m (25 ft) from the wreck site, directly below the descent line; however, divers 

encountered well-consolidated sediments that offered significant resistance to coring. Less than 5 

cm (2 in) were captured in the core barrel. A second core was attempted on August 23, 2010 

approximately 1.8 m (5 ft 9 in) off of the wreck site. Core no. 2 resulted in a 52 cm stratigraphic 

sample of sediments at the wreck site. 

Samples were collected from each of five units observed within the core lithology from Core 

no. 2 and measured for grain size. Median and graphic mean calculations demonstrate gradual 

fining downcore from samples 1 through 3; sample 4 is a coarser fraction and represents a 

possible disturbance event or storm deposit layer. Shear strength measurements were not 

obtained for this site, due to disturbance from sampling for radioisotopes, which did not leave 

sufficient material for the penetrometer or the mini-torvane to measure in the 2” diameter core 

sleeve. 

3.6.4.3 Radioisotope Analysis 

Site 15366 shows a post-disturbance linear accumulation rate (LAR) of 0.15 cm/yr, overlying 

a disturbance event noted downcore between 3.5 and 12.7 cm. Based on the sampling interval, it 

was determined that the disturbance, which could have resulted from an extreme storm event or 

ground disturbing activity such as the wrecking event, occurred 23–85 years before the 2010 

core collection. Pre-disturbance sediments show variable activity downcore. If the low activity 

outlier at 38 cm depth (Fig. 3.6.6) is the result of a coarse-grained interval it could be classified 

as ignored decay, and the remaining points would indicate a very high LAR (>1 cm/y). This 

would suggest a significant decrease in accumulation post-dating the disturbance event. 
3.6.4.4 O

The p

conducte

shipwrec

water wi

Datum 2

category 

directly u

the site (N

Based

and smal

density a

fluidizati

(Rego et 

for each 

by re-dep

at Datum

scour ran

calculate

consolida

at Site 15

Fi

Oceanogra

potential imp

ed at three d

ck site (Rego

ith cohesive

2 is located 

2 storms; da

under the ey

NHC NOAA

d on a separ

ll amounts o

and plasticit

ion are ther

al. 2011). S

of the mode

position of s

m 2 resulted 

nged from 3

d for Rita, w

ated bed sce

5366, but sho

igure 3.6.10. 

aphic Analy

pact of hurri

datum sites 

o et al. 2011

-clay domin

between th

atum 2 was c

ye of Hurrica

A). 

rate study, gr

of very fine 

ty were not.

refore unkno

cour estimat

led hurrican

ediments, re

in maximum

0 cm (loose

with a maxim

nario, there 

ould be com

Downcore 

accumulati

T15366.

ysis 

canes on sea

in the GOM

1). Datum 2

nated sedime

he eyes of H

closer to the

ane Ike, whi

rain sizes at 

sand. Altho

. The degre

own and sco

tes were gen

nes. In all cas

esulting in sm

m scour of b

e) to 0.03 cm

mum of 84 cm

was little to

mparable. 

99 

210Pbxs act

on rate (LA

afloor scour 

M as a prox

2 simulated h

ents, similar

Hurricanes R

eye of Hurr

ich was a C

Datum 2 in

ugh grain si

e of sedime

our estimate

nerated for b

ses, maximu

maller net sc

etween 1.0 m

m (consolida

m (loose) an

 no net scou

tivity and lin

AR) calculat

is suggested

xy for seaflo

hurricane im

r to the con

Rita and Ik

ricane Ike. S

Category 2 hu

clude coarse

izes were m

ent consolid

es are based

both loose an

um hurricane

cour estimate

m (loose) an

ated) (Rego 

nd a net scou

ur resulting f

near sedime

tions for S

d by oceanog

oor conditio

mpacts at a s

nditions foun

ke, both of 

Site 15366 w

urricane wh

e, medium, a

measured for 

dation and p

d solely on 

nd consolida

e-induced sc

es. Ike-relate

nd 0.2 cm (c

et al. 2011)

ur of 10 cm (

from Rita. R

ent 

ite 

graphic mod

ns at the cu

site in 15.5 

nd at Site 15

which passe

was located al

en it passed

and very fine

Site 15366,

potential for 

flow condi

ated bed scen

our was foll

ed scour mo

consolidated

). Less scour

(loose); unde

Results likely

deling 

urrent 

m of 

5366. 

ed as 

lmost 

d over 

e silt, 

, bulk 

mud 

itions 

narios 

owed 

deled 

d); net 

r was 

er the 

y vary 
100 

3.7 SITE NO. 389, SOUTH TIMBALIER AREA, PROBABLE J.A. BISSO

3.7.1. Site Background 

Site number 389 is located in the South Timbalier Federal Lease Area south of Timbalier 

Island, in Terrebonne Parish, Louisiana. This wreck was not one of the six original contract sites, 

but it was added to the contract as an amendment during diving operations in August 2010. 

Site 389 was originally discovered during a pipeline pre-lay survey performed by 

Oceaneering International, Inc., for Transcontinental Gas Pipe Line Company in 1991 

(Marmaduke 1991; Figure 3.7.1). Only the archaeological section of the report was available for 

review and no maps or tables of sonar or magnetic anomalies were enclosed. The archaeological 

assessment was prepared by William Marmaduke of Northland Research, Inc. Latitude-longitude 

coordinates were provided for the shipwreck in the text of the archaeological assessment. The 

reported coordinates plot approximately 1,585 ft west of Site 389 as identified in this study. 

According to the text of the report, all coordinates were acquired in State Plane, Louisiana South. 

It is possible that the coordinate was converted improperly or mistyped when converting to 

latitude/longitude which could account for the discrepancy along the x axis only. 

Marmaduke describes the target as: 

. . . side-scan sonar depicts an elongated, lozenge-shaped object on the sea 

floor . . . , measuring 29 meters (95 ft) long and 7.6 meters (25 ft) wide.” . . . 

“The wreck appears to consist of a hull and central superstructure, the whole 

wreck possible [sic] canted to one side. Its side-scan image suggests that it is 

largely intact on the sea floor, and the magnetometer recorded only single 

anomalies on the lines that passed close enough to the wreck for detection. The 

sizes and durations of these anomalies suggest steel construction. A dark, 

amorphous, smaller image is visible on the side-scan records just beyond the far 

end of the main image, partially obscured by the acoustic shadow cast by the 

superstructure. This may represent a piece of attached hull. (Marmaduke 1991:8–

9) 

According to historical records, the closest wreck to the area was reportedly the towing 

vessel J.E. Bisso1

. Marmaduke (1991) stated, “The overall length and width of the object imaged 

on side-scan sonar is appropriate for this type of vessel, although there is no precise data on the 

J.E. Bisso itself available for examination at this time.” Based on correspondence exchanged 

between Marmaduke and MMS Archaeologist Rik Anuskiewicz, it appears that there was, at one 

time, some speculation that the wreck might be U-166, a German U-boat lost in 1942. The 

BOEM shipwreck database reads, in part, “The German sub, U-166 once thought to have sunk in 

the vicinity in WWII and Northland report suggests object may be sub. In April, 2001 remains of 

U-166 [were] located in Mississippi Canyon Area, so this object can not [sic] be that sub.” The 

 

1 It appears that “J.A. Bisso” was misspelled as “J.E. Bisso” in the NIMA database and, at one time, in the 

MMS database. MVUS records clearly use “J.A. Bisso” for the wreck that reportedly sank nearby. 
Northlan

the ident

data does

avoid the

activities

Befor

entire lea

Survey A

Neuraute

identified

identified

were 200

height w

review. 

unidentif

location.”

anomalie

nd report cle

ification of J

s not sugges

e position o

s.” 

Figure

re the 1991

ase on behalf

Archaeologis

er then of R

d, but an u

d that corres

0 and 365 nT

was provided

The archae

fied target a

” The concl

es may be ca

arly states, h

J.E. Bisso to

st the presen

f the [sic] J

e 3.7.1. 100

Dir

 survey, in 

f of CNG Pr

st Jack Huds

Racal-Decca 

unidentified 

spond with 

T, respective

d. Neither th

eological an

appears . . . 

usions secti

aused by an 

however, tha

o the wreck, 

nce of a ship

J.E. Bisso by

0 kHz side 

rection 320° N

1981 Racal

roducing Com

on of Cultur

Survey, Inc

sonar targ

the verified 

ely. No info

he original 

nalysis sect

in associati

on of the re

unknown oi

101 

at the vessel

stating, “Ex

pwreck.” an

y at least 30

scan sonar

NNW (Marmad

l-Decca Sur

mpany. The 

ral Resource

. (Hudson a

get and two

position of

rmation on 

data nor an

tion written

ion with the

port implies

il and gas w

l is too shor

xcept for the

nd “Northlan

00 meters (9

r image set 

duke 1991). 

rvey, Inc., c

 resulting re

e Services, In

and Neuraute

o associated

f Site 389. T

anomaly du

n image of 

n by Hudso

e large mag

s that the tar

well. It also s

rt to be U-1

e Wreck of th

nd recomme

984 ft) in al

at 75-m ra

conducted a 

eport was pre

nc. and Geop

er 1981). N

d magnetic 

The two ma

uration, signa

the target w

on states, 

gnetic anoma

rget and ass

states, “How

66 and attrib

he J.E. Bisso

ends that Tra

l its constru

ange. 

survey ove

epared by M

physicist Th

No shipwreck

anomalies 

agnetic anom

ature, or tow

was availabl

“A distinct

alies at the 

ociated mag

wever, it wou

buted 

o, the 

ansco 

uction 

er the 

Marine 

homas 

k was 

were 

malies 

w-fish 

le for 

t but 

same 

gnetic 

uld be 
102 

advisable to avoid the immediate vicinities of these locations unless or until they can be shown to 

be other than cultural resource features.” It appears certain that this target and the associated 

magnetic anomalies represented the same shipwreck as Site 389 but poor data quality precluded 

the ability to correctly identify it. 

In August 2001, as part of an MMS-funded study, Pearson et al. (2003:5.18-5.19) attempted 

to investigate Site 389. They surveyed a 518 m by 300 m (1,700 by 1,000 ft) grid centered 27 m 

(90 ft) from the coordinates provided in the 1991 survey report. As discussed above, the 

coordinates from the 1991 report plot approximately 483 m (1,585 ft) from the present location 

of Site 389; therefore, the survey grid used by Pearson et al. was not centered over the wreck 

site, and was unable to relocate the target. 

In 2005, Tesla Offshore, LLC, conducted a geophysical survey for Millennium Offshore 

Group, Inc., and identified a shipwreck at the current location for Site 389 (Floyd and Clemmons 

2005a and 2005b). The resulting reports (one site specific report (2005b) and one pipeline 

assessment (2005a)) prepared by Marine Archaeologist Robert J. Floyd and Marine Geologist 

Rick Clemmons indicated that the wreck measured 25.9 m (85 ft) by 9.1 m (30 ft) and protruded 

3.1 m (10 ft) above the seafloor. The wreck was recommended for avoidance by 152.4 m (500 

ft). The Tesla sonar imagery identified an ancillary object off the port side of the vessel (Figure 

3.7.2). 

An MMS-funded contract performed by PBS&J in 2007 acquired sonar imagery over Site 

389 as one of three ancillary sites added to their contract while fieldwork was in progress. The 

PBS&J report indicates that the site was suspected to be the wreck of J.A. Bisso based on the 

MMS (now BOEM) database. PBS&J acquired sonar imagery of the wreck but did not dive on 

the site (Figure 3.7.3). The report focused only on the potential impacts of Hurricane Katrina to 

the wreck site, based on a comparison of the 2005 Tesla sonar imagery and the 2007 PBS&J 

imagery (Gearhart et al. 2011:129-130). No dimensions for the wreck are given in the PBS&J 

report, and no evidence of the ancillary object identified from the 2005 data was identified on the 

2007 sonar imagery. 
Figure 3.7.

Figu

2. 410 k

m ran

re 3.7.3. 500

set

20

103 

Hz side scan

ge (Floyd and

0 kHz side s

t at 75-m rang

11). 

n sonar image

d Clemmons 

scan sonar im

ge (Gearhart 

e set at 75-

2005). 

mage 

et al. 
The c

approxim

abandone

3.7.2 Div

Site 3

August o

Mesotech

Divin

 A

 T

 V

1

Inform

preserved

superstru

port hole

closest oil a

mately 866 m

ed pipeline a

ving 

389 was add

of 2010. Th

h was deploy

ng operation

Average reco

Total bottom 

Visibility: 3–

.5 ft) on seab

Figure 3.7

mation gath

d, and man

ucture have d

es and unid

and gas infra

m (2,840 ft)

are located a

ded to the sco

he M/V Spr

yed to verify

s commence

orded water d

time on site

–6 m (10–20 

bed. 

7.4. Sector 

hered during

ny aspects o

deteriorated 

dentified tan

astructure to

) north of th

approximatel

ope of work 

ree arrived 

y the site loc

ed the morni

depth on bot

e: 17.82 hour

ft) on wreck

scanning son

g diving op

of its hull a

or collapsed

nks in the s

104 

o the shipwr

he wreck. T

ly 975 m (3,2

for this stud

on site the

ation and or

ing of Augus

ttom: 18.3 m

rs. Average d

k, 0.3–1 m (1

nar image of S

perations in

are still in 

d, revealing

stern of the 

reck is a 6”

The No. 6 c

200 ft) to the

dy during div

e evening o

rientation (Fi

st 14, 2010.

m (60 ft). 

dive time: 33

1–3 ft) towar

Site 389. 

ndicated that

fairly good

g interior stru

vessel (Fig

” abandoned

caisson and 

e NNE. 

ving operati

f August 1

igure 3.7.4).

3.41 minute

rds port stern

t the hull s

d condition. 

uctures and 

gure 3.7.5). 

d pipeline lo

an associate

ions perform

3, 2010 and

. 

s. 

n, 0–0.5 m (

structure is 

Portions o

features, su

A baseline

ocated 

ed 4” 

med in 

d the 

(0–

well 

of the 

uch as 

e was 
establish

measured

recorded 

upright c

superstru

related to

vessel is 

of the po

identified

Figu

3.7.3 Ge

Geop

Nikola. T

Navigatio

magnetom

and Appe

paramete

Wate

zones are

that the w

ed running 

d drawings, 

on this ves

capstans (one

ucture that a

o the vessel

buried unde

ort and starb

d from the 20

ure 3.7.5. P

eophysical

physical data

The 30 x 10

on Post-Plo

meter, multi

endix A for 

ers). 

er depths are

e evident aro

wreck is list

from bow t

video, and

ssel included

e on the bow

llowed a rec

l’s steering 

er seafloor se

board sides 

005 geophys

Porthole restin

l 

a was acquir

00 m grid w

ot Map App

ibeam and s

complete se

e 18.4–21 m

ound the shi

ing towards 

to stern, and

d still image

d a double-h

w and one off

construction 

system. App

ediments. Ar

of the vesse

sical data, bu

ng on deck. (P

red at Site 3

was oriented

pendix B; F

ingle beam 

ensor specifi

m throughou

ipwreck exte

the port sid

105 

d divers foc

es. Other si

headed, long

ffset to the po

of cabin sp

proximately 

rchaeologist

el, in an eff

ut encounter

Photograph C

389 on Febr

d parallel an

Figure B-7).

bathymetry 

ications, surv

ut the surve

ending to th

de (Figure 3.

cused on ga

ignificant di

gitudinally-o

ort stern), th

pace, and a d

8 m (25 ft

ts conducted

fort to ident

red no additi

Courtesy of Co

ruary 13 and

nd perpendi

 Side scan 

were acquir

rvey vessel c

ey grid (Figu

he NW. The 

.7.7). A sign

athering data

iagnostic fe

oriented bitt 

he lower pres

deck-mounte

t) of the aft 

d extensive c

tify addition

ional debris o

olm O’Reilly.)

d 14, 2011, 

icular to the

sonar, sub

red at the sit

configuration

ure 3.7.6). S

multibeam 

nificant porti

a in the for

eatures that 

on the bow

served remai

ed stern qua

t port side o

circle searche

nal superstru

or structure.

)

aboard the 

e wreck site

-bottom pro

te (see Chap

n, and navig

Significant 

clearly illust

ion of the bo

rm of 

were 

w, two 

ins of 

adrant 

of the 

es off 

ucture 

M/V 

e (see 

ofiler, 

pter 2 

gation 

scour 

trates 

ow is 
exposed 

the water

due to a lar

r column tha

Figure 3.7.6. 

ge scour zon

n the stern o

Bathymetr

ne, highligh

of the vessel

ry surrounding

106 

hting an appa

. The starbo

g Site 389 in 

rent raked 

ard stern is f

2-decimeter i

bow that wo

lush with th

intervals. 

ould sit high

he seafloor. 

er in 
Figure 3.7.7. 3-D multibeam renderings o

107 

f Site 389. 
108 

Sonar indicates that the wreck site is oriented with the bow facing 30 degrees NNE. The 100-

kHz survey grid clearly imaged the wreck, but did not have sufficient resolution to define 

changes in seafloor texture attributed to scour. The 410-kHz survey grid clearly outlined the 

wreck as well as variation in sediment grain size. As noted previously, the wreck site is right side 

up, but listing significantly towards the port. The effect is that the sonar data obtained on the 

eastern side of the wreck casts a significant acoustic shadow obscuring all deck components. 

Figure 3.7.8 shows a sonar mosaic created utilizing only the survey lines that parallel the wreck 

site. It includes the 410-kHz sonar data overlaying the 100 kHz data. An inset shows the wreck 

from Survey Line 204. No evidence of the ancillary objects identified on the 2000 or 2005 sonar 

data sets was observed. 

The combined geophysical data indicates that the vessel measures 32 m (105 ft) by 7 m (23 

ft). The wreck lists to port, with the starboard side projecting farther into the water column. The 

highest point of the wreck sits an estimated 3 m (10 ft) above the ambient seabed at the bow, 

approximately 1.5 m (5 ft) at midships, and is flush with the seabed at the stern. 

Sub-bottom profiler data indicates a consistent stratigraphic profile throughout the survey 

area. A strongly reflective seafloor is followed by approximately 1.8 m (6 ft) of parallel to subparallel layered, but somewhat discontinuous moderately reflective beds. A fairly strong reflector 

that parallels the seabed is evident and followed by another sporadic reflector beneath this 

horizon before acoustic attenuation sets in. Another strongly reflective horizon is evident at 

approximately 7.6 m (25 ft) BSL. The scour zones surrounding the wreck site are the only 

significant irregularity in the sub-bottom data set; however, no apparent infill of relict scour was 

observed. Instead, the subseafloor reflectors appear to be truncated by the scour depressions. 

Figure 3.7.9 shows a stratigraphic profile (Survey Line 305) close to the wreck site where the 

typical scour sequence is evident as well as a typical profile further away from the wreck (Survey 

Line 209) where no scour was observed. 

Magnetometer data produced a number of very high intensity, long duration anomalies 

directly over and adjacent to the hull of the shipwreck (Figure 3.7.10; Appendix C). A total of 15 

magnetic anomalies were recorded which could not be directly attributed to the main hull of the 

wreck. Fairly significant anomaly clusters were identified NNE and SSW of the wreck. The 

northern cluster consisted of Anomalies no. 16, 19, and 20. All of these anomalies had fairly 

short durations; Anomaly no. 20, a 55 nT, 20-m (66-ft) negative monopole, had the greatest 

intensity. The southern cluster was comprised of Anomalies no. 14, 17, 22, and 28. The largest of 

these in intensity was no. 14, a 22 nT, 27-m (89-ft) positive monopole. These anomaly clusters 

may be related to smaller quantities of debris associated with the wrecking event that may be 

buried in the surficial sediments surrounding the hull of the vessel. 
109 

Figure 3.7.8. 120 and 410 kHz side scan sonar mosaic of Site 389. Inset at 410 kHz. 
110 

Figure 3.7.9. Shallow stra

Seafloor ren

tigraphy cube a

dering based on

t intersection of 

 multibeam bathy

sub-bottom profi

metry data. 

ler Lines 305 and 209. Vertical scale 
Figure 3.7.10. Magnetic contours in 5-n

111 

T intervals at Site 389. 
112 

3.7.4 Site Environment 

3.7.4.1 Water Sampling 

One 8-ounce water sample was collected from Site 389 on August 14, 2010 at a depth of 20 

m (66 ft) BSL. Water temperature at the time of acquisition was 86° F. Repeat measurements 

were taken for pH, salinity, and dissolved oxygen content and averaged (Table 3.9). Salinity was 

measured in parts per thousand. Dissolved oxygen (DO) is reported in mg/L. 

Table 3.9 

 

Water Sample Results for Site 389 

Type Average 

Salinity (ppT) 31.4 

pH 7.496 

Dissolved oxygen (mg/L) 7.017 

3.7.4.2 Core Lithology and Grain Size 

Two cores were collected from Site 389 on August 14, 2010. The first was collected from the 

north side of the vessel, approximately 8 m (25 ft) from the bow of the vessel at a depth of 20 m 

(66 ft). Visibility at this location was extremely limited and diminished as coring activities 

disturbed near-surface sediments. Core no. 1 resulted in a maximum of 60 cm of sediment. A 

second core was collected from the SE side of the vessel just off of the starboard stern at a depth 

of 20 m (66 ft). Core no. 2 resulted in a 47 cm stratigraphic sample. 

Core no. 2 was positioned closer to the hull than Core no. 1 and was therefore chosen for 

grain size and radioisotope sampling. Core no. 1 was used primarily for correlation of nearseafloor stratigraphy and shear strength measurements. Samples were collected from each of the 

three units observed within Core no. 2 and measured for grain size. Median and graphic mean 

calculations demonstrate that sediments from Site 389 become increasingly fine from sample 1 

to sample 2, transitioning from fine sand to fine silt. Sample three, however, represents a coarser 

fraction of very fine sand, possibly representing a storm deposit or other intrusion. 

Subsequent salinity, pH, and DO measurements were measured for pore water trapped in the 

sediment core, resulting in higher salinity and lower pH and DO values. Average pore water 

salinity was 34.267 ppT; average pore water pH was 7.31; average DO was 5.1 mg/L. Sediment 

pH values were obtained for sediments closest to the wreck site, captured within Core no. 2. The 

pH values were measured downcore and were generally higher than all water sample 

measurements, ranging from 8.12 to 7.73 between the seafloor and 60 cm below surface. 

3.7.4.3 Radioisotope Analysis 

Sediment samples from Site 389 demonstrate a post-disturbance linear accumulation rate 

(LAR) of 0.08 cm/yr. Based on the sampling interval, a disturbance layer was identified within 

the sediment column at a depth of 4.0 to 14.2 cm. The disturbance was most likely caused by 
either the

core coll

data sugg

3.7.4.4 O

The p

conducte

current sh

of water 

a site in 

small am

Site 389,

sediment

resulted i

from 21 

modeled 

(consolid

Less sco

(loose) a

no net sc

e wrecking e

lection. Pregest this is li

Figure 

Oceanogra

potential imp

ed at separate

hipwreck sit

with cohesiv

15.5 m of w

mounts of ver

, which is be

t grain sizes 

in maximum

cm (loose) 

at Datum 

dated); net sc

ur was calcu

and a net sco

cour resultin

event or an e

-disturbance 

ikely the pro

3.7.11. Dow

rate

aphic Analy

pact of hurri

e datum site

te (Rego et a

ve-clay dom

water with a

ry fine sand

etween the t

between the

m scour of be

to 0.03 cm 

2 resulted 

cour ranged 

ulated to ha

our of 10 cm

ng from Rit

extreme storm

sediments 

oduct of obse

wncore 210Pb

e (LAR) calcu

ysis 

canes on sea

s in the GOM

al. 2011). Da

minated sedim

a seafloor co

. Both datum

two depths r

e datums and

etween 1.5 m

(consolidat

in maximu

from 30 cm 

ave occurred

m (loose); un

a. Modeled 

113 

m event, and

show no do

erved change

bxs activity a

ulations for Si

afloor scour 

M that serve

atum 1 simu

ments, while

onsisting of 

ms are used 

represented b

d Site 389. S

m (loose) an

ed) (Rego e

um scour o

(loose) to 0

d during Hur

nder the con

estimates fr

d occurred 5

owncore dec

es in coarse 

nd linear sed

te T389.

is suggested

e as a proxy 

ulated hurric

e Datum 2 si

coarse, med

in this comp

by the datum

Storm-relate

nd 3 cm (con

et al. 2011).

of between 

.03 cm (con

rricane Rita,

solidated be

from the dat

50–178 years

cay; porosity

sediment fre

diment accum

d by oceanog

for seafloor 

cane impacts

mulated hur

dium, and v

parison due 

m sites, and 

ed scour mod

nsolidated); 

 Hurricane 

1.0 m (loo

solidated) (R

, with a max

ed scenario t

tums indicat

s before the 

y, and grain

equency. 

mulation 

graphic mod

r conditions a

s at a site in 

rricane impa

very fine silt

to water dep

the variabili

deled at Dat

net scour ra

Ike-related 

ose) and 0.2

Rego et al. 2

ximum of 8

there was lit

te possible s

2010 

n size 

deling 

at the 

26 m 

acts at 

t, and 

pth at 

ity of 

tum 1 

anged 

scour 

2 cm 

2011). 

84 cm 

ttle to 

storm 
114 

scour ranging from a maximum 1.5 m to 84 cm (loose) and 3 cm to 0.2 cm (consolidated); net 

scour estimates range from 21 to 10 cm (loose) and 3 cm to none (consolidated). 

3.8 SITE NO. 236, GALVESTON AREA, USS HATTERAS

3.8.1 Site Background 

Site No. 236 was added to the scope of work during August 2010 dive operations and an 

amendment was subsequently added to the contract to include geophysical data acquisition over 

the site. This site is the known location of the USS Hatteras, a Union Civil War gun-boat that is 

listed on the NRHP and is a Texas State Archaeological Landmark (Texas Site 41GV68). 

Although the site’s identity is known, it was felt that the acquisition of geophysical data and 

including the site in the scope of work would provide beneficial data for continued monitoring of 

the site. This was also the first known archaeological investigation of the site since Hurricane Ike 

heavily impacted the Galveston region in September of 2008. 

As Arnold and Hudson (1981:13) stated, the site is shown on nautical charts and has been 

known to the Texas diving community for some time. The site was “re-discovered” in the 1970s 

through investigations performed by an amateur treasure hunting group (Cloutier 1976; Arnold 

and Hudson 1981; and Arnold and Anuszkiewicz 1995). This group organized as Hatteras Inc., 

and filed an admiralty arrest in U.S. District Court, Galveston Division. The arrest was 

eventually challenged by the U.S. government, which won the lawsuit on February 25, 1981 on 

the grounds that the vessel remained U.S. Navy property (U. S. District Court, Southern District 

of Texas, Galveston Division 1984). During the case, at least eight artifacts that had been 

recovered from the site were placed in the custody of the U.S. Marshal. 

Following the court case, the Bureau of Land Management (later the Minerals Management 

Service), with support from the Texas Historical Commission and the Institute for Nautical 

Archaeology at Texas A&M University, took an active role in monitoring and mapping the site 

(Arnold and Hudson 1981; Arnold and Anuszkiewicz 1995; Irion 2000). Their investigations 

resulted in the preparation of site maps and documentation of the site matrix, and provided a 

record of the condition of the exposed portions of the site at various points in time. 

Recent known archaeological investigations at the Hatteras wreck site have occurred as parts 

of MMS-funded studies conducted by PBS&J in 2004 and 2007 (Enright et al. 2006; Gearhart et 

al. 2011). PBS&J acquired sonar and magnetometer data over the site and performed a brief 

diver investigation in 2004 (Enright et al. 2006). A single sonar image was published that 

provides an indication of the degree of exposure at the wreck site. Subsequent sonar data was 

obtained as part of a hurricane-impact study in 2007, but because no evidence of disturbance was 

observed on the sonar data, no diving was done to verify site conditions (Gearhart et al. 

2011:133) 

The remains of Hatteras are located within a modern shipping fairway that runs parallel to 

shore from Port Aransas on the Texas coast toward Sabine along the Louisiana-Texas border. 

The closest infrastructure to the site is a P&A Well located 2,210 m (7,250 ft) ENE of the site. 
115 

3.8.2 Diving 

Hatteras was the final site investigated during diving operations, which took place on August 

24 and 25, 2010 from the M/V Spree. The purpose of investigating this site was to report on the 

current condition of the wreck, and record any changes in or newly-revealed features at its 

location since the passage of Hurricane Ike in 2008. 

 Average water depth at seafloor: 17.5 m (58 ft). 

 Total bottom time: 26.07 hours. Average dive time: 30 minutes. 

 Visibility: 2.4–3 m (8–10 ft) at slack tide when bottom currents were minimal, 0.3–0.9 m 

(1–3 ft) when tides were coming in or out. 

Two full days of diving were performed on the wreck. Divers recorded diagnostic features of 

the vessel, such as the paddle-wheel hubs, the paddle-wheel shaft, the stern assemblage, 

machinery that may be related to the vessel’s cylinder or steam chest, iron frames in the vessel’s 

stern, the sternpost, and also a previously-noted but unnamed iron structure that was identified as 

the vessel’s walking beam. A makeshift erosion pin was also placed on site adjacent to the 

starboard paddlewheel (Section 5.3.8.3). 

Previously, Hatteras had been investigated by archaeologists (Arnold and Hudson 1981; 

Arnold and Anuskiewicz 1995; Enright et al. 2006; Gearhart et al. 2011; Don Keith pers. comm. 

2011), but comparisons to site plans generated from previous visits indicated that the wreck had 

been more exposed during the 2010 fieldwork than had been previously documented. Project 

archaeologists in 2010 conducted in-depth recording and underwater photography of features in 

order to create an expanded site plan. Features and details noted during dive operations are listed 

below. 

Paddlewheel Components: The most evident portion of the extant vessel is the paddlewheel 

shaft, which lies in a north-south orientation and terminates at either end with the paddlewheel 

hubs (Figures 3.8.1, 3.8.2, and 3.8.3). The shaft is 30 cm (12 in) in diameter, but increases to 50 

cm (19.5 in) near the paddlewheel hubs. The entire shaft, extending from the southern hub to its 

northern counterpart, measures 13.3 m (43.5 ft). The paddlewheel hubs are composed of an inner 

and outer hub, which form a 1-m (3.25-ft) space for the paddle arms and buckets; both hubs are 

1.9 m (6.25 ft) in diameter. The northern paddlewheel hub includes partial remains of 

paddlewheel spokes and at least one partial bucket. The spoke measures approximately 4 m (13 

ft) in length, and the broken bucket fragment is 0.5 m (1.6 ft) wide. 
Figure 3.8.1

Figure 3.8.

. Divers A

paddlewh

2. The sta

increme

Andy Marr 

heel. (Photog

arboard padd

nts. 

116 

and Jake 

raph courtesy

dlewheel and

Shidner ma

y of Colm O’R

d shaft. Scal

apping the 

eilly.) 

e is 10 cm 

starboard 

with 2-cm 
Prop

a cylinde

largest ob

ft) wide. 

been the 

ft) in dia

partially 

Walk

shrimp n

the paddl

partially 

through t

walking b

walking b

by net m

connectin

Stern

paddlewh

approxim

possible 

Figure 3

ulsion Comp

er, valve ass

bject, tentati

The smalle

steam chest

meter. Adja

exposed ove

king Beam: M

net, cables, a

lewheel shaf

exposed wa

the crank sh

beam on its 

beam, and c

material befo

ng rod were 

n Frames: Th

heel shaft. 

mately 25 par

rudder post

3.8.3. Rec

star

ponents: Nea

sembly, and

ively identifi

er componen

t, are located

cent to these

er a distance

Masses of w

and line are 

ft. Closer ins

alking beam

haft and con

eastern exte

ould feel the

ore it descen

estimated at

he sector sca

Archaeolog

rtially expos

. Though th

ctangular hou

board paddle

ar the southe

d/or steam ch

ied as the en

nt, made up 

d immediate

e component

e of 4.8 m (1

what are pres

situated tow

spection of t

m, which tran

nnecting rod

ent. Divers n

e vertical stru

nded below 

t approximat

anning sona

gists condu

sed iron cant

hey appear c

117 

using on pad

ewheel. 

ern paddlewh

hest lay exp

ngine’s cylin

of two 2-m

ly to the sou

ts, what is te

5.75 ft). 

umed to be 

ward the mid

the western 

nsferred pow

d. In fact, th

oted nearly 

ut at the cen

the seafloo

tely 20 cm (8

ar data indica

cted search

t frames, and

corroded or 

ddlewheel sh

heel, feature

posed and w

nder, is 5.4 m

m (6.5-ft) lon

uth of the cy

entatively id

engine com

ddle of the s

component 

wer from th

he connectin

3.65 m (12 f

nter of the be

or. The widt

8 in). 

ated that a f

hes in this 

d the upper p

primitively 

haft adjacen

es that have b

were recorde

m (17.75 ft) l

ng pieces of

ylinder, and 

dentified as t

mponents hea

ite, adjacent

verified that

e engine to 

ng rod is stil

ft) of the upp

eam despite 

th of the wa

feature lay t

direction, 

portions of t

fashioned, f

t to the 

been describ

d by divers

long and 1.6

f what may 

average 0.6 

the piston ro

avily obscure

t to either si

t it represent

the paddlew

ll attached t

per portion o

it being obsc

alking beam

o the west o

and discov

the stern pos

frames avera

bed as 

. The 

 m (5 

have 

m (2 

od lay 

ed by 

ide of 

ts the 

wheel 

to the 

of the 

cured 

m and 

of the 

vered 

st and 

age 6 
118 

cm (2.5 in) in width, and the potential stern post measures 10 cm (4 in) square. The space 

between frames varies from 10 cm (4 in) to 30 cm (12 in). 

3.8.3 Geophysical 

Geophysical data was acquired at the Hatteras site (Site 236) on February 13 and 14, 2011 

aboard the M/V Nikola. Survey coverage was centered on the paddlewheel assemblage, and 

extended out in a 300-m (1,000-ft) radius surrounding the wreck site. Two separate survey grids 

were run over the site, both containing survey lines paralleling the wreck site. A total of 12 

survey lines were run using 100 kHz sonar frequency and spaced 100 and 200 m apart for 

reconnaissance and to maximize sonar coverage. A total of 24 survey lines were run directly over 

the wreck site using 410 kHz sonar frequency and spaced 15 and 30 m apart for increased sonar 

resolution, multibeam coverage, sub-bottom profiling, and magnetic contouring (see Navigation 

Post-Plot Map Appendix B; Figure B-8). Side scan sonar, sub-bottom profiler, magnetometer, 

multibeam, and single beam bathymetry were acquired at the site (see Chapter 2 and Appendix A 

for a full description of geophysical sensor suite, vessel configuration, and navigation 

parameters). 

Water depths are 16.6–17.8 m (54.5–58 ft) throughout the survey grid (Figure 3.8.4). The 

seafloor is irregular surrounding the wreck site, with water depths decreasing to the south 

approaching a sand ridge that extends east/west throughout the survey grid. Ambient water depth 

is 17.8 m (58 ft) at the wreck site, with a zone of apparent wreck-induced scour that surrounds 

the wreck components and reaches a maximum depth of 18 m (59 ft). Multibeam data indicated 

that structural components projecting into the water column include the paddlewheel assemblage, 

the cylindrical objects east of the paddlewheel, the stern assemblage, and two instances of 

unidentified objects located towards the bow of the ship. 

Side scan sonar indicates that the seafloor composition is highly variable. Throughout the 

northern and southern portion of the survey grid, the seafloor is lightly to moderately reflective, 

indicative of fine grained silts and clays. A highly reflective ridge extends just south of the wreck 

site that is comprised of course-grained sands. The 410 kHz sonar data clearly resolved sand 

ripples throughout this zone. The sonar resolved all of the exposed components and indicates that 

the wreck primarily lies in a zone of finer grained sediment along the northern flank of the 

courser grained sand ridge. It is unknown if this zone formed naturally or was formed due to the 

intrusion of the wreck site. Figure 3.8.5 shows a sonar mosaic created by using all of the 410 

kHz sonar lines overlain with the 100 kHz sonar lines perpendicular to the wreck. An inset 

shows the wreck site as seen from Survey Line 204. 

The geophysical data indicates that the distance between the stern of the vessel and the 

paddlewheel assemblage at midships is 33 m (108 ft). The distance between the two 

paddlewheels is 17 m (54 ft). In addition to the primary components mapped during diving 

operations, three additional targets were identified in the vicinity of the exposed portion of the 

site and may be associated with the wreck. The first of these lies 11.5 m (38 ft) NNW of the stern 

of the vessel. The second two targets are in close proximity to each other (7.3 m or 24 ft apart) 

and lie approximately 30 m (100 ft) SE of the cylinder and interpreted steam chest components. 
119 

Sub-bottom profiler data indicates a fairly consistent stratigraphic profile throughout the 

survey area. A strongly to moderately reflective seafloor is followed by approximately 3 m (10 

ft) of mostly amorphous moderately reflective strata. Further penetration is all but eliminated by 

an irregular unconformity. The poor penetration and lack of stratification is caused by the high 

sand content within the surficial sediments. Irregular areas of more highly reflective amorphous 

strata are occasionally evident within the upper 30–90 cm (1–3 ft). This zone is much more 

prominent and appears to extend as deep as 4.5 m (15 ft) BML in certain areas directly 

surrounding the wreck site (Figure 3.8.6). 

 
Figure 3.8.4. Bathymetry surrounding si

120 

te 236 in 2-decimeter intervals. 
121 

Figure 3.8.5. 120 and 410 kHz side scan sonar mosaic of Site 236. Inset at 410 kHz.
Fig

Magn

known th

spacing 

contourin

over the p

Anom

primarily

running d

but small

north-sou

identified

are low i

are produ

anomalie

indicatin

beneath t

gure 3.8.6. 

netometer da

hat a signif

interval was

ng. The larg

paddlewhee

malies in thi

y very large

directly over

ler intensity 

uth axis, bu

d towards th

intensity, hig

uced from th

es, such as n

g that some 

the seafloor 

Sub-bottom 

wreck, with 

Horizontal sc

ata very cle

ficant portio

s reduced fr

gest and mos

l assemblage

is area inclu

e intensity, l

r a large con

anomalies, 

ut further fr

he stern of th

gh duration, 

he central ma

os. 24, 25, a

smaller, bu

west of the v

profile of sur

a heading of

cale lines in 2

early highlig

on of this sh

from 30 m 

st significan

e. 

ude nos. 8, 2

larger durat

ncentration o

such as nos

rom the wre

he vessel. So

monopolar a

ass of the wr

and 46, are d

ut still signif

vessel’s stern

122 

rvey Line 307

f 92 degrees.

2-ms Intervals

ghted the wr

hipwreck w

(91 ft) to 1

nt concentrat

26, 27, 29, 3

tion complex

of ferromagn

. 13, 36, 38,

eck site. A 

ome of these

anomalies id

reck site furt

dipolar or co

ficant, quant

n. 

7, Site 236. Li

 Vertical sca

s. 

reck site (Fi

was buried, 

15 m (49 ft

tion of anom

39, 41, 42, a

x, or dipola

netic debris.

, 39, 46, and

dense conc

e, such as A

dentified on 

rther to the e

omplex anom

tities of ferro

ne 307 is loc

le lines in 15

igure 3.8.7)

the central 

t) to enhanc

malies was id

and 43. The

ar anomalies

As expected

d 47, are see

centration o

Anomalies no

north-south

east. Within t

malies with h

omagnetic d

cated north of

50-m increme

. Because it

survey grid

ce magnetom

dentified dir

ese anomalie

s produced 

d, larger dura

en along the 

f anomalies

o. 17, 20, an

h survey line

this area, tho

higher intens

debris are pr

f the 

ents. 

t was 

d line 

meter 

rectly 

es are 

from 

ation, 

same 

s was 

nd 23, 

s that 

ough, 

sities, 

resent 
F

Anom

site. All t

Figure 3.8.7. 

alies no. 1

hree are mo

Magnetic co

0, 31, and 3

nopolar ano

ontours in 5-nT

32 are locate

omalies with

123 

T intervals ov

ed along no

h large durati

ver location of

rth-south su

ions and are

f the USS Ha

urvey lines e

e likely produ

tteras. 

east of the w

uced by the 

reck 

main 
124 

component of the wreck to the west; however, the relatively high intensities of Anomaly nos. 31 

and 32 may indicate that some significant concentration of debris may be located closer to the 

bow of the vessel. A larger cluster of anomalies is located SW of the wreck, but all are small 

intensity, low duration anomalies. This cluster indicates that some smaller quantities of scattered 

debris are present in this area; these may be related to the vessel’s loss following battle. 

Additional small anomalies were identified scattered further from the site, but it is unknown if 

these are related to the shipwreck or are intrusive. Because the site is within a shipping fairway, 

debris associated with passing marine traffic is common. 

3.8.4 Site Environment 

3.8.4.1 Water Sampling 

One 8-ounce water sample was collected from Site 236 on August 24, 2010 at a depth of 18 

m (60 ft) BSL. Water temperature at the time of acquisition was 84° F. Repeat measurements 

were taken for pH, salinity, and dissolved oxygen content and averaged (Table 3.10). Salinity 

was measured in parts per thousand. Dissolved oxygen (DO) is reported in mg/L. 

Table 3.10 

 

Water Sample Results for Site 236 

Type Average 

Salinity (ppT) 34.40 

pH 8.033 

Dissolved oxygen (mg/L) 7.467 

3.8.4.2 Core Lithology and Grain Size 

Two cores were collected from Site 236. Sediments across the site were extremely variable. 

The first core was collected on August 24, 2010, approximately 1 m (3 ft) north of the port-side 

paddlewheel, at a depth of 18 m (60 ft). Visibility at this location was limited and diminished as 

coring activities disturbed near-surface sediments. Core no. 1 resulted in a maximum sample of 

65 cm of sediment. A second core was collected from the south side of the vessel just off of the 

starboard paddlewheel at a depth of 18 m (59 ft) on August 25, 2010. Divers noted increased 

resistance to core barrel penetration through sediments in this area, suggesting greater sediment 

cohesion. Core no. 2 resulted in an 82 cm stratigraphic sample. Sediments at the western end of 

the wreck, near the identified sternpost and rudder, contained high concentrations of coursegrained sands. Because the Wildco Hand-corer was not designed for sampling in unconsolidated 

sands, two modified core sleeves were used to collect approximately 10 cm plugs of near-surface 

sediment. 

A total of ten samples was collected from the nine lithologic units observed within Core no. 2 

and measured for grain size. Grain size measurements were also made on two samples taken 

from the second sand plug obtained near the stern area. Median and graphic mean calculations 

demonstrate that sediments from the paddlewheel area on Site 236 represent varying intervals of 

silts and sands, likely representing storm deposits. Samples measured from the stern area 
125 

represent fining downcore, from sand to silt, without the varying intervals noted in Core no. 2 

samples. Core no. 1 was primarily used to correlate near surface lithology, but due to the 

frequency of coarse-grained sand intervals in both cores, shear strength measurements were not 

obtained, as neither the penetrometer nor mini-torvane are suitable for measuring cohesionless 

sediments, such as sand. Core no. 2 was measured for pH in downcore sediments. 

Subsequent salinity, pH, and DO measurements were conducted on pore water trapped in 

Sediment Core no. 2 and sand plug no. 2. Pore water samples from both the core and the sand 

plug resulted in higher salinity and lower pH and DO values. Average pore water salinity from 

Core no. 2 was 34.567 ppT; average pore water pH was 6.877; average DO was 1.237 mg/L. 

Average pore water samples from sand plug no. 2 resulted in salinity of 35.567 ppT; pH was 

7.28; DO was 3.4 mg/L. Sediments in Core no. 2 were measured downcore for pH; measured 

values were similar to water samples measurements, ranging from 7.36 to 8.11 from the seafloor 

to a depth of 80 cm below surface. 

3.8.4.3 Radioisotope Analysis 

Sediments at Site 236 display excellent pre- and post-disturbance 210Pb trends with depth. 

Disturbance produced a sharp hiatus in excess activity at a depth somewhere between 8.6 and 

11.1 cm in the seabed. Using the post-disturbance linear accumulation rate (LAR) of 0.14 cm/yr 

allows this disturbance to be dated in the range of 61 to 79 years before the 2010 core collection. 

While there are only three pre-disturbance excess points (r2=0.86), sufficient evidence exists to 

assign an LAR before the disturbance of 0.33 cm/yr. This indicates that sediment LAR at Site 

236 has decreased by almost 2 mm/yr since the disturbance event. 

 
3.8.4.4 O

In the

scour eve

Oceanog

as a prox

impacts a

simulated

coarse, m

represent

represent

datum 3 

sediment

Storm

(loose) a

(Rego et 

of betwe

cm (cons

maximum

Oceanogra

e absence of

ents, such as

graphic mode

xy for seaflo

at a site in 26

d hurricane 

medium, and

t water depth

t scour estim

sediments a

ts at the stern

m-related sc

nd 3 cm (co

al. 2011). H

en 1.0 m (lo

solidated) (R

m of 84 cm (

Figure 3.8.

aphic Analy

f long-term s

s hurricanes,

eling was co

oor condition

6 m (85 ft) o

impacts at 

d very fine 

hs less than 

mates for a s

are coarser 

n area of Site

our modele

onsolidated);

Hurricane Ik

oose) and 0.2

Rego et al. 2

(loose) and a

.8. Downc

sedime

calcula

ysis 

sediment sco

, can provide

onducted at t

ns at Site 23

of water with

a site in 15

silt, and sm

and greater

site at a dept

than either 

e 236. 

d at Datum

; net scour ra

e-related sco

2 cm (consol

2011). Less 

a net scour o

126 

core 210Pbxs

ent accumu

ations for Site 

our monitori

e an estimate

three datum 

36 (Rego et 

h cohesive-c

.5 m (51 ft)

mall amoun

r than depths

th of 31 m (

of the other

m 1 resulted 

anged from 

our modeled

lidated); net 

scour was c

of 10 cm (loo

s activity a

ulation rate

 T236. 

ing, the mod

e of sedimen

sites in the 

al. 2011). D

clay dominat

) of water w

nts of very 

s measured a

(102 ft), mu

r datums an

in maximu

21 cm (loos

d at Datum 2

scour range

calculated du

ose); under t

nd linear 

e (LAR) 

deling of pun

nt transport 

GOM, all o

Datum 1 sim

ted sediment

with a seaflo

fine sand. D

at Site 236. 

uch deeper th

nd more acc

um scour of

se) to 0.03 c

2 resulted in

ed from 30 c

during Hurric

the consolida

nctuated, ext

and redepos

of which are

mulated hurr

ts, while Dat

oor consistin

Datums 1 a

Datum 3 m

han Site 236

curately repr

f between 1

cm (consolid

n maximum 

m (loose) to

cane Rita, w

ated bed sce

treme 

sition. 

 used 

ricane 

tum 2 

ng of 

and 2 

models 

6, but 

resent 

1.5 m 

dated) 

scour 

o 0.03 

with a 

enario 
127 

there was little to no net scour resulting from Rita. Using the loose bed scenario, maximum scour 

at Datum 3 ranged from 1.3 m (Ike) to 60 cm (Rita); consolidated bed scenarios resulted in net 

scour of 30 cm (Ike) but a net sediment accretion of 5 cm from Hurricane Rita (Rego et al. 

2011). Modeled estimates from the datums indicate possible storm scour ranging from a 

maximum 1.5 m to 60 cm (loose) and 3 cm to 0.2 cm (consolidated); net scour estimates range 

from 30 cm to a net accretion of 5 cm (loose), and 3 cm to none (consolidated). 

3.9 SITE NO. 15326, EAST CAMERON AREA, UNKNOWN BARGE 

3.9.1 Site Background 

Site number 15326 was not one of the six original study sites. It was added to the contract 

during diving operations in August of 2010, and was investigated only by divers, with no 

contract-specific geophysical acquisition. The wreck site located in East Cameron Area was 

originally identified during a 2004 Tesla Offshore, LLC, geophysical survey (Floyd and 

Clemmons 2004) and relocated in a 2005 survey by the same company (Evans and Floyd 2005). 

Side scan sonar records highlighted massive wreckage of a large barge that appears to be broken 

in two (Figures 3.9.1 and 3.9.2). Large magnetic anomalies verified that the wreckage is 

primarily metal. “The wreckage protrudes 5 feet above the seafloor in places, but much of the 

hull has settled into the surficial sands. The target components cover 200 to 225 feet of 

horizontal distance with 30 feet of width (Evans and Floyd 2005).” The wreck was 

recommended for avoidance by 304.8 m (1,000 ft) until the wreckage could be further 

investigated to determine the actual age and nature of the vessel. 

Sonar imagery from both the 2004 and 2005 data shows numerous trawl scars from 

shrimping. Data recorded in both the 2004 and 2005 surveys depict trawl scars on the seafloor, 

some of which intersect the wreck (Figure 3.9.1 and 3.9.3). 
A 4” 

has since

ft). Othe

approxim

WNW. 

F

pipeline wa

e been aband

r than the n

mately 580 m

Figure 3.9.1. 

as installed b

doned. This p

now-abandon

m (1,900 ft)

500 kHz si

Image north

based on the

pipeline rou

ned pipeline

) ESE and a

128 

de scan son

h up (Floyd an

e 2005 surve

ute was desig

e, the closes

a platform l

nar image of

nd Clemmons

ey data, whic

gned to avoi

st infrastruc

located appr

f Site 15326

s 2004). 

ch re-verifie

d the wreck 

cture include

roximately 6

. 

ed the wreck

by 313 m (

es a well lo

655 m (2,15

k, and 

1,025 

ocated 

50 ft) 
Figure

Fig

 3.9.2. 500 

Surv

Tes

gure 3.9.3. 

kHz side s

vey Line 301

la Offshore, L

Side scan s

trawl scars. (

129 

scan sonar i

1. Image no

LLC.) 

sonar image

Image courte

image of Sit

orth up (Imag

of Site 153

esy of Tesla O

te 15326 fro

ge courtesy 

326, highlight

Offshore, LLC

om 

of 

ting 

C.) 
3.9.2 Div

Divin

 A

 T

 V

Oper

Sonar. M

its entiret

data (Fig

Durin

surround

portion o

were req

divers no

extensive

entanglem

visibility

ving 

ng operation

Average reco

Total bottom 

Visibility: 0–

ations at the

Mesotech ima

ty or provide

gure 3.9.4). 

Figure 3.9.

ng diving op

ding sedimen

of the wreck

quired to nav

oted a squa

e quantity o

ment hazard

y, most obse

s on Site 153

orded water d

time: 7.12 h

–0.3 m (0–1 f

e site comm

agery identif

e additional 

4. Sector s

perations, vis

nts. Archae

k 13 m (43 f

vigate in the

are shape to

of shrimp ne

d and obscu

ervations we

326 took pla

depth on site

hours. Avera

ft). 

menced with

fied the outli

detail beyon

scan of Site 1

sibility was e

eologists est

ft) to the NE

e zero-visibi

o the ends, 

et and prob

uring most o

ere based on

130 

ace on Augu

e: 16.75 m (5

age dive time

h the deploy

ine of the wr

nd what was 

5326 oriented

extremely po

tablished a 

E for initial 

ility environ

indicative o

able fishing

of the poten

n touch. Wh

ust 20, 2010, 

55 ft). 

e: 26.69 min

yment of the

reck, but did

available fr

d north up. 

oor and the 

baseline ex

exploration

nment. Ther

of an indus

g line cover

ntially diagn

hile investig

from the M/

nutes. 

e Mesotech 

d not succes

rom the pre-e

site had littl

xtending fro

n of the site,

re is little ve

strial bargers the wreck

nostic featur

ating the wr

/V Spree. 

Sector Scan

sfully image

existing side

e relief abov

om the sou

, since guide

ertical relief

-type design

kage, creatin

res. Due to 

reck’s perim

nning 

e it in 

e scan 

ve the 

uthern 

elines 

f, and 

n. An 

ng an 

poor 

meter, 
131 

divers reported feeling a windlass or winch type device near the southern extent of the site. 

Disarticulated hull and decking were identified as far as 4 m beyond the outer-hull. Observed 

frames were evenly spaced and constructed of steel or iron. 

3.9.3 Site Environment 

This site was investigated during diving operations only. The contract modification did not 

include additional analysis of the site through geophysics, modeling, and sampling; therefore, 

only analyses that could be conducted at little or no additional cost were performed. 

3.9.3.1 Water Sampling 

One 8-ounce water sample was collected from Site 15326 on August 20, 2010 at a depth of 

17.4 m (57 ft) BSL. Water temperature at the time of acquisition was 86° F. Repeat 

measurements were taken for pH, salinity, and dissolved oxygen content and averaged (Table 

3.11). Salinity was measured in parts per thousand. Dissolved oxygen (DO) is reported in mg/L. 

Table 3.11 

 

Water Sample Results for Site 15326 

Type Average 

Salinity (ppT) 32.1 

pH 7.323 

Dissolved oxygen (mg/L) 6.69 

Subsequent salinity, pH, and DO measurements of pore water trapped in Sediment Core no. 2 

resulted in higher salinity and lower pH and DO values. Average pore water salinity was 33.867 

ppT; average pore water pH was 6.997; average DO was 2.01 mg/L. 

3.9.3.2 Core Lithology and Grain Size 

Two cores were collected from Site 15326 on August 20, 2010. The first was collected 

within 2 m (6 ft 6 in.) of the western end of the wreck, on the south side, resulting in a maximum 

of 89 cm of sediment at a depth of 17.4 m (57 ft). A second core was collected from the south 

side of the vessel at midships, near the observed break in the hull at a depth of 17 m (56 ft) and 

resulted in a 92 cm stratigraphic sample. 

Grain size measurements and radioisotope analysis were not conducted for samples from 

these cores, but lithology was noted, and approximate grain size classifications were made based 

on the observed sediments. Based on published data, the seafloor in this area is expected to be 

clayey sand (MMS 1983); however, qualitative assessment indicates near-surface sediments are 

sandy silt and fine downcore to clayey silt, with occasional intrusive sand lenses. Downcore 

measurements of pH values were taken from both cores, and indicated higher pH levels in 

sediments immediately surrounding the wreck than in the water column; average pH values from 
132 

Sediment Core no. 1 measured 8.034 to a depth of 85 cm below surface and average values from 

Sediment Core no. 2 measured 8.163 to a depth of 80 cm below surface. 

3.10 SITE NO. 322, EAST CAMERON AREA, UNKNOWN MODERN WRECK 

3.10.1 Site Background 

Site number 322 was not one of the six original study sites. It was added to the contract 

during diving operations in August 2010, and was investigated only by divers, with no contract 

specific geophysical data acquisition. 

Site number 322 is located in the East Cameron federal lease area and was identified 

originally by a geophysical survey conducted by John E. Chance and Associates in 1991 (Floyd 

and Thomas 1991). The survey report indicates that the wreck measured 6 m (20 ft) by 20 m (65 

ft) and exhibited 1.2 m (4 ft) of relief. 

While conducting subsequent operations in the area in 2005, Tesla Offshore, LLC, ran six 

survey lines over the wreck site to provide additional imagery of the wreck (Floyd 2005; Figure 

3.10.1). The wreck is oriented with the bow facing the NW. Based on the 2005 data set, the 

wreck measured approximately 17.3 m (57 ft) in length, 3–3.9 m (10–13 ft) in width, and rises 

off the seafloor approximately 0.6 m (2 ft) at the bow. The stern has subsided into the sediments. 

Only the “pilothouse” portion sits 0.6–0.9 m (2–3 ft) above the deck. 
Exist

m (3,030

3.10.2 D

Divin

 A

 T

 V

The 

indicated

house an

ting infrastru

0 ft) to the NN

Diving 

ng operation

Average reco

Total bottom 

Visibility: 0–

Mesotech S

d that the ve

d surroundin

Figure 3.10

ucture closes

NE and a P&

s on Site 322

orded water d

time: 3.93 h

–0.3 m (0–1 f

Sector Scann

essel remaine

ng deck struc

.1. 410 kH

322 fro

up (Flo

st to Site 322

&A well loca

2 took place

depth on bot

hours. Avera

ft). 

ning Sonar 

ed upright, a

cture were c

133 

Hz side scan

om survey Lin

oyd 2005). 

2 includes a

ated approxi

e on August 2

ttom: 16.75 m

age dive time

was deploy

and, althoug

clearly identi

n sonar imag

ne 305. Orien

a 16” pipelin

imately 1,26

20, 2010, fro

m (55 ft). 

e: 23.6 minu

yed upon a

gh the data q

ified (Figure

ge of Site 

nted north 

ne located ap

68 m (4,160 

om the M/V 

utes. 

arrival to th

quality was 

e 3.10.2). 

pproximately

ft) to the NN

Spree. 

he site. The 

limited, the 

y 924 

NW. 

data 

pilot 
Diver

sitting up

visible, i

noted wh

starboard

fishing li

boom ext

3.10.3 S

This 

include a

only anal

3.10.3.1

One 

m (56 ft)

were tak

was meas

Figure 3.10.

rs determine

pright on the

ncluding po

hat appeared

d running lig

ine, creating

tending off o

Site Enviro

site was inv

additional an

lyses that co

 Water Sam

8-ounce wat

) BSL. Wate

ken for pH, s

sured in part

.2. Mesote

ed that this 

e seafloor. A

ort holes with

d to be rubb

ghts on the 

g significant 

of one side s

nment 

vestigated on

nalysis of th

ould be condu

mpling

ter sample w

er temperatu

salinity, and

ts per thousa

ech scan of S

site represe

Approximate

h intact glas

ber gasket m

pilot house.

entanglemen

suggests that

nly during d

he site throu

ucted at littl

was collected

ure at the tim

d dissolved o

and. Dissolv

134 

ite 322 orient

ents a relativ

ely 6 m (20 

ss, and a win

material arou

. The site is

nt hazards o

t the vessel i

diving opera

ugh geophys

e or no addit

d from Site 3

me of acqui

oxygen cont

ed oxygen (D

ted north up.

vely small, 

ft) of the su

nch and bitt

und the por

s covered ex

on site. A po

is a fishing o

ations. The c

sics, modelin

tional cost w

322 on Augu

isition was 8

tent and ave

DO) is repor

metal-hulled

uperstructure

t on the deck

rt holes, as 

xtensively in

ortion of wha

or shrimp bo

contract mod

ng, and sam

were perform

ust 20, 2010

88° F. Repe

eraged (Tab

rted in mg/L

d working v

e/pilot house

k. One dive 

well as por

n shrimp ne

at appears to

at. 

dification di

mpling; there

med. 

0 at a depth 

eat measurem

le 3.12). Sa

L. 

vessel 

e was 

team 

rt and 

et and 

o be a 

id not 

efore, 

of 17 

ments 

alinity 
135 

Table 3.12 

 

Water Sample Results for Site 322 

Type Average 

Salinity (ppT) 31.9 

pH 7.23 

Dissolved oxygen (mg/L) 6.735 

3.10.3.2 Core Lithology 

Two cores were collected from Site 322 on August 20, 2010, both of which were within 5 m 

(16 ft) of the hull. The first core resulted in a maximum of 81 cm of sediment at a depth of 17 m 

(56 ft) and the second core resulted in a 91 cm stratigraphic sample from a depth of 17.4 m (57 

ft). 

Grain size measurements and radioisotope analysis were not conducted for samples from 

these cores, but lithology was noted, and approximate grain size classifications were made based 

on the observed sediments. Based on published data, the seafloor in this area is expected to be 

clayey sand (MMS 1983); however, qualitative assessment indicates near-surface sediments are 

sandy silt and fine downcore to clayey silt, with occasional intrusive sand lenses. 

Salinity, pH, and DO measurements were taken of pore water trapped in Sediment Core no. 

1, which resulted in higher salinity and pH values but lower DO values. Average pore water 

salinity was 34.167 ppT, average pore water pH was 7.507, and average DO was 5.77 mg/L. 

Downcore sediment measurements of pH values were taken for both cores and indicated higher 

pH levels in sediments immediately surrounding the wreck than in the water column. The 

average pH values from Sediment Core no. 1 measured 8.072 to a depth of 80 cm below surface 

and average values from Sediment Core no. 2 measured 8.046 to a depth of 80 cm below surface. 

3.11 SITE NO. PENDING, WEST CAMERON AREA, MODERN DEBRIS 

3.11.1 Site Background 

This site was added to the contract during diving operations in August 2010 and was 

investigated through dive operations. The site had not been added to the BOEM database at the 

time of the field work and, to date, no site number has been attributed to this object. 

The study site located in West Cameron Area was previously identified by a geophysical 

survey performed in 2007 by Tesla Offshore, LLC. The resulting report was prepared by Marine 

Archaeologist, Amanda Evans; Marine Geophysicist, Erika Geresi; and Marine Geophysicist, J. 

Wyn Prior (Evans et al. 2007). Target no. 7 was identified as a potentially significant object that 

warranted avoidance (Figures 3.11.1 and 3.11.2). According to the report, the target: 
p

co

T

re

un

sh

d

...appears

arts which a

overs an are

The largest s

ecorded from

nidentified m

hould be av

isarticulated

F

Figure 3.

s to be a sig

are observed

ea of approxi

single featur

m survey li

magnetic an

voided by a 

d shipwreck o

Figure 3.11.1

.11.2. 410 k

Line 

gnificant com

d from diffe

imately 44’ 

re within the

ine 102. Ta

nomalies inc

distance of

or ballast pil

. 410 kHz 

from surv

et al. 200

kHz side scan

89. Oriented 

136 

mpound targ

erent angles 

x 47’ with a

e target mea

arget no. 7 

cluding #12

f 1,000’. Son

le. (Evans et

side scan so

vey Line 88. 

07). 

n sonar image

west up (Eva

get consistin

on four sur

a maximum 

asures appro

is associate

20, 124, 127

nar target no

t al 2007 Ap

onar image of

Oriented we

e of sonar tar

ans et al. 2007

ng of severa

rvey lines. T

recorded re

oximately 17

ed with a c

7, 128, and 

o. 7 may re

ppendix F:3) 

f target No. 7

est up (Evans

rget No. 7 fro

7). 

al discrete 

The target 

elief of 5’. 

7’ x 6’ as 

cluster of 

136, and 

epresent a 

7

s

om survey 
Addit

Offshore

2010 fie

suppleme

a rectang

above the

investiga

by hurric

dense sea

the incor

As of

on unpub

bottom-d

platform 

precludes

The p

developm

installed 

pipeline 

associate

 

2 The 

correspond

tional geoph

 was contrac

eld study 

ental high re

gular target w

e seafloor (E

ated feature a

cane or anthr

afloor textur

rrect impress

f 2011, the a

blished, revi

disturbing ac

or pipeline)

s both the pr

primary thr

ment, but san

in April of 

assembly is

ed pipelines i

 

published Sab

dence with BO

hysical data 

cted by an o

operations. 

esolution son

was evident,

Evans and B

as Sonar Ta

ropogenic pr

re, immediat

sion of a mul

Figure 3.11

area surround

ised bounda

ctivity that 

) can take pl

ractical extra

eat to archa

nd extraction

2011 located

 located app

is located 4,

 

bine East OCS 

EM, this zone 

acquisition 

operator to c

The field

nar data over

, measuring 

Bronikowski 

arget No. 9. A

rocesses, a re

tely apparent

lti-componen

.3. 410 kHz

from su

(Evans 

ding the site

aries dictated

will last lo

lace within a

action of oil 

aeological re

n. The closes

d a minimum

proximately 

595 m (15,0

 

Sediment Reso

has been exten

137 

was not part

onduct a sub

d-investigate

r the site. Th

5.5 m (18 ft

2010). The 

Although it 

e-examinatio

t on the high

nt site. 

z sonar imag

urvey Line 2

and Bronikow

e is a designa

d by the BO

nger than 1

a designated

and gas as w

esources in 

st existing in

m of approx

2,995 m (9

072 ft) to the 

ource Area lies

nded to encomp

rt of the curr

bsequent sur

ed target w

he new sona

ft) by 1.8 m 

2010 survey

is possible 

on of the 200

her resolutio

ge of sonar ta

20. Oriented

wski 2010). 

ated sand re

OEM2. Acco

180 days (s

d sediment re

well as the in

this area w

nfrastructure

ximately 1,89

,822 ft) to t

east. 

s just west of th

pass the site. 

rent contract

rvey over th

was “boxed

ar imagery in

(6 ft) and si

y report refe

that the site

05 data sugg

on 2010 data

arget No. 9 

d north up 

esource extra

ording to NT

uch as the 

esource area

nstallation of

will not be 

e to the targe

90 m (6,200

the west and

the site (NTL 2

t; however, 

his area follo

d–in,” prov

ndicated that

itting 1.2 m 

erred to the 

 has been al

gests that are

a, may have g

action zone b

TL 2009-G0

installation 

a. This regul

f pipelines. 

new oil and

et is a 6” pip

0 ft) to the N

d a platform

2009-G04). Ba

Tesla 

owing 

viding 

t only 

(4 ft) 

fieldltered 

eas of 

given 

based 

4, no 

of a 

lation 

d gas 

peline 

NE. A 

m with 

sed on 
3.11.2 D

Divin

 A

 T

 V

The s

45-m ran

toward t

protrusio

Diver

heavily c

securing 

conducte

divers re

m (11.5 f

the highe

object. M

the meta

curved o

Including

(Figure 3

Diving 

ng operation

Average reco

Total bottom 

Visibility: 0–

sector scann

nge (150-ft) 

the outer ex

ons extending

rs located th

concreted st

a descent l

ed probing a

corded the s

ft) in length 

est point. In

Metal sheetin

l sheeting cu

bject was at

g the sheetin

3.11.4). 

Figure

s at this site 

orded water d

time: 10.68 

–0.5 m (0– ~

ning sonar w

imaged a r

xtent of the

g past each e

he site throu

tructure, pro

line and bu

and metal d

structure. Th

and 88 cm (

nternal lever

ng extends al

urves back u

ttached to th

ng and the m

e 3.11.4. S

took place o

depth: 9.75 m

total dive ho

1.5 ft). 

was deployed

relatively fe

 data. This 

end in oppos

ugh circle s

ojecting app

oy to the ta

detector surv

he primary t

(2.9 ft) in w

rs and a pos

long the obje

up out of th

he main feat

main rectangu

Sector scan h

138 

on August 22

m (32 ft). 

ours. Averag

d upon arriva

eatureless se

object app

site direction

earches in n

proximately 

arget, dive 

veys around

target is a re

width. The ob

ssible concre

ect into the s

he seafloor; m

ture but buri

ular compon

ighlighting un

2, 2010 from

ge dive time

al on site. S

eafloor with 

peared to be

ns. 

near-zero vi

1.2 m (4 ft

teams began

d the object,

ectangular-sh

bject sits 1.2

eted winch 

seafloor. Div

minimal han

ied under se

nent, the obje

nidentified obj

m the M/V Sp

e: 30.52 minu

Sector scanni

a single un

e rectangula

isibility. The

ft) above the

n exploring

, while othe

haped featur

2 m (4 ft) abo

drum are in

vers observe

nd fanning i

everal cm of

ect is 4.1 m 

ject. 

Spree. 

utes. 

ing sonar se

nidentified o

ar in shape 

ey encounte

e seafloor.

 the site. T

er archaeolo

re, measurin

ove the seab

ntegrated int

ed one area w

indicated tha

f sandy sedim

(13.5 ft) in w

et at a 

object 

with 

red a 

After 

Teams 

ogical 

ng 3.6 

bed at 

to the 

where 

at the 

ment. 

width 
139 

Magnetic readings extend several meters in every direction from the central structure, and 

divers recorded “hits” in an area extending 2 m (6.5 ft) to the north, 3 m (9.8 ft) to the south, 7 m 

(22 ft) to the east, and 2.5 m (7.5 ft) to the west. Based on the diver observations, it was 

determined that the object was heavy machinery associated with industry activities, likely oil and 

gas or fishing. 

3.11.3 Site Environment 

Because of the absence of any archaeological materials, neither sediment cores nor water 

samples were collected at this site. It was decided in the field that the resources required to 

analyze samples from this site would be better used on the remaining study sites. Therefore, no 

information is available for sediment stratigraphy, grain size, radioisotope, or shear strength in 

this area. 
141 

4. HISTORICAL SIGNIFICANCE 

4.1 REGIONAL EXPECTATIONS FOR THE GOM

The Gulf Coast region has experienced steady maritime traffic for the last four hundred 

years. Documented shipwrecks along the Texas and Louisiana coasts include a diverse array of 

vessel types, ranging from sailing vessels, to steamships, to modern crew boats. In a study 

funded by MMS (now BOEM) for the purpose of researching site expectations throughout the 

GOM region, Garrison et al. (1989) divided shipwrecks of the northern GOM into five distinct 

cultural and chronological periods: New Spain Period, 1500 to 1699; Colonial Period, 1700 to 

1803; American Period, 1803 to 1865; Victorian Period, 1866 to 1899; and the 20th century, 

1900 to present. The periods of exploration and early settlement were characterized by the 

Spanish, French, and English ventures, each of which contributed to the composition of the Gulf 

Coast region. Settlers in the GOM region depended on ships and boats for transportation of 

people and supplies, and wrecks of numerous nationalities are located in this region. As maritime 

transportation and travel escalated and evolved, so did the network of routes used by these 

vessels. 

Beginning in the 16th century, the GOM was heavily traveled as part of the primary trade 

routes between Europe and the Spanish Main. Ships exploited a steady pattern of wind and water 

currents to travel across the Atlantic Ocean. Seasonal winds known as trade winds created a 

reliable sailing route for ships traveling from the west coast of Africa into the Caribbean Sea, the 

Antilles and, ultimately, the GOM. Blowing westward across the Atlantic for 300 days of the 

year, trade winds maintained a near-constant speed, and rarely exceeded 14 knots, creating ideal 

sailing conditions (Greenwood 1991:13). Trade winds influenced early sailing routes, and 

mariners capitalized on both surface winds and a reliable series of ocean current regimes. The 

North and South Equatorial currents merge in the Atlantic to flow westward into the southern 

Caribbean, fluctuating between speeds of five and eight knots. Hurricanes typically follow this 

same pattern. Once on the leeward side of the Lesser Antilles, vessels are sheltered from trade 

winds and make use of a system of predictable water currents. These currents flow clockwise, 

following first the South and then Central American coastlines until passing through the Yucatan 

Channel (Greenwood 1991:13). At the Yucatan Channel, the powerful Gulf Stream flows from 

west to east along the Gulf Coast, carrying ships towards the Florida Straits and back out into the 

open Atlantic, where strong eastward winds called westerlies aid ships sailing out of the GOM to 

Europe (Greenwood 1991:13). Caribbean hurricanes generally form in the Atlantic Ocean, near 

the Cape Verde Islands off the West African coast, exhibiting an average diameter of 600 km to 

800 km (372 to 497 miles), and move at a relatively low rate of speed (Bolay 1997:65). 

 

During the age of sail, the persistence of favorable wind and current regimes facilitated the 

establishment and growth of coastal ports along the northern GOM. Steady increases in ship 

traffic resulted in an increasing frequency of shipwrecks throughout the region. Known sites 

representative of each time period have been identified throughout the GOM, from the sixteenth 

to the twentieth centuries. 
142 

The oldest wrecks found in the GOM region are located off Padre Island, Texas. In 1554, 

four Spanish vessels set sail from San Juan de Ulua, Mexico for Havana, Cuba, and ultimately 

Europe. These vessels had no intention of nearing the Texas coast, but three of the four ships 

were blown off course or attempted to outrun a storm and consequently ran aground on the 

shoals near Padre Island, Texas (Francaviglia 1998:44). Remains of the three wrecked vessels, 

Santa Maria de Yciar, San Estéban, and Espíritu Santo, were uncovered by Hurricane Carla in 

1961; these are three of the earliest wrecks to be located and excavated in the New World 

(Arnold and Weddle 1978). A second set of 16th-century wrecks is located on the eastern side of 

the GOM. The Emanuel Point wrecks are artifacts of Don Tristan de Luna’s failed attempt to 

colonize Florida in 1559 (Smith at al. 1998; Smith et al. 1999; Cook 2009). 

Following these early Spanish wrecks are examples from each subsequent century, as 

exploration expanded and shipping became more established in the GOM. The 17th century is 

represented by a French colonial wreck, the 1686 site of La Belle in Matagorda Bay, Texas. The 

ship was part of the fleet under the command of French explorer Rene Robert Cavelier Sieur de 

la Salle during his attempt to relocate the mouth of the Mississippi River, and also demonstrates 

French encroachment into the predominately Spanish region (Bruseth and Turner 2005; 

Francaviglia 1998). Eighteenth-century wrecks in the GOM include El Nuevo Constante, one of 

two Spanish vessels lost in a hurricane in 1766 off the coast of Louisiana while traveling from 

Mexico to Spain (Pearson and Hoffman 1995). 

The Mardi Gras shipwreck dates to approximately 1815 and holds the distinction of being 

one of the first scientifically excavated deepwater wrecks (Ford et al. 2008). Commercial 

shipping was aided in the 19th century with the development and increasing availability of 

steam-powered vessels. The mid to late 19th century ushered in an era of rapid port development 

and expansion across the GOM. New York venture capitalist Charles Morgan expanded his New 

York–New Orleans shipping empire by linking small ports of the Texas Gulf Coast with New 

Orleans, creating a “triangular” trade route (Francaviglia 1998:128). Sidewheel steamships were 

well suited to the conditions found along the Gulf Coast, and steamship commerce was 

successful in large part because of their unique construction. By 1838, regular steamship service 

operated between Texas and New Orleans. 

Despite the growing popularity of steamships, sailing sloops and schooners comprised the 

bulk of all vessels operating in and out of the GOM in the mid-19th century. Vessels carried a 

diversity of cargo, as illustrated by the manifest of the ship Maria, sailing from New Orleans to 

Matagorda, which included “corn, flour, sperm candles, tobacco, starch, hardwood, sewing 

items, spices, medicines, cowbells, molasses, hardware, fancy goods, crockery, shoes, hats, and 

dry goods (Francaviglia 1998:141-142).” Maritime commerce continued to increase along the 

Gulf Coast with the inclusion of transoceanic ships, Atlantic freighters, and river steamships 

(McAlister 1993:63). Additionally, improvements were made in maritime infrastructure to 

support the increasing numbers of vessels operating across the coast. In addition to shipping, the 

shipbuilding industry prospered along the Gulf Coast. 

Continuing into the 20th century, shipping vessels continued to diversify. Wooden vessels 

began to be replaced by larger metal-hulled ships, especially tankers and refrigerated cargo 

vessels. Commercial sailing ships and steam-screw engines were largely replaced by oil- and 
143 

diesel-screw ships. Today, vessels commonly used in the GOM include shrimp boats, 

commercial fishing vessels, tow vessels, and specialized industrial boats, such as pipelay barges, 

dive boats, crew boats, and drilling rigs. Modern shipwrecks also include recreational vessels, 

such as sail boats, catamarans, charter fishing boats, and other small craft. 

The GOM has also been an active theater of war. During the mid-19th century, the GOM 

region proved strategically important during the Civil War as Union blockades attempted to shut 

down Confederate commerce and prevent the transportation of goods and troop supplies. In the 

20th century, World War II brought German U-boats into the GOM. Over approximately 18 

months between 1942 and 1943, U-boats disrupted trade and commerce, attacking a total of 116 

vessels from Texas to the eastern Florida coast, and as far south as Cuba and Honduras (Wiggins 

1995:114-115). The hulls of vessels attacked during the U-boat campaign litter the seafloor, 

along with one German U-boat. 

Shipwrecks included in this study span three general time periods: the Civil War-era, World 

War II, and the era of modern Gulf Coast industry and commerce. Each of these periods has 

specific vessel types and is related to unique events important in U.S. history. 

 

4.1.1 Civil War Era 

During the American Civil War, Union and Confederate forces fought for control over the 

various ports of the GOM. Specifically, the ports of New Orleans and Galveston were coveted 

for their economic and regional importance. After forming as a state, Texas sided with the South 

in the Civil War. As part of the Confederate States of America, the port of Galveston was 

blockaded early in the war by Union Naval vessels. Galveston was the largest city in Texas at the 

outbreak of the Civil War, with a population of over 7,500; the Union blockade slowed 

commercial traffic and slowly squeezed the economy of the entire state (Francaviglia 1998:194). 

Evidence of the multiyear Union blockade and the Battle for Galveston is found near present-day 

Galveston, in the form of Confederate Blockade runners (such as Denbigh (41GV143) and Will 

of the Wisp [41GV90]) and Union gunships (such as Westfield [41GV151]). 

The city of Galveston was surrendered to Union forces on October 4, 1862, but was soon 

retaken by the Confederates. On New Year’s Day, 1863, General Magruder’s Confederate forces 

successfully reclaimed Galveston after defeating the Union gunships Westfield and Harriet Lane 

(Underwood 2003:84-91). Union naval forces were sent to protect the city against attack, 

including the vessel Brooklyn, commanded by Commodore H.H Bell, and six other gunships. As 

discussed in Chapter 3, shortly after it arrived off of Texas, the USS Hatteras engaged the 

Confederate raider CSS Alabama and was sunk offshore of Galveston Island. The sinking of 

Hatteras was important in reducing the Union’s ability to re-take Galveston and all but 

eliminated their plan to push further into the interior of Texas (U.S. Naval War Records 1895; 

2003 [1921]; Snyder 1938). 

4.1.2 World War II 

In early 1941, the U.S. was not an active participant in World War II, but it was peripherally 

involved through the Lend-Lease Act, supplying oil and gasoline to Great Britain (Morison 
144 

1970:37). Increased supply to overseas markets resulted in oil and gasoline shortages in the U.S., 

and necessitated domestic increase in production capacity (Wiggins 1995:13). This increase in 

production required an increase in shipping to transport oil and gas products to inland and 

overseas markets. In the early 1940s, approximately twenty percent of all tankers in the U.S. 

were put into service supplying oil and gas to Great Britain, and the remaining domestic tankers 

were altered to increase their capacities in an attempt to meet the growing demand for fuel 

(Wiggins 1995:14). Tankers were of paramount importance to the war effort. Plans to build an 

interstate oil pipeline from Texas to Philadelphia and New York, and a smaller pipeline from 

Louisiana to North Carolina, were canceled with the formation of the Supply Priorities and 

Allocations Board (Wiggins 1995:14). According to Rear Admiral Emory Land, too much steel 

would need to be diverted from naval uses to build the pipelines: “I’d rather build tankers than 

pipelines. If that’s not satisfactory, I’d rather build barges. I don’t know where they can get 

750,000 tons of steel, but if it’s coming from the navy or our ships, I’m against it” (Wiggins 

1995:14). The cancellation of the proposed pipelines meant that the majority of the U.S. oil and 

gas supply was transported by ships. 

The U.S. officially entered World War II when Congress declared war on Japan on 

December 8, 1941, following the attack on Pearl Harbor (Morison 1970:114). Germany, in turn, 

declared war on the U.S. on December 11, and quickly began operations against U.S. interests 

(Morison 1970:114). The first German U-boat attack in U.S. waters took place on January 14, 

1942, when U-123 sank Norness, a Panamanian tanker, 97 km (60 miles) from Long Island in 

the Atlantic Ocean (Rohwer 1983:74; Wiggins 1995:16). During the next two years, the Gulf 

Front was patrolled by U-boats whose mission was to disrupt transportation of wartime fuel and 

supplies to Allied forces. The first known German submarine in the GOM was U-507, which 

attacked and sank Norlindo, on April 30, 1942 (Wiggins 1995:22-24). U-507 was almost 

immediately joined in patrolling the GOM by U-506. 

A total of 70 ships were attacked in the GOM by 24 U-boats that patrolled its waters during 

1942 and 1943 (Rohwer 1983; Wiggins 1995). Of the 70 recorded attacks, 56 resulted in the 

sinking of the ship and the remaining 14 sustained damage, but were not sunk (Wiggins 1995). 

During this tense time in the GOM, Merchant Mariners and the Naval Armed Guard were the 

frontline defenders of Allied vessels. Coastal defense was further bolstered by a mandatory dimout order issued to combat the rising U-boat threat. The dim-out began in Galveston on June 1, 

1942, and on June 2 was expanded to include most of the Texas and Louisiana coastlines 

(Wiggins 1995:88). The purpose of dimming coastal lights was to prevent artificial light from 

silhouetting ships, which made them visible to U-boats and therefore vulnerable to attack. The 

dim-out along the Gulf coast was lifted in November of 1943 after the threat was observed to 

wane as a result of the effectiveness of armed convoy travel and other antisubmarine tactics 

(Wiggins 1995); as also, the construction of the “Big Inch” pipeline from Texas to New Jersey 

reduced the need for oil transport by tanker (Irion 2000:145). 

4.1.3 Industry and Commerce 

Vessel types typical of the past two centuries range from vernacular craft to international 

ships with functions that include fishing, commercial transport, military use, and, more recently, 

oil and gas-related vessels and personal pleasure craft. The ports of the GOM served as a 
145 

backdrop to commerce and trade bolstered by various burgeoning industries. Settlers found the 

wealth of cypress and oak forests of Louisiana beneficial as both building materials and trading 

exports. Rafts were used to transport lumber and moss to market and major exports of sugar, 

cotton, and tobacco were shipped to the wider markets of Europe. According to Terrell (1990), 

despite the abundance of local fauna, early fur trading in the area focused on exports traveling 

down river from Canada. In Louisiana, the fur industry and fishing commerce did not fully 

develop until the 19th century (Terrell 1990). River and coastal commerce thrived before the 

advent of inland railway systems and interstate roadways of the 20th century (Terrell 1990). 

Oil and gas exploration and development are crucial in the economy, cultural, and social 

fabric of the Louisiana and Texas Gulf Coast. The evolution of this industry came about as 

industry pioneers moved from drilling on land to drilling in marshes and shallow water 

environments in the late-19th and early-20th centuries, and then eventually moved out into the 

open waters of the GOM. The first oil well drilled in Louisiana on land was in 1901. The first 

offshore fixed platform wells and the first wells drilled out of the sight of land was offshore of 

Louisiana in the Ship Shoal area in 1947 (BOEMRE 2011; NOIA 2011). By the 1930s and 

1940s, mobile drilling units moved across the Louisiana and Texas coasts and, before long, 

coastal exploration expanded further seaward (Austin et al. 2008). 

Oil and gas production began to grow throughout the Gulf Coast, evolving from a specialized 

industry to become the backbone of the regional economy. World War II activities in the GOM 

restricted the growth of the offshore industry, but the end of the war signaled the start of an 

industrial boom. The increase in offshore technological development was aided by the 

availability of surplus war materials. Items originally intended for the war effort found other 

applications in this growing industry as they were auctioned off following the end of the war 

(William Bisso 2011, pers. comm.). Today, the oil and gas industry in the GOM consists of a 

massive landscape of infrastructure, including abandoned and extant wells connected to the 

onshore processing centers through a complex network of pipelines and cables. The industry has 

developed into a steadfast economic and cultural force in the region bringing with it fleets of 

task-specific vessels. Today, oil and gas exploration is one of the largest industries in offshore 

areas throughout the world, from the North Sea to West Africa to Brazil. The formative stage of 

this massive global industry can be traced to the earliest innovators offshore of Louisiana and 

Texas. 

The modern maritime landscape includes not only oil and gas associated vessels, but 

numerous and varied ship types that exhibit new innovations in equipment, propulsion, and even 

composition. Historically, fishing has been an important economic driver for the Gulf Coast. The 

various types of fishing vessels active in the central GOM include trawlers, oyster dredges, 

menhaden purse seiners (commonly referred to as pogy boats), and pelagic or demersal fishing 

vessels (Sainsbury 1986). In 1937, commercial trawlers were introduced to Louisiana to begin 

harvesting newly-discovered shrimp populations in the GOM. The first trawlers were South 

Atlantic-style vessels used off the coast of Florida. These vessels were quickly adapted by 

Louisiana and Mississippi fishermen who called the vessels “floridiane trawlers” because of their 

Florida origins (Center for Traditional Louisiana Boat Building 2007). Early shrimp trawlers 

were constructed of wood with deep, soft-chined hulls (Brassieur 2004). Trawlers used in the 

GOM were distinct from other trawlers used in and around the U.S. because of their forward-
146 

cabins or wheelhouses. Early-style trawlers, such as the South Atlantic and Floridiane, are still 

built and used by Louisiana shrimpers in the offshore GOM region. Although ancillary 

components, such as engines, navigation equipment, buoys and other fishing gear, may have 

changed, the overall shape of the vessel has remained static. 

According to Sundstrom’s (1957) classification system, large trawlers in the GOM region 

could be constructed of either steel or wood. Steel was not generally used in ship construction 

until the Bessemer process was developed in 1856. The use of steel became more common in the 

1880s, but did not become commonplace until the 20th century. The earliest shrimp trawlers in 

coastal Louisiana were made from wood, and some continue to be made this way today. 

Wooden-hulled vessels can date to virtually any time period, but construction techniques and the 

condition of the wood can provide a good indication of temporal association. A few boat builders 

in coastal Louisiana continue to build wooden-hulled trawlers for use in the GOM, but metalhulled trawlers are much more prevalent (Brassieur 1989). 

4.2 ARCHAEOLOGICAL AND HISTORICAL ANALYSIS OF STUDY SITES 

4.2.1 Site No. 380, South Pelto Area, Reported Wooden Wreck 

In a study prepared for MMS, Pearson et al. (2003) developed a probability model for 

historic shipwreck occurrence throughout the GOM, designating certain areas within federal 

jurisdiction as having a higher probability than others based on variables such as location to 

historic shipping routes and reported hangs, obstructions, and vessel losses in the area. Based on 

that probability model, site no. 380 is located within an area deemed to have a high probability 

for shipwreck occurrence. Coastal Environments, Inc., (1977) published the location of major 

historic shipping routes used from the 16th through 20th centuries. These maps show that Site 

380 was landward of the most frequent routes of coastal exploration used during the 16th and 

17th centuries (CEI 1977; Plate 6), and in close proximity to coastal sailing routes used during 

the 18th and 19th centuries (CEI 1977; Plates 7 and 8). Site 380 is completely unidentified, but, 

based on its location in relation to these historic shipping routes, it is possible that the vessel 

could be associated with coastal sailing routes from the 18th and 19th centuries. The site is not 

located within any major shipping routes used during the first half of the 20th century, but would 

have been along the most common route for vessels traveling inland into areas surrounding 

Houma, Louisiana (CEI 1977; Plate 9). 

A comprehensive list of 55 wrecks within 48 km (30 miles) of Site 380 was compiled to 

ascertain the identity of the reported wooden wreck. Of these reported wrecks, lengths and/or 

gross tonnage were available for 49 of them. Known shipwrecks in the general vicinity appear to 

be primarily modern vessels probably related to either the oil and gas or fishing industries; some 

of these wrecks may be historically significant. Shipwrecks reported within 48 km (30 miles) of 

the study site with similar published dimensions or features to those reported by NOAA are 

detailed in Table 4.1. 
147 

Table 4.1 

 

Reported Shipwrecks in the Vicinity of Site 380 with Similar Dimensions 

Vessel 

Name 

Gross 

Tonnage Length Breadth Date of Sinking Vessel Type 

Carl Tide 184 106.2' 22.2' December 18, 1965 Tow service 

Sargent 112’ 1985 Motor vessel 

Jake (3) 88 86’ 24’ 1985 Motor vessel 

Miss Four 

Hundred 65 61.6’ 18.4’ January 5, 1969 

Wooden fishing 

vessel 

L & L 38 47.8’ 18.1’ January 26, 1969 

Wooden fishing 

vessel 

Measurements are taken from Merchant Vessels of the U.S. (MVUS). 

Of these vessels, Miss Four Hundred and L&L are reported to be wooden ships, although 

they are both much smaller than the dimensions recorded for the study vessel listed in the NOAA 

AWOIS record. The vessels Sargent and Carl Tide are the only wrecks with available 

dimensions that fit within the general reported dimensions of the unidentified wooden wreck. 

The composition of these two vessels is unknown. Sargent has the closest dimensions to the 36.5 

m (120 ft) by 5.5 m (18 ft) reported in the NOAA database. This vessel sank in 1985; the date of 

construction is unknown. The NOAA record for Site 380 is fairly limited and does not give any 

indication about the condition or age of the reported wooden shipwreck. Although wooden 

construction is often indicative of a historic shipwreck, wooden-hulled vessels are still built 

today (Section 4.1.3). 

For the majority of human maritime history, wood was the most common building material 

for ocean-going vessels. Wooden shipbuilding declined in the late-19th century when old growth 

timber supplies became scarce and iron and, later, steel production were industrialized. Wooden 

shipbuilding came back into fashion for a short time during World War II due to steel shortages 

(Christensen and Angerer 1977). Today, although composite materials are the most common for 

hull construction, some shipyards still build wooden-hulled vessels for recreational, commercial, 

and even military applications (Christensen and Angerer 1977; Brassieur 1989). 

No evidence of a sunken wooden ship was evident within the area inspected by divers. The 

objects identified on site were not indicative of a historic shipwreck. It appears that either the 

coordinates for the wreck site supplied in the NOAA database were incorrect, or the wreck is no 

longer present at this location. If the published coordinates are incorrect, it is likely that they are 

off by more than 300 m (~1,000 ft). The geophysical data indicates that although scattered 

magnetic anomalies were identified within the survey grid, the majority of these were small or 

restricted to a single survey line. No sonar targets were apparent on the seafloor and no buried 

objects were identified on the sub-bottom profiler data. Multibeam data was also unable to 

identify any seafloor targets or structures. The only magnetic anomaly cluster was centered in the 

area investigated by divers. It is also possible that in the intervening time since 1994, when the 

NOAA AWOIS record was entered, the shipwreck designated as Site 380 was salvaged, possibly 

as a direct result of the diver investigation mentioned in the reference. The scattered objects, 

specifically the metal strap, appear to be the source of the magnetic anomalies at the site. These 
148 

objects may have been intrusive and unrelated to a shipwreck, but it is possible that they are 

associated with a previously salvaged wreck site or salvage operations. If these objects were 

associated with the wreck, there is not enough material to determine the nature or construction of 

the vessel. If the wreck was salvaged, it most likely consisted of an intact hull. In this 

environment, because of wood-boring organisms and high energy dynamics, a wooden-hulled 

wreck would not maintain structural integrity for long. If an intact wooden wreck was salvaged 

at this location, it was likely a recent wreck that had not had time to experience significant 

deterioration. 

4.2.2 Site No. 433, Ship Shoal Area, Probable R.W. Gallagher 

Based on the probability model developed by Pearson et al. in 2003, the study site is located 

within an area considered to have a high probability for shipwreck occurrence. According to CEI 

(1977), Site 433 was seaward of the most frequent routes of coastal exploration used during the 

16th and 17th centuries (CEI 1977: Plate 6), and in close proximity to coastal sailing routes used 

during the 18th and 19th centuries (CEI 1977: Plates 7 and 8). The site is not located directly 

within any major shipping routes used during the first half of the 20th century, but it is adjacent 

to routes running from Cameron, Louisiana, and Port Arthur, Texas, between the Straits of 

Florida (CEI 1977: Plate 9). Based solely on the wreck’s location, the vessel is most likely 

associated with activities from the 18th century onward. 

 

Based on the acquired geophysical datasets and diver investigations conducted in 2010, the 

study site is interpreted as a steel-hulled tanker or freighter with massive breaches in the hull; 

these are interpreted as torpedo holes. A total of 15 vessels of similar type and dimension were 

reportedly sunk by torpedo attack off the Louisiana coast during World War II. A comprehensive 

list of 55 vessels lost within a radius of 56 km (35 mi) was compiled and analyzed as potential 

candidates for the wreck at Site 433. Of these reported wrecks, details such as length and gross 

tonnage were available for 45 vessels. The size of the Site 433 wreck and the apparent torpedo 

holes indicated that the vessel was most likely the victim of a German U-boat attack. Of these, 

the vessels detailed in Table 4.2 have been selected as possible candidates for Site 433, based on 

their reported location at the time of sinking and their overall dimensions. The vessels 

Sheherazade and R.M. Parker. Jr. are located in the general vicinity of Site 433, but have been 

identified through a previous study and nominated for inclusion on the NRHP (Enright et. al. 

2006). 

 

 
149 

Table 4.2 

 

Reported U-boat Casualties in the Vicinity of Site 433 

Vessel Name 

Gross 

Tonnage Length Breadth Date of Sinking Vessel Type 

Ontario 1 3009 292.2’ 42.2’ May 7, 1942 Freighter 

Gulfoil 2 5188 383’ 51’ May 16, 1942 Tanker 

Heredia 2 4732 378.8’ 49.8’ May 19, 1942 Freighter 

Hamlet 3 6578 

408.5’ 

(LOA)7 55.2’ May 27, 1942 Tanker 

Cities Service Toledo 2 8192 465.2’ 60’ June 12, 1942 Tanker 

Cities Service Toledo 5

480’ 

(LOA) 

Rawleigh Warner 1 3663 322’ 46’ June 23, 1942 Tanker 

Bayard 4 2160 

315.2’ 

(LOA) 44.3’ July 6, 1942 Passenger 

R.W. Gallagher 2 7989 445.4’ 64.2’ July 13, 1942 Tanker 

R.W. Gallagher 5, 6 

463’ 

(LOA) 

Sources: (1) BOEM Database, (2) MVUS (length on tonnage deck), (3) Kjærvik and Tandberg 1985, (4) Redaksjonen 2011, 

(5) Bethlehem Shipbuilding 1938, (6) Standard Oil 1946 (7) Length Overall (LOA). 

The measured dimensions from the geophysics indicate that Site 433 measures 

approximately 140 m (458 ft) by 22 m (72 ft). Because the vessel is upside down and the top half 

is buried in the seafloor, it was not possible to obtain the overall length of the vessel from stem to 

stern. A transom stern appears to extend into the mudline, indicating that the overall length of the 

vessel at topsides may be slightly longer than the exposed portion. It is also possible that the 

large break in the hull could impact the accuracy of length overall measurements. Because much 

of the vessel appears to be listing to starboard and the upper portion of the hull is buried in the 

mudline, it is not possible to obtain accurate breadth measurements. 

As discussed in Chapter 2, published measurements often vary because of differing reference 

points. The overall variability among these numbers can be as small as 3 percent and as large as 

13 percent. This is based on a comparison of measurements from large World War II-era tanker 

and freighter class vessels for which length and breadth measurements were available using both 

length overall measurements and length on tonnage deck. Based on the measurements included 

in Table 4.2, Cities Service Toledo and R.W. Gallagher appear to be the only vessels in the same 

length class as Site 433. Both vessels also have similar breadths. Based on the results of the 

geophysics, it is apparent that Site 433 is not Heredia as was once postulated (Section 3.2.1), due 

in part to the 24-m (79-ft) difference in length and 3-m (10-ft) difference in breadth between Site 

433 and the known dimensions of Heredia. 

The published length overall measurement for Cities Service Toledo is 146 m (480 ft). Based 

on the geophysics, Site 433 is 6.7 m shorter (22 ft) and 3.7 m (12 ft) narrower than Cities Service 

Toledo. Site 433 measures 13.7 m (45 ft) longer and 2.4 m (8 ft) narrower than the MVUS 
150 

dimensions for R.W. Gallagher, but there is only a 1.5-m (5-ft) difference in the published 

overall length. No other known wrecks are reported in this portion of the GOM with similar 

dimensions as the wreck at Site 433. 

Overall dimensions taken from Tesla’s geophysical data and observations made during the 

2010 diver investigation were found to be consistent with known details of the R.W. Gallagher. 

The published length overall of R.W. Gallagher, 141 m (463 ft), is slightly longer than the 140 m 

(458 ft) measured from the geophysical data. Considering that a small portion of the transom 

stern appears to be buried in the mudline, these measurements appear to correlate very closely. 

R.W. Gallagher was investigated in the 1980s by Avery Munson, and his observations of the 

wreck site were similar to those made during the 2010 dive investigation (Avery Munson 2011, 

pers. comm.). At the time of his investigations, Munson determined that Site 433 was the 

remains of R.W. Gallagher (BOEM Database 2011). During his years of researching World War 

II-era wrecks in the GOM, Munson obtained a copy of the plans for a class of vessels that 

included R.W. Gallagher from Bethlehem Shipbuilding before the company was sold in 2003. A 

copy of the plans was provided to the study by Mr. Munson and is included in Appendix E 

(Figure E-1). The plans are specifically for Esso hull no. 4306, but were duplicated and used for 

hulls no. 4307 (R.W. Gallagher), no. 4308, no. 4309, and no. 4349 (Bethlehem Shipbuilding 

1938). After the sale of Bethlehem, company records were accessioned to the Hagley Museum 

and Library, including a table containing hull measurements and launching dates. A measured 

drawing of R.W. Gallagher was obtained from the William A. Baker Nautical Collection housed 

at the MIT Museum (Appendix E; Figure E-2). 

R.W. Gallagher was a steel-hulled, steam-screw tanker built in 1938 by Bethlehem 

Shipbuilding Corporation of Sparrow’s Point, Maryland, for Standard Oil Company of New 

Jersey (Department of Commerce (MVUS) 1942) as part of Standard Oil’s “Esso” fleet (Figure 

4.1). The vessel was built to operate as a crude oil tanker within Standard Oil’s fleet and was one 

of five sister ships (Standard Oil 1946). Esso Baton Rouge (hull no. 4306), R.W. Gallagher (hull 

no. 4307), Esso Baltimore (hull no. 4308), and Esso Charleston (hull no. 4309) were all built 

from the same plan in 1938. Esso Nashville (hull no. 4349) followed in 1940. In an official 

number request that Bethlehem Shipbuilding submitted for the vessel on July 29, 1938, the 

vessel is described as having a plain head, elliptical stern, one deck, and two masts. Ship 

construction commenced on January 11, 1937, and the launch date was recorded as January 22, 

1938. The 7,989 gross ton vessel reportedly measured 135.8 m (445.4 ft) in length on tonnage 

deck, 19.6 m (64.2 ft) in breadth, with 10.7 m (35.2 ft) depth of hold (Bureau of Marine 

Inspection and Navigation [BMIN] 1937; MVUS 1942). An overall length measurement of 

approximately 141 m (463 ft 1-1/4 in) was reported in a document detailing the Esso fleet 

published by Standard Oil in 1946 and was corroborated by the table acquired from the Hagley 

Museum and Library (Standard Oil 1946; Hagley Museum and Library Bethlehem Steel 

Collection). The vessel was likely named for Ralph W. Gallagher, Vice President and member of 

the Executive Committee of Standard Oil in 1937 (Larson et al. 1971). 
 

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152 

Of the 52 men aboard the vessel at the time of the attack, nine crewmen and one naval guard 

were lost in the sinking (USCG 1942-1944a). A total of 12 U.S. Naval Armed Guardsmen were 

on board the vessel during its final run (USCG 1942-1944a). The injured were reportedly taken 

to the Marine Hospital in New Orleans; one crew member reportedly died in the Marine 

Hospital in Baton Rouge (Henderson 1942; USCG 1942-1944a). 

As stated above, the account of the sinking indicates that the vessel was struck by two 

torpedoes on the starboard side, at the no. 3 cargo tank and the pump room forward of the engine 

room. A site map based on the combined geophysical data and diving operations indicates that 

there are two large holes in the hull, both located on the starboard side of the wreck (Figure 4.2). 

The larger of the two is forward of amidships and the smaller is aft of amidships. Line drawings 

and site plans of R.W. Gallagher illustrate the location of these compartments (Appendix E; 

Figures E-1-2) and verify that the breaches in the hull of Site 433 match closely with these 

locations on the wreck. The vessel reportedly listed to starboard during sinking, which 

corresponds with the observed condition of the wreck on the seafloor. 
Figure 4.2. Site plan of Site 433, based o

153 

n diver investigation and remote sensing data. 
154 

Two generally available primary sources contain location information for World War II 

casualties in the GOM. The first is the Navy’s Summary of Statements by Survivors, prepared 

based on interviews conducted shortly after the sinking. The second source is the coordinates 

recorded by the German U-boat captains. Rohwer published locations from U-boat records in the 

German archives that describe the approximate coordinates for attacks based on the German map 

convention used in the GOM (Appendix D; Map D-3). Unfortunately, the published version of 

this map is small and does not provide a great deal of detail; however, it is still useful for 

estimating the approximate position of World War II torpedo victims. Rohwer also included 

coordinates that he reports as having come from “Allied Sources,” but he does not elaborate on 

the source of that information (Appendix D; Map D-1). In some cases, Rohwer’s “Allied Source” 

coordinates correspond with the Summary Statements locations, in some cases they correspond 

with the coordinates published in the MVUS publication, and in other cases they do not correlate 

with any source identified through this research. 

There is a degree of variability in the reported positions of sinking for R.W. Gallagher

(Appendix D; Map D-2). In the Navy’s Summary of Statements by Survivors (Henderson 1942), 

the reported position for R.W. Gallagher when attacked falls almost directly between the location 

of Sites 433 and 386, falling approximately 3.5 km (2.2 miles) SSW of Site 433. The MVUS lists 

this same set of coordinates for R.W. Gallagher (1945). 

Information archived by the Navy includes a document (Serial no. 19284) dated January 18, 

1944, from Lieutenant Paul W. Kraemer (Kraemer 1944). This document, titled “R.W. Gallagher 

(Tk), Wreck no. 628, Determination of depth of water above the wreck of” reports that the 

shipwreck site was identified in 27.4 m (90 ft) of water. Significant oil slicks were present for 

several hundred yards north of the buoy that had been placed to signify the wreck’s location. 

Divers investigated the wreck in order to attach marker buoys. They determined that the wreck 

was “turned over on her beam ends and well buried in the soft bottom.” Soundings were then 

performed to verify that at least 15.2 m (50 ft) of clearance were available for navigation over the 

wreck. It was determined that a minimum of 18 m (59 ft) of clearance was present. Coordinates 

in this document are similar to those provided in the Summary Statement of Survivors account 

and put the wreck 1,341 m (4,400 ft) NE of the position published by Henderson and MVUS. 

Based on the U-boat accounts published in Rohwer (1983), the position for R.W. Gallagher

seems to plot in the general vicinity of Site 433. Rohwer (1983), however, provides a second set 

of coordinates for the wreck, which places the site in approximately 4.5 m (15 ft) of water near 

Ship Shoal. Rohwer does not cite the source for the second set of coordinates, instead simply 

referencing “Allied Sources.” Map D-2 in Appendix D shows both the Rohwer and 

Henderson/MVUS positions for R.W. Gallagher in relation to Site 433. It should be noted that 

Rohwer (1983) states that all latitude-longitude coordinates are given in degrees minutes. This 

correlates with the convention used in U.S. government documents at the time, including the 

Summary of Statements by Survivors and MVUS publications. The coordinates given by 

Rohwer for R.W. Gallagher do not match any other coordinate identified through this research. 

Interestingly, if Rohwer’s coordinates for the wreck are plotted as latitude-longitude decimal 

degrees instead of degrees minutes, they plot in close proximity to Site 433. 
155 

A more detailed account of R.W. Gallagher’s sinking is given by Captain Aage Petersen, and 

published in Ships of the Esso Fleet in World War II (Standard Oil 1946). This account indicates 

that the vessel was following a standard coastal route on course for the Ship Shoal Buoy (which 

was supposed to flash white). The buoy was not seen (the Captain later postulates that the U-boat 

may have extinguished its light), so the vessel continued on course toward the green Ship Shoal 

Wreck Buoy. As R.W. Gallagher approached the green Ship Shoal Wreck Buoy, the ship was 

attacked. Ship Shoal refers to both a drowned sand shoal that runs parallel to the Louisiana Coast 

in approximately 6.7 m (22 ft) of water and also to the federal oil and gas lease protraction that 

encompasses this portion of the GOM. Water depths over the shoal itself range from 3 to 4.8 m 

(10–16 ft). Numerous accounts of U-boat attacks are referenced in relation to the Ship Shoal 

Buoy (Henderson 1942; Powers 1942a; and Smith 1942). It is unknown if this buoy would have 

been located directly over the shoal itself, or further offshore closer to the locations provided by 

Henderson (1942), Kraemer (1944), and MVUS (1945). According to the U.S. Coast Pilot (U.S. 

Department of Commerce 1936), there were two navigation beacons in the vicinity of Ship Shoal 

at this approximate time. The first is Ship Shoal Lighthouse, which was located directly over the 

shoal in approximately 4.3 m (14 ft) of water. The lighthouse was reportedly visible from a 

distance of 19 km (12 miles). The second was Ship Shoal Lighted Whistle Buoy 2, located 29 

km (18 miles) from the Ship Shoal Light at a bearing of 177 degrees (U.S. Department of 

Commerce 1936). The Lighted Whistle Buoy 2 would have been in close proximity to Site 433 

and the coordinates for R.W. Gallagher published in Henderson and MVUS. If one assumes that 

Capt. Petersen was referring to the lighthouse and the Lighted Whistle Buoy, then his account 

correlates closely with Navy and MVUS coordinates for the wreck as well as the location of Site 

433. 

Site 433 lies upside down on the seabed; therefore, diagnostic elements are somewhat 

limited. R.W. Gallagher is known to have been an oil tanker built in 1938, with a single screw 

propeller. A single screw propeller was identified on Site 433. In addition to the measurements 

and observations at the vessel’s stern, what has been identified as a bilge keel was recorded from 

diver observations. By the early- to mid-20th century, bilge keels were extremely popular for 

reducing rolling in vessels while at sea. Manning writes, in his 1942 Manual for Ship 

Construction, that bilge keels had been proven in this capacity, and “they are therefore fitted on 

practically all ships at the turn of the bilge, extending from 50 to 75 percent of the length of the 

hull...” (1942:75). The ubiquity of the bilge keel and the single screw do not provide enough 

evidence to conclusively identify the site alone. Figure 4.3 details the sterns of Sites 433 and 373 

as recorded during diver investigation, and compares these details with the ship’s plans acquired 

for the R.W. Gallagher hull type and J.A. Bostwick (Cities Service Toledo). The diver 

observations support the identification of Site 433 as R.W. Gallagher, based on the straight 

transition from keel to propeller well and the observed shape of the rudder. What was left at Site 

373 indicates that the propeller well was curved, corresponding with the detailed plans acquired 

for J.A. Bostwick. Both vessels underwent refits after their initial construction, but there is no 

evidence that the rudder and propeller assemblies and stern hull shapes were altered and so can 

be used as identifying details. 
The 

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156 

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157 

1977: Plate 9). Based solely on the wreck’s location, the vessel is most likely associated with 

activities from the 18th century onward. 

Site 386 has been tentatively identified as the SS Heredia. The reported location of R.W. 

Gallagher lies approximately 6.18 km (3.84 miles) to the north; no other reported shipwrecks are 

located in the immediate area. Based on the acquired geophysical data and diver investigations 

conducted in 2010, the study site is interpreted as an upright steel-hulled ship with severe site 

disarticulation. A comprehensive list of 55 reported wrecks within 56 km (35 miles) of Site 386 

was compiled and analyzed as a starting point for identifying the wreck. Of these reported 

wrecks, details, such as length and gross tonnage, were available for 45. The number of 

similarly-sized vessels that are reported to have sunk in this part of the GOM is limited and 

virtually all were victims of German U-boat attacks during World War-II; a total of fifteen 

comparable vessels were identified (Appendix D, Map D-1). The following table details World 

War II-era casualties of German U-boats that have been selected as possible candidates for Site 

386, based on their reported location of sinking and their overall dimensions. The vessels 

Sheherazade and R.M. Parker. Jr. are located in the general vicinity, but have been identified 

through a previous study and nominated for inclusion on the NRHP, and have therefore been 

excluded as possible candidates for Site 386 (Enright et. al. 2006). 

Table 4.3 

 

Reported U-boat Casualties in the Vicinity of Site 386 

Vessel Name 

Gross 

Tonnage Length Breadth

Date of 

Sinking 

Vessel 

Type 

Ontario 1 3009 292.2’ 42.2’ May 7, 1942 Freighter 

Gulfoil 2 5188 383’ 51’ May 16, 1942 Tanker 

Heredia 2 4732 378.8’ 49.8’ May 19, 1942 Freighter 

Hamlet 3 6578 

408.5’ 

(LOA) 55.2’ May 27, 1942 Tanker 

Cities Service 

Toledo 2 8192 465.2’ 60’ June 12, 1942 Tanker 

Cities Service 

Toledo 5

480’ 

(LOA) 

Rawleigh Warner 1 3663 322’ 46’ June 23, 1942 Tanker 

Bayard 4 2160 

315.2’ 

(LOA) 44.3’ July 6, 1942 Passenger 

R. W. Gallagher 2 7989 445.4’ 64.2’ July 13, 1942 Tanker 

R. W. Gallagher 5,6

463’ 

(LOA) 

Sources: (1) BOEM Database, (2) MVUS (length on tonnage deck), (3) Kjærvik 2011, (4) Redaksjonen 2011, (5) Bethlehem 

Steel Collection courtesy of Hagley Museum & Library, (6) Standard Oil 1946. 

The combined geophysical data over Site 386 indicates that the wreck measures between 112 m 

(367 ft) and 119 m (390 ft) in length, with an estimated breadth of 19 m (62 ft). Based on the 

combined sonar and multibeam bathymetry data, it appears that a portion of the vessel’s stern has 
158 

broken off and lies virtually flush with the seabed. This debris scatter is irregular and makes it 

difficult to obtain a precise measurement. It appears that the 119 m measurement is a more 

accurate assessment of the vessel’s original overall length. Because the vessel is listing to 

starboard and appears to have been heavily damaged, there is no way to obtain a precise 

measurement of the vessel’s breadth. 

Table 4.3 indicates that vessels in the same class as Site 386 are limited to GulfOil, Hamlet, 

and Heredia. Measurements for GulfOil and Heredia are length on tonnage deck, so it is likely 

that both ships are an estimated 3-14 % longer than the published dimensions; published length 

for Hamlet is length overall and should correlate directly with observed overall measurements 

from geophysical data. 

Based on Rohwer’s (1983) coordinates (Appendix D; Map D-1), Hamlet was sunk in the 

Eugene Island federal lease protraction in approximately 42.6 m (140 ft) of water. Gulf Oil was 

lost in the Mississippi Canyon lease protraction in over 300 m (1,000 ft) of water (Rohwer 1983). 

A wreck was located at a depth of approximately 610 m (2,000 ft) and identified as GulfOil

during the Lophelia deepwater studies commissioned by MMS (later BOEMRE, now BOEM) 

(BOEMRE 2010). Hamlet has been tentatively identified by a geophysical lease survey 40 km 

(25 mi) ESE of Rohwer’s published coordinates (BOEM database 2011). The BOEM database 

indicates that, based on sonar data, the length of the wreck was 152 m (500 ft). This length is 

inconsistent with information obtained for Hamlet, which indicates that the vessel was 124.5 m 

(408.5 ft) in length overall (Kjærvik and Tandberg 1985). 

Before investigation in 2010, Site 386 was tentatively identified as the freighter Heredia, 

based on Avery Munson’s communications with MMS (BOEM database 2011). Although the 

vessel could not be comprehensively investigated by divers during the course of this study, the 

reported location of sinking, overall measurements, vessel shape, and visible diagnostic 

components observed on geophysical data were found to be consistent with those of Heredia. 

Heredia was built in 1908 by Workman, Clark & Co., in Belfast, Ireland, for the UK 

Tropical Steamship Company, a subsidiary of United Fruit (Goldberg 1993:332). The 4,943 

gross ton passenger liner reportedly measured 115.5 m (378.8 ft) in length, 15.2 m (49.8 ft) in 

breadth, with a 9 m (30 ft) depth of hold (MVUS 1942; Figure 4.4). She was built as part of the 

“Great White Fleet” of passenger liners (Appendix E; Figures E-16-17). The triple deck, steelhulled, steam screw-propelled vessel was fitted with a triple expansion engine and a refrigerated 

cargo compartment. During a run in 1909, Heredia ran aground off the coast of Nicaragua and 

could not be extricated from its position for about a month and a half (Goldberg 1993:333). 

Following the incident, the passenger liner was sent to Newport News, Virginia, for repairs 

(Goldberg 1993:333). She was officially registered in the U.S. in April of 1915, servicing 

shipping and passenger routes to and from New Orleans, Louisiana, with her home port listed as 

New York, New York (BMIN 1914). In 1921, Heredia underwent a major overhaul in the 

Brooklyn yard of Robins Repair Company and her adjusted gross tonnage was reported as 4,734. 

The boilers were converted from steam to oil burners and passenger spaces were rearranged 

throughout the superstructure (OCNO 1942a; 1942d; Goldberg 1993:335). 
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160 

carrying a cargo of 1,400 tons of fruit, 412 tons of coffee, 38 tons of cocoa, 6 tons of 

pharmaceuticals, 3 tons of miscellaneous cargo and eight passengers (USMC 1942d; USCG 

1942-1946). Reports following the attack indicate that the vessel was fired upon by at least two 

submarines. The dual U-boat attack reports, however conflict with other sources. According to 

Rohwer (1983), only U-506 claimed responsibility for the attack. Research conducted at the 

German archives by C. J. Christ and supplemented by interviews with German U-boat personnel 

did not find any evidence that two submarines fired upon the same vessel in the GOM theatre 

(Christ 2011 pers. comm.). 

What is not in dispute is that the first and second torpedoes struck portside and the third 

struck amidships on the starboard side of the vessel (Powers 1942a). The reports of torpedo 

strikes on both sides of the vessel may be responsible for the accounts of multiple U-boats. 

Conversations with C. J. Christ of the Regional Military Museum in Houma, Louisiana indicated 

that another explanation could account for the conflicting locations of torpedo strikes. When a 

vessel was hit on one side while under way, the vessel would have listed to one side while the 

engines were turned “hard over,” subsequently turning the vessel about. This may account for the 

location of additional torpedo strikes on the opposite side of the original strike (Christ 2011 pers. 

comm.). At the time of sinking, Heredia was fitted with a three-gun complement and six 

lookouts were on duty (Powers 1942a). Survivor statements reported that the vessel burned as 

she sank and was completely submerged in approximately three minutes (USCG 1942-1946). 

Würdemann’s account of the sinking reported that Heredia sank quickly but unevenly, with the 

stern hitting bottom first (Wiggins 1995). According to remarks attributed to Würdemann, after 

the stern end sank “the forecastle up to the bridge for the moment is still sticking up out of the 

water but going down too ... several brightly illuminated lifeboats and rafts were lowered” 

(Wiggins 1995:46). 

Of the reported 48 crewmen and six naval armed guards, 30 crewmen were lost in the attack, 

including 28 regular crew and two crew members who had joined the ship during the voyage, 

five of the Navy gun crew, and one passenger (Powers 1942a; USCG 1942-1946). Most 

surviving passengers and crew were rescued by passing trawling vessels, including Papa Joe, 

Conquest, and J. Edwin Treakle, and were transported to Morgan City, Louisiana (Powers 

1942a; USCG 1942-1946). Three survivors were rescued by seaplane and taken to New Orleans 

(Powers 1942a; USCG 1942-1946). 

There is a significant degree of variability in the reported positions of sinking for Heredia. In 

the Navy’s Summary of Statements by Survivors (Powers 1942a), no coordinates for the wreck 

are given. Instead, survivors reported that the vessel was attacked 3 km (2 miles) SE of the Ship 

Shoal Buoy. This is assumed to be the same buoy that R.W. Gallagher reportedly passed just 

before her attack. However, no records could be identified which provide a location for any buoy 

with this name in 1942. Heredia reportedly went down quickly and forcefully, driving the stern 

into the seafloor while the bow was still afloat. Under these circumstances the vessel should have 

sunk in place and would not have floundered or floated far from the reported location of attack. 

Coordinates published by Rohwer (1983) place Heredia in relatively shallow water near Ship 

Shoal (in close proximity to his coordinates for R.W. Gallagher). These coordinates place the 

vessel 42 km (26 miles) NNW of Site 386 (Appendix D; Map D-2). The vessel that attacked 
161 

Heredia, U-506, had a draft of 4.7 m (15.5 ft) (Möler and Brack 2004:98), meaning it could not 

submerge in water depths much less than 6 m (20 ft). Water depths over Ship Shoal currently 

range from 3 to 4.8 m (10 to 16 ft) and ambient water depths around the shoal are approximately 

6.7 m (22 ft), making it unlikely that a U-boat would have attacked Heredia in such shallow 

waters, or that a liner of Heredia’s size would have sailed so close to a charted shoal. However, 

as discussed in Section 4.2.2, if Rohwer’s coordinates are assumed to be latitude-longitude 

decimal degrees, they plot in close proximity to the reported location for Site 386. 

The coordinates reported in the MVUS (1945) place the wreck of Heredia in 915 m (3,000 

ft) of water, directly south of Sites 386 and 433 (Appendix D; Map D-2). No direct source is 

attributed for the MVUS coordinates, and it appears probable that they are incorrect, because 

these water depths do not correlate with the account of the sinking which stated that the vessel’s 

stern hit the seafloor (Wiggins 1995:46). Complicating the issue, the position published in 

Rohwer based on German U-boat map convention places Heredia in relatively deep water, and 

in close proximity to the MVUS plotted position (Appendix D; Map D-3). 

Despite the discrepancies in published coordinates, the combined data sets, including 

survivor statements, vessel dimensions, information provided by Avery Munson and C.J. Christ, 

and geophysical data, especially the imagery obtained from the side scan sonar and multibeam 

bathymetry data, Site 386 appears to be the remains of Heredia. Figure 4.5 shows a site plan 

prepared from the combined multibeam and sonar data compared with a historic photograph of 

Heredia (when it was operating as General Pershing). 
 Ham

to one an

(408.5 ft

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length co

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Figure 4.5.

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162 

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and Munson

70s and 1980

dia. 

4.6. Photo

, South Ma

obability mod

dered to hav

ite 373 was 

17th centuri

he 18th and 1

es used dur

Arthur, Texa

n, the vessel 

e list of 63 

reported wre

ed geophysic

a steel-hulle

ips 1944). Th

fic informat

s a result of

as menaces 

molished, or

t for the wre

re uncovered

n (2011, per

0s, they iden

graph of Ham

arsh Island

del develope

e a high prob

seaward of 

ies (CEI 197

19th centurie

ring the firs

as to the Str

is most like

wrecks with

ecks, 59 had

cal datasets a

ed tanker or 

163 

he survey w

tion on the 

f operations 

to navigatio

r was demo

eck’s appeara

d as part of 

rs. comm.) i

ntified diagn

mlet, date unk

d Area, Pro

ed by Pearso

bability for 

the most fre

77: Plate 6), 

es (CEI 1977

t half of th

aits of Flori

ely associate

hin 56 km (3

d recorded de

and diver inv

freighter w

work was con

survey loca

in 1944, at 

on, and it i

olished as 

ance and ext

this research

indicate that

nostic elemen

known (Helga

obable Citie

on et al. in 2

shipwreck o

equent route

and in close

7: Plates 7 an

he 20th cent

ida (CEI 197

ed with acti

35 miles) of

etails, such 

vestigations 

with apparent

nducted by th

ation is prov

least 11 nam

s possible t

an unidenti

tremely disa

h. Conversa

t during divi

nts on the w

son 2011). 

es Service

2003, the stu

occurrence. A

s of coastal 

e proximity 

nd 8). The s

tury running

77: Plate 9).

ivities from 

f Site 373 w

as length an

conducted i

t torpedo ho

he Navy Tra

vided, other 

med wrecks 

that Heredia

ified menac

articulated na

ations with C

ing investiga

wreck which 

e Toledo 

udy site is lo

According to

exploration

to coastal sa

ite lies withi

g from Cam

. Based sole

the 18th ce

was compiled

nd gross ton

n 2010, the 

les. A total 

aining 

than 

were 

a was 

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ature. 

Christ 

ations 

were 

ocated 

o CEI 

n used 

ailing 

in the 

meron, 

ely on 

entury 

d and 

nnage. 

study 

of 15 
164 

vessels of similar type and dimension were reportedly sunk by torpedo attack off the Louisiana 

coast during World War II. Of these, the vessels detailed in table 4.4 have been selected as 

possible candidates for site number 373. The vessels Sheherazade and R.M. Parker. Jr. are 

located in the general vicinity, but were identified through a previous study and may be eligible 

for nomination to the NRHP (Enright et. al. 2006). They are excluded as possible candidates for 

the vessel at Site 373. 

Table 4.4 

 

Reported U-Boat Casualties in the Vicinity of Site 373 

Vessel Name 

Gross 

Tonnage Length Breadth 

Date of 

Sinking Vessel Type 

Ontario 1 3009 292.2’ 42.2’ May 7, 1942 Freighter 

Gulfoil 2 5188 383’ 51’ May 16, 1942 Tanker 

Heredia 2 4732 378.8’ 49.8’ May 19, 1942 Freighter 

Hamlet 3 6578 

408.5’ 

(LOA) 55.2’ May 27, 1942 Tanker 

Cities Service Toledo 2 8192 465.2’ 60’ June 12, 1942 Tanker 

Cities Service Toledo 5

480’ 

(LOA) 

Rawleigh Warner 1 3663 322’ 46’ June 23, 1942 Tanker 

Bayard 4 2160 

315.2’ 

(LOA) 44.3’ July 6, 1942 Passenger 

R.W. Gallagher 2 7989 445.4’ 64.2’ July 13, 1942 Tanker 

R.W. Gallagher 5,6 

463’ 

(LOA) 

Sources: (1) BOEM Database, (2) MVUS (length on tonnage deck), (3) Kjærvik 2011, (4) Redaksjonen 2011, (5) Bethlehem 

Steel Collection courtesy of Hagley Museum & Library, (6) Standard Oil 1946. 

Based on the geophysical data, Site 373 measures 141 m (463 ft) by 19.8 m (65 ft). In Table 

4.4., vessels identified with similar dimensions are limited to Cities Service Toledo and R.W. 

Gallagher. 

Before investigation, this vessel had been tentatively identified as Cities Service Toledo. 

Component measurements taken during the 2010 diver investigation were consistent with ship 

plans (Appendix E; Figures E-27-29) acquired from the Hagley Museum’s Bethlehem Steel 

archival collection (Bethlehem Shipbuilding 1938); however, this was not sufficient to absolutely 

identify the wreck as Cities Service Toledo. The published overall length of R.W. Gallagher is 

141 m (463 ft), which matches precisely with the measured length of Site 373, but this 

measurement may be misleading. The uppermost portion of the transom stern is partially buried 

at the site of the inverted hull, reducing the overall measurement available from the data. If this 

is indeed the case, R.W. Gallagher is too short to be the wreck at Site 373 and the measurements 

acquired from geophysical data are more consistent with the 146 m (480 ft) measurement of 

Cities Service Toledo. In addition to the measurements, the account of the sinking and 

corresponding locations of the torpedo holes supports the identity of this wreck as the tanker 

Cities Service Toledo. 
Cities

Delaware

for offici

1918 (BM

describes

decks, on

listed me

(26.4 ft) 

industria

Vessels o

was desi

converted

Service T

Company

On A

Administ

of that y

Highway

held acco

armed in

Brownin

guns loc

8,192 (O

On Ju

under th

governm

Kapitänle

tanker w

s Service To

e, for Standa

ial number w

MIN 1918).

s the vessel 

ne mast, qua

easurements 

depth of h

list and oneof the U.S. as

gnated in th

d to oil no l

Toledo follo

y (BMIN 19

Figure 4.7

April 20, 1

tration unde

year, the ves

y Yard in Ba

ommodation

nstallations: 

g MK 2 mac

ated on pill

CNO 1942c

une 12, 194

e command

ment. During

eutnant Eric

was transporti

ledo was bu

ard Oil Com

was filed by

 The reques

as a 7,929

adruple expa

were given 

old (BMIN 

-time Standa

s an oil-pow

he annual M

later than 19

wing a chan

29). 

7. Cities Serv

1942 Cities 

r contract no

ssel underw

altimore, Ma

ns for 12 arm

one 5-inch 

chine guns l

lboxes on th

c; 1942g). 

2, the vesse

d of Captain

g this run, 

ch Rostin (

ing a cargo 

uilt in 1918 b

mpany of New

y Bethlehem

st lists the o

9 gross ton, 

ansion engin

as 141.8 m (

1918). The

ard Oil execu

wered steams

MVUS listing

927. On Mar

nge of regist

vice Toledo, d

Service To

o. WSA-161

went arming 

aryland (OCN

med guardsm

.51-caliber M

located on pi

he bridge. T

el was travel

n K. Toivola

the vessel 

(USCG 194

of 80,237 b

165 

by Bethlehem

w Jersey (M

m Shipbuildin

original nam

steam screw

ne, a plain h

(465.2 ft) in 

e vessel was

utive. In 192

hip (MVUS

g as using fu

rch 19, 1929

tered owner 

date unknown

Toledo was 

11-R (USMC

and defensi

NO 1942c; 

men and one

MK 8 gun l

illboxes aft, 

The new ton

ling from H

a, who was 

was attack

2-1944b; Po

barrels of Lig

m Shipbuildi

MVUS 1918-

ng Corporat

me of the ve

w-propelled 

head, and rou

length, 18 m

s likely nam

27, J. A. Bos

S 1927). This

uel oil, and 

9 the vessel 

from Stand

n (Moore 198

time chart

C 1942a). Be

ive restructu

1942g). Whe

e officer. Th

located one 

and two .30

nnage post-re

Harbor Island

operating u

ked by U-1

owers 1942

ght Refugio 

ing Compan

-1942; Figur

tion, Harlan 

essel as J. A

tanker equ

und stern (B

m (60 ft) in b

med J. A. B

stwick was li

s was the fir

suggests tha

name was c

dard Oil to th

83:54). 

ered to the

etween Apri

uring at the

en the vesse

he vessel wa

platform aft

0-caliber Co

estructuring 

d, Texas, to 

under orders

58 under t

2b; Rohwer 

 Crude oil, 

ny in Wilmin

re 4.7). A re

Plant on Ju

A. Bostwick

uipped with 

BMIN 1918)

breadth, with

ostwick afte

isted in Merc

rst time the v

at the vessel

changed to C

he Cities Se

e War Ship

il 27 and Ma

e Bethlehem

el was releas

as also fitted

t, two .50-ca

lt MK 3 ma

was report

Portland, M

s from the U

the comman

1983:103).

or approxim

ngton, 

equest 

uly 9, 

k, and 

three 

. The 

h 8 m 

er the 

chant 

vessel 

l was 

Cities 

ervice 

pping 

ay 20

m Key 

sed, it 

d with 

aliber 

chine 

ed as 

Maine, 

U. S. 

nd of 

 The 

mately 
166 

10,626 tons (USMC 1942e). Four torpedoes were fired into the starboard side, hitting the nos. 

six, seven, four, and five tanks respectively (Powers 1942b). On the fourth strike the vessel 

caught fire, and sank two hours after the attack (Powers 1942b). At the time of the attack there 

were six lookouts on duty (Powers 1942b; Browning 1996:140). 

Of the ship’s 37 crew and nine U.S. Naval Armed Guardsmen, there were reportedly 31 

survivors (USCG 1942-1944b). The survivors include 17 men who escaped in a lifeboat and 14 

others who jumped into the water and were rescued by the passing tankers Belinda, Gulf King, 

and San Antonio (USCG 1942-1944b; Powers 1942b). The merchant crew survivors were taken 

to Burwood, Louisiana, and then transported to New Orleans; the Navy crew members were 

taken to the Naval Section Base in Algiers, Louisiana. The bodies of six crew and three 

guardsmen were recovered and taken to Morgan City, Louisiana. Five crewmen and one Naval 

guard were reported as missing (USCG 1942-1944b; Times Picayune 1942). 

There is some degree of variability in the reported positions of sinking for Cities Service 

Toledo. In the Navy’s Summary of Statements by Survivors (Powers 1942b), the position of the 

attack, when plotted, falls approximately 18 km (11 miles) NNE of Site 373 in 17 m (55 ft) of 

water. This same position is published in Rohwer (1983), who may have used the Summary 

Statements as the source of his information. Although imprecise, the German map convention 

position for the wreck seems to also correlate with this general portion of South Marsh Island, 

offshore of Louisiana (Appendix D; Map D-3). 

The MVUS publication has a different set of coordinates, placing the sinking 74 km (46 

miles) WNW of Site 373 in the East Cameron Federal lease protraction (Appendix D; Map D-2). 

It is unknown where the MVUS coordinates were obtained. 

Despite this degree of variability, of the eight unaccounted-for World War II causalities 

reported in this part of the GOM, only Cities Service Toledo is reported to have been lost in the 

general vicinity of Site 373 (Appendix D; Map D-1). 

Additional evidence supplements the relative correlation of the overall dimensions and the 

reported position of sinking in suggesting that Site 373 is, in fact, the wreck of Cities Service 

Toledo. The account of the sinking appears to correspond with the condition of the wreck site. As 

discussed above, four torpedoes were fired on the starboard side and hit the nos. 6, 7, 4, and 5 

tanks, respectively (Powers 1942b). The largest break in the hull is predominately on the 

starboard side of the vessel, just fore of midships. In addition, a large hole was also observed 

near the starboard bow of the ship. Although the location of each tank is not specified on the 

ship’s plans (Appendix E; Figures E-27-29), it can be assumed from other contemporary ship 

plans that the tanks were numbered consecutively from bow to stern. Following this convention, 

the no. 4 tank corresponds with the foreward hole while the nos. 5, 6, and 7 tanks correspond 

with the much larger break in the hull, just fore of midships. Based on the plans for J.A. 

Bostwick, the vessel was designed so that midships corresponded with the inferred no. 6 tank, 

with nos. 7 and 8 located aft of midships and all other tanks located fore of midships. The 

majority of the aft section of the vessel consisted of the engine room, the boiler room, and the 

fuel oil tanks (Appendix E; Figures E-27-29). 
167 

Since the wreck was inverted, many potentially diagnostic elements were obscured during 

both geophysical and diver survey. The vessel’s hull was comprised of overlapping plates, 

suggesting that the ship was built with the “raised and sunken” system of plate attachment, rather 

than flush or clinker plate arrangements. Contemporary ship construction sources state that this 

was the most common means of steel hull construction during this period (Manning 1942:19-20). 

Although J.A. Bostwick’s plans show extensive detail of the vessel’s stern, as discussed in 

Chapter 3, the propeller and rudder were missing from the wreck site. It is unknown when this 

occurred, but it should be noted that diver investigations in 1971 reported that the rudder was 

present, but that the propeller had been removed (Christ 2006). Due to the sheer size of these 

components, removal would have required a sizable boat and equipment for salvage. Although 

records were not discovered, it is possible that the propeller was removed by the U.S. Navy after 

the sinking, because of war-time shortages of brass, but again this is only conjecture. It is 

unknown when or why the rudder was removed. It does not appear that it was broken; instead, 

the clean nature of the remaining components indicates that the rudder was cut from its fittings. 

Divers investigating the wreck for this study noted that there was a single propeller shaft, whose 

dimensions matched precisely with the dimensions shown on the plans for J.A. Bostwick. Also, 

divers observed that the shape of the propeller well and the stern hull correlate with the design 

depicted on the blueprints of J.A. Bostwick (Figure 4.8; Appendix E; Figure E-29). As illustrated 

in Figure 4.3, stern details of Sites 433 and 373, based on diver observations, show remarkable 

similarities with the ship’s plans acquired for J.A. Bostwick and the R.W. Gallagher hull type. 

Both vessels are known to have undergone refits, and it is possible that some design elements are 

likely to have changed, but it is unlikely that major integral features, such as the rudder assembly 

and hull shape, would be modified significantly from the original construction plans. Therefore, 

it is believed that the stern features recorded from diver observations can be used to identify the 

wreck with a degree of certainty. The diver observations support the identification of Site 373 as 

Cities Service Toledo based on the curved propeller well. The combined lines of inquiry all 

support the identification of Site 373 as the tanker Cities Service Toledo. 
Figure 4.8. Site plan of Site 373, based 

168 

on diver investigation and remote sensing data. 
169 

4.2.5 Site No. 15488, High Island Area, Unknown Modern Wreck 

Based on the probability model developed in 2003 by Pearson et al., the study site is located 

within an area considered to have a high probability for shipwreck occurrence. According to CEI 

(1977:Plates 6-9), Site 15488 was seaward of the most frequent routes of coastal exploration 

used during the 16th and 17th centuries (CEI 1977: Plate 6), seaward of coastal sailing routes 

used during the 18th century (CEI 1977: Plate 7), and between routes used during the 19th 

century (CEI 1977: Plate 8). Site 15488 is located between major shipping routes used during the 

first half of the 20th century running from Port Arthur and Galveston, Texas to the Straits of 

Florida (CEI 1977: Plate 9). Based solely on the wreck’s location, the vessel is most likely 

associated with activities from the 19th century onward. 

Study site number 15488 had no tentative identification prior to this study. A comprehensive 

list of 48 wrecks reportedly lost within 48 km (30 miles) of Site 15488 was compiled, and of 

those included on the list details such as length and gross tonnage were found for 34. Reported 

wrecks in the vicinity of Site 15488 and with similar hull type or dimensions have been detailed 

in Table 4.5 and are the most likely candidates for wreck identification. 

Table 4.5 

 

Reported Shipwrecks in the Vicinity of Site 15488 with Similar Dimensions 

Vessel Name 

Gross 

Tonnage Length Breadth 

Date of 

Sinking 

Vessel 

Type 

Victory 68’ 1990 

Fishing 

vessel 

Laurentine III 77 72.1’ 22.2’ 

September 30, 

1999 

Fishing 

vessel 

Gulf Lee 68’ 1984 

Susan & Gretta 63 60.2’ 17.8’ 

August 12, 

1956 

Fishing 

vessel 

San Antonio (7) 

73/ 

96 

67.3’/ 

78.6’ 

19’/ 

25.9’ 1976 

Towing/M

isc. 

Miss Behave 65’ 

All measurements from Merchant Vessels of the U.S. The 1977 record of loss for San Antonio could not be located. 

Seven vessels named San Antonio were located the year before loss, and dimension ranges for these are shown. 

Geophysical data indicates that Site 15488 measures 21 m (70 ft) by 6 m (20 ft). Each of the 

wrecks shown in Table 4.5 could be the identity of Site 15488; Victory, Laurentine III, Gulf Lee, 

and San Antonio are the most likely candidates. All of the vessels in the table sank before 2001 

(when the wreck was initially discovered) and all have similar dimensions. Based on the diver 

inspections, it appears likely that this vessel is a small workboat similar to any of the above 

vessels. Based on the dimensions, Laurentine III, a steel-hulled fishing vessel built in 1978 in 

Bayou La Batre, Alabama is the most likely candidate, but this vessel was reportedly identified 

by a 2003 geophysical survey in another area (BOEM database 2011). It was not possible to 

acquire additional geophysical data or dive on the wreck previously identified as Laurentine III; 

therefore, no comparisons can be made between the data sets. 
170 

During dive operations at Site 15488 in 2010, the running gear appeared to be a fairly 

common type used in many small working boats. Raised sections or “vanes” were noted near the 

bow and stern, which may have been added to increase stability and/or efficiency while under 

way. Alternatively they could have been components of the engine’s coolant system (Dix 2011, 

pers. comm.). The through-hull transducer is a fairly common addition to both modern working 

and pleasure boats. Due to poor visibility on the site and lack of diagnostic components, a 

detailed site plan was not generated for this wreck. 

Of the known wrecks with similar dimensions reported in the area, Susan and Gretta, built in 

1944 and one of the vessels named San Antonio, built in 1940, meet National Register eligibility 

requirements based on their age alone. Since these vessels are all modern working boats and 

many are owned by small companies or private individuals, there is usually limited information 

available regarding specifications or plans. Based on the dimensions, material of construction, 

propeller, apparent through-hull transducer, anti-fouling paint, and hull vanes, this vessel appears 

to represent a modern working vessel that would not be eligible for the National Register. No 

evidence could be found to indicate specialized design elements that would distinguish this 

vessel from other work vessels, nor does it represent the best example of its type. 

4.2.6 Site No. 15366, Galveston Area, Unknown Modern Wreck 

Based on the probability model developed by Pearson et al. in 2003 the study site is located 

within an area considered to have a high probability for shipwreck occurrence. According to CEI 

(1977:Plates 6-9), Site 15366 is located just seaward of the most frequent routes of coastal 

exploration used during the 16th and 17th centuries (CEI 1977: Plate 6), and in close proximity 

to coastal sailing routes used during the 18th and 19th centuries (CIE 1977: Plates 7 and 8). The 

site lies within major shipping routes used during the first half of the 20th century running to and 

from Galveston, Texas (CEI 1977: Plate 9). Based solely on the wreck’s location, the vessel is 

likely associated with activities from the 18th century onward, with an emphasis on the 20th 

century. 

 

Study site number 15366 had no tentative identification prior to this study. Reported wrecks 

within the vicinity of Site 15366 of similar type and dimension have been researched. A 

comprehensive list of vessels reported within a 48-km (30-mile) radius of the study site was 

prepared. Of the 58 vessels reported within the search radius, 54 had detailed information 

including length or gross tonnage available. Table 4.6 details the strongest candidates for wreck 

identification, based on proximity to the site and overall dimensions. 

Table 4.6. 

 

Reported Shipwrecks in the Vicinity of Site 15366 with Similar Dimensions 

Vessel Name 

Gross 

Tonnage Length Breadth Date of Sinking Vessel Type 

William Hayes 69 76.4’ 21.2’ July 16, 1957 Fishing vessel 

Barbara D. 96 70’ 26’ December 27, 1983 Tugboat 

Bonita 44 72.5 19.6’ July 21, 1909 Schooner 
171 

Vessel Name 

Gross 

Tonnage Length Breadth Date of Sinking Vessel Type 

Keturah 77 83.4’ 21.3’ June 20, 1957 Fishing vessel 

High Liner 73’ September 15, 1998 Fishing vessel 

Measurements from Merchants Vessels of the U.S. 

The geophysical data at Site 15366 indicates that the vessel measures approximately 24.3 m 

(80 ft) by 7 m (23 ft). Bonita is a schooner that wrecked in 1909; based on the diver observations 

of the wreck, it can be excluded from consideration. The remaining five vessels are working 

vessels and are more likely candidates. Keturah and William Hayes have the most similar 

dimensions to the wreck at Site 15366, based on the information summarized in Table 4.6. Based 

on age alone, both vessels are eligible for nomination to the National Register; however, these 

dates do not correlate with the potential terminus post quem of 1986 established in Chapter 3 and 

based on pre-existing survey data surrounding the wreck site. Of the vessels identified in Table 

4.6, only High Liner wrecked later than 1986, and has a similar length measurement as the wreck 

at Site 15366. 

The primary diagnostic component of Site 15366, as identified by divers, was the shrouded 

propeller (Figure 4.9). The shrouded nozzle could have been used on any of the vessels identified 

in Table 4.6, with the exception of Bonita. There are various designs of nozzles, such as the 

“Kort Nozzle,” but, in general, these are shrouded, ducted propeller assemblies typically 

designed for increasing thrust at low speeds, and commonly used on workboats, such as tugs and 

shrimping trawlers (Kort 1938). These devices became common in the early-20th century, and 

versions remain in use today. The hull protrusions and black and white anti-fouling paint could 

help to identify the wreck; however, like Site 15488, archival research is widely unavailable for 

working vessels, such as fishing boats and tugboats in the GOM. Based on the dimensions, 

construction material, shrouded propeller, anti-fouling paint, and hull protrusions, this vessel 

appears to represent a modern working vessel that would not be considered eligible for the 

National Register. No evidence could be found to indicate specialized design elements that 

would distinguish this vessel from other work vessels, nor does it represent the best example of 

its type. Site 15366 is therefore not interpreted as historically significant. 
4.2.7 Sit

Based

within an

(1977), S

during th

routes us

within an

been dire

Louisian

that this w

since the

Befor

(Section 

of the sit

were ide

compreh

compiled

te No. 389,

d on the pro

n area consid

Site 389 is l

he 16th and 

sed during th

ny major shi

ectly along 

a (CEI 1977

wreck repres

 16th centur

re the start o

3.7.1), but t

te. Reported

entified; Tab

ensive list o

d. Of the iden

Figu

, South Tim

obability mod

dered to hav

ocated direc

17th centuri

he 18th and 

ipping route

the path fo

7: Plate 9). B

sents a histo

ry. 

of this study,

there are sev

d wrecks of 

ble 4.7 detai

of 144 wrec

ntified losse

re 4.9. De

mbalier Are

del develope

e a high prob

ctly within t

ies (CEI 197

19th centurie

es used durin

or any vesse

Based solely

oric resource

, Site 389 ha

veral reporte

similar type

ils the stron

cks within 

s, details suc

172 

etail of shroud

ea, Probab

ed in 2003 b

bability for 

the most fre

77: Plate 6), 

es (CEI 197

ng the first h

els traveling

y on the wre

, as it is loca

ad been tenta

ed shipwreck

e and dimens

ngest candida

a 58-km (3

ch as length 

ded propeller.

ble J.A. Bis

by Pearson e

shipwreck o

quent routes

and in close

7: Plates 7 a

half of the 2

g inland into

eck’s locatio

ated in an ar

atively ident

ks located w

sion within 

ates for the 

36-mile) sea

or gross ton

sso 

et al., the stu

occurrence. A

s of coastal 

e proximity 

and 8). The s

20th century

o areas surr

on, there is a

rea of consis

tified as the 

within the im

the vicinity 

wreck at S

arch radius 

nnage were a

udy site is lo

According to

exploration 

to coastal sa

site is not lo

y, but would 

rounding Ho

a high proba

tent vessel tr

vessel J.A. B

mmediate vic

of the study

Site 389. A 

of Site 389

available for 

ocated 

o CEI 

used 

ailing 

ocated 

have 

ouma, 

ability 

raffic 

Bisso

cinity 

y site 

more 

9 was 

80. 
173 

Table 4.7 

 

Reported Shipwrecks in the Vicinity of Site 389 with Similar Dimensions 

Vessel Name 

Gross 

Tonnage Length Breadth Date of Sinking Vessel Type 

J.A. Bisso 224 102.3’ 23.7’ December 7, 1957 Towing vessel 

Carl Tide 184 106.2’ 22.2’ December 18, 1965 Tow service 

Lance 110’ 1993 

Sargent 112’ 1985 Motor vessel 

Joseph H. Davis 135 105,2’ 19.6’ March 2, 1959 Fishing vessel 

Jan H. 185 114.8’ 32.1’ 1965 

Sailboat/ 

Freight 

Atlas (16) 7 to 183 

29.4’–

117’ 

9’–

29.5’ 1974 

Measurements from Merchant Vessels of the U.S. The 1974 record of loss for Atlas could not be located. Sixteen vessels 

named Atlas were located the year before loss, and the range of dimensions for all 16 vessels is shown in the table. 

Based on the geophysical data, Site 389 measures 32 m (105 ft) by 7 m (23 ft). A number of 

vessels that reportedly sank in the area were identified with similar measurements, including J.A. 

Bisso, Carl Tide, and Joseph H. Davis. The vessel sits upright on the seabed; measurements of 

the vessel’s length overall, based on the geophysical data, appear to be fairly accurate. All of the 

available measurements for the vessels in Table 4.7 come from MVUS, and may not fully 

represent overall length from stem to stern (Section 2.1). Based on the combined geophysical 

data and the diver investigations, Site 389 was identified as a probable towing vessel or oceangoing tug. J.A. Bisso and Carl Tide are the only towing vessels identified in Table 4.7 as possible 

candidates for the wreck at Site 389. Based on the reported coordinates of sinking, J.A. Bisso was 

reportedly lost 4 km (2.5 miles) WNW of Site 389, while Carl Tide was reportedly lost 16 km 

(10 miles) to the NNW. The proximity to the reported sinking location, coupled with 

measurements of the wreck site, and photographs of J.A. Bisso supplied by William “Cappy” 

Bisso, support the identification of Site 389 as the towing vessel J.A. Bisso. 

Originally named Alaska, J.A. Bisso was a 224 gross ton, steam screw-propelled tugboat built 

in 1906 in Sorel, Quebec, by G. A. Pontbriand for Sincennes-McNaughton (Figure 4.10; Mills 

2002; Library and Archives Canada 2009). Vessel dimensions are listed as approximately 31 m 

(102 ft) in length, 7 m (24 ft) in breadth with 4 m (14 ft) depth of hold (MVUS 1919). The 

Canadian Vessel Index (Library and Archives Canada 2009) states that Alaska’s registry was 

closed in 1918, and notes that it was sold to Americans. In 1919, J.A. Bisso is first recorded 

under American registry with the owner listed as the New Orleans Coal and Bisso Towboat Co. 

(MVUS 1919). In 1948, Bisso’s registration was amended to refer to an oil screw-propelled tug 

(MVUS 1948). During an interview with William Bisso, it was indicated that J.A. Bisso was one 

of the first of the Bisso fleet to be converted after the conclusion of World War II (William Bisso 

2011 pers. comm.). 
Fi

J.A. B

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hotograph of

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174 

e unknown. (

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to the 
175 

site, a number of potentially diagnostic features were recorded aboard the wreck that supports the 

identity of the vessel as a tug, and, more specifically, as J.A. Bisso. 

Caldwell (1946) discusses the design of screw tugs at a time when coal powered steam 

vessels were still being built, but oil had become recognized as a much more efficient and cost 

effective fuel alternative. He argues that a converted oil powered engine was an estimated 2.5 

times more efficient than coal, while a similar vessel that used a diesel internal combustion 

engine was 4.5 times more efficient than coal (Caldwell 1946:3-4). Although focusing primarily 

on the development of British tugs, Caldwell’s observations appear to be valid for tugs built in 

North America, as well. This fuel efficiency led companies, such as Bisso Towing, to undertake 

the expense of converting an entire fleet of vessels to diesel power. 

Caldwell (1946) grouped early 20th century tugs into four types: Type 1) Ocean-going; Type 

2) Coastwise and Estuary; Type 3) Estuary and Harbor; and Type 4) River and Dock. Based on 

the length alone, Site 389 could fall into Types 1, 2, or 3. When comparing length to breadth 

ratios, Site 389 and the published dimensions of J.A. Bisso fit neatly between Caldwell’s ideal 

dimensions for an Ocean-going tug and a Coastwise/Estuary tug. Ocean-going vessels have an 

ideal length to breadth ratio of 4.75:1 while Coastwise/Estuary tugs typically have a length to 

breadth ratio of 4.25:1 (Caldwell 1946:29). Based on the geophysical data, Site 389 has a length 

to breadth ratio of 4.56:1. The published dimensions for J.A. Bisso indicate that it had a minimal 

length to breadth ratio of 4.32:1. 

Features identified on Site 389 during diving operations that are consistent with period tugs 

include the stern quadrant, stern and bow capstans, bits, Samson post, and the overall shape of 

the vessel. Caldwell (1946:29) argues that the breadth of a tug at midships should taper in 

immediately for the tug to perform various close quarters tasks safely and efficiently. 

The deck-mounted stern quadrant seems to be a typical feature of many tugs of this period. 

Caldwell (1946:44) argues that it was not advisable to have the steering gear on the deck of an 

ocean-going tug due to the inability to access it during rough seas. His corresponding diagrams 

of ocean-going tugs confirm the lack of a deck-mounted quadrant, while his diagrams of Type 2 

and 3 tugs both show quadrants on the stern deck similar to both Site 389 and J.A. Bisso. The 

location and dimensions of the quadrant identified during diving corresponds closely with 

photographs of J.A. Bisso (Figure 4.12). 

 
Figure 4.11. Site plan of Site 389.

176 
177 

The wreck’s stern capstan included holes near the top for manually operating the machinery 

with a capstan bar, and it appears similar to “warping capstans” that could be hand-, steam- or 

electrically-driven. These were common in the early- to mid-20th century for warping a vessel to 

a pier, wharf, or for attaching to a vessel in the case of tug boats (Manning 1942:73). The bow 

upright may be a Samson post. The Samson post was fitted on the center line of the tug’s 

foredeck just abaft of the stem. It was typically a steel tube 9–12 inches in diameter, standing 24 

inches above the top bulwark (Caldwell 1946:46). 

 

During diving operations, unknown tanks were observed through holes in the vessel’s deck 

near the stern. William “Cappy” Bisso indicated that when the Bisso fleet’s vessels were refitted, 

they often left the original steam engine and boiler in place because it was more cost-effective 

and less labor-intensive than removing them. The tanks had the added advantage of providing 

additional ballast and weight (William Bisso 2011 pers. comm.). As Caldwell (1946:3) points 

out, “. . . the most valuable characteristic that any tug can possess is weight.” This is because a 

tug must handle vessels much larger than itself while also maneuvering in winds and seas that 

can cause the tug to lose traction despite the power of its engines. The added weight or 

displacement gives the tug additional traction that enables it to more effectively handle its tow 

load. If these tanks do, in fact, represent the vessel’s original engine and boiler, this could 

provide valuable information about the original steam engine, the early replacement internal 

combustion engine, or even the transition between the two. 

Due to the breaches in the hull, a number of additional components were observed that 

remain unidentified because of limited time on site, biofouling and corrosion that obscured site 

components, and limited visibility. Subsequent visits to the site could provide additional useful 

information about the vessel and add to the existing site plan. 

 
Figure 4.12. Comparison between last kno

178 

wn photograph of J.A. Bisso and the site plan. 
179 

4.2.8 Site No. 236, Galveston Area, USS Hatteras 

Site 236 was previously identified as the USS Hatteras in U.S. Court and is listed on the 

NRHP. 

Originally named St. Mary’s, this merchant vessel was built in 1861 for Charles Morgan by 

the Harlan & Hollingsworth Company of Wilmington, Delaware. On September 25, 1861, St. 

Mary’s was acquired by U.S. Navy Admiral S. F. Du Pont for $110,000 (U. S. Naval War 

Records 2003 [1921]). At the time of construction, the dimensions were given as 64 m (210 ft) in 

length, 10.3 m (34 ft) beam, and 5.5 m depth (18 ft) with a tonnage of approximately 1,126. St. 

Mary’s was classified as an iron-hulled, side-wheel steamer, with the rigging classified as that of 

a “3-masted schooner.” The machinery was listed as one engine, including a “condensing, beam” 

with a cylinder diameter of 127 cm (50 in). The engine stroke was listed as 335 cm (132 in) and 

was outfitted with a sickel’s cut-off. The boilers were described as having the flues below and 

the tubes above (U. S. Naval War Records 1895). In October 1861, St. Mary’s was officially 

commissioned by the Navy and renamed the USS Hatteras (Silverstone 2001). The vessel’s 

original battery included four 32-pound cannons weighing 2,700 pounds each, but was amended 

on November 21, 1861, by the inclusion of one 20-pound rifle. (U.S. Naval War Records 1895). 

Hatteras began naval service in November 1861 under the command of Commander George 

F. Emmons and was dispatched to Key West, Florida to join the South Atlantic Blockading 

squadron. Hatteras was subsequently assigned to the blockade of Apalachicola, Florida and 

shortly after transferred to Cedar Key, Florida for blockade duty. It was at Cedar Key that 

Hatteras helped stop a fleet of nine blockade runners. After a successful tour in Florida, Hatteras

was transferred to Berwick Bay, Louisiana to join the Gulf Blockading squadron. During this 

tour, the crew captured ships off of Pass Christian, Mississippi and Vermilion, Louisiana, 

including the steamers Governor A. Mouton and Indian No. 2, the schooners Magnolia and 

Sarah, the sloops Poody (which was subsequently renamed Hatteras Jr.) and Elizabeth, and the 

brig Josephine (U. S. Naval War Records 2003 [1921]). In November 1862, the command of 

Hatteras was transferred to Commander Homer C. Blake (Arnold and Anuskiewicz 1995:84). 

On January 3, 1863, Rear Admiral David Farragut ordered the steam sloop of war Brooklyn, 

under the command of Commodore H.H. Bell and six gunboats from the Mobile, Alabama 

blockading squadron to retake control of Galveston from the Confederates (Underwood 

2003:92). Hatteras, under Commander Blake, was part of this squadron. 

On January 11, 1863, fleet commander Commodore Bell ordered Hatteras to investigate an 

unknown bark-rigged vessel (Underwood 2003:92). At around 3 p.m., Hatteras was ordered to 

pursue the “strange sail” (U.S. Naval War Records 1895:18). After some four hours of pursuit, 

Hatteras was within distance to ask the identity of the vessel. After being told that the 

unidentified vessel was of British flag, Blake ordered a small boat launched with six crewmen. 

These crewmen were to board the strange vessel and confirm its identity. After the boat had been 

launched, the “British” vessel revealed its true identity as the notorious Confederate vessel 

Alabama. Alabama began an assault upon Hatteras (Figure 4.13). With the Union ship ablaze 

and rapidly sinking, Blake signaled the enemy in surrender, hoping to save the lives of his crew. 

Alabama accepted, and began transferring crew and officers from Hatteras to Alabama. Those 

aboard the small boarding boat escaped capture and were able to return to Galveston. As a result 
of the at

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181 

with hull number 41 whose published measurements are given as 76.2 cm by 2.4 m (30 in by 8 

ft). The Harlan and Hollingsworth (1886) table of vessels further documents that in 1862, 

following the sale of hull number 75 to the U.S. government, Charles Morgan had another sidewheel steamship commissioned and also named this vessel St. Mary’s. This vessel, hull number 

80, bears the exact measurements given for Hatteras; the only difference is the new steamer was 

approximately 50 tons lighter. Both hull numbers 75 and 80 are listed as 64 m (210 ft) in length, 

10.4 m (34 ft) in breadth, with 5.5 m (18 ft) of draft, and engine measurements are listed for both 

as 127 cm by 3.4 m (50 in by 11 ft). A notation in the remarks column indicates that hull number 

75 was “afterward called Hatteras by U. S. Govt.” (Harlan and Hollingsworth 1886). 

Diver observations at Site 236 indicate that the stern cant frames are iron and the stern post 

and rudder stock appear to be made of wood. No outer-hull components were evident, therefore 

it was not possible to determine if the vessel was of composite construction, with iron frames and 

wood planking, or iron-plated. St. Mary’s was built in the Wilmington, Delaware yard of Harlan 

and Hollingsworth in 1861. The Delaware valley saw the birth and development of iron 

shipbuilding in the U.S., with the first documented iron steam vessel Codorus, built in 1826 

(Morrison 1945:1-2). Wilmington was one of the U.S.’s pioneering iron shipbuilding centers, 

and the industry benefitted from access to the nation’s greatest number of iron rolling mills in 

eastern Pennsylvania. Samuel Harlan and Elijah Hollingsworth established their repair shop in 

1836 primarily for the locomotive industry, but quickly diversified to include iron shipbuilding. 

By the start of the Civil War, Wilmington shipyards produced more iron vessels than any other 

city in the U.S., and the Harlan and Hollingsworth shipyard was the most prolific iron 

shipbuilding firm in the country (Thiesen 2006:80-86). It is no accident, then, that Hatteras’

origins lay in this regional shipbuilding center. 

Thiesen (2006) argues that early iron ships evolved from wooden shipbuilding and were built 

in the tradition of wooden-hulled vessels, often with the same design parameters and techniques. 

Although the exposed portions of Hatteras were limited, this appears to correspond with the 

construction of the exposed cant frames, which were irregular and pointed and appear to have 

been forged individually rather than mass-produced. 

All of the information gathered during the 26 total dive hours on Site 236 was plotted to 

create a master site plan (Figure 4.14). Only mechanical and hull components were identified 

during diving operations, no individual artifacts were observed by any of the divers, but it should 

be noted that no excavation was conducted. 
182 

Figure 4.14 .Site plan of exposed portions of the USS Hatteras. 
183 

Artifacts have been previously recovered from the Hatteras shipwreck site. In the 1970s, 

treasure hunters recovered eight artifacts from the site (Appendix E; Figure E-40), which 

included: 

(a) Builder’s plate marked “Harlan and Hollingsworth and Co., Iron Ship and Steam Engine 

Builders no. 327, Wilmington Delaware, 1861”; 

(b) Two small bronze oil cups with covers; 

(c) One brass steam valve; 

(d) Two large bronze priming cups, one with attached pipe stem; 

(e) One oiling pipe stem; and 

(d) One iron ball with eye, weighing approximately 45 pounds. (U.S. District Court, Southern 

District of Texas, Galveston Division 1984:2). 

These artifacts were confiscated and are now in the care of the Corpus Christi Museum of 

Science and History. The brass builder’s plate was the central diagnostic element that was used 

to confirm the identity of the ship as the steamship Hatteras. It is unknown what the number 

“327”, refers to on the builder’s plate. All records indicate that Hatteras was designated by 

Harlan and Hollingsworth as hull no. 75. The “327” may refer to the engine number or some 

other internal designation. Although Harlan and Hollingsworth built steam engines, it is not 

possible to indicate conclusively if they manufactured Hatteras’ engine. One of the more 

interesting recovered artifacts is the 45-pound ball (Appendix E; Figures E-40-42). Research and 

consultation with archaeologists and ordnance experts familiar with Civil War artifacts have not 

provided a conclusive identity for the ball. The object can be discounted as ordnance due to the 

flat bottom, size of the handle, and the fact that neither Hatteras nor Alabama had guns of this 

size aboard. Speculation has included use as part of a shackle for weighing down prisoners, a 

sounding device, tension weight, gaming equipment (similar to weights used in Highland game 

throwing events), and even an early form of a correcting sphere for a binnacle. Because no 

records have been identified containing contextual or provenience information for this artifact, it 

has been extremely difficult to identify its function or purpose. This demonstrates the need to 

document sites thoroughly before recovering artifacts, which is a requirement for proper 

archaeological excavation. 

4.2.9 Site No. 15326, East Cameron Area, Unknown Barge 

Based on the probability model developed in 2003 by Pearson et al., the study site is located 

within an area that is not considered to have a high probability for shipwreck occurrence. 

According to CEI (1977), Site 15326 was seaward of the most frequent routes of coastal 

exploration used during the 16th and 17th centuries (CEI 1977: Plate 6), and just seaward of 

coastal sailing routes used during the 18th and 19th centuries (CEI 1977: Plates 7 and 8). The site 

is located within shipping routes used during the first half of the 20th century running between 

Cameron, Louisiana and the Straits of Florida (CEI 1977: Plate 9). Based solely on the wreck’s 

location, it is most likely associated with modern activities, rather than the historic shipping 

lanes. 

There are no reported shipwrecks located in the immediate vicinity of site number 15326 and 

prior to this investigation no tentative identification was assigned to the site. The available 

geophysical dataset exhibits wreckage that protrudes 0.9 to 1.5 m (3 to 5 ft) above the seafloor in 
184 

places, but much of the hull has settled into the surficial sediments. The hull components are 

approximately 67 m (220 ft) in length and measure 12.5 m (41 ft) in width. The vessel is 

interpreted as iron or steel, based on observed magnetic signatures. Reported wrecks in the 

vicinity of Site 15326 have been researched and a comprehensive list of 29 wrecks within a 32-

km (20-mile) radius was assembled. Of the reported losses, 22 contained detailed information, 

such as length or tonnage, and only two of these wrecks exceeded 30 m (100 ft) in length (Table 

4.8). The remaining wrecks are too small to be the vessel at Site 15326. 

Table 4.8 

 

Reported Shipwrecks in the Vicinity of Site 15326 with Similar Dimensions 

Vessel Name 

Gross 

Tonnage Length Breadth 

Date of 

Sinking Vessel Type 

Shoal Harbor 193 120.5’ 20.5’ 1955 Fishing vessel 

Lafourche 198 130.6’ 34.1’ 1971 Oil exploration 

Measurements taken from Merchant Vessels of the U.S. 

No means of propulsion were identified on the wreck site during diving operations in 2010, 

and geophysical data was limited to a previous survey of the area (Section 3.9.1); no new 

geophysical data was acquired over this site. It is possible that the barge was lost during a towing 

operation and, because it is not a self-propelled vessel, its loss was not recorded in any available 

databases. 

This site appears to be a steel or iron barge that is split into two pieces. Barges are commonly 

used to transport goods or equipment in the GOM region, and have also been used in offshore 

construction. Due to limited visibility and netting which obscured much of the site, not enough 

information is available to make a determination on age or identity. During diving, no diagnostic 

elements were identified that would establish historical significance for this site. The large, 

rectangular barge is not interpreted as historically significant based on this limited data set. 

4.2.10 Site No. 322, East Cameron Area, Unknown Modern Wreck 

Based on the probability model developed in 2003 by Pearson et al., the study site is located 

in an area that is considered to have a low probability for shipwreck occurrence. According to 

CEI (1977), Site 322 is located seaward of the most frequent routes of coastal exploration used 

during the 16th and 17th centuries (CEI 1977: Plate 6), and just seaward of coastal sailing routes 

used during the 18th and 19th centuries (CEI 1977: Plates 7 and 8). The site is located within 

shipping routes used during the first half of the 20th century running between Cameron, 

Louisiana and the Straits of Florida (CEI 1977: Plate 9). Based solely on the wreck’s location, it 

is most likely associated with modern activities, rather than the historic shipping lanes. 

There are no reported shipwrecks located in the immediate vicinity of Site 322 and, before 

this investigation, no tentative identification had been assigned to this site. The available 

geophysical datasets depict an upright hull measuring between approximately 17.3 m (57 ft) and 
185 

20 m (65 ft) in length and between approximately 3 m (10 ft) and 6 m (20 ft) in width. The 

results of the 2010 diver investigation suggest that the vessel may be a 20th-century fishing 

vessel. A comprehensive list of 70 wrecks and obstructions within a 48-km (30-mile) radius of 

Site 322 was assembled. Of these vessels, details such as length and tonnage were available for 

45 vessels. Candidate vessels closest in type and dimensions to Site 322 are shown in Table 4.9. 

Table 4.9 

 

Reported Shipwrecks in the Vicinity of Site 322 with Similar Dimensions 

Vessel Name 

Gross 

Tonnage Length Breadth 

Date 

Built 

Date of 

Sinking 

Vessel 

Type 

Vona Mabry 63 58.7’ 18.6’ 1950 1956 

Fishing 

vessel 

Martha Gene 14 56’ 1939 

June 10, 

1959 

E. M. 

Hartrick 34 55.7’ 15.1’ 1916 1950 

Oil screw 

wood tug 

Ramos Pride 49 54.2’ 18.1’ 1944 1960 

Fishing 

vessel 

Sarah Marie 54’ 1985 

Fishing 

vessel 

Coastal 

Rambler 95 66’ 20’ 1965 

February 

26, 1986 

Fishing 

vessel 

Voncille 38 51.2’ 17.3’ 1943 1953 

Fishing 

vessel 

Miss Patsy 13/127 

46.6’/ 

68.8’ 

15.3’/ 

22.1’ 

1949/ 

1974 

Fishing 

vessel 

Lucky Moon 70’ 

October 29, 

1999 

Fishing 

vessel 

Measurements from Merchant Vessels of the U.S. 

Diver observations indicate that this vessel represents a relatively modern steel-hulled 

working vessel, most likely a fishing trawler. E.M Hartrick was a wooden tug, and is therefore 

excluded as a candidate for Site 322. Seven separate fishing vessels with similar dimensions as 

the vessel at Site 322 are reported in the general area; this makes them possible candidates for 

the identity of the wreck (Table 4.9). Very little diagnostic information is available for Site 322, 

and without additional data about the candidate vessels, it is not possible to discern one wreck as 

the most probable identity of Site 322. Many of the fishing vessels reported lost in the search 

radius meet the 50-year age requirement for National Register eligibility, based on the date they 

were built. Age, however, is not the only requirement, and as demonstrated by the number of 

reported fishing vessel losses in the area, many of which sank in the 1950s, these are unlikely to 

demonstrate a unique representation of type. 
186 

4.2.11 Site No. Pending, West Cameron Area, Modern Debris 

Based on the probability model developed in 2003 by Pearson et al., the study site is located 

within an area that is considered to have a low probability for shipwreck occurrence. According 

to CEI (1977), this site is located seaward of the most frequent routes of coastal exploration used 

during the 16th and 17th centuries (CEI 1977: Plate 6), seaward of coastal sailing routes used 

during the 18th century (CEI 1977: Plate 7), and between sailing routes used during the 19th 

century (CEI 1977: Plate 8). The site is located within shipping routes used during the first half 

of the 20th century running to and from Port Arthur, Texas (CEI 1977: Plate 9). Based solely on 

the wreck’s location it is most likely associated with activities in the 19th century or later. 

There are no reported shipwrecks located in the immediate vicinity of this site and no 

tentative identification was assigned before the start of this study. Reported wrecks and 

obstructions within the vicinity of this study site have been researched and a comprehensive list 

of 138 wrecks and obstructions within a search radius of 48 km (30 miles) was compiled. Of the 

identified losses, 64 have records that contain details such as length that can be compared with 

the feature at this site. None of the reported objects or shipwrecks found in available databases 

provides a suitable identification or clear association with this target. 

The combined diver investigations and geophysical datasets indicate that a single rectangular 

object representative of heavy machinery, likely associated with commercial activity (such as oil 

and gas or fishing), sits on the seafloor (Figure 4.15). Metal detectors used on site identified 

buried components extending a significant distance beyond the exposed portion of the site. No 

documentary records were found which can be correlated to this target. The site may be the 

result of an accident loss or intentional dump. It is possible for objects, such as winches, to fall 

off of a ship or barge as a result of a storm or an accident during heavy lift operations. Other 

possibilities for the presence of this feature include the intentional discarding of modern debris, 

either for disposal purposes or for use as an unofficial, private fishing habitat. 
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scattered components on or in the sea bed, lake bed, river bed, mud flats, beaches, or other 

shorelines ...” (NPS 1992:3). 

The significance of an historic vessel can be determined only through a systematic 

investigation of the vessel's qualities, associations, and characteristics. 

The archaeological assessments of the study sites were designed to address the following 

types of information: 

1. Identification of the specific type of vessel and documentation based on a physical 

inspection of the vessel and a documentation of its history. 

2. Identification of the historic context(s) associated with the vessel based on a 

documentation of its history. 

3. Determination that the characteristics of the vessel make it either the best or a good 

representative of its type. 

4. Evaluation of the significance of the vessel based on the National Register criteria. 

5. Evaluation of the vessel's integrity and a listing of features that the vessel should retain to 

continue to possess integrity. 

6. Evaluation of a vessel's special characteristics that might qualify it for National Register 

listing even though it might be less than 50 years old or some aspect of its present 

condition generally would not qualify it for listing. 

4.3.1 Civil War 

The USS Hatteras was the only site investigated as part of this study that dates to the Civil 

War-era, and is already listed on the NRHP. Hatteras is the only U.S. warship sunk at sea in the 

GOM (Irion 2000:141). It has been referred to as one of the most important underwater 

archaeological sites in the U.S. (Arnold and Anuskiewicz 1995:86; Irion 2000:143). After its 

loss, no contemporaneous salvage attempts were made on Hatteras (U. S. District Court, 

Southern District of Texas, Galveston Division 1984). Assuming that the artifacts that treasure 

hunters recovered from the site in the 1970s, and referenced in the ensuing court case, are the 

only items salvaged from the site, the remaining assemblage should be relatively intact, 

including the crew’s belongings and personal effects and military and vessel equipment. This 

could provide an invaluable trove of information on shipboard life during the Civil War. In 

addition to the context of the war, the ship itself represents an early iron-hulled vessel that was 

constructed during a time when shipbuilders were experimenting with the transition from 

wooden shipbuilding techniques to a separate methodology for metal-hulled vessels. Although 

some details of the wreck’s engine components and dimensions are known, no known plans or 

diagrams of the vessel are available. The ship itself therefore also represents a significant historic 

resource. 
189 

4.3.2 World War II 

Based on the combined results of this study, Site 433 is believed to be the remains of R.W. 

Gallagher; Site 373 is believed to be the remains of Cities Service Toledo; and Site 386 is 

believed to be the remains of Heredia. All three vessels were casualties of German attacks in the 

GOM during an eighteen-month period between 1942 and 1943 that saw intensive U-boat patrols 

in U.S. waters. Heredia was sunk on May 19, 1942; Cities Service Toledo was sunk on June 12, 

1942; and R.W. Gallagher was sunk on July 13, 1942. Heredia was the only one of the three that 

was not chartered by the U.S. War Shipping Administration and remained in private hands at the 

time of the attack. All of the vessels, though, show modifications and additions meant to counter 

the U-boat menace. All three vessels were armed with multiple guns and accompanied by a 

complement of naval armed guards. 

Based on Criterion A, the affiliation with events important to U.S. history, all three vessels 

may potentially be eligible to the NRHP because of their roles in supplying the U.S. economy 

during the war, their efforts to evade the German U-boat attacks, and the tragic events of their 

sinking, during one of the few incursions in modern history by foreign powers into U.S. waters at 

a time of war. 

Heredia was originally built in 1908 as a steam powered liner, and the vessel’s boilers were 

converted from steam to oil in 1921. Heredia was also one of the earliest vessels outfitted with 

refrigerated cargo holds for transportation of produce (Goldberg 1993). Cities Service Toledo

(originally named J.A. Bostwick) was built in 1918 as a steam powered tanker. Sometime before 

1927, the vessel was fitted for use with fuel oil. Both vessels are representative of a major 

technological shift from steam power to oil. In both cases, the boilers appear to have been 

retained, and re-fitted as opposed to installing new diesel engines. These vessels are both 

representative of steam powered vessels forced to convert to a much more efficient fuel source to 

stay profitable and competitive in an expanding industry. Because of this, these two vessels are 

potentially eligible under Criterion C, because they are representative of a distinctive, but shortlived technological shift that played a crucial role in the nation’s industrial history. 

All three vessels are potentially eligible under criterion D, having yielded, or being likely to 

yield, information important in prehistory or history. National Register Nomination forms for all 

three sites have been prepared for submittal to the National Park Service. 

4.3.3 Modern Industry 

The towing vessel J.A. Bisso operated in the oil fields of the GOM from 1919 until 1957, 

when it sank during towing operations. Built in 1906, J.A. Bisso was a turn-of-the-century tug 

with the potential to provide valuable information about early commercial activity in the GOM. 

The vessel was converted from steam but retained its original boilers and so is a rare remaining 

example of early steam-powered tugs. As of 1980, Ted Miles and Norman Brouwer had 

compiled a partial list of extant historic steam tugs and towboats throughout the U.S. and 

Canada. They were able to find only four steam tugboats still active and a total of 14 that had 

been converted to diesel (Lang and Spectre 1980). Most of the steam tugboats located were 
190 

found conserved within nautical museum collections throughout both countries (Lang and 

Spectre 1980). A general review published by William Burt (2000) of tugboats registered in the 

U.S. indicated that approximately four percent were less than five years old and the majority 

were older than 20 years. The publication also noted that an active steam tugboat is rare; the 

remaining examples are either conserved and on display in museum collections or in such 

disrepair that they are unseaworthy (Burt 2000). During an interview with a descendant of the 

owner of J. A. Bisso and current president of Bisso Marine, it was reported that no steam or 

converted diesel tugboats are active within their fleet; all were scrapped for parts (William Bisso 

2011 pers. comm.). 

J.A. Bisso is potentially eligible for inclusion on the National Register under criteria C and D 

because of the rarity of the type and the information it can provide on technology and industry at 

this early point in the nation’s offshore development. 

In addition to J.A. Bisso, Site 15326 (modern barge) and the modern debris located in the 

West Cameron area (no site number assigned) both appear to be related to commercial activity, 

possibly oil and gas development. Although the exact purpose of the debris identified at the West 

Cameron site remains unidentified, it appears to represent out-of-context, disarticulated remains. 

These appear to represent an industrial winch and hydraulics and are not likely to represent any 

unique or historic technological achievement. This target is not believed to represent a 

historically significant resource and does not warrant further investigation. 

Because of the degree of site burial, limited visibility, and a large quantity of netting 

obscuring the site, the assessment of Site 15326 was fairly limited. Portions of the site that were 

observed appear to be consistent with modern construction and equipment and did not appear to 

represent a unique technological achievement or exemplary representation of vessel type. Based 

on the limited results of the diving survey, this site is believed to be related to modern 

construction and is not interpreted as historically significant,. Although these sites may have had 

economically important roles in the region, they do not appear to represent unique examples of 

type nor do they meet any other criteria for historical significance necessary for inclusion on the 

National Register. 

 

Sites 15488, 15366, and 322 may all be associated with fishing or trawling. The identities of 

these three vessels remain unknown, and they are unassociated with known events or persons of 

historical significance. None of these vessels appears to exhibit any unique characteristics that 

would qualify them for inclusion on the National Register. These types of vessels are ubiquitous 

in the GOM, and are not a unique or exceptional representation of type. 

4.4 SUMMARY 

Of the 11 total sites investigated through this contract, four are potentially eligible for 

National Register nomination: R.W. Gallagher, Heredia, Cities Service Toledo, and J.A. Bisso. 

The three World War II-era vessels are considered historically significant because they are more 

than 50 years old and meet the requirements of criteria A and D. Their association with German 

U-boat attacks in the GOM during World War II puts these vessels firmly in the context of 
191 

events that had important roles in the broad patterns of both U.S. and world history. The sites 

themselves could contain additional information that would expand our knowledge of history and 

that makes them eligible under criterion D. Information that could be gained through more 

detailed study includes a better understanding of the environmental impacts of sunken tankers 

and submerged hydrocarbon cargos, civilian and military responses to submarine attack (as 

evidenced by the reported degaussing equipment and armament), and information about life 

aboard these ships that has not been published in official records. Finally, Heredia (Site 386) and 

Cities Service Toledo (Site 373) meet Criteria C because each represents the transition from 

steam powered vessels to fuel-oil propulsion. 

The tugboat J.A. Bisso is also older than 50 years, and meets the requirements of criteria C 

and D. Originally built as a steam-powered tug, J.A. Bisso retains its boilers and other original 

equipment after its conversion to oil propulsion. J.A. Bisso is representative of the beginnings of 

the offshore oil and gas industry, which is an entrenched economic and cultural way of life in 

Louisiana and Texas. 
193 

5. SITE FORMATION PROCESSES 

It has been well established that shipwreck sites are subject to numerous processes that 

produce measurable changes that impact the ship, the artifacts, and their context over time 

(Muckelroy 1978; Stewart 1999; Quinn 2006). For most shipwreck sites, the wrecking event 

itself is the single most catastrophic event that occurs to the site, and it is followed by a number 

of inter-related processes that cumulatively impact the shape and condition of the site. These site 

formation processes can be caused by environmental and anthropogenic factors and can impact 

both the interpretation of the site and decisions about its long-term management. 

The following sections introduce pertinent research and data examining the role of 

environmental site formation processes across the study area (Section 5.1) and anthropogenic 

activities that have impacted or could impact wreck sites (Section 5.2). These environmental and 

anthropogenic processes are identified at each of the contract study sites (Section 5.3) and 

observed patterns and comparisons are made across sites (Section 5.4). 

5.1 ENVIRONMENTAL SITE FORMATION PROCESSES 

5.1.1 Introduction 

Environmental processes that impact submerged shipwrecks are the cumulative results of the 

interaction of geologic, biologic, chemical, and oceanographic variables. As part of the marine 

environment of the GOM, shipwrecks are subjected to warm water organisms, bioturbation, 

seasonally variable water chemistry, varying wave directions and current velocities, sedimentary 

movement, and occasional but extreme storm events. 

Bioturbation is one of the leading causes of the deterioration of wooden shipwrecks and 

organic components (Muckelroy 1978:53; Wachsmann 2011:206-207). One of the most wellknown wood-damaging organisms is the Teredo navalis (also known as shipworm), a small saltwater bivalve that causes structural damage to ship timbers by burrowing into planks and other 

exposed surfaces. Other wood-damaging organisms that are prevalent throughout the GOM 

include Gould’s shipworms (Bankia gouldii), wood piddocks (Martesia cuneiformis), striated 

wood piddocks (M. striata), and gribbles (Limnoria tripunctata), all of which bore or burrow 

into submerged wood (Kaplan 1988:258, 261). In warm salt water these organisms accelerate 

decay, deteriorating the condition of organic components that are not protected by burial beneath 

seafloor sediments. 

With the exception of Hatteras (Site 236), the vessels included in this study are metal-hulled 

ships that sit largely exposed on the seafloor and project into the water column. For these sites, 

corrosion and mechanical processes are the primary mechanisms of deterioration. Mechanical 

processes include the physical impact of waves, currents, and storms on the integrity of the hull 

and any disarticulated components. The rates and extents of corrosion depend on a number of 

complex factors; the most significant of these is water chemistry, which can be measured 

through variables such as salinity, pH, and dissolved oxygen (DO). When buried in sediment, 
194 

metal-hulled shipwrecks are protected against the long-term effects of corrosion through DO and 

salinity; however, pH levels in the sediment may still be conducive to anaerobic corrosioncausing, sulphate-reducing microbes. 

Sediment accretion and scour are directly related to site burial or exposure and can be 

measured in a number of ways. For long-term studies at a given site, erosion pins and sediment 

traps can be placed around the site, allowing researchers to collect repeat measurements over 

time and assess rates and patterns of change. Repeat visits were not possible for this study; 

therefore, variables related to accretion and scour were measured from unique samples and 

existing data was modeled to indicate possible rates of change at each site. Grain size, sediment 

transport potential as a function of flow regimes, and, where possible, shear strength 

measurements were used to provide information on the potential for sediment scour. Sediment 

cores acquired on each site were sampled for analysis of 210Pb and 137Cs isotopes in order to 

provide estimates of sediment accretion rates. This data also provided insight into the impacts of 

storms on the seabed at the study sites. 

5.1.2 Sediment Movement and Hydrodynamics 

Physical, biological, and chemical factors all contribute to the deterioration of shipwreck 

sites, but sediment overburden is the most significant means of site preservation (Ward et al. 

1999). This is particularly true in warm saline environments, such as the GOM. Shipwreck 

exposure and/or burial can occur in several ways. Objects on the seafloor may subside below 

surficial sediments, become buried by the accretion of sediment on top of the existing feature, 

become exposed through scour and erosion of existing sediments, or any combination of these 

processes. Sedimentation rates are most accurately determined through long-term monitoring and 

repeat site visits; however, estimates of recent sedimentation can be determined by examining 

nearby current and sediment data, and can also be assessed through analysis of radioisotope 

tracers, as discussed in Section 5.1.2.3 (Allison and Lee 2004; Allison et al. 2005; Neill and 

Allison 2005). Hurricanes may also be used in oceanographic modeling because in water depths 

equivalent to the study area, they represent extreme conditions that may result in a punctuated 

change in seafloor equilibrium. Seafloor properties, such as sediment cohesion and shear 

strength, may also impact subsidence potential, and can be analyzed through analysis of core 

data (Conlin 2005b; Keith and Evans 2009). 

Waves and currents impact the physical remains of an archaeological site and the sediments 

that act as a protective barrier to buried materials. The mechanical actions of currents and waves, 

particularly in shallow sites, can severely damage submerged structures, including thick iron 

plating. On the USS Arizona, hull plates have been observed to flex significantly during windinduced tidal surge (Lenihan 1990:97). Although these impacts are acknowledged, the 

measurement of such forces was beyond the scope of this study. A separate study performed for 

BOEMRE (previously MMS, now BOEM) focused on the impacts of hurricane forces on the 

hulls of submerged shipwreck sites (Gearhart et al. 2011). 

Scour and erosion can impact shipwreck sites in several ways. McNinch et al. (2006) 

demonstrated that erosion and scour caused by waves and seasonal tides contribute to artifact 

burial, thereby promoting preservation below the seafloor. Alternatively, erosion or scour can 
195 

remove protective sediment layers and reintroduce historic shipwreck components to 

deterioration from organisms and the environment. As demonstrated by Quinn (2006), this can 

occur when shipwreck sites are subjected to various current flow regimes, or the shipwreck site 

itself can induce scour by altering the natural flow regime and impact vortex development in a 

given area. 

The GOM is typically categorized as a micro-tidal, low energy environment (Curray 

1960:231-234); this may lead to the incorrect assumption that bottom sediments, and ultimately 

shipwrecks, in this area are not impacted by oceanographic processes. Physical processes, such 

as semi-permanent currents, tidal currents (normal and hurricane), and waves (normal and 

hurricane), impact the initial distribution of sediments from their sources and can also rework 

and modify post-depositional sediments (Curray 1960:234). General characteristics for the GOM 

were outlined by Curray (1960) and have been supplemented and refined by subsequent casestudies of specific micro-environments to determine the potential for sediment transport and 

scour under varying conditions (i.e., Suhayda 1977; Teague et al. 2006). Diurnal and mixed 

diurnal tidal fluctuations in the GOM typically average less than 0.3 m (1 ft); however, tidal 

ranges are highly variable during meteorological events and hurricane-induced tides in the GOM 

may exceed 3 m (10 ft) (Curray 1960:233). According to Curray (1960:231), average deepwater 

wave periods range from 3 to 8 seconds, and waves rarely exceed 1 m (3 ft) in height. Mean 

significant wave heights measured offshore of the Chandeleur Islands have been modeled from 

hindcast data and indicate wave heights of 0.8–1.0 m with a period of 5 seconds (Georgiou et al. 

2005). Generally, these small-size waves are capable of moving sediment only in the shallow 

surf-zone (Curray 1960:231). Shallow water sediments are principally sands and coarser-grained 

material than that found on the continental shelf, because sands fall out of suspension before silts 

and clays and so are preferentially deposited along the coast (Masselink and Hughes 2003). 

Under bed stress and flow conditions, cohesionless sands “behave individually,” while silts and 

clays (grain size less than 63 microns [μm]) are electro-statically charged and therefore cohesive 

(Masselink and Hughes 2003:124). According to Masselink and Hughes (2003:124), “the 

dynamic behavior of cohesive sediment depends less on single-grain properties and more on 

bulk-sediment properties (e.g., floc size and water content).” This has important repercussions 

for estimates of sediment scour. 

 

Sediment that has been eroded from an area on the seabed through the effects of waves 

and/or currents is referred to as scour (Whitehouse 1998:9). Scour can occur locally (e.g., steepsided holes), globally (e.g., a shallow or wide depression under or around features, also referred 

to as dishpan scour), or as overall seabed movement (Whitehouse 1998:9). Seafloor structures, 

including shipwrecks, create disturbances in the flow and direction of waves and currents 

through the water column, and create vortices emanating from the structure (Whitehouse 1998:9; 

Quinn 2006). With regard to shipwrecks, “the characteristics of the ambient flow depend on the 

size and shape of the structure and its orientation to the flow direction ... angular or irregularly 

shaped structures will produce a more complex and turbulent flow than that formed around 

streamlined structures” (Whitehouse 1998:250-26). Sediment mobility can be predicted for 

specific locations, based on an analysis of waves, currents, wave-current interaction, and the 

specific sediment characteristics of the area (Whitehouse 1998:64). 
196 

Sediments on the continental shelf are generally considered to be at equilibrium, and finegrained sediments correspond to areas with weaker currents (Whitehouse 1998:62). Hurricane 

waves and tidal currents disrupt this equilibrium and are largely responsible for reworking and 

modifying sediments on the shelf (Curray 1960:234). According to Curray (1960:233), “a 

velocity of 35cm/second is ... the approximate mean velocity at 1 meter above the bottom which 

is required to pick up and move fine quartz sand,” although actual net transport also requires a 

“velocity gradient to the bottom and unidirectional flow.” Using hindcast wind and wave data for 

normal wave conditions in the GOM, Curray estimated that areas in water depths less than 10 

fathoms (18.3 m or 60 ft) experienced bottom velocities greater than or equal to 35 cm/sec for 

more than 500 hours per year, or approximately 5% of the time (1960:233). Similar calculations 

using actual hurricane wave statistics indicated that areas in water depths between 10 and 15 

fathoms (18.3 to 27.5 m or 60 to 90 ft) experienced this same velocity less than once every 18 

months (Curray 1960:233). All of the shipwrecks in this study are located in areas that, 

according to Curray’s estimates, experience bottom current velocities sufficient to result in 

transport and scour of fine, cohesionless, sands. 

Wind- and wave-induced bottom pressures play a significant role in bottom sediment 

deformation and transport in water depths less than 150 m (500 ft) (Suhayda 1977:139). Wind 

and waves create bottom orbital velocities, whose tangential velocities create stress on the 

sediment surface in contact with the fluid plane. If the shear stress generated by the wave 

exceeds the cohesion of the sediments, then the sediments may become mobile, resulting in 

either transport or scour (Whitehouse 1998:67; Masselink and Hughes 2003:118). Wave height 

and period, and bottom depth will variably impact the amplitude of orbital velocity, and therefore 

the overall shear stress impacting potential scour (Whitehouse 1998:67). Wave heights and 

periods in the GOM are relatively low, but become exaggerated during hurricane events, 

contributing to increased instances of punctuated scour. 

Based on data acquired by Forristall and Reece (1985), Teague et al. (2006) estimate that for 

every 3 m (9.8 ft) of wave height, approximately 1 cm of sediment displacement can be 

expected. According to Teague et al. (2006), Hurricane Ivan produced waves with significant 

heights of approximately 18 m (59 ft) (maximum wave height of 28 m or 92 ft) and near-bottom 

orbital wave velocities that were higher than 2 m/sec at 60 m (197 ft) of water depth, directly 

beneath the wave field. Following the estimates of Forristall and Reece (1985), they estimated 6 

cm of sediment displacement in the areas with wave heights of 18 m. During Hurricane Ivan 

velocities recorded away from the center of the hurricane’s path ranged between 0.4 to 1.2 m/sec, 

which were lower than velocities recorded under the maximum wave fields, but still above the 

threshold for sediment transport (as defined by Curray 1960). These water depths, though, are 

greater than at the present study sites and represent calculations based on data directly in the path 

of a specific hurricane. More important, these scour calculations and storm estimates do not 

differentiate between the types of sediments impacted by specific wave fields and current 

velocities. 

A large percentage of scour studies are concerned with the coastline and nearshore areas 

because of the effects of shoreline erosion. For example, Keen et. al. (2004) documented large 

hurricanes’ powerful capabilities in transporting sediments and forming event bed layers both 

seaward and shoreward of barrier islands in the northern GOM. These are the same high energy 
197 

shallow zones in which Curray (1960) predicted higher sediment transport potential under 

normal wave and current conditions. Goff et. al. (2010) found that Hurricane Ike was capable of 

adding up to 2.5 m (8.2 ft) of sediment to a site north of Big Reef, offshore Texas. These authors 

also observed that shell-gravel ridges that were approximately 3 m (10 ft) high and 150 m (492 

ft) wide before the storm were drastically degraded by the hurricane, and became up to 2 m (6.6 

ft) shorter and migrated seaward by 40 to 50 m (131 to 164 ft). Even during lower energy events, 

with significant wave heights of 1 m and current speeds higher than 40 cm/sec in shallow water 

depths of 4 m, significant resuspension and bed reworking have resulted (Sahin et al. 2011). The 

work of Keen et al. (2004), Goff et al. (2010), and Sahin et al. (2011) demonstrate significant 

sediment transport and reworking in shallow water areas, such as those surrounding barrier 

islands, the surf-zone, and the inner shelf, which are characterized by sandy to muddy sediment 

and are much shallower than the current study sites. 

According to Whitehouse (1998:4), “it is primarily the bed shear stress which causes scour 

regardless of whether the flow is wave-alone or current-alone, or the combined wave-current 

case.” Bed shear stress is the force exerted per unit area, and resistance to shear stress is 

dependent on friction and sediment cohesion, which is a product of grain size and plasticity. 

Given uniform wave heights and currents, different bed types and configurations vary in their 

response to scouring conditions. Suhayda (1977) attempted to characterize bottom sediment 

movement responses for fine-grained clays in the GOM; bottom sediments in the northwestern 

GOM, where the study sites are located, are predominately silts and clays (MMS 1983). Suhayda 

(1977) tested sediments to a depth of 30 cm (12 inches) below the mud line (BML) in East Bay, 

Louisiana, in water depths of 10 to 12 m (33 to 39 ft). Under moderate waves (1 m high and 

period of 5 seconds), Suhayda (1977) measured a wave induced vertical displacement of 

approximately 1 mm in fine-grained clay. More relevant to the study sites, Suhayda (1977:146) 

found that muddy bottoms absorb and dissipate a high percentage of wave energy, and, when 

compared to sandy bottoms, “a relatively greater amount of wave energy is lost on a muddy 

coast at intermediate water depths than is dissipated along a sandy coast.” As discussed by 

Komen et al. (1996:342), Forristall and Reece’s research illustrated that the attenuation of wave 

heights measured between two study datums (as published in 1985) could largely be attributed to 

soft mud deposits, which dissipated significant wave energy. 

Scour can be identified from geophysical remote sensing data, physical samples, and cores of 

sediment stratigraphy, and examination of topographic profiles and 3D digital elevation models 

of the seafloor around wrecks. Sub-bottom profiler data can detect eroded areas of seafloor and 

of sediment infill in which younger sediments have different densities than the surrounding 

sediments (Quinn 2006; Evans and Voisin 2011). Scour also leaves a unique physical signature 

within sediment stratigraphy, as evidenced by box cores collected on the inner continental shelf 

(8 to 13 m or 26 to 43 ft water depth) of the GOM after Hurricane Ivan. Research by Goff et al. 

(2010) resulted in the identification of an “event layer” stratigraphy that consisted of 5 to 8 cm (2 

to 3 inches) of mud overlying 1 to 3 cm (0.4 to 1.2 inches) of sand and a shelly, bioturbated, 

Holocene sandy mud, with a basal hiatal surface in between. The observed event layer 

stratigraphy was interpreted as a direct result of disturbance caused by major hurricanes on the 

seabed (Goff et al. 2010:353), and has been correlated in other studies from previous hurricanes 

in the GOM (Allison et al. 2005). According to Goff et al. (2010) the basal hiatal surface of the 

event layer is formed by wave- and current-induced scour during the peak of the storm, and is 
198 

overlain by sediments deposited as the storm weakens over the area. Allison et al. (2005) 

measured three stacked event layers down a box core collected from approximately 20 m (66 ft) 

BSL, offshore Louisiana. They found that the bottommost event layer, measuring approximately 

7 cm (2.8 inches) thick, was attributable to Hurricane Ivan. The overlying two layers were 

produced by Hurricane Katrina and are about 19 cm (7.5 inches) thick, with the uppermost 9 cm 

(3.5 inches) representing sediment reworking as a result of Hurricane Rita. 

Based on Curray’s calculations, it is evident that only hurricanes and other extreme storm 

events occurring less than once every 18 months produce sufficient velocity to cause the 

mobilization of fine sands in water depths between 18 and 28 m (60 to 90 ft) in the GOM. While 

the seabed in water depths less than 18 m (60 ft) undergoes greater forces than deeper water, 

sufficient force is present only 5% of the time and sediment mobilization is therefore a rarity. 

Curray’s calculations were specifically for sands, but the cohesive clays and silts that 

characterize the study sites typically require greater force for transport or scour than the 

cohesionless sediments discussed by Curray. For these reasons, it is expected that extreme storm 

events are the most likely cause of sediment transport at the study sites, although it must be noted 

that the impact of the wreck sites on flow velocity (and resultant localized scour) could not be 

quantified through this study and is therefore an unknown variable. Punctuated instances of 

sediment scour and redeposition may leave evidence in the form of an event layer that can be 

identified using sub-bottom profiler data and/or sediment cores from the survey area. Grain size 

measurements, both surficial and downcore, may lead to a better understanding of the differences 

in scour patterns at each site since sediment type has significant control over sediment 

mobilization potential. Combined with oceanographic modeling and radioisotope analysis, it is 

possible to discuss potential sediment scour and accretion rates across the study sites. 

Subsidence is a separate and significant factor in the burial of shipwrecks. As discussed by 

Keith and Evans (2009), subsidence occurs as the result of, and immediately following, the 

wrecking event. One of the best ways to quantify the potential for subsidence is through shear 

strength measurements of seafloor sediments. These measurements provide an indication of the 

amount of force necessary for the sediments to shear, which allows for displacement and burial 

of the wreck site. As is discussed in Chapters 2 and 3, shear strength measurements were 

obtained from sediment cores when possible and used to supplement the interpretation based on 

the factors discussed above. Due to the limited amount of sediment acquired at each site and the 

number of samples acquired within those cores, shear strength measurements could not be 

conducted on every site; therefore, published data sets (McClelland 1979; Dunlap et al. 2004) 

were also used to provide supplemental interpretation. Figure 5.1 shows published shear strength 

measurements based on Dunlap et al. 2004. 

 
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ome of the s

y based on th

s should be u

hear strength 

Data from Dun

Data 

rectly related

quired from 

ations made

possible “ev

ment morpho

st of the nor

ed with the 

ction (Table

study sites. 

he differenc

used with ca

measureme

nlap et al. 200

d to sedimen

the study s

. Grain siz

ent layers” o

ology data f

rthwestern G

published d

e 5.1); howe

This sugges

ce between e

aution. 

199 

nts across th

04.) 

nt cohesion,

ites were sa

e measurem

or storm dep

for the GOM

GOM consist

data, actual 

ever, divers

sts that estim

expected and

he Northern G

, shear stren

ampled and 

ments down

posits, such a

M (MMS 1

t of varying 

grain size 

s noted sign

mates of sed

d actual gra

GOM, in relat

ngth, and se

quantitative

core were m

as those ind

983) indica

percentages

measuremen

nificant grain

diment trans

ain sizes pre

tion to study

ediment tran

e and qualit

made to di

dicated by Al

ates that sur

 of sand, silt

nts are gene

n size varia

sport will va

sent, and th

sites. 

nsport 

tative 

iscern 

llison 

rficial 

t, and 

erally 

ability 

ary in 

hat all 
200 

Table 5.1 

 

Measured Surficial Grain Sizes for Study Sites 

Site No. Grain Size Classification 

Graphic Mean 

Grain Size (μm)

Wentworth 

Classification1

433 (R.W. Gallagher) 48.6 Course silt 

386 (Heredia) n/a n/a 

373 (Cities Service Toledo) 12.5 Medium silt 

15488 (Unknown wreck) 46 Coarse silt 

15366 (Unknown wreck) 9.76 Medium/Fine silt 

389 (J.A. Bisso) 173 Fine sand 

236, paddlewheel area 

(Hatteras) 13 Medium silt 

236, stern area (Hatteras) 343 Medium sand 

15326 (Unknown wreck) n/a n/a 

322 (Unknown wreck) n/a n/a 

1 Calculated graphic mean grain size from measured samples after Folk (1980) and 

Shackley (1975). 

5.1.2.2 Oceanographic Data 

As discussed previously, oceanographic modeling in this study focused on extreme storm 

events, due to their increased potential for inducing sediment transport and scour compared with 

non-storm conditions in the GOM (Section 5.1.2). Pre-existing data, including wave height and 

wave period, was available for recent storms, including Rita and Ike, and illustrate the 

oceanographic conditions likely to induce scour (Figures 5.2 and 5.3). In order to estimate 

sediment transport and scour potential across a multitude of study sites, three datum sites were 

selected and modeled (Rego et al. 2011). The results of the analysis at each datum were then 

used to model conditions at each of six study sites, as discussed in Chapter 2. Grain sizes were 

measured for each datum, because sediment type is a significant factor in determining sediment 

mobility potential, as discussed above (Section 5.1.2). The datums generally represent water 

depths and sediment types found across the study sites, and include both maximum scour and net 

scour (scour measured after redeposition of suspended sediments following the modeled storm 

event) (Table 5.2). 

 
Figur

Characte

Datum 

1 

2 

3 

re 5.2. Sign

regio

Datu

ristics of Sur

De

26

15

31

nificant wave 

onal model). T

ums (Rego et 

T

rface Sedim

epth (m) 

.0 

.5 

.0 

height and 

The three wh

al. 2011). 

201 

Table 5.2 

 

ents at Ocea

S

Grain Siz

Graphic 

12.5 

 88.7 

 74.4 

mean waveite circles in t

anographic 

Surficial Sed

ze (μm) 

Mean 

M

Ve

Ve

-period during

the Northwes

Modeling Da

diments 

Wentwort

Classificati

Medium silt 

ery fine sand

ery fine sand

g Hurricane 

stern GOM ma

atums 

th 

ion 

d 

d 

Rita (results

ark the three 

 from 

study 
Fig

Based

have exp

sediment

range of 

specific 

reduced b

modeled 

actually 

following

85% to 9

is likely 

have a si

sites whe

cumulativ

of sub-bo

patterns. 

of 6 to 10

part of th

approxim

based on

gure 5.3. Sig

reg

stu

d on the res

perienced so

t porosity an

expected co

grain sizes 

by between 

storm and 

resulted in 

g a hurrican

99% followin

to occur at 

ignificant lon

en examined

ve scour rate

ottom profil

The sub-bot

0 cm (2.4 to 

his study use

mately 6 to 

n hurricane 

gnificant wav

gional model

udy Datums (

sults of the 

ome degree 

nd plasticity 

onditions, bo

found at eac

70% and 91

reported as

net sedime

e event. Und

ng sediment

the shipwre

ng-term effe

d as a longeres. Scour can

ler data; how

ttom profiler

3.9 inches) 

ed a restricte

8 cm (2.4 t

scour estim

ve height and

). The three w

Rego et al. 2

oceanograph

of maximu

were not m

oth loose an

ch datum po

% following

s “net” scou

ent accretion

der consolid

t redepositio

eck study sit

ect on hull e

-term pattern

n and has be

wever, there

r system use

when using 

ed 2 to 10 kH

to 3.2 inch) 

mates from h

202 

d mean wave 

white circles 

011). 

hic datum m

um scour (T

measured for

nd consolida

oint. For loo

g sediment r

ur; Table 5.

n, but this 

dated bed sce

on (Rego et a

tes, single in

exposure rate

n of sedimen

een observed

e are limits 

ed in this stu

a 2 to 16 kH

Hz frequenc

range. Even

hurricanes Ik

period durin

in the Northw

modeling, ea

Table 5.3).

r the datum 

ated bed sce

ose bed sce

redeposition 

.3). At Datu

was the on

enarios, max

al. 2011). Th

nstances of 

es. Scour is 

nt movement

d on the ship

to the reso

udy has publi

Hz range; ho

cy range that

n using the 

ke and Rita

ng Hurricane 

western GOM

ach of the st

As discusse

sites; theref

enarios were

narios, max

(calculated 

um 3 sedim

nly site to d

ximum scour

his suggests

storm-relate

more likely

t, either thro

pwreck sites

olution of ne

ished vertica

owever, the d

t increased d

higher freq

a, only scou

Ike (results f

M mark the th

tudy sites sh

ed in Chapt

fore, to prov

 modeled fo

ximum scour

7 days after

ment redepos

display accr

r was reduce

s that while 

ed scour ma

y to impact w

ough long-ter

s through ana

ear-surface 

al resolution

data acquired

data resoluti

quency spec

ur in a loose

from 

hree 

hould 

ter 2, 

vide a 

or the 

r was 

r each 

sition 

retion 

ed by 

scour 

ay not 

wreck 

rm or 

alysis 

scour 

n rates 

d as a 

ion to 

trum, 

e bed 
203 

scenario would be observed in the sub-bottom profiles. Consolidated-bed scour estimates are 

below the threshold for vertical resolution on sub-bottom data, and would only be detectable 

through physical sediment sampling and analyses, such as radioisotope analysis. 

 

It should be understood that modeling estimates were based on flow conditions only. The 

estimates represent some, but not all of the possible scour scenarios during hurricane events. In 

particular, they do not account for the increased turbulence and local higher velocity flows and 

potential scour that would highly likely occur around the actual wrecks during storms and 

hurricanes. 

Table 5.3 

 

Scour Estimates Based on Oceanographic Modeling1

Hurricane Bed Scenario Scour Type Scour Depth 

 Datum 1 Datum 2 Datum 3 

Ike 

Loose Maximum 1.5 m 1.0 m 1.3 m 

Net 13 cm 30 cm 30 cm 

Consolidated Maximum 0.3 cm 0.2 cm 0.24 cm 

Net 0.03 cm 0.03 cm -- 

Rita 

Loose Maximum 1.5 m 84 cm 60 cm 

Net 21 cm 10 cm + 5 cm 

Consolidated Maximum 0.3 cm 0.2 cm 0.10 cm 

Net 0.03 cm ~ 0 cm -- 

1

 Rego et al. 2011 

5.1.2.3 Radioisotope Comparisons 

Radioisotope analysis of 210Pb and 137Cs has had limited application in shipwreck 

archaeology. Previous examples of this type of data analysis include studies of H.L. Hunley

(Murphy 1998) and USS Housatonic (Conlin 2005a). In the case of Hunley, analysis of 210Pb and 

137Cs was done to determine sediment disturbance depth within the last 50 to 100 years (Lenihan 

and Murphy 1998:16). Radioisotope analysis conducted on sediments sampled above the buried 

vessel’s hull indicated that there had not been any sediment disturbance within the last 100 years 

(Murphy et al. 1998:98). The results were correlated with biological data and used in further 

discussions of hull corrosion, because the radioisotopes demonstrated that the hull had been 

covered by a protective layer of sediment for at least 100 years, with an error margin of +/- 20 

years (Murphy et al. 1998:98). Radioisotopes (210Pb and 137Cs) were used on the USS 

Housatonic shipwreck site for the intended purpose of delimiting the extent of post-depositional 

sediment disturbance, since two salvage efforts and one instance of dynamiting were known to 

have impacted the wreck (Conlin 2005a:47-48). Housatonic and Hunley wrecked in 

approximately the same area, and results from both sites were correlated and compared in the 

2005 Housatonic study (Conlin 2005a). Unlike the hulls examined in the current study sites in 

the GOM, the hulls of both Hunley and Housatonic were completely buried under sediments; 

radiometric dating of sediments indicated averaged sedimentation rate estimates of 0.74+/-0.25 
204 

cm/yr at the Hunley site, and 0.89+/-0.3 cm/yr at the Housatonic site. Analysis did not identify 

any evidence of punctuated erosion (i.e., disturbance events in the downcore decay of 210Pb) at 

either site, suggesting continuous burial that contributed to excellent states of preservation on 

both sites (Conlin 2005b:145). 

For the purposes of the current study, radioisotope analysis was conducted at six shipwreck 

sites to determine approximate sedimentation rates in lieu of sediment traps or long-term 

monitoring. A secondary goal, developed during the analysis, focused on identifying a 

disturbance event layer in the sediment core. Unfortunately, the study budget allowed for only 

radioisotope analysis of a single core from each of six sites; therefore, it was understood that the 

sampling strategy was too coarse to make definitive statements about sediment disturbance based 

on one sample per site. 

Following analysis of radioisotopic traces, all of the sampled sites showed excess 210Pb and 

137Cs in surface (0-1 cm) sediment intervals (Table 5.4). This indicates that all core sites have 

sediments that have interacted with the marine water column in the last 56–100 years; the 

smaller interval represents the time since the onset of thermonuclear testing (1954), which 

released radiocesium into the atmosphere and resulted in ongoing fallout. Five of the six sites 

also show downcore decay in 210Pb excess activity, indicating the seabed at those five sites is 

presently depositional (Table 5.5). The sixth site, Site 373, has variable activity downcore that 

may be a function of recent bioturbation by benthic macrofauna, coring/diver disturbance, or 

physical reworking (e.g., tropical storms). In none of the cores did downcore cesium profiles 

show a clear 1954 onset or 1963 peak testing time marker. This may be a function of overall low 

activities, and/or trends masked by downcore variability in grain size. Lead and cesium 

radiotracers are adsorbed preferentially onto clay mineral surfaces; therefore, variations in coarse 

fraction between sampled sediments, such as an increase in sand compared with coarse silt 

percentages in the sediments, serve to decrease activities. Grain size may also impact lead 

sediment accumulation rates, and therefore the potential impact of grain size was evaluated for 

each site using both direct measurements of grain size, and indirect measurement (e.g., sediment 

porosity). 

Table 5.4 

 

Sites Analyzed for Radioisotopes and the Number of Data Points Sampled from Each Site 

Site No. Core No. Data Points 

433 (R.W. Gallagher) 2 14 

373 (Cities Service Toledo) 1 12 

15488 (Unknown wreck) 1 11 

15366 (Unknown wreck) 1 9 

389 (J.A. Bisso) 2 9 

236 (Hatteras) 1 13 

 
205 

Table 5.5 

 

Linear Accumulation Rates (LAR) and Disturbance Event Date Ranges Indicated from 

Radioisotope Data 

Site No. Distance 

Offshore (nm) 

Disturbance 

Event Date 

Range 

LAR (cm/yr) 

433 (R.W. Gallagher) 35 1921–1932 0.17 

373 (Cities Service Toledo) 44 Indeterminate Indeterminate 

15488 (Unknown Wreck) 24 1947–1965 0.06 

15366 (Unknown Wreck) 17 1925–1987 0.15 

389 (J.A. Bisso) 21 1832–1960 0.08 

236 (Hatteras) 21 1931–1949 0.14 

At all five sites where a 210Pbxs decay profile was observed in near surface sediments, there 

was also a point at depth where activities increased significantly. This is interpreted as a 

disturbance to the pattern of quasi steady-state sediment accumulation at the site, which can be 

interpreted as a disturbance event. The surficial sediment decay in Pb activity, therefore, 

represents a post-disturbance accumulation rate. Disturbances in the radioisotope data may be the 

result of extreme storm events that erode the seafloor and are followed by a resumption of 

accumulation rates, or the settling of a shipwreck onto the seafloor, that in turn impacts nearseafloor sediment transport. Without stratigraphic evidence like core x-radiographs of internal 

layers, it is not possible to differentiate these causations. However, it can be said that the fact that 

a disturbance layer was observed at all accumulating sites, including those near the maximum 

inner-shelf depths (40 m or 130 ft) where hurricane seafloor disturbance is less prevalent, points 

to a cause other than extreme storm events. The rate of sediment accumulation and depth of the 

disturbance interval can be used to arrive at an age range of the disturbance horizon. This age is 

presented as an interval in years, given that it is also a function of the sampling density with 

depth; denser sampling allows the depth of the disturbance interval to be better defined (Tables 

5.4 and 5.5). 

At four of the five accumulating-disturbance shipwreck core sites, the interval below the 

disturbance zone did not display a downcore decay of 210Pbxs with depth. This may be an artifact 

of insufficient sampling density, variation in grain size, or disturbance of in situ sediments. At 

Site 236, there is sufficient evidence to assign an accumulation rate before the disturbance (e.g., 

pre-disturbance). The pre- versus post-disturbance difference in sediment accumulation rate 

provides a powerful analytical tool for examining the potential impact of the disturbance event 

(if identified) on site sediment accumulation or erosion. 

On average, linear accumulation rates across the sampled shipwreck sites are 0.12 cm/yr. 

Absent of shipwreck subsidence, these low rates of sediment accretion indicate that the exposed 

hulls observed by divers during the 2010 field work will remain exposed for the foreseeable 

future; at current LARs, it will take 100 years to accumulate an average 12 cm (4.7 inches) of 

sediment at each site absent of any simultaneous scour. Due to the lack of significant sediment 
206 

accretion, the hulls examined in this study will remain subjected to water column variables, and 

will likely suffer continued corrosion. 

5.1.3 Water Quality 

Metal-hulled shipwrecks in salt water environments are susceptible to corrosion, which 

occurs through oxidation, the electrochemical removal of atomic electrons from the exposed 

metal (Cronyn 1990:168; Keith 2004:24). Both extremely acidic and extremely alkaline 

environments accelerate active corrosion, in which soluble metal by-products dissipate into the 

water column (Keith 2004:24). Corrosion can also occur through a passive process during which 

various by-products, including carbonates, oxides, hydroxides, and sulphates, combine to form a 

concretion on the surface of the metal (Keith 2004:24). Oxygen is the primary agent in corrosion, 

but hydrogen, sulphide, and chloride ions also act to stimulate corrosion of submerged metal 

(Cronyn 1990:167-168). Corrosion is an important site formation process acting on modern 

steel-hulled wrecks because it ultimately weakens the integrity of the metal, contributing to 

structural failure over time. Ironically, more recent steel-hulled vessels deteriorate at a faster rate 

than their iron counterparts (Keith 2004). According to McCarthy (1985:222), “due to the lasting 

properties of wrought iron compared with steel, (iron ships) will remain with us ... long after 

their steel contemporaries have disintegrated.” 

Corrosion occurs in both submerged and seabed-embedded structures. In both cases steel 

corrosion rates are affected by salinity, temperature, pH, and dissolved oxygen, carbonates, 

biological organisms, and pollutants (Matsushima 2000:545). Estimates indicate that corrosion 

results in an average loss of 0.1 mm/year per exposed surface; however, individual variable 

levels in seawater fluctuate seasonally and with depth, and evidence suggests that corrosion rates 

decrease over time (MacLeod 1989:13; Matsushima 2000:548). Corrosion is an important factor 

in considering the long-term preservation or structural stability of steel-hulled shipwrecks 

because instability can ultimately result in the collapse of all or part of the extant hull. Using 

finite element analysis on the USS Arizona’s hull, Foecke et al. (2010) demonstrated that a 50% 

loss of hull steel through corrosion would result in localized collapse; a 60% loss would result in 

general collapse of the upper decks, adding significant stress to underlying decks. At the time the 

study was conducted, Arizona was estimated to be at 20% corrosion, with 50% corrosion 

projected to occur by the year 2120 (Foecke et al. 2010). 

The passive corrosion of iron typically produces a remnant layer on the metal’s surface that 

may protect it against further corrosion (Matsushima 2000:548). This remnant layer can also be 

a proxy for the original metal thickness, allowing archaeologists to compare measurements of the 

total original and reduced actual thicknesses (Russell et al. 2006:312). If the wrecking date is 

known, corrosion rates can be determined by calculating the change in thickness (amount of 

metal lost through corrosion) over the duration of submergence (Russell et al. 2006:313). Carbon 

steel, which is predominately used in shipbuilding, however, does not leave this remnant layer. 

Corrosion rates for steel hulls can be calculated only by subtracting the direct measurement of 

actual steel thickness from thicknesses specified in the documentary record, such as ship’s plans 

(Russell et al. 2006:313). Actual measurements can be taken directly from sampled materials or 

through the use of ultrasonic measuring devices; however, both methods require the removal of 

metal samples from the hull (Russell et al. 2006:312-313). Despite the importance of corrosion 
for longwas bey

operation

impactin

Publi

potential

individua

(NODC) 

1.0 degre

during th

at depths

should us

and signi

Figur

term site pre

ond the sco

ns at the dep

g corrosion 

ished data ex

, but sampli

al wreck si

demonstrate

ee grid (Figu

he winter and

s of 20 and 3

se depth-app

ificant projec

re 5.4. Seas

indic

eservation an

ope of this 

pth of the ac

and to provi

xists for wat

ing intervals

ites. Salinity

e both seaso

ure 5.4 throu

d lowest in s

30 m (66 and

propriate dat

ction into th

sonal averag

cated in red. (

nd managem

project; ho

ctual wreck 

ide comparat

er quality in

s vary and m

y data from

onal variabili

ugh Figure 5

summer at th

d 98 ft) BSL

ta for salinity

e water colu

e salinity me

(Data from NO

207 

ment, physica

owever, wat

sites in ord

tive data for 

n the GOM; i

may not acc

m NOAA’s 

ity of water 

.7). Salinity 

he surface (F

L, (Figures 5

y, considerin

umn surround

easurements 

OAA NODC.)

al sampling 

ter samples 

der to provid

r future resea

it could be u

curately rep

National O

quality and

y values in th

Figure 5.4), b

5.6 and 5.7).

ng both the m

ding the hull

of surface wa

of metal fro

were acqui

de baseline d

arch. 

used in estim

resent cond

Oceanograph

variability w

he GOM are 

but remain re

 Therefore, 

maximum de

l. 

ater. Shipwre

om the study

ired during 

data on vari

mates of corr

ditions presen

hic Data C

with depth o

typically hi

elatively con

corrosion st

epth of the w

eck study site

y sites 

field 

iables 

osion 

nt on 

Center 

over a 

ighest 

nstant 

tudies 

wreck 

es are 
F

Fi

igure 5.5. S

s

gure 5.6. S

s

easonal ave

study sites ar

Seasonal ave

tudy sites are

erage salinity

re indicated in

rage salinity

e indicated in 

208 

y measureme

n red. (Data N

measuremen

red. (Data fro

ents at a dep

NOAA NODC

nts at a dept

om NOAA NO

pth of 15 m B

.) 

th of 20 m B

ODC.) 

BSL. Shipwre

BSL. Shipwre

ck 

ck 
Fi

Disso

Turner 2

hypoxic 

base stati

of July 2

does not 

bottom c

impact th

corrosion

myopic v

gure 5.7. 

olved oxyge

010) indicat

zones to app

ions in wate

2010 in the 

extend as fa

onditions an

he remainde

n (Matsushim

view. 

Seasonal av

study sites a

n data acqu

ted that mea

proximately

er depths of 

GOM (Rab

far west as S

nd is an accu

er of the sh

ma 2000:54

verage salinity

are indicated 

uired as part 

asured DO c

y 7 mg/liter 

15 and 20 m

alais and Tu

Sites 15488, 

urate assessm

hipwreck sit

45; MacLeo

209 

y measureme

in red. (Data 

of a long-t

content of bo

(Figure 5.8)

m (49 and 66

urner 2010).

15366, and 

ment of cond

es. DO is t

d 1989) bu

ents at a dep

from NOAA N

term GOM h

ottom-water 

). Daily mea

6 ft) were rec

. Although d

236, the da

ditions at a g

the most im

ut one-time 

pth of 30 m B

NODC.) 

hypoxia stud

r ranged from

asurements o

corded throu

data from th

ata that was 

given point in

mportant fact

measuremen

SL. Shipwrec

dy (Rabalais

m < 1 mg/lit

of DO conte

ughout the m

he hypoxia 

collected re

n time that w

tor in meas

nts show on

ck 

s and 

ter in 

ent at 

month 

study 

flects 

would 

suring 

nly a 
Figure

Wate

seasonal 

correlatio

(Append

and F-9)

salinity a

variation

published

Site

3

3

4

4

3

3

153

3

154

154

153

153

2

e 5.8. Disso

Turne

er samples c

fluctuation 

ons, includin

ix F; Figure

. No discern

and DO me

ns due to m

d averages fo

e No. Sam

No

80 1

89 1

33 1

33 2

86 1

73 1

26 1

22 1

88 1

88 2

66 1

66 2

36 1

olved oxygen 

er 2010). 

collected at e

(Table 5.6).

ng by water

es F-2, F-5, 

nible pattern

easurements 

methodology

for the region

Avera

mple 

o. 

Distan

Offsho

(nm

11 

21 

35 

2 35 

41 

44 

19 

16 

24 

2 24 

17 

2 17 

21 

content of bo

each study s

 Data was p

r depth (App

and F-8), an

ns were obvi

exceeded p

y or greater 

n. 

T

aged Results

nce 

ore 

m) 

Wat

Tem

(°F

86

86

77

77

83

83

86

88

88

88

88

88

84

210 

ottom-water, a

site represen

plotted in sev

pendix F; F

nd distance 

ous in the p

published da

variability 

Table 5.6 

 

s of Water Q

ter 

mp. 

F) 

Dept

BSL

(m)

11.3

20.

30.8

27.4

21.3

24.7

17.4

17.

14.3

14.3

18

18

18.3

as sampled J

nt single dat

veral ways t

Figures F-1, 

offshore (Ap

plotted data a

ata for the 

at each sit

Quality Testin

th 

L

)

Salinit

(ppT)

3 31.6

1 31.4

8 32.7

4 32.1

3 33.6

7 30.8

4 32.1

1 31.9

3 31.5

3 31.8

8 33.2

8 33.1

3 34.4

July 25–31, 2

ta points wi

to aid in the

F-4, and F

ppendix F; F

across sites,

GOM. This

te than exp

ng 

ty 

) pH 

6 7.240 

4 7.496 

7 7.767 

1 7.837 

6 7.563 

8 8.013 

1 7.323 

9 7.230 

5 8.020 

8 7.837 

2 8.097 

1 8.160 

4 8.033 

2010 (Rabalai

ithin a patte

e identificati

F-7), site loc

Figures F-3,

, but the ran

s suggests e

pected, base

Dissolved

Oxygen 

(mg/L)

6.747 

7.017 

6.795 

6.980 

6.780 

7.450 

6.690 

6.735 

6.915 

6.870 

7.455 

7.480 

7.467 

is and 

ern of 

on of 

cation 

, F-6, 

nge of 

either 

ed on 

d
211 

5.2 ANTHROPOGENIC PROCESSES 

Anthropogenic processes of shipwreck site formation can occur during the wrecking event, 

such as through selective discard of materials during efforts to avert sinking. They can also occur 

as long-term, cumulative, or single-occurrence impacts at any time or for any duration after the 

wrecking event. Anthropogenic or cultural processes that can affect a site include construction, 

dredging, fishing, salvage, and the disposal of refuse (Stewart 1999). 

As discussed in Chapter 1, BOEM is responsible for managing and regulating offshore 

energy development within the U.S.’s exclusive economic zone. The agency’s primary concern 

in regard to cultural resources is ensuring that lease development has no adverse impacts on 

archaeological sites. Discussion in this section focuses primarily on the impacts of construction 

activities related to federally-permitted oil and gas development but also briefly addresses other 

anthropogenic impacts. 

The primary impacts to the seafloor that can be expected from oil and gas operations are 

drilling and structure and pipeline installation and removal. Impacts associated with these 

activities are regulated by the Code of Federal Regulations and published Notices to Lessees 

(such as NTLs 2005-G07, 2008-G05, 2009-G39, and 2009-G40). These NTLs require, before 

lease development or pipeline installation, geophysical surveys or visual inspections of the 

seafloor to assess seafloor conditions, and identify any potential hazards, sessile biologic 

communities, and archaeological sites present in the area of potential effect. The reports prepared 

in compliance with the NTLs are reviewed by BOEM and, if compliance standards are met, the 

permitted activity is approved. Avoidance criteria or mitigation measures may be applied to 

certain magnetic anomalies, sonar targets, and subsurface features, identified on the geophysical 

data, which may represent potential archaeological resources. These avoidance criteria will be 

included in the notification of approval issued to the operator. 

Jack-up rigs and submersible drilling rigs are the most common means of drilling in water 

depths equivalent to the study sites; jack-up rigs are the more prevalent. Both of these rigs result 

in setting the rig on the seafloor during drilling operations. The two most common types of jackup rig are mat-supported and independent legged rigs. Typically, all jack-ups have three legs that 

support the rig, but the mat-supported rig also has a large A-shaped mat that distributes the 

weight across the legs (Figures 5.9 and 5.10). Although the permitted area of impact associated 

with drilling activities on the outer continental shelf is typically fairly restricted, the overall 

disturbance associated with drilling can extend beyond the footprint of the rig. 
Figur

 

In ad

mud may

of earth 

“mud.” T

synthetic

extend ou

was drille

site and/o

that in sh

the seabe

1977:548

impact o

2000; an

shipwrec

contamin

impacts 

contamin

Without 

fluid or a

impact sa

archaeolo

res 5.9 and 5.

ddition to the

y splay outw

produced d

There are th

c-based. In w

utward from

ed in proxim

or make futu

hallow water

ed but, inste

8; Neff et a

f cuttings on

d UKOOA 2

ck sites. Ba

nation of rad

to radiocar

nation impac

further stud

additives in w

ample testin

ogical site an

.10. Left: M

Drilling

Right: 

seabe

Courte

e bottom dist

ward from the

during drillin

hree differen

water depths 

m the well sit

mity to a wre

ure investiga

rs similar to 

ead, quickly 

l 2000:15). 

n biologic c

2005), no kn

ased on rese

diocarbon sa

rbon dating 

cts on radio

dy, though, i

water-based 

ng or data re

nd make doc

Model of a m

g Rig & Mus

Side scan s

ed, showing 

esy of Tesla O

turbance cau

e well site du

ng and rem

nt types of 

deeper than

te up to 50 m

eck site in eq

ation more d

those of the

dissipate be

Though num

ommunities 

nown studies

earch condu

amples were

were ident

ocarbon dati

it is unknow

or synthetic

ecovery. Cer

cumentation 

212 

 

mat-supported

eum, Galves

sonar image o

imprints from

Offshore.) 

used by the 

uring drilling

moved from 

drilling flu

n the study a

m (164 ft) in

quivalent wa

difficult or e

e study area,

ecause of the

merous stud

(NRC 1983

s have been

ucted in the

e examined 

tified from 

ng is still u

wn to what 

c-based fluid

rtainly, buria

more difficu

d jack-up rig 

ston, Texas. (

of a mat-sup

m previous m

area of impa

g operations

the well ho

uids: water-b

area, drill cu

n diameter (N

ater depths, th

xpensive. O

, drill cutting

e effects of 

dies have be

3; Boesch an

conducted t

e wake of 

at ten diffe

these samp

under invest

degree, if a

ds could con

al under dril

ult or time-c

at Ocean S

(Photo by au

ported jack-u

mat-supported

act, drill cut

s. Drill cuttin

ole through 

based, petro

uttings have 

Neff et al. 20

he cuttings c

Observations 

gs typically 

currents and

een conduct

nd Rabalais 

that examine

the Exxon 

erent oiled s

ples; howev

tigation (Re

any, petroleu

ntaminate a s

lling splay w

consuming. 

Star Offshore 

uthors 2009). 

up rig on the 

d rigs. (Data 

ttings and dr

ngs are fragm

drilling flu

oleum-based

been observ

000:15). If a

could obscur

have also sh

do not colle

d waves (Zin

ted analyzin

1987; Neff 

e their impac

Valdez oil 

sites. No ad

ver, the issu

eger et al. 1

um-based dr

site and adve

would obscu

rilling 

ments 

uid or 

, and 

ved to 

a well 

re the 

hown 

ect on 

ngula 

ng the 

et al. 

cts on 

spill, 

dverse 

ue of 

992). 

rilling 

ersely 

ure an 
213 

The installation of a permitted structure, such as a platform or caisson, typically takes place 

at the site of a successfully drilled well location. During drilling and subsequent platform 

operation phases, activities at a well site may include drilling additional wells with different rig 

footprints, the use of seafloor-mounted lift boats for maintenance or repair work, and anchoring 

associated with dive boats or other support vessels. Materials are frequently discarded from the 

rig or platform or from other service support vessels, usually through accidental loss. In addition 

to ancillary activities associated with resource extraction, platforms and well caissons often 

become popular sites for fishermen and recreational divers who can also produce impacts to 

archaeological sites. Despite the wide range of potential impacts associated with drilling a well, 

the area of impact is generally relatively localized, focused on the immediate vicinity of the well 

site. 

If a well is successful, then product will need to be transported off-site for refining and 

distribution. The installation and use of subsea pipelines is the most common method for moving 

oil and gas from wells to production facilities. Pipelines in the GOM are required to be buried to 

a depth of at least 0.9 m (3 ft) BML in water depths under 61 m (200 ft). Within shipping 

fairways, pipelines are required to be buried 3 m (10 ft) below the seafloor, and within anchorage 

areas, 4.9 m (16 ft) to avoid incidental damage from anchoring (30 CFR 250.1003(a)(1)). The 

two most common methods for pipeline installation are through the use of anchored lay-barges 

(Figure 5.11) or dynamically positioned reel-barges. Although dynamically positioned pipeline 

installation can occur in water depths as shallow as 33 m (100 ft), it is generally not used in less 

than 61 m (200 ft) of water (Cranswick 2001). Anchored lay-barges are the most common 

pipeline installation method in water depths equivalent to those of the study area. Operational 

procedures for anchored lay-barges restrict their use to areas less than 300 m deep (1,000 ft) 

(Cranswick 2001), although the amount of anchor cable available on an individual vessel may 

restrict the operating depth to even shallower waters. Pipeline is buried during installation with 

the use of a jet-sled or plow. The lay-barge deploys the pipe from the surface through a device 

called a stinger and the jet-sled or plow digs a trench into the seabed in which the pipeline is laid. 

Jetting can cause substantial impacts to a shipwreck, but it should be noted that it is also in the 

installer’s best interests to avoid impacting any wrecks, because the wrecks could damage the 

highly specialized and expensive equipment or cause considerable construction delays. 
In ad

disturbin

installatio

depth. A

between 

support t

move the

anchors 

(Cranswi

During b

along the

The large

to a shipw

Ancil

support (

fairly sig

diverse n

on a cas

pipeline 

responsib

stipulated

requirem

Figure 5.

ddition to th

ng activities c

on. A standa

An anchored

30,000 to 5

tugs which a

e barge alon

are set, they

ick 2001). G

barge movem

e bow ancho

e diameter w

wreck site. 

llary activiti

(such as div

gnificant bott

number of co

se-by-case b

installation

bility to ens

d for avoida

ments. These

.11. Pipeline

he impacts c

can also be c

ard pipeline 

d barge typi

50,000 tons 

are used to d

ng the rout

y need to be

Ground distu

ments, slack

or lines; this

wire rope use

 

ies, such as

e ships), are

tom disturba

ompanies, it 

basis. Botto

n are regul

sure that co

ance. Off-lea

e activities 

e lay-barge w

caused by j

caused by an

lay-barge ex

ically requir

(Cranswick 

eploy the an

e by tighten

e repositione

urbance is n

k is placed o

s may allow 

ed to handle 

s those cond

e not explici

ances but, du

would be d

om-disturbin

ated under 

ontractors do

ase bottom-d

are usually

214 

with anchors d

etting and l

nchors and an

xtends ancho

res between

2001). The 

nchors along

ning up on 

ed every 61

not limited t

on the stern 

portions of

these massi

ducted by li

itly regulated

ue to the fre

difficult to re

g activities 

the permi

o not impac

disturbing ac

y risk-aversi

deployed (Shu

laying the p

anchor chain 

ors out a dis

n eight and 

anchors are

g the route. W

the forewo

10 m (2,000

to the actua

lines befor

f the chain to

ive anchors c

ift boats an

d by BOEM

equency with

egulate these

associated 

itted activit

ct targets o

ctivities are 

ion activitie

u 2011). 

pipeline, sub

used by the

stance of fiv

12 anchors

e lifted onto

Winches abo

ord anchors. 

0 ft) along th

al anchor tou

e pulling th

o rest or dra

can cause su

nd anchored 

M. These ves

h which they

e bottom-dis

with lease 

ty, so it is

or anomalies

typically ex

es that cann

bstantial bot

 lay-barge d

e times the w

s, each weig

 anchor-han

oard the lay-b

Generally, 

he pipeline 

uch-down po

he vessel for

ag on the bo

ubstantial dam

vessels off

ssels can pro

y operate an

sturbing activ

developme

s the opera

s that have 

xempt from 

not be expl

ttomduring 

water 

ghing 

ndling 

barge 

after 

route 

oints. 

rward 

ottom. 

mage 

fering 

oduce 

nd the 

vities 

nt or 

ator’s 

been 

NTL 

licitly 
215 

regulated, for example, anchoring a vessel or setting a platform on the seafloor during severe 

weather conditions to mitigate risk to the vessel and crew. 

Wreck-site impacts that are not related to oil and gas include fishing, recreational boating 

(including scuba diving), shipping, disposal, salvage, and dredging. Fishing and shrimping are 

perhaps the greatest bottom-disturbing activity on the seafloor across the northwestern GOM 

(Evans et al. 2009). Shrimp trawlers cover a great deal of seabottom while dragging nets 

weighted down with otter boards that scrape across the seabed. It is rare that a shipwreck site on 

the GOM’s continental shelf is not covered in shrimp netting or fishing line. Recreational boaters 

and divers can also impact sites, either by disposing of refuse or by diving on known sites and 

removing artifacts. Debris disposal, both accidental and purposeful, is common on the OCS. In 

most cases, intrusive modern debris can easily be identified on a site and does not present a 

significant detriment to the archaeological record; however, military dumping of Unexploded 

Ordnance (UXO) and chemical weapons in the deepwater GOM presents a unique challenge in 

those areas (Samuel and Herbert 2007; Evans and Voisin 2011). Military testing grounds have 

also been known to cloud the archaeological record through the distribution of practice bombs 

and shells (Keith 2004; Keith and Skeist 2004). No known UXO dumping zones or military 

testing grounds are reported within the study area. Salvage, what Schiffer and Stewart refer to as 

“reclamation” (Schiffer 1987; Stewart 1999), can be categorized as either firsthand salvage or 

secondhand salvage. Firsthand salvage occurs when those involved in the wrecking process or 

with a stake in the vessel (i.e., investors or insurers) attempt to recover the entire wreck, recover 

usable gear from the wreck, or recover significant portions of the cargo. This is done with the 

technologies available at the time, and, though it disturbs the archaeological context, the act of 

salvage can provide information about the economic value ascribed to various items and 

available technologies used in salvage operations. Secondhand salvage is undertaken at a later 

date by those not affiliated with the vessel, usually for profit. The dredging of shipping channels 

is not common in the water depths examined for this study, and is generally restricted to the 

maintenance of existing channels. On-going dredging is therefore unlikely to impact new sites, 

although the dumping of dredge spoil could bury or obscure a site, making it difficult to identify. 

The most common types of dredging in water depths similar to those of the study sites are done 

for coastal restoration and sediment extraction. NTL 2009-G04 published by BOEM (2009a) 

specifies areas on the OCS that have been set aside for sand extraction. 

5.3 ANALYSIS OF SHIPWRECK SITE FORMATION PROCESSES 

The following sections discuss observations about the impact of site formation processes at 

each wreck site. This discussion builds directly on the methodology outlined in Chapter 2 and the 

data provided in Chapter 3. 

5.3.1 Site No. 380, South Pelto Area, Reported Wooden Wreck 

Because no wreck was identified, no soil or water samples were acquired and this site was 

not included in any modeling. 
216 

The reported location of Site 380 was 62.5 m (205 ft) from an existing pipeline. It appears 

that the pipeline installation pre-dates the record of the site. 

5.3.2 Site No. 433, Ship Shoal Area, Probable R. W. Gallagher

5.3.2.1 Radioisotope Data 

The wreck at Site 433 has been identified as the probable R.W. Gallagher, which was a 

victim of U-boat campaigns in the GOM in 1942 (Rohwer 1983; Wiggins 1995). Samples were 

obtained from Core no. 2 at a water depth of 27 m (90 ft). Core no. 2 was obtained in an 

interpreted area of ambient seafloor that was not influenced by significant seafloor scour. 

Radioisotope analysis indicates that normal sediment accretion was interrupted by a disturbance 

event that occurred 78 to 98 years before core acquisition, or between 1912 and 1932, with 

normal accretion resuming after the disturbance. The most likely cause of the disturbance is an 

extreme storm event, which could have disturbed the seafloor, and thus disrupted the LAR, 

through heavy wave and current activity. The wrecking event is not interpreted as the most likely 

cause of disturbance because it occurred in 1942, post-dating the disturbance by a minimum of 

ten years. 

Between 1868 and 2008, 34 tropical systems, ranging from tropical depressions to category 4 

hurricanes, have been centered within 37 km (20 nautical miles) of Site 433 (NOAA NHC). Of 

these storms, three occurred during the same time period as the disturbance event recorded in the 

radioisotope data; they include an unnamed tropical storm in 1931, an unnamed category 2 

hurricane in 1926, and an unnamed category 1 hurricane in 1923 (Figure 5.12; NOAA NHC). 

The fact that no disturbances were recorded since the disturbance event 78 to 98 years ago may 

suggest that more recent, stronger hurricane events have not had a significant scouring effect on 

the seafloor at Site 433. Included in this time period are Hurricane Carmen, centered east of the 

site as a category 4 hurricane in 1974, and Hurricane Andrew, centered east of the site as a 

category 5 hurricane in 1992 (NOAA NHC). Although Carmen and Andrew were more intense 

than either the 1926 or 1923 hurricanes, they were centered to the east of the site; the 1926 and 

1923 storms were centered to the west of the site, placing the wreck in the strongest quadrant of 

these storms. Site 433 was not within the swath of hurricane force winds associated with recent 

Hurricanes Katrina, Rita, Ike, and Gustav (Appendix D; Maps F-4 and F-5), although tropical 

storm strength winds associated with these storms could have impacted this area. 

 
Figur

5.3.2.2 S

The w

significan

the wreck

the predo

from the

predomin

bow (to t

along the

inverted 

average 

prevailin

hull wou

wreck, w

therefore

pronounc

sediment

the scour

re 5.12. Ind

of 

Scour 

wreck at Site

nt scour patt

k (Figures 3

ominant area

 wreck. The

nantly from 

the south), a

e margins o

hull project

relief for S

ng currents fr

uld experienc

which would

e exhibit gre

ced local sco

t beds and s

r surrounding

dividual track

Site 433 betw

e 433 is orie

tern, evident

3.2.5 and 5.1

as of global 

e observed p

the ESE and

nd at the bre

f the wreck

ts prominen

Site 433 is 

from the ESE

ce greater d

d induce sc

ater develop

our on this s

tratigraphy 

g the wreck 

ks for all tropic

ween 1912 an

ented along a

t on the geop

13). The obs

scour exten

pattern indic

d SE regions

eaches in the

. The degre

ntly into the 

approximate

E and SE, th

development 

cour. The le

pment of rev

side of the w

within the s

(Figures 3.2

217 

cal systems c

nd 1932. (Ima

a SSW head

physical data

served scour 

nding westw

cates waves. Major loc

e hull of the 

e of scourin

water colum

ely 7.3 m (

he up-curren

of helical, r

eeward face 

versing and h

wreck. Sub-b

scour, indica

2.8 and 5.14)

centered withi

age courtesy 

ding, with th

a, is oriented

r occurs in a

ward approxi

and current

cal scour hol

wreck. Add

ng may be a

mn along th

(24 ft) abov

nt, or in this

reversing vo

of the hul

horseshoe v

bottom profi

ating very lit

). 

in 37 km (20 

NOAA NHC.)

he bow facin

d perpendicu

an asymmetr

imately 204 

t-induced sc

les occur at 

ditional scour

attributed to 

he entire len

ve the mean

 case east fa

ortices along

ll (the weste

vortices, cont

iles indicate 

ttle accretio

nautical miles

) 

ng 204 degre

ular to the ax

rical pattern,

m (670 ft) 

cour being d

the stern (no

ring has occ

the fact tha

ngth of the 

n seabed. G

acing, side o

g the edge o

ern side), w

tributing to 

truncation o

on or infill w

s) 

ees. A 

xis of 

, with 

away 

driven 

orth), 

curred 

at the 

keel; 

Given 

of the 

of the 

would 

more 

of the 

within 
Figure 5.13. Multibeam bathymetry re

218 

ndering at Site 433, highlighting seafloor scour. 
Figure 5.14. Profiles of seafloor surroundin

219 

g Site 433.
220 

Although radioisotope measurements are restricted to a single core from the site, when 

correlated with the lack of in-filled scour recorded on sub-bottom data, no evidence of recent 

scour and subsequent infill can be directly attributed to recent storms. This creates two distinct 

possibilities. On the one hand, the induced vortex effect that the wreck site has on prevailing 

currents may create sufficient force to exceed minimum requirements for bedload transport, 

resulting in ongoing scour at this site. On the other hand, if storm-induced scour exceeded the 

calculated linear accumulation rate, the lack of subsequent sediment accretion could account for 

the lack of a recent evident disturbance within the radioisotope decay curve. Calculated sediment 

LAR of 0.17 cm/yr suggests that little deposition is currently occurring in this area. The 

consolidated bed scenario for Datum 1 estimates that 0.03 cm of net scour occurred as the result 

of Hurricanes Ike and Rita. The loose bed scenario attributes between 13 and 21 cm (5.1 and 8.3 

inches) of net scour to these two storms. According to Dunlap et al. (2004), shear strengths at the 

seafloor across this portion of the GOM are very soft (<0.2 ksf). Analysis of shear strength data 

from the single sediment core acquired on site (Table 3.3) confirmed this, providing a nearseafloor measurement of 0.032 ksf at 5 cm (2 inches) BML. Grain size indicates that surficial 

sediments at this site are coarse silts (48.6 μm) that fall beneath the 63 μm threshold for 

classification as cohesive sediments (Masselink and Hughes 2003:124). Based on the available 

data, either punctuated or ongoing flow, or a combination of the two, could be the cause of the 

observed scour on Site 433. Whether the scour is the result of normal currents, or punctuated 

events, the lack of sediment infill suggests that disturbed sediments are either compacted, or 

transported out of the surveyed area before they can settle out of suspension and redeposit within 

the scour zone. 

5.3.2.3 Water Quality and Site Preservation 

Water quality data acquired during diving operations indicate that average salinity at depth 

was 32.4 ppT, average pH was 7.802, and DO was 6.888 mg/L. Values for pH obtained within 

the core sediments produced an average reading of 7.938, although samples within the upper 10 

cm exceeded pH values of 8. This is interesting because sulfate-reducing bacteria that can thrive 

in the anaerobic environment of the sediments typically require a pH level of 5.5 to 8 (Keith 

2004:26). Sulfate-reducing bacteria are believed to cause the oxidation, and thus the corrosion, of 

iron and steel through the production of sulfide ions (Robinson 1981:6-7; Cronyn 1990:169; 

Kuang et al. 2007). 

The inverted hull at Site 433 is relatively smooth, and a significant portion of the observed 

metal is covered by biofouling and organic growth. Trawlers or anchor lines associated with 

modern activities could potentially damage the extant hull, especially if they were to snag on 

already compromised metal near the torpedo holes. Active oil leakage observed on site and at the 

surface indicates that product remains trapped in the holds, but the amount of remnant bunker oil 

is unknown. The vessel is located on a soft, cohesive seafloor, and has experienced subsidence 

into surficial sediments. The hull, however, retains over 7 m (23 ft) of relief into the surrounding 

water column. The vessel is at risk of future deterioration of the exposed portions of the hull 

through the combined effects of chemical deterioration of the hull, metal fatigue, and changing 

current profiles and intensities. If the measured pH levels in the near-seafloor sediments are 

accurate indicators of the ambient acidity, higher pH levels within the soils may hinder the 

development of sulfate reducing bacteria within the near-seafloor sediments and thus help protect 
221 

buried portions of the hull from oxidation. However, sediment samples were not tested for the 

presence of sulfate reducing bacteria as part of this study. Kuang et al. (2007) demonstrated in 

laboratory experiments that sulfate-reducing bacteria may alter the pH level of surrounding 

seawater by as much as 0.25. It is therefore unknown if the measured pH at Site 433 is an 

accurate indicator of sediment quality or a response to existing bacterial activity surrounding the 

wreck. 

Sonar data at Site 433 revealed evidence of a large anchor scar measuring 53 m (173 ft) in 

length by an estimated 2.4 m (8 ft) in width. Although the cause of this scar cannot be attributed 

to a specific action, the size and location indicates probable oil and gas support. This scar was 

outside of the avoidance zone surrounding the site. 

5.3.3 Site No. 386, Ship Shoal Area, Probable Heredia 

The wreck at Site 386 is identified as the probable Heredia, which is known to have sunk in 

1942 (Rohwer 1983; Wiggins 1995). The wreck’s current condition is severely degraded, with 

large areas of disarticulated debris evident on sonar and multibeam data (Figures 3.35 and 5.15). 

Heredia was classified as a hazard to navigation after the wrecking event, and was scheduled for 

mitigation efforts, including controlled explosions on site to remove the uppermost wreck 

components to allow safe navigation over the site. According to records, however, the wreck site 

was not relocated and therefore demolition did not occur (Appendix E; Figure E-24-26). Given 

the condition of the site, it is possible that subsequent demolition did occur, but this is based 

purely on conjecture, as no documentary evidence has been found verifying site demolition. 

5.3.3.1 Scour 

No cores or diver observations of the seabed were conducted on site. The site is located 6.1 

km (3.8 statute miles) SW of Site 433, and observed sub-bottom profiles were similar between 

the two sites. The environment at Site 386 is likely very similar to the conditions found at Site 

433. Sub-bottom profiles recorded adjacent to and underneath the wreck show normal, parallelbedded sediments. Scour zones, although not as prominent as those observed at Site 433, indicate 

truncation with no evidence of redeposition. Dunlap et al. (2004), indicate that shear strengths at 

the seafloor across this portion of the GOM are soft to very soft (0.6 to <0.2 ksf). No grain size 

data is available for this site, but it appears likely that sediments are similar to Site 433 where 

cores indicated that surficial sediments were cohesive coarse silts (48.6 μm). 

Oceanographic modeling indicates relatively low rates of maximum and net scour occurring 

during hurricane events, but considered only flow conditions for sediment transport; it is 

unknown the degree to which smaller, disarticulated wreck components may be disturbed during 

hurricane-induced currents (Rego et al. 2011). Since the wrecking event, a total of 16 tropical 

systems, ranging from tropical depressions to a category 4 hurricane, have been centered within 

37 km (20 nautical miles) of the site (NOAA NHC). 

The wreck at Site 386 is oriented east-west, and lies along the path of greatest current and 

wave forces (Figures 3.3.3 and 5.16). The wreck is situated on its keel but is not completely 

upright; it lists to starboard. The highest portion of the wreck site is toward the stern, where the 
wreck sit

most sign

prominen

seafloor 

east of th

along the

will cont

because c

drag abo

depositio

the north

currents c

is possibl

increased

Figur

ts approxima

nificant area

nt scouring o

south of the

he wreck, w

e northern si

tribute to the

components 

ve the bed, t

on over this p

hern margin 

coming from

le that the w

d storm-relat

re 5.15. Mu

ately 7 to 7.

a of scour is

occurs aroun

e stern aft of

which is cons

de of the wr

e burial of w

of varying 

thereby decr

portion of th

of the wrec

m the southe

wreck’s axis c

ted impacts. 

ultibeam rend

3 m (23 to 2

s located on

nd the stern a

f midships. 

sistent with 

reck. It is an

wreck site c

sizes and sh

reasing curre

he site. It is a

ck. The wre

ast, which is

could contrib

dering of the s

222 

24 ft) above 

n the port sid

and surround

The general

a pattern of

nticipated tha

components 

hapes sitting 

ent velocitie

also anticipa

eck’s east-w

s the predom

bute to exag

seafloor at Sit

the ambient

de of the wr

ding an anci

l zone of glo

f larger and 

at, over time

on the south

above the s

es, which, in

ated that incr

west orientat

minant direct

ggerated stor

te 386. 

t seafloor (F

reck, north 

illary compo

obal scour e

stronger vor

e, wave and 

hern side of

seafloor are 

n turn, may i

reased scour

tion forms a

tion of sever

rm related vo

Figure 3.3.4)

of the bow.

onent lying o

extends north

rtices develo

current proc

f the site. Th

likely to inc

ncrease sedi

r will occur a

an acute ang

re storm even

ortices, leadi

). The 

Less 

on the 

h and 

oping 

cesses 

his is 

crease 

iment 

along 

gle to 

nts. It 

ing to 
Figure 5.16. Profiles of the seafloor surr

223 

ounding Site 386. 
224 

5.3.3.2 Water Quality and Site Preservation 

A single water sample was obtained at 21 m (70 ft BSL) near the upper portion of the 

vessel’s hull. Salinity measured 33.6 ppT, pH 7.563, and DO was 6.780 mg/L. No water samples 

were acquired at the seafloor. 

It is possible that future hurricane or extreme storm events may damage disarticulated debris 

at the seafloor and/or extant portions of the site that extend into the water column, since dynamic 

current profiles and intensities could break or scatter features. The wreck is expected to 

experience continued chemical deterioration of exposed portions of the hull resulting in metal 

fatigue; however, portions of the wreck with less relief may become buried over time. 

5.3.4 Site No. 373, South Marsh Island Area, Probable Cities Service Toledo 

5.3.4.1 Radioisotope Data 

The wreck at Site 373 has been tentatively identified as the tanker Cities Service Toledo; as a 

victim of U-boat campaigns in the GOM, it has a known wreck date of 1942 (Rohwer 1983; 

Wiggins 1995). Radioisotope analysis indicates that there is no discernible sediment accretion at 

the site. No evidence of sediment disturbances from tropical systems since the wrecking event 

were identified from the radioisotope data, supporting the minimal estimates of seafloor scour 

calculated from flow conditions for consolidated sediments during Hurricanes Rita and Ike. The 

lack of excess Pb activity downcore appears to indicate that a single disturbance event occurred, 

followed by a lack of subsequent sediment accretion. It is possible that the disturbance event may 

have been the wrecking event and settling of the ship onto the seafloor, which disturbed (mixed) 

in situ sediments. Combined with very low (or no) net sediment accumulation postdisturbance(s), no new isotopes have been introduced to the site’s stratigraphy, resulting in the 

lack of a discrete disturbance layer. 

Nine tropical systems, ranging from tropical depressions to category 1 hurricanes, have been 

centered within 37 km (20 nautical miles) of Site 373 since the wrecking event in 1942 (Figure 

5.17; NOAA NHC). Site 373 was outside the swath of hurricane force winds related to 

Hurricanes Katrina and Gustav, and only nominally within the eastern extents of Hurricanes Rita 

and Ike (Appendix D; Maps D-4 & D-5). Radioisotope measurements are restricted to a single 

core from the site, but there is sufficient evidence to suggest that the observed scour at Site 373 

is the cumulative result of the wrecking event, rather than of punctuated events such as past 

hurricanes. 
F

5.3.4.2 S

The w

scour occ

6.7 m (22

the wreck

indicate 

surround

be dewat

relatively

Figure 5.17. 

Scour 

wreck at Site

cur at the bo

2 ft) above t

k site, but g

that accretio

ding the wrec

tered and co

y undisturbed

Individual 

miles) of S

e 373 is orie

ow, stern, an

the mean sea

generally obs

on or rewor

ck (Figure 3

ompacted, su

d. 

tracks for tro

Site 373 since

nted NNE/S

nd at the brea

abed. A shal

servable sco

rked sedime

.4.3, Figure 

uggesting tha

225 

pical systems

e 1942. (Imag

SSW, along a

ach in the hu

llower but b

our appears t

ents have in

5.18, Figure

at the infill w

s centered wi

ge courtesy N

an axis of 17

ull just south

broader scour

to be localiz

n-filled the m

e 5.19). The 

was not rece

ithin 37 km (2

OAA NHC.) 

7 degrees. Pr

h of midship

r zone exten

zed. The sub

most signific

in-filled sed

ently deposi

20 nautical 

rominent are

ps. The wrec

nds to the we

b-bottom pro

cant scour z

diment appea

ited and has 

eas of 

ck sits 

est of 

ofiles 

zones 

ars to 

been 
Figure 5.18. Multibeam bathymetry ren

226 

dering at Site 373, highlighting seafloor scour. 
Figure 5.19. Profiles of the seafloor su

227 

rrounding Site 373. 
228 

5.3.4.3 Water Quality and Site Preservation 

The measured pH value (8.013) from water samples is slightly alkaline on the site. The 

measured DO on this site was 7.450 mg/L and salinity was 30.8 ppT. As MacLeod (1989) 

argues, DO content will have the greatest impact on the degradation of a steel hulled vessel. 

These measurements represent snapshots and are not part of a systematic or long term sampling 

strategy which would be required to properly study the chemical processes on site. 

As with Site 433, the inverted hull at Site 373 is relatively smooth, with a significant amount 

of biofouling and organic growth. Trawlers or anchor lines associated with modern activities 

could potentially damage the extant hull, specifically if they were to catch on already 

compromised metal near the torpedo holes. Active oil leakage observed on site and at the surface 

indicates product remains trapped in the holds, but the amount of remnant crude oil is unknown. 

It is not possible to quantify the potential for future deterioration of the exposed portions of 

the hull caused by the combined effects of chemical deterioration of the hull, metal fatigue, and 

changing current profiles and intensities based on data acquired as part of this study. Corrosion 

studies at Site 373 would require site-specific monitoring and acquisition of metal samples from 

the hull. Despite this, lacking discernible sediment accretion at the site, hull degradation is 

expected to continue due to prolonged exposure in the water column. The propeller and rudder 

have been removed from the site, so the most susceptible portions of the hull to mechanical 

forces and corrosion surrounds the large break in the vessel’s hull near midships and the hole 

near the starboard bow. 

5.3.5 Site No. 15488, High Island Area, Unknown Modern Wreck 

5.3.5.1 Radioisotope Data 

The wreck at Site 15488 is that of an unidentified modern vessel with an inverted hull. 

Radioisotope analysis indicates that normal sediment accretion was interrupted by a disturbance 

event at Site 15488 that occurred 45 to 63 years before core acquisition, or between 1947 and 

1965, with normal accretion resuming at a rate of 0.06 cm/yr after the disturbance. 

There are two likely explanations for the disturbance event: either excessive waves and/or 

currents caused by a hurricane or tropical storm passing in proximity to the site, or a seafloor 

disturbance caused during the wrecking event. Sixteen tropical systems, ranging from tropical 

depressions to category 4 hurricanes, have been centered within 37 km (20 nautical miles) of Site 

15488 since record keeping began, including 11 that have occurred since 1947, the earliest date 

for the identified disturbance event (Figure 5.20; NOAA NHC). Only one tropical system 

occurred during the period of possible disturbance (1947 to 1965): the eye of Hurricane Audrey 

passed to the east of Site 15488 as a category 4 hurricane in 1957. 
Fi

Given

and Rita 

coring at

without f

certainty

ago sugg

seafloor 

of Site 15

No k

ordnance

wreck co

known w

shown by

in the mi

likely the

are appro

5.3.5.2 S

Dunl

the area 

outcrops

gure 5.20. 

n the low rat

at Datum 2

ttempt, it is 

further analy

. The fact th

gests that mo

at Site 1548

5488, and Ik

known study

e with radio

ould be the c

wreck with d

y the radiois

iddle of the 

e same or a 

oximately 3 m

Scour 

ap et al. (20

lies directly

. Grain size

Individual tr

miles) of Site

tes of maxim

2 (Rego et a

unlikely tha

yses or site 

hat no disturb

ore recent hu

8. Included 

ke, which pas

y has been c

oisotope mea

cause of the

dimensions s

sotope data. 

identified d

similar type

m (10 ft) sho

004) indicate

y west of inc

e measurem

racks for trop

e 15488 betw

mum hurrican

al. 2011) and

at the distur

specific oce

bances were

urricane eve

in this time 

ssed to the w

conducted to

asurements.

e disturbance

similar to th

The fishing 

isturbance e

 of vessel as

orter than th

e that shear 

creased zone

ments at the 

229 

pical systems

ween 1947 an

ne scour for 

d the observ

rbance at Sit

anographic 

e recorded si

nts have not

period are H

west of the si

o correlate 

It is theore

e event. As 

his shipwreck

vessel Susan

event date ra

s the uniden

e measured 

strength at t

es of shear 

seafloor ob

s centered w

d 1965. (Imag

consolidate

ved seafloor

te 15488 is 

modeling, th

ince the dist

t had a signi

Hurricanes R

ite (Appendi

seafloor imp

etically poss

shown in T

k falls into 

n & Gretta w

ange of 1947

ntified wreck

dimensions 

this site is v

strength ass

btained from

within 37 km 

ge courtesy N

ed beds durin

r compaction

hurricane-r

his is impos

turbance eve

ificant scour

Rita, which p

ix D; Maps D

pacts such a

sible that th

Table 4.5, ho

the disturba

wrecked in 

7 to 1965. S

k, but its rep

of Site 1548

very soft (<0

sociated with

m the core 

(20 nautical 

NOAA NHC.) 

ng Hurricane

n during the

elated. How

ssible to say

ent 43 to 65 

ring effect o

passed to the

D-4-5). 

as shipwrec

he impact o

owever, only

ance event p

1956, which

Susan & Gre

orted dimen

88. 

0.2 ksf), alth

h Beaumont

indicate tha

es Ike 

e first 

wever, 

y with 

years 

on the 

e east 

ks or 

of the 

y one 

period 

h falls 

etta is 

nsions 

hough 

t clay 

at the 
230 

surficial sediments are coarse silts (46 μm). Seafloor sediments directly adjacent to the wreck 

were conducive to coring, but farther away from the wreck site, grain size and shear strength 

were sufficient to preclude successful core acquisition. 

The wreck at Site 15488 is oriented along a WSW/ENE axis, oblique to the dominant storm 

waves and currents. The wreck has maximum observed relief of 2.4 m (8 ft). Minor instances of 

local scour are evident at the bow on the northern side and at the stern; less prominent scour 

zones occur along the northern and southeastern edges. The general scour zone is asymmetric to 

the NW. The observed pattern of scour indicates that waves and currents from both the NE and 

SE are probably affecting the site. Sub-bottom profiles of survey lines adjacent to and 

underneath the wreck recorded generally unstratified sediments (Figure 3.5.3); scour was 

restricted to the seafloor immediately surrounding the wreck, which has been in-filled; minimal 

scour zones are apparent at the seafloor (Figure 3.5.4). Based on sub-bottom profiles of the site, 

it is possible that the difference in seafloor resistance at the two core sites is a direct result of the 

wreck itself (i.e., finer-grained sediments settling around the wreck site), or could be associated 

with an underlying near-seafloor channel system. The wreck lies directly over a poorly-resolved 

channel system associated with the Deweyville Floodplain, which is located adjacent to the 

Sabine River valley (Pearson et al. 1986). Sub-bottom profiler data indicates that courser grained 

sediments are present throughout the area, the observed channel system appears to be around 3.7 

to 4.6 m (12 to 15 ft) BML, but a significant sag zone overlies the channel reaching close to the 

seafloor. This sag zone indicates that sediments have not dewatered and compacted and may 

contribute to subsidence of the wreck site.

5.3.5.3 Water Quality and Site Preservation 

The average measured pH value was 7.9285, the average DO was 6.8925 mg/L, and salinity 

was 31.65 ppT. These measurements represent snapshots and are not part of a systematic or long 

term sampling strategy which would be required to properly study the chemical processes on 

site. 

There is not sufficient data to quantify the potential for future deterioration of the exposed 

portions of the hull through the combined effects of chemical deterioration of the hull, metal 

fatigue, and changing current profiles and intensities. Despite this, and lacking discernible 

sediment accretion at the site, hull degradation is expected to continue because of prolonged 

exposure to the water column. 

Site 15488 lies 190 m (625 ft) from an existing pipeline. The pipeline was installed in 1999, 

two years before the wreck was first identified. This could indicate that the wreck occurred 

sometime between pipeline installation in 1999 and discovery in 2001. Because no record of a 

geophysical survey associated with the pipeline was discovered, it is not known if the wreck was 

identified and not reported/recorded, if the data was misinterpreted (as in the case of the 1981 

Racal-Decca Survey over Site 389, which failed to identify J.A. Bisso [Hudson and Neurauter 

1981]), or even if a survey was conducted in association with the pipeline. There were no evident 

impacts to the site that could be attributed to installation or maintenance of the nearby pipeline. 

Scars caused by shrimp trawling were evident on the seafloor surrounding the wreck site. During 
diving ob

impact an

5.3.6 Sit

5.3.6.1 R

The w

Radioiso

event 23

accretion

There

disturban

the wreck

the area b

A tot

have bee

including

event (Fi

15366 in

Site 153

directly o

bservations, 

nd likely wil

te No. 1536

Radioisoto

wreck at Si

tope analysi

3 to 85 yea

n resumed af

e are two p

nce in the rad

king event, 

between 192

tal of 21 tro

en centered w

g 11 that occ

igure 5.21; N

n 1934, and i

66 within th

over Site 153

Figure 5.21

netting was

ll continue to

66, Galves

ope Data 

ite 15366 is

is indicates t

ars before co

fter the distur

probable sce

dioisotope d

or the sedim

25 and 1987.

opical system

within 37 km

curred betwe

NOAA NHC

is the most i

he period of

366 in 2008 

1. Individua

nautical 

courtesy

s also observ

o affect the w

ton Area, U

s that of an 

that normal 

ore acquisit

rbance. A po

enarios for t

data indicates

ment disturba

. 

ms, ranging 

m (20 nautic

een 1925 and

C). An unna

ntense storm

f probable d

(Appendix D

al tracks for

miles) of S

y NOAA NHC

231 

ved on the s

wreck. 

Unknown M

unidentified

sediment ac

tion, or betw

ost-disturban

the disturba

s either sedim

ance was ca

from tropic

cal miles) of

d 1987, the t

amed catego

m to have pa

disturbance.

D; Map D-5)

r tropical sys

Site 15366 

C.) 

site, verifyin

Modern W

d modern v

ccretion was 

ween 1925

nce LAR wa

ance event a

ment displac

aused by a tr

cal depressio

f Site 15366

time period 

ory 4 hurric

assed within 

Also, the e

). 

stems center

between 192

ng that shrim

Wreck 

vessel with 

 interrupted 

and 1987, 

as measured 

at Site 1536

cement and 

ropical syste

ons to catego

6 since recor

identified fo

cane passed 

37 km (20 n

eye of Hurr

red within 3

25 and 198

mping has ha

an inverted 

by a disturb

and that no

at 0.15 cm/y

66. The reco

mixing relat

em that imp

ory 4 hurric

rdkeeping b

or the disturb

just west of

nautical mile

ricane Ike p

37 km (20 

87. (Image 

ad an 

hull. 

bance 

ormal 

yr. 

orded 

ted to 

pacted 

canes, 

egan, 

bance 

f Site 

es) of 

assed 
232 

Given the low rates of maximum hurricane scour for consolidated beds during Hurricanes Ike 

and Rita at Datum 2, and the observed seafloor compaction during the first coring attempt it is 

unlikely that the disturbance at Site 15366 is hurricane-related; however, without further 

analyses or site specific oceanographic modeling, this is impossible to say with certainty. 

No known study has been conducted to correlate seafloor impacts, such as shipwrecks or 

ordnance, with radioisotope measurements. It is theoretically possible that the impact of the 

wreck could be responsible for this disturbance. As shown in Table 4.6, three of the five vessels 

reported within 48 km (30 miles) of the site, and with similar dimensions, wrecked during this 

relatively broad window from 1925 to 1987. The fishing vessel William Hayes wrecked in 1957, 

the tugboat Barbara D. wrecked in 1983, and the fishing vessel Keturah wrecked in 1957. 

William Hayes and Keturah are closest in size to the measured dimensions of Site 15366. The 

results of the John E. Chance and Associates geophysical survey of this area could indicate a 

potential terminus post quem of 1986 for the formation of the wreck site. If this is the case and 

the vessel was not present at the time of the survey, then none of the above-referenced vessels 

can be Site 15366; however, it should be noted that the disturbance event still falls within this 

window, but the wrecking event would have had to occur within a year of the survey. 

5.3.6.2 Scour 

The wreck at Site 15366 is oriented on an approximate north-south axis, with the bow facing 

to the south. Relief at the wreck site varies from approximately 3 to 3.7 m (10 to 12 ft) above the 

ambient seafloor at the bow to approximately 1.7 to 2 m (6 to 7 ft) at the stern. There appears to 

be limited scour around the wreck; what scour is apparent occurs in a teardrop-shape, extending 

to the SSW (Figure 3.6.5). This pattern is consistent with scour caused by currents and waves 

coming out of the NNE, such as those produced during Hurricane Rita over this area. Subbottom data recorded minimal observable scour (Figure 3.6.4), although some possible minor 

accretion or infill was noted to the SSE near the bow of the wreck. 

Dunlap et al. (2004) indicate that shear strength at this site is stiff to very stiff (1 to >2 ksf). 

Grain size at the seafloor obtained from the core indicates that the surficial sediments are 

medium fine silts (9.76 μm). Seafloor sediments directly adjacent to the wreck were conducive 

to coring, but farther away from the wreck site, grain size and shear strength were sufficient to 

preclude successful core acquisition. It appears likely that the difference in seafloor sediments 

between sediment cores is a direct result of the wreck itself, which may act as a sediment trap for 

finer grained particles. 

5.3.6.3 Water Quality and Site Preservation 

The average measured pH value was 8.129, the average DO was 7.468 mg/L, and salinity 

was 33.15 ppT. These measurements represent snapshots and are not part of a systematic or long 

term sampling strategy, which would be required to properly study the chemical processes on 

site. 
233 

There is not sufficient data to quantify the potential for future deterioration of the exposed 

portions of the hull through the combined effects of chemical deterioration of the hull, metal 

fatigue, and changing current profiles and intensities. Despite this, and lacking discernible 

sediment accretion at the site, hull degradation is expected to continue due to prolonged exposure 

in the water column. 

No oil and gas infrastructure is located in immediate proximity to the wreck and no apparent 

impacts to the site caused by oil and gas development were evident. Scars caused by shrimp 

trawling were evident on the seafloor surrounding the wreck site. 

5.3.7 Site No. 389, South Timbalier Area, Probable J. A. Bisso 

5.3.7.1 Radioisotope Data 

Although this site was not part of the original study, it was added to the scope of work; water 

samples and cores were acquired and analyzed as part of a contract amendment. The wreck at 

Site 389 has been identified as the tug J.A. Bisso, which sank in 1957. Radioisotope analysis 

indicates that normal sediment accretion was interrupted by a disturbance event that occurred 50 

to 178 years before core acquisition in 2010, or between 1842 and 1960, with normal accretion 

resuming after the disturbance. Radioisotope data indicates that post-disturbance LAR is a 

relatively low 0.08 cm/yr, resulting in very little sediment accretion on site. 

Samples obtained from Core no. 2 at a depth of 20 m (66 ft) reflect sediments immediately 

adjacent to the aft starboard hull. This area of the seafloor is devoid of observed scouring, and 

likely reflects the ambient seafloor including the most recently deposited sediments. Several 

possible causes of the disturbance are considered, principally the wrecking event, which falls 

within the time frame identified for the disturbance. Although the wrecking event is a strong 

candidate, an extreme storm event could also have caused the disturbance. A total of 28 tropical 

systems, ranging from tropical depressions to category 4 hurricanes, have been centered within 

37 km (20 nautical miles) of Site 389 since 1842, when storms were first recorded systematically 

(Figure 5.22; NOAA NHC). Of these storms, 21 occurred during the same time period as the 

disturbance event recorded in the radioisotope data, including an unnamed category 3 hurricane 

that passed just west of the site in 1909 (NOAA NHC). 
Fig

More

seafloor 

radioisot

both pass

5.3.7.2 S

The w

The most

reaching 

scour we

extending

side of

gure 5.22. 

o

e recent ext

sediments a

ope data, in

sed east of th

Scour 

wreck at Site

t pronounced

depths of 3

ere observed

g approxima

f the hull

Individual trac

of Site 389 be

treme storm

at the wreck

ncluding Hur

he site (Appe

e 389 is orien

d area of sco

3 m (10 ft) b

d on the geo

ately 400 to 

l, extendin

cks for tropic

etween 1842 

m events do 

k site, and d

rricanes Iva

endix D; Ma

nted NNE to

our occurs at

below the a

ophysical dat

450 m (1,30

ng approxi

234 

al systems ce

and 1960. (Im

not appear 

do not appe

n (2004) an

aps D-4-5). 

o SSW, with

t the bow of

ambient seaf

ta along the 

00 to 1,475 f

imately 65

entered withi

mage courtes

to have ca

ear as distur

nd Gustav (2

h the bow fac

f the vessel, 

floor were re

 starboard, o

ft) to the ES

50 m (21

n 37 km (20 

sy NOAA NHC

aused signif

rbance even

2008) (NOA

cing northwa

where signi

ecorded. Ad

or eastern, s

SE, and to th

125 ft) f

nautical miles

C.) 

ficant impac

nt markers i

AA NHC), w

ard (Figure 5

ficant local 

dditional are

side of the v

he port or we

from the 

s) 

cts to 

n the 

which 

5.23). 

scour

eas of 

vessel 

estern 

hull. 
235 

Figure 5.23. Multibeam rendering of Site 389, highlighting scour. 
236 

Scouring is most prominent at the bow because the vessel is upright on its keel and the bow 

has approximately 4.5 to 5.5 m (15 to 18 ft) of relief above the base of the observed scour hole. 

The bow protrudes significantly into the lower boundary layer of the water column, creating 

strong local jet flows and likely horseshoe vortices (e.g., Quinn 2006). On average, the scour 

zone adjacent to the wreck is slightly asymmetric on the eastern side of the hull, indicating that 

the higher, forward two-thirds of the wreck are impacting the degree of scour more than the 

lower and/or more buried southern aft end of the hull. The overall larger pattern of scour is 

circular and relatively asymmetric, suggesting that the dominant current/wave flow is from the 

ESE. Gearhart et al. (2011:19-21,130) indicate that maximum significant wave heights in the 

region of the wreck were approximately 6 to 8 m (20 to 26 ft) during Hurricane Katrina, with 

waves moving to the west, which is consistent with the orientation of the scour zones relative to 

the wreck. 

Dunlap et al. (2004) indicate that shear strength at this site is soft (0.2 to 0.6 ksf). Grain size 

measurements at the seafloor obtained from the core indicate that the surficial sediments are fine 

sands (173 μm). Successful cores were acquired at the starboard stern of the vessel and at the 

bow within the large area of local scour. Sub-bottom profiles of survey lines adjacent to and 

underneath the wreck depict near-seafloor strata that are truncated by the observed scour zones; 

there is little to no evidence of sediment infill or redeposition (Figure 3.7.9). 

5.3.7.3 Water Quality and Site Preservation 

Water quality data acquired during diving operations indicates that average salinity at depth 

was 31.4 ppT, average pH was 7.496, and DO was 7.017 mg/L. 

Calculated LAR of 0.08 cm/yr suggests that little sediment is currently deposited in this area 

and does not contribute significantly to site burial. This is confirmed by the results of the sonar 

imagery from 2005 to 2010, which indicate very little change to the seafloor at the wreck site. 

The lack of significant sediment accretion makes it unlikely that the ancillary object identified 

through previous sonar investigations has become buried over time. It is probable that the object 

was displaced either by Hurricane Katrina or as the result of anthropogenic activities. It is likely 

that, over time, the bow will continue to scour and the stern will continue to accrete slowly, 

likely through localized sediment movement around the wreck. If the scour continues, and has 

not stabilized at the current level, over time more of the bow region could be exposed. The scour 

zone could extend further under the ship toward the south. This scenario would have greater 

likelihood of occurring if strong waves and currents approached the ship from the northern 

quadrant. If this occurs, the current integrity of the wreck could be compromised; for example, 

the hull could break leeward of the bow. These scenarios reflect long-term formation processes 

based on sediment scour alone. Based on the available data, it is not possible to quantify the 

potential for future site burial through movement of existing sediments at the wreck site, or 

deterioration of the exposed portions of the hull, through the combined effects of chemical 

deterioration of the hull, metal fatigue, and changing current profiles and intensities. 

As discussed in Sections 3.7.1 and 3.7.3, sonar data recorded over the site during previous 

surveys illustrates that disarticulated components at the wreck site have disappeared from the site 

and are believed to have been removed during recent hurricane activity. An object was evident 
237 

off of the vessel’s bow from the 1991 geophysical survey (Marmaduke 1991). The March 2005 

survey identified an object off of the port side of the vessel, forward of midships (Floyd and 

Clemmons 2005a and 2005b). Surveys conducted in 2007 (Gearhart et al. 2011) and in 2010 (for 

the current study) found no evidence of any large ancillary wreck components. As noted by 

Gearhart et al. (2011:132-133), Hurricane Rita was the only major storm to cross through this 

area in the intervening time between the noted changes to the site (Appendix D; Map D-4). 

No clear evidence of anthropogenic impacts to the wreck site was evident. While it is 

possible that portions of the superstructure and ancillary object identified through previous 

surveys may have been removed through salvage, it is just as probable that these impacts could 

be the result of natural processes. The presence of intact port-holes on site makes it unlikely that 

the site has been impacted by recreational divers. 

5.3.8 Site No. 236, Galveston Area, USS Hatteras 

5.3.8.1 Comparison with Previous Investigations 

Although this site was not part of the original study, it was added to the scope of work; water 

samples and cores were acquired and analyzed as part of a contract modification. Hatteras is the 

most well-documented of the study sites. Results of previous archaeological investigations 

indicate that the wreck site has been fairly static in appearance over the course of investigations 

from the 1970s through 2004; however, site conditions were dramatically different during dive 

operations in 2010. 

Initial archaeological investigations were conducted at Site 236 in the 1970s by the Bureau of 

Land Management (BLM) with the cooperation of the Texas Historical Commission (THC) and 

the Institute for Nautical Archaeology (INA) at Texas A&M University (Arnold and Hudson 

1981). The site studies conducted in the 1970s resulted in geophysical data acquisition, 

specifically magnetometer survey data. A second series of investigations, conducted in the early 

1990s by the MMS and THC for monitoring and mapping purposes, resulted in the generation of 

a preliminary site map (Figure 5.24; Arnold and Anuszkiewicz 1995). 

Arnold and Anuszkiewicz (1995:85) state that a sediment meter was placed on site and that 

from 1992 to 1994 sediment levels remained fairly constant with no apparent disturbances. They 

also indicate that, based on imagery provided by Donald Keith, the only significant change to the 

site was a missing upright engine component (Arnold and Anuszkiewicz 1995:85). Site 

conditions observed during investigations conducted in the 1990s were described as follows: 

 

Little of the wreck is exposed above the sand. Paddlewheel hubs on both sides 

of the ship and some parts of the steam engine rise partially above the sand 

bottom. The only other remains showing above the bottom in 1992 and 1993 were 

a very small section of encrusted iron near the bow which was tentatively 

identified on the assumption that it was located forward of the paddlewheels and 

on its orientation and distance from other exposed remains. In 1994, the bow 

wreckage was buried. (Arnold and Anuszkiewicz 1995: 83) 
An in

those rec

included 

shaft wer

the rema

identified

were iden

similar c

Anuszkie

Figu

Inspe

changed 

(Figure 5

paddlewh

what is b

Also, a la

(30 ft) in

on site. 

indicates

surround

(Figure 5

nvestigation 

corded in th

in the PBS&

re partially 

ainder was b

d as a knuck

ntified south

ondition to w

ewicz. 

ure 5.24 and 

ections cond

significantl

5.25) acquir

heel shaft an

believed to b

arge depress

n diameter an

A detailed 

 that the sea

ding the hole

5.30). 

conducted b

he 1970s an

&J report sh

exposed (Fi

buried under 

kle was rec

h of the star

what was id

5.25. Lef

An

(En

ducted in 20

ly from pre

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nd walking b

be the first ti

sion was evi

nd, based on

geophysica

afloor hole 

e was still ev

by PBS&J in

nd early 199

ows that the

gure 5.24).

surficial se

orded betwe

rboard paddl

dentified from

ft: Preliminary

uskiewicz 19

nright et al. 20

010 for this 

eviously pu

ust, 2010 sh

beam were a

ime since arc

ident on the 

n the shape an

al investigat

at the bow 

vident, but a

238 

n 2004 indic

90s site visit

e starboard p

Only the top

diments. A 

een the pad

lewheel. In e

m the prelim

y site plan, rot

995). Right: 

006). 

study indica

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howed that,

also exposed

chaeological

seabed. Thi

nd size, may

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had in-filled

appeared on 

cates that sit

ts (Enright 

paddlewheel 

p of the por

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effect, the w

minary site p

tated and orie

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ated that the

servations. S

 in addition

d. The stern 

l monitoring

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et al. 2006)

and connec

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was subsequ

ylindrical ob

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of Hatteras

s at the site 

nning sonar 

addlewheels

 was expose

onducted on

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diments. The

as a slight m

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uently 

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n very 

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d

s

have 

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s, the 

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n site. 

d 9 m 

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e area 

mound 
5.3.8.2 R

Hatte

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acquisitio

the distu

sediment

the distur

disturban

period o

unlikely 

more like

Sedim

Disturban

11.1 cm 

(LAR) of

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Figure 

Radioisoto

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sediment acc

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rbance. Sam

ts immediate

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nce. Althoug

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ely that an ex

ments at Sit

nce produce

(3.4 and 4.4

f 0.14 cm/yr

re collectio

5.26. Comp

data 

ope Data 

documented

cretion was 

or between 

mples were o

ely adjacent 

considered; h

gh it is know

ce pre-dates

sturbance ev

xtreme storm

e 236 displa

ed a sharp h

4 inches) in 

r allows this 

n. While th

posite of mu

was acquired

d wrecking 

interrupted 

1931 and 1

obtained from

to the port 

however, the

wn that treas

 the comme

vent can be

m event caus

ay excellent

hiatus in exc

the seabed.

disturbance

here are on

239 

ltiple Mesote

d at 150-ft ran

date in 186

by a disturb

949, with d

m Core no. 

paddlewhee

e wrecking 

sure hunters 

ercial availa

 attributed t

sed the ident

t pre- and p

cess activity 

Using the p

e to be dated 

nly three pr

ech scans of 

nge. 

63. Radioiso

bance event

decreased sed

2 at a depth

el, amidships

event occurr

caused distu

ability of sc

to on-site an

tified disturb

ost-disturban

at a depth 

post-disturba

d in the range

re-disturbanc

USS Hatter

otope analys

t 61 to 79 y

dimentation 

h of 18 m (6

s. Several p

red well bef

urbances to 

cuba diving 

nthropogeni

bance. 

nce 210Pb tr

somewhere 

ance linear a

e of 61 to 79

ce excess p

ras site; 

sis indicates

years before

 levels follo

60 ft) and re

ossible caus

fore the obse

the site, the

gear, maki

ic activities.

rends with d

between 8.6

accumulation

9 years befor

points (r2=0

s that 

e core 

owing 

eflect 

ses of 

erved 

e time 

ing it 

 It is 

depth. 

6 and 

n rate 

re the 

0.86), 
sufficient

sediment

Twen

have bee

first reco

period as

4 hurrica

Figu

More

radioisot

Site 236 

storm SW

following

5.3.8.3 S

Dunl

very stiff

by two d

coarse sa

third zon

previous 

port pad

surficial 

sediment

t evidence e

t LAR at Site

nty-three tro

en centered w

orded system

s the disturba

ane that passe

re 5.27. 

e recent ext

ope data, in

as a categor

W of the site

g earlier stor

Scour and 

ap et al. (20

f (1 to >2 ks

distinct prim

and and the n

ne is eviden

two sedime

ddlewheel hu

sediment, w

t plug exhib

exists to assig

e 236 has de

opical system

within 37 km

matically (NO

ance event r

ed almost di

Individual tra

miles) of Site 

treme storm

cluding Hur

ry 2 storm, a

 in 1983 (NO

rm events. 

Seafloor M

004) indicate

sf). Geophys

mary sedime

northern reg

nt from son

ent types. Tw

ubs, and tw

were acquired

it extreme v

gn an LAR b

ecreased by a

ms, ranging 

m (20 nautic

OAA NHC).

ecorded in th

irectly over t

acks for all tro

236, betwee

m events di

rricane Ike (A

and Hurrican

OAA NHC)

Morpholog

e that the sea

sical data in

ent zones; th

gion is chara

nar backscatt

wo full sedim

wo sediment 

d at the vesse

variations be

240 

before distu

almost 2 mm

from tropic

cal miles) of

Of these sto

he radioisoto

the site in 19

opical system

n 1932 and 1

id not prod

Appendix D

ne Alicia, wh

. This may b

gy 

afloor shear 

ndicates that 

he southern

acterized by 

ter, but this

ment cores w

plugs cont

el’s stern. G

etween the tw

urbance of 0.

m/yr since th

al depressio

f Site 236 sin

orms, five oc

ope data, inc

932 (Figure 5

ms centered 

949. (Image 

duce disturb

D; Map D-5)

hich strength

be due to low

strength in 

the seafloor

n region is c

finer-graine

s likely repr

were taken a

taining over

Grain size dat

wo areas. G

.33 cm/yr. T

e disturbanc

ons to catego

nce 1842, w

ccurred duri

cluding an u

5.27; NOAA

within 37 km

courtesy NOA

bance event 

), which pass

hened from 

w rates of se

this area ran

r at Site 236

characterize

d sediments

resents an a

adjacent to t

r 10 cm (4 

ta from one 

Grain size at 

This indicate

ce event. 

ory 4 hurric

when storms 

ing the same

unnamed cate

A NHC). 

m (20 nautica

AA NHC.) 

markers in

sed to the ea

a category 2

ediment accr

nges from st

6 is characte

d by mediu

s (Figure 5.2

admixture o

the starboard

inches) eac

full core and

the paddlew

s that 

canes, 

were 

e time 

egory 

al 

n the 

ast of 

2 to 3 

retion 

tiff to 

erized 

um to 

28). A 

of the 

d and 

ch of 

d one 

wheel 
241 

exhibited medium/fine silts (13 μm) while grain size at the stern consisted of coarse/medium 

sands (343 μm). Sonar and sub-bottom profiler data highlight the areal extents of these nearseafloor sediment variations. Areas of decreased backscatter, indicative of finer grained 

sediments with greater sediment cohesion, were observed in the immediate vicinity of the 

paddlewheel, which corresponds with grain sizes measured from Core no. 2 (Figure 5.28). As is 

discussed in Section 3.8.3, sub-bottom profiles of survey lines adjacent to and underneath the 

wreck depict a moderately reflective seafloor underlain by amorphous sediments; acoustic 

attenuation was attributed to sand content within the near-surface sediments (Figure 5.29). The 

change in seafloor composition is also reflected in the bathymetry (Figure 3.8.3), which indicates 

that the courser grained sand deposits are part of a berm located south of the wreck and 

extending in an east-west direction. The wreck itself may be influencing the differential 

settlement of fine sediments observed across the site. 

 
Figure 5.28. Sonar backscatter d

242 

ata highlighting changes in sediment grain size. 
The p

seafloor. 

varying d

relief of 

circular s

ft), with 

assembly

around th

Figure 5.29

paddlewheel

It has been

degrees of ex

approximat

scour zone e

more prono

y (as illustra

he wreck to a

9. Sub-bo

l area of this

n observed c

xposure. Du

tely 1.5 to 1

extends arou

ounced scour

ated in Chap

an approxim

ottom scour co

s ship is the

consistently 

uring the 201

1.8 m (5 to 

und the padd

r observed d

pter 3, Figu

mate radius o

243 

ontours. 

e most prom

during prev

10 survey, th

6 ft) above

dlewheel are

directly unde

ure 3.8.8). A

f 70 m (236 

minent portio

vious survey

he paddlewh

e the ambien

ea to a radiu

erneath and 

A shallow a

ft). 

on of the wre

ys of the sit

eel assembly

nt seafloor 

s of approxi

adjacent to 

area of mino

eck visible a

te, although 

y had a mea

(Figure 5.30

imately 15 m

the paddlew

or scour ex

at the 

with 

sured 

0). A 

m (50 

wheel 

xtends 
Figure

Radio

to sugge

investiga

previousl

the hull a

Core no. 

within th

depict a 

sediment

scour an

1970s. T

paddlewh

likely to 

The r

accretion

substanti

indicates

within si

rates dec

years be

condition

wreck its

significan

reworkin

e 5.30. Mu

oisotope me

est that scou

ation docum

ly observed 

acts as a sed

2 did not d

he upper port

circular dep

ts in this are

nd reburial a

This dynami

heel, sugges

remain burie

relatively low

n rates over 

ial role in r

 that the lar

x months. A

creased by ne

efore core a

n of the site 

self influenc

nt storm (su

ng sediments

ultibeam rend

asurements 

ur at Site 2

mented great

on site. The

diment trap f

isplay any e

tion of the c

pression surr

ea, this part 

as evidenced

c accretion 

sting that th

ed. 

w LAR of 0

the last 61 

re-burying t

rge hole obs

As discussed 

early 2 mm/

acquisition. 

before the 

ces sediment

uch as the 

s that buried

dering at Site 

are restricted

236 is affe

ter rates of 

e observed i

for finer-gra

evidence of a

core. Bathym

rounding the

of the wrec

d by the va

and scour 

he remainder

0.14 cm/yr a

to 79 years

the exposed

erved in Au

above, pre-

/yr following

Because th

disturbance 

t accretion o

1932 Categ

d the hull. O

244 

236. 

d to a single

cted by ext

exposure fo

increase in s

ained particle

a disturbanc

metry data ac

e paddlewhe

ck appears t

arying obser

is spatially 

r of the wre

at the Hatter

s remain con

d hull comp

ugust 2010 w

and post-di

g the observ

he only obs

is unknown

on site by di

gory 4 hurr

Once buried, 

e core from t

treme storm

following H

silt content n

es; however

ce event or a

cquired over

eel assembly

to experienc

rvations of s

restricted to

eck experien

ras site indic

nstant, accre

ponents on 

was in-filled

sturbance 21

ved disturban

servations a

n. As stated 

srupting nat

ricane) may 

the wreck w

the site, but 

m events, be

Hurricane Ike

near the wre

, the radiois

a significant 

r the wreck s

y and, given

e more dyn

surveys con

o the imme

nces less sc

cates that if 

etion is not 

site. Despit

d with fine g

0

Pb trends in

nce event be

available are

above, it is 

tural flow. In

have impa

would no lo

there is evid

ecause the 

e than had 

eck suggests

sotope analy

increase in 

site (Figure 

n the fine-gr

amic episod

nducted sinc

diate area a

cour and is 

natural sedi

likely to ha

te this, evid

grained sedim

ndicate that 

etween 61 an

e post-1970

possible tha

n this scena

acted the sit

onger project

dence 

2010 

been 

s that 

sis of 

LAR 

5.30) 

rained 

des of 

ce the 

at the 

more 

iment 

ave a 

dence 

ments 

LAR 

nd 79 

0, the 

at the 

ario, a 

te by 

t into 
245 

the water column, and would not have a significant impact on sediment transport, or, more 

specifically, it would not create drag within the boundary layer. This profile reduction could have 

caused an observable decrease in LAR on site over the next 78 years. 

Following this argument, oceanographic modeling indicates that loose bed scenarios at 

Datum 2 range from 10 to 84 cm (4 to 33 inches) of erosion from Hurricane Rita to 1 to 30 cm 

(0.4 to 12 inches) of erosion from Hurricane Ike. The mix of sands, silts, and clays at Site 236 

suggests the presence of some cohesionless sediment, which is likely to have scoured away from 

the site, as is suggested in the loose bed scenario. Both storms occurred between the 2004 

PBS&J investigation and the 2010 investigation for this study; they may be responsible for the 

significant amount of wreck exposure observed by divers in 2010. Wreck exposure at the 

paddlewheel assembly is not likely to remain static, because the hull is again projecting into the 

water column and impacting sediment transport by creating drag. It is hypothesized that the site 

will experience a temporary increase in LAR on site until a greater portion of the paddlewheel 

assembly is reburied. It is possible that the relatively short amount of time between Hurricanes 

Rita and Ike, and the 2010 investigation may account for the lack of significant increase in the 

post-disturbance LAR calculated from radioisotope data. 

The Hatteras site represents an observably dynamic seafloor environment from which 

additional data could be collected to quantitatively monitor the inter-related processes affecting 

seabed morphology. During the 2010 diving operations, a makeshift erosion pin was placed on 

site adjacent to the starboard paddlewheel to facilitate future sediment change observations. The 

pin is located on the northeastern, inner side of the paddlewheel towards the bow of the vessel. A 

1.8 m (5.9 ft) long length of rebar was hammered into the substrate so that 1 m (3.3 ft) was 

buried below the seafloor and the remaining 80 cm (32 in) were exposed in the water column. 

Yellow marine paint markings were scaled every 20 cm (8 in) down the length of the bar; 

redundant plastic cable ties were placed at every visual interval marking for tactile identification 

in case of poor visibility or biofouling. A double yellow line with cable ties distinguishes the 

seafloor as of 2010: sediment accretion will reduce bar exposure to less than 80 cm (32 in); 

sediment scour will fully expose the double yellow band and increase exposure to more than 80 

cm (32 in). 

The location of Site 236 within a designated fairway complicates the modeling of current 

flow regimes and velocities, which contribute to seafloor scour and sediment transport. It is 

recommended that current profilers and sediment traps be proactively deployed and monitored to 

develop a more complete set of variables acting on the site, and that can be used in site specific 

modeling and quantitative analysis. 

5.3.8.4 Water Quality and Site Preservation 

Water quality data indicate that salinity was 34.3 ppT, pH was 8.033, and DO was 7.467 

mg/L. 

Because Hatteras is located within a shipping fairway, it offers some additional protection 

from oil and gas development and possibly from trawling. Current regulations do not allow 

structures (caissons and platforms) within fairways; they also place more onerous requirements 
246 

on pipeline installation, requiring them to be buried 4.6 m (15 ft) below the mudline, rather than 

the standard 0.9 m (3 ft). For this reason, many operators choose to avoid routing pipelines 

through fairways, if possible, but it is not prohibited. Pipelines do cross this fairway, and 

pipelines are present on either side of the Hatteras site, 2,743 m (9,000 ft) to the SW and 4,420 

m (14,500 ft) to the NE. It is unknown at this point, but the authors speculate that preferential 

sediment accretion on Site 236 will rebury a large portion of the paddlewheel assembly, so that 

the site will resemble its pre-Hurricane Ike appearance in the next several years. Despite the 

influence of Ike, the anthropogenic impacts to the site are unknown. A large hole identified on 

the sector scanning sonar does not appear natural and could be the result of a prop-blower used 

to displace sediments to allow divers access to buried site components. If such activities were 

taking place on the site, there is no way to know, at this point, the extent and degree to which 

these processes are responsible for the condition of the site seen during diving operations and on 

the geophysical data. In most cases, due to the irregular nature of monitoring visits, there is no 

way to determine if these changes were brought on by natural processes or through 

anthropogenic means. 

5.3.9 Site No. 15326, East Cameron Area, Unknown Barge 

This site was not one of the original contract sites and was not included in modeling or 

analysis of site formation processes. Both water quality and cores were collected on site; the 

results are included in Section 3.9.3.1 and 3.9.3.2. Because the site was determined to have no 

obvious historical significance, it was decided that resources used for analysis be allocated to 

other sites. 

Site 15326 lies 312 m (1,025 ft) from an existing pipeline. The wreck was identified through 

the pipeline route pre-lay survey; the pipeline route was subsequently re-designed to avoid the 

wreck by 300 m (1,000 ft). Numerous trawl scars attributed to shrimping were evident on the 

original sonar data, some of which appear to directly impact the site. No evidence of damage or 

scarring associated with pipeline installation was observed during diving operations; however, no 

post-installation sonar data was acquired at this site. Divers observed large quantities of shrimp 

netting covering the site. 

5.3.10 Site No. 322, East Cameron Area, Unknown Modern Wreck 

This site was not one of the original contract sites and was not included in modeling or 

analysis of site formation processes. Both water quality and cores were collected on site and the 

results are included in Section 3.10.3.1 and 3.10.3.2. Because the site was determined to have no 

obvious historical significance, it was decided that resources used for analysis would be allocated 

to other sites. 

5.3.11 Site No. Pending, West Cameron Area, Modern Debris 

This site was not one of the original contract sites and was not included in modeling or 

analysis of site formation processes. This site was determined to have no historical significance. 

Neither water quality nor sediment cores were acquired at this site. 
247 

5.4 COMPARISON OF OBSERVED SITE FORMATION PROCESSES

Eleven sites were investigated, and nine shipwrecks identified. All of the investigated 

shipwreck sites, with the exception of Site 236 (USS Hatteras), consisted of metal-hulled 

(probable carbon steel) wrecks that project into the water column above the surrounding seabed. 

Of these, Sites 389 (J.A. Bisso), 433 (R.W. Gallagher), 373 (Cities Service Toledo), and 15366 

(Unknown wreck) were oriented along a similar, north-south axis. Sites 15488 (Unknown 

wreck), 386 (Heredia), and 236 (Hatteras) were identified along an approximate east-west 

orientation. The remaining two wrecks, 15326 (Unknown barge) and 322 (Unknown wreck), 

were along a diagonal axis, approximately NE-SW (15326) and NW-SE (322). Of the nine steelhulled study sites, the majority were upright, including Sites 389 (J.A. Bisso), 386 (Heredia), 236 

(Hatteras), 15326 (Unknown barge), and 322 (Unknown wreck); the remaining hulls were all 

inverted. Sites 15488 (Unknown wreck), 15366 (Unknown wreck), 15326 (Unknown barge), and 

236 (Hatteras) had the lowest profiles in the water column. Over their lifetimes, all of the wrecks 

will be subjected to minor current and wave action that can impact exposed portions of hull, and 

to larger scale impacts of major storms and hurricanes. The fact that many of the hulls are 

inverted will reduce the impact of these forces on the hull and limit resulting damages. As 

evidenced by Sites 389 and 386, the superstructure and disarticulated remains of upright wrecks 

are subject to greater risks and impacts, both natural and anthropogenic, which can cause greater 

degrees of site disarticulation and damage. 

Radioisotope decay curves indicate that rates of sediment deposition are very low at all of the 

sampled study sites. Of the six sites sampled, Sites 236, 15366, and 433 exhibited the highest 

accumulation rates, at 0.14, 0.15, and 0.17 cm/yr, respectively. Sites 15488 and 389 exhibited the 

lowest rates at 0.06 and 0.08 cm/yr, respectively. At these rates, it will take 100 years to 

accumulate between 6 and 17 cm (2.4 to 6.7 inches) of sediment at the study sites, not even 

accounting for the effects of compaction and dewatering. This indicates that ongoing sediment 

accretion alone is unlikely to play a significant role in burying site components at any of the 

study sites. 

All of the wreck sites had some degree of scour located directly adjacent to the shipwreck. 

These zones were typically larger and deeper surrounding the bow and stern of the wreck, and at 

breaks in the hull that create a zone where currents are locally accelerated and jet flows (high 

velocity localized flows) may be experienced. The majority of the sites also had broad shallow 

global scour zones that extended outward from the wreck site. The two exceptions to this were 

Sites 15488 and 373, where seafloor scour appeared to be restricted to the area directly 

surrounding the wreck site. In the case of Site 373, sub-bottom profiler data indicates that scour 

has been in-filled. This may indicate that the scour pattern was, at one point, similar to the other 

wreck sites, but sediment deposition has since filled in these scour zones. However, a lack of 

observed Pb downcore decay indicates that infill occurred close to the time of disturbance, as a 

lack of recent activity indicates little to no ongoing sediment accretion. 

Site 386 is upright, oriented along a different axis than most of the other hulls, in deeper 

water, and is disarticulated to a greater extent producing a lower profile in the water column. 

Despite this, the site still exhibits a broad scour pattern similar to Sites 389, 433, and 15366. This 

appears to indicate that while the orientation of the wreck site will influence the orientation of 

the scour, it is not the most significant factor in determining extent or depth. 
248 

An interesting comparison can be made between RW Gallagher (Site 433) and Cities Service 

Toledo (Site 373). Both are similarly sized, inverted tankers that were sunk within a few months 

of each other. Both wrecks are oriented along virtually the same axis, and both have significant 

breaks in the hulls near midships. Both sites exhibit similar scour orientation surrounding the 

bow, stern, and at the break in the hull. Despite these similarities, RW Gallagher (Site 433) has a 

substantial, broad scour zone that extends outward from the wreck site to the west with no 

evidence of subsequent infill. Cities Service Toledo (Site 373) does not exhibit a prominent 

active scour zone, but evidence of in-filled scour is present. Both sites are located along the 

Louisiana continental shelf, in similar water depths; 26.5 m (87 ft) at Site 433 and 27 m (89 ft) at 

Site 373. Surficial sediments at Site 433 are coarse silts (48.6 μm) and those at Site 373 are 

medium silts (12.5 μm). While the pattern of average currents between Site 433 and Site 373 

changes somewhat with the shoreline, the sites are relatively close together and the overall 

current direction across the two sites is from the ESE towards the WNW. Site 433 has slightly 

greater relief above the seafloor (7.3 m or 24 ft) than Site 373 (6.7 m or 22 ft). 

The two most significant factors that differentiate the RW Gallagher (Site 433) and Cities 

Service Toledo (Site 373) sites appear to be seafloor sediment type/consistency and severe storm 

impacts. Although bulk density and plasticity are unknown, the sediments at Site 373 are finer 

grained, and would therefore be expected to travel further in suspension. This appears to be the 

opposite of what is observed at the two sites, where Site 373 appears to have experienced scour 

and immediate infill; no evidence of in-filled scour was evident on Site 433. For these reasons, 

storms appear to be the most likely culprit for the differing scour patterns at the two sites. Site 

433 was located beyond the extents of hurricane force winds associated with Katrina, Rita, 

Gustav, and Ike (Appendix D; Maps D-4-5), while Site 373 was within the extents of hurricane 

force winds associated with Hurricanes Rita and Ike (Appendix D, Maps 4 & 5). Site 373 was 

modeled as Datum 2 and modeled net consolidated, or cohesive, bed scour rates are less than 

0.03 cm (Rego et al. 2011; Table 5.3). When extrapolated to Site 433, Datum 2 results indicate 

that recent storm scour is unlikely to account for the differing observations when compared to 

Site 373. 

It is evident that scour zones surrounding the wreck sites are variable, controlled by too many 

factors to quantify based on this study alone. However, there is a general pattern associated with 

wreck orientation. Wrecks oriented to the east (i.e., bow facing to the east) tend to display the 

most scour on the bow and stern regions, while those oriented across the dominant current flow 

direction tend to display more scour along the length of the ship, and have larger scour zones 

extending down-current of the wreck. 

Further data is necessary to determine precisely the role of ongoing currents versus 

punctuated storm events within cohesive sediments. Despite this, observations of the extent and 

morphology of scour zones through geophysics and radioisotopes provided indications that 

scoured sediments were not typically falling back out of suspension and in-filling at the majority 

of the studied sites. This indicates that sediments were being shifted off site and modern 

accretion rates are insignificant. For this reason, it can be expected that these sites will continue 

to experience some degree of scour that could result in greater degrees of exposure over time and 

even reduce the stability of the wreck resulting in damage or collapse of the site. 
249 

Seafloor shear strength measurements at the wreck sites range from very soft to very stiff 

(<0.2 to >2.0 ksf). Although shear strength measurements were not acquired for the majority of 

the sites, some qualitative observations can be made based on the diving investigations. 

Resistance to coring was greater on sites off of Texas and closer to the LA-TX border, likely due 

to a lack of soft Holocene sediment overburden in this area. At Sites 15488 and 15366 coring 

away from the wreck site was unsuccessful due to shallow refusal, but successful cores were 

obtained directly adjacent to each of the wreck sites. This appears to indicate that the wreck sites 

have a significant impact on the composition of the seafloor. Radioisotope data did not provide 

any indication that these sediments are comprised of significant quantities of recently deposited 

sediment. This may indicate that the variability in seafloor strength was caused by the wrecking 

event, or that the effect may not be in the form of a disruption in sediment flow, but instead may 

result in a change in water content and plasticity. 

As shown in Table 5.6, water quality samples indicate that pH values ranged from 7.230 to 

8.160, salinity from 30.8 to 34.4 ppT, and DO from 6.690 to 7.480 mg/L. Water temperature was 

between 77 and 88 degrees at depth. The coldest temperatures were observed at the deepest 

samples on Site 433. Salinity readings were lower on the study sites than the published depthspecific seasonal averages (NOAA NODC), which range from 34.5 to 36 ppT; higher salinity 

rates are expected at the deeper sites. Published seasonal data trends indicate that surface salinity 

measurements are typically lowest in the summer, although salinity values do not change by 

more than a small margin from season to season at depths greater than 15 m (49 ft) BSL. Water 

quality data and measurements of sediment samples provide baseline data only. While these 

measurements provide an indication of conditions on site that impact corrosion of metal-hulled 

wrecks, they represent only a snapshot and not the cumulative impacts of time and seasonal 

variations. Tables in Appendix F demonstrate that no clear patterns were evident that can be 

correlated with water depth, latitude, longitude, or other natural variables. Supplemental data, 

such as that available through the NODC (NOAA NODC; Figure 5.4 – Figure 5.7), can be used 

to assist gross management strategies, but cannot substitute for onsite measurements for accurate 

site modeling. 

Some evidence of anthropogenic impacts to the wreck sites was also observed. Both the 

rudder and the propeller are missing from Site 373, the probable Cities Service Toledo. Christ 

reports that the rudder was present in 1971 when he visited the site (Christ 2005), so the removal 

was not part of any initial salvage to the wreck site immediately following the sinking in 1942. It 

remains unknown when or how the rudder was removed but the clean and precise nature of the 

cut on the propeller shaft suggests intentional and planned removal. Site 389, J.A. Bisso, lacks a 

pilot house or other superstructure, even though the vessel is right-side up on the seafloor. 

Geophysical data obtained over the site in 2005 showed a large ancillary object just off of the 

port side of the vessel. Two subsequent geophysical surveys, coupled with diver investigations in 

2010, failed to find any evidence of this object. These components of the wreck could have been 

removed or damaged by human impacts to the sites, through shrimp trawling or purposeful 

deconstruction or salvage, or they could have been the result of natural processes (Hurricanes 

Gustav and Katrina came through this area after the initial sonar imagery). Hatteras is the most 

well documented of the study sites. Results of previous archaeological investigations indicate 

that the wreck site has been fairly constant in appearance over the course of investigations from 

the 1970s through 2004. It would appear that the condition of the site was fairly stable; however, 
250 

site conditions were dramatically different during dive operations in 2010. An examination of 

storm history over the Hatteras site indicates that the only significant storm to cross near Site 

236 since the monitoring began in the 1970s was Hurricane Ike, which occurred less than one 

year before the 2010 field work. It is unknown at this point, but the authors speculate that 

preferential sediment accretion on Site 236 will rebury a large portion of the paddlewheel 

assembly, so that, within the next several years, the site will resemble its pre-Ike appearance. 

Despite the influence of Hurricane Ike, the anthropogenic impacts to the site are unknown, 

although possible evidence of sediment removal was identified on the sector scanning sonar data 

(Section 5.8.3.4). If such activities were taking place on the site, at this point there is no way to 

know to what extent and to what degree these processes are responsible for the condition of the 

site seen during diving operations and on the geophysical data. 

Through the accumulation of more data and through a better understanding of how natural 

processes impact these sites, archaeologists can learn to identify when the impacts to sites are 

cultural and when they are the result of natural events. Often the most significant processes that 

impact a shipwreck site involve the movement of the seabed. This movement may be in the form 

of sediment removal (erosion/scour) and addition (accretion/deposition), or may be the result of 

mass sediment mobilization (mudflows or liquefaction). Scour is one of the most notable and 

universally present impacts to a shipwreck site; it occurs in one of two ways: natural or induced. 

Natural scour can result from ongoing wave and current processes or can be sudden, related to 

severe storm events. An object that sits proud above the seafloor (such as a shipwreck) can 

induce scour by impacting and re-directing natural wave and current patterns. The geophysical 

data acquired at each of the primary study sites indicates that scour is prevalent surrounding 

these wreck sites, but varying scour patterns and degrees are evident from site to site. Because of 

significant hull exposure on the majority of the wreck sites, coupled with low sediment accretion 

rates, corrosion is the most significant long-term site formation process expected to impact the 

studied shipwreck sites. 
251 

6. CONCLUSIONS AND RECOMMENDATIONS 

The primary goal of this study was to investigate possible shipwreck sites and make a 

determination of their potential historical significance using eligibility criteria for the NRHP. Of 

the 11 sites investigated, five are considered eligible for listing on the NRHP: RW Gallagher

(Site 433), Heredia (Site 386), Cities Service Toledo (Site 373), JA Bisso (Site 389), and 

Hatteras (Site 236). Each of these sites may eligible under multiple criteria, as is discussed in 

Chapter 4. The site of the USS Hatteras (Site 236) is already listed on the National Register and 

was added to the scope of work for monitoring purposes. Nomination forms have been prepared 

for Sites 433 (R.W. Gallagher), 386 (Heredia), 373 (Cities Service Toledo), and 389 (J.A. Bisso) 

and were submitted under this contract’s scope of work. The four remaining shipwrecks verified 

as part of this study represent relatively modern vessels that did not display any unique qualities 

or apparent historical significance and include Sites 15488 (Unknown wreck), 15366 (Unknown 

wreck), 15326 (Unknown barge), and 322 (Unknown wreck). No shipwreck was identified at the 

reported location of Site 380. The feature investigated in the West Cameron area (no site number 

available), was determined to represent modern industry-related debris rather than a shipwreck 

site, and was not interpreted as eligible for listing on the National Register. 

A secondary goal of the study was to provide an assessment of shipwreck site formation 

processes. Because of the number of sites, contract specifications, and the fiscal and temporal 

constraints of the study, the methodology focused on three primary investigative techniques: the 

acquisition of sediment cores, oceanographic modeling (using the grain size analysis results from 

the cores), and water sampling. The results of the site formation data are provided to help BOEM 

with the ongoing management and protection of submerged cultural resources on the OCS. As 

discussed in Chapter 1, the most common management strategy is the designation of avoidance 

zones to known wrecks, targets, and anomalies to ensure that these areas are not impacted by 

development. 

6.1 MANAGEMENT STRATEGIES

6.1.1. Regulatory Practice 

In situ preservation is a recognized management strategy used by archaeologists all over the 

world (UNESCO 2001) and is best used in combination with avoidance zones. In the GOM, 

BOEM enforces avoidance zones around shipwreck sites during permitted activities on the OCS. 

Other agencies throughout the world that regulate bottom-disturbing activities and their 

potential impacts on archaeological resources have developed their own ways to ensure that 

archaeological and potentially archaeologically significant materials are avoided. The state of 

Texas is one of the few U.S. states with substantial offshore oil and gas development and 

archaeological survey requirements designed to ensure that historic resources are not impacted 

by offshore development. Texas maintains economic rights within 15 km (9 mi) of the coast 

rather than the 5 km (3 mi) identified as state waters in Louisiana, Mississippi, and Alabama. 
252 

Texas’ avoidance criteria apply to any sonar target or magnetic anomaly deemed 

archaeologically significant by the project archaeologist, and are determined by the target’s 

distance offshore. Avoidance zones of 50 m (164 ft) are used for targets within 5 km (3 nautical 

miles) of shore and 150 m (492 ft) surrounding sites or objects located between the 3 and 9 

nautical mile limit (Texas Administrative Code Title 13, Part 2, Chapter 28, Rule §28.1). Similar 

to the BOEM requirements, if the avoidance can be adhered to during construction, the 

archaeological permit is generally approved by the State of Texas and construction can 

commence. If avoidance is not possible, an investigation of the target or anomaly may be 

required. One significant difference from BOEM is that Texas does not require surveys in all 

areas; instead, it assigns survey requirements only to tracts with known shipwrecks or high 

potential. 

Agencies in other states that require archaeological surveys may not necessarily deal with oil 

and gas development, but regulate other bottom-disturbing activities. South Carolina, for 

instance, regulates disturbance activities associated with dredging, construction, and aggregate 

extraction (Chris Amer 2011 pers. comm.). Although the South Carolina Institute for 

Archaeology and Anthropology (SCIAA) is not the permitting agency, by law they must be 

consulted by the permitting agency as part of the permitting and review process. When an 

activity is planned, SCIAA reviews the proposed activity and recommends to the permitting 

agency (such as the U.S. Army Corps of Engineers) whether a survey is necessary. Once the 

survey is completed, SCIAA reviews the report and may recommend either further investigation 

of targets to determine National Register potential, mitigation, or avoidance by a distance of 100 

m (328 ft) or greater. Avoidance zones use either a centerpoint and radius, or an oval, defined to 

the operator by three points including the target’s centerpoint and two offsets (Chris Amer 2011 

pers. comm.). 

In the U.K., the Crown Estate manages the seabed out to the 22 km (12 nautical miles) 

territorial limit (Crown Estate 2011). The crown maintains rights only to submerged bottom 

lands within the territorial limit; oil and gas production are specifically excluded from these 

regulations (BMAPA & English Heritage 2003). A more common bottom disturbance activity 

within the territorial limit is marine aggregate extraction. The British Marine Aggregate 

Producers Association (BMAPA) and English Heritage have published a guidance note that 

details measures to mitigate effects of dredging on historic resources (BMAPA & English 

Heritage 2003). This document indicates that avoidance is the preferred method of mitigation. 

When sites are identified during dredging activities, English Heritage is notified and a temporary 

exclusion zone is provided to the site. The operator is then directed to contract an archaeological 

investigation to determine the extent and nature of the site. Depending on the results of the 

archaeological assessment, a permanent archaeological exclusion zone may be applied to the site. 

BOEM has maintained survey guidelines for submerged archaeological resources since the 

1970s, and has continually evaluated and updated these strategies by conducting and/or funding 

studies that inform their management strategies. The development of archaeological survey and 

management guidelines in other regions has happened differently in response to other pressures 

and influences. Recommendations have been made previously to require tighter survey grid 

intervals in the GOM (e.g., 30 m or 98 ft or tighter) over all potential areas of impact (Garrison et 

al. 1989; Pearson et al. 2003; Enright et al. 2006). The effectiveness of various line spacing 
253 

intervals was discussed extensively in these previous BOEM studies; therefore, this study does 

not address magnetometer line spacing recommendations. Existing survey requirements have 

been developed by the predecessor agencies to BOEM in order to balance responsible site 

protection with economic development of the OCS, and avoid unduly restricting energy 

production. Archaeological survey requirements and management strategies in different regions 

appear to be very similar; survey line spacing is one of the primary differences. 

When determining an avoidance zone around a shipwreck site, there are two primary 

considerations. The first is the extent of the wreck site itself. This constitutes the main 

component of the ship and any ancillary materials that may have become separated during the 

wrecking event or as the result of subsequent secondary scattering processes. The second 

includes bottom disturbing activities that may occur near the wreck, especially the footprint of 

the activity and operators’ ability to adhere to the prescribed avoidance zones, given real-world 

operating conditions (see section 5.2 for a discussion of activities typically associated with oil 

and gas industry development). 

6.1.2 Determining Avoidance Zones 

When establishing an avoidance zone, the size of the wreck, water depth, and maximum 

extent of ancillary wreck components all need to be taken into account (Church et al. 2007; 

Enright et al. 2006). Broader avoidance zones up to 610 m (2,000 ft) are often used in deep 

water; in shallower depths, 300 m (1,000 ft) avoidance zones are fairly standard. This is, in part, 

because it has been demonstrated that debris fields associated with deep water wrecks can extend 

significant distances from the wreck site (Church et al. 2007). In shallower water, objects freefall 

a shorter distance through the water column, generally producing a denser scatter of objects. 

Shallow water sites are more likely to suffer from site disturbances and scattering. The more 

dynamic shallow water current and wave processes, coupled with anthropogenic activities (such 

as trawling), may contribute to significant movement of wreck components. In certain areas of 

the GOM, mud-flows or other mass sediment mobilization events could not only disrupt the site 

matrix, but relocate either an entire wreck site or individual site components a significant 

distance (Church et al. 2007:28). 

Shipwrecks must be located before they can be avoided. Deepwater wreck sites are likely to 

be observed at the seafloor, with minimal sediment overburden, because the low energy deepwater environment typically contains moderate to well-consolidated bottom sediments. Unlike in 

deepwater, shallow water sediments of the GOM have a high silt content, and are within a higher 

energy environment that contributes to sediment deposition and reworking. These conditions can 

result in the burial of secondary site components or, in some cases, such as wooden shipwrecks, 

obscure the site and make it more difficult to identify through acoustic imaging and diving. The 

GOM’s unique environment reduces the effectiveness of many strategies that are typically used 

in marine archaeology that rely on visual inspections. 

Another problem with identifying smaller wreck components through acoustics is the use of 

low frequency (typically 100 kHz) sonar data. As discussed in Chapter 2, low frequency data 

provides coverage of a wide swath of the seafloor but with reduced detail; low frequency data is 

a compromise between survey detail and logistics and is often used for large-scale 
254 

reconnaissance surveys conducted on the behalf of industry. The current study sites were 

surveyed using both low and high frequency sonar grids, and, although the low frequency grids 

produce adequate data for identifying many wreck sites, resolution is typically insufficient to 

resolve specific hull details and smaller components on the seabed. The Edgetech 120/410 kHz 

sonar that was used for this study is one of the side scan sonar devices most commonly used for 

BOEM-compliant surveys on the OCS. At 120 kHz, the sonar has an advertised across-track 

frequency of 8 cm (3 inches) but an along-track resolution of 5 m (16.4 ft). At 410 kHz, the sonar 

has an advertised across-track resolution of 2 cm (0.787 inches) but an along-track resolution of 

0.6 m (2 ft) (Edgetech 2011). The use of high frequency sonar imagery over wreck sites may 

facilitate the identification of smaller pieces of debris, but it decreases sonar range and therefore 

increases the time and cost involved in conducting surveys. No matter the frequency, sonar data 

has its limitations. Even when a target is identified in proximity to a wreck site, without visual 

inspection (usually by a diver or ROV), it still may not be possible to determine if it is associated 

with the wreck or if it represents intrusive debris from another source. To ground truth such 

sonar targets and magnetic anomalies, visual inspections are typically necessary; however, the 

generally poor visibility in the northwestern GOM makes this a difficult, time consuming, 

expensive, and sometimes dangerous undertaking. 

All of the wreck sites investigated as part of this study appear to be relatively consolidated. 

No site components that could be definitively associated with any of the study sites were 

identified beyond the 300-m (1,000-ft) avoidance zone surrounding each site. The largest wreck 

scatter was associated with Site 386, the upright and heavily damaged hull of Heredia; however, 

even this site exhibited a generally tight pattern of debris scatter. Small quantities of 

unidentifiable debris were observed surrounding some of the sites, but these appeared as discrete, 

isolated sonar and or magnetometer targets, and did not represent scattered debris fields, such as 

those that had been identified as part of the 2006 deepwater shipwreck study (Church et al. 

2007). Attempts to locate small, isolated features evident from geophysical data at the current 

study sites during diving operations were unsuccessful because of poor visibility at the seafloor 

and time constraints. 

The purpose of this project was not to develop universal avoidance zones, but to determine 

the nature of site formation, particularly site change over time. The scope of this study was not 

intended to predict the extents of debris associated with all shipwrecks located at depths of 9 to 

37 m (30 to 120 ft) BSL. However, it is possible to discuss the effectiveness of avoidance zones 

at each of the individual sites and make recommendations for the overall use of avoidance as a 

mitigation strategy and management tool. 

6.1.3 Evaluating Effectiveness of Avoidance Zones 

As discussed in Section 5.3, seafloor impacts caused by oil and gas lease development 

activities regulated by BOEM can be considerable. The onus is on the operator to ensure that 

their contractors and subcontractors comply with these avoidance zones regulations. After 

operations are completed, the operator is required to submit to BOEM a diagram, or plat, that 

details areas of bottom disturbing activities, to ensure that no avoidances were compromised. 

When an avoidance zone is not adhered to, an incident of non-compliance can be issued; this 

may require an investigation of the target to determine historic significance. If a Section 106 
255 

consultation deems the target to be historically significant, mitigative actions may be required 

and, in some cases, civil penalties imposed. 

Although BOEM has strategies in place to ensure that avoidance zones are properly 

observed, these are based primarily on self reporting and a real-time awareness by the operator of 

bottom disturbance locations relative to the avoidance zone. Identifying potential unreported 

impacts is a more difficult endeavor. In deeper water, consolidated seafloor sediments, low 

accretion rates, and minimal current and wave impacts create conditions in which anchor scars, 

mat imprints, and other seafloor disturbances can be seen on the seafloor for extended lengths of 

time. Seafloor scars recorded by sonar or video data can provide information about industry 

impacts to that area, but the data alone can’t determine the age of the seafloor disturbance. Along 

the shallow Continental Shelf where the study took place, depending on the type of sediment, 

seafloor imprints may be eroded and reworked within a higher energy environment or in-filled 

by new or reworked sediments. In these cases, evidence of previous seafloor impacts is unlikely 

to be recorded and may go completely unnoticed unless obvious damage is present, and/or the 

source of the damage remains behind (such as a lost anchor). An example of this was observed 

on Hatteras (Site 236). An approximately 10-m (33-ft) diameter hole, believed to be of 

anthropogenic origin, was observed near the bow of the vessel in August of 2010, but, by the 

time the geophysical data was recorded over the site in February 2011, less than six months later, 

it had been filled in with sediment. 

All of the sites within this study have active avoidance zones. No evidence identified at any 

of the study areas indicated that the wrecks had been impacted recently by industry activities. 

J.A. Bisso (Site 389) had the most apparent post-depositional impacts, consisting of missing 

superstructure and loss of the port side ancillary component noted from the 2005 data, but it is 

not known if these were the result of natural or anthropogenic processes. Two of the study sites 

contained pipelines within the 300-m (1,000-ft) avoidance zone surrounding the site and another 

had a pipeline installed in close proximity to the avoidance zone. Only in the case of the 

unknown barge at Site 15326 is it known for certain that the pipeline post-dates the shipwreck. In 

this case the pipeline route was designed to avoid the wreck by a distance greater than the 

assigned 300-m (1,000-ft) avoidance zone. No subsequent geophysical survey was conducted at 

this site. Divers found no evidence of obvious damage to the wreck itself; however, visibility on 

the site was poor and these results are not definitive. Although a number of the sites exhibited 

damage to the hulls or superstructure, it was typically not possible to determine if the damage 

occurred as part of the wrecking event or was post-depositional, through either anthropogenic or 

natural causes. 

Netting and remnants of trawling gear were evident on a number of the study sites. Parallel 

scars consistent with trawling were evident on the sonar data in the vicinity of the unknown 

barge (Site 15326) and the unknown wrecks at Sites 15366, and 15488. Based on the study 

results, either trawling has had a greater impact on the study sites than oil and gas development, 

or the remnants of trawling are simply more evident. It should also be noted that trawl scars were 

not prevalent on any of the sites east of R.W. Gallagher (Site 433), but were evident on most of 

the sites west of this location. Although trawling territories and seasons may have a part in this, 

the higher clay content across the seafloor in the western portion of the GOM, combined with 

low sediment accretion and limited reworking, better preserve the impression of such scars. 
256 

Trawlers were observed during diving operations in 2010 in the High Island and Galveston 

Areas, but it is unknown how recent the observed trawl scars were in relation to the acquisition 

dates for geophysical data. 

Although no clear evidence of oil and gas industry damage to any of the study sites was 

observed, these sites are part of a dynamic environment susceptible to both natural and 

anthropogenic impacts that have occurred and will continue to occur, regardless of oil and gas 

industry regulations. The impacts of shrimping and fishing are evident on many of the sites, 

through the presence of netting and line on many of the sites, and known visits by the U.S. Coast 

Guard and others to the World War II sites have resulted in secondary modifications and content 

removal. Changes will occur to offshore shipwreck sites, but the application of avoidance zones 

can protect shipwrecks against egregious damage. 

Enright et al. (2006) argue that when designing an avoidance zone, in addition to ensuring 

that construction activities do not impact sites, it is also necessary to consider the proximity of 

infrastructure that could potentially shift or move, such as during a storm, and adversely impact 

the shipwreck site. While this is a valid point, it is also necessary to consider the likelihood that 

adjacent infrastructure would be impacted to such a degree that it would move and cause damage 

to a shipwreck within an avoidance zone. Based on extensive experience conducting posthurricane geophysical inspections of pipelines and platforms in the GOM, we can make the 

following observations: 

 Buried pipelines were most likely to shift or move when sediments became liquefied 

and slump during mass sediment transport events. Documented mudflow areas 

surrounding the modern Mississippi River delta lobe have been identified (Coleman et 

al. 1980) and updated maps (Hitchcock et al. 2006) showed little change to the extent of 

the mudflow zones over time. Pipelines outside of this mudflow zone in shallow water 

depths are unlikely to be subjected to mass sediment movement. Therefore, known 

wrecks and sites susceptible to these processes can be cross referenced with existing 

data to determine the likelihood of pipeline movement. 

 Buried pipelines outside of mudflow areas are generally unlikely to be impacted by 

hurricanes unless the riser at the platform or well is damaged, causing the attached 

pipeline to shift (as noted by Enright et al. 2006). 

 Anchors from ships and moored semisubmersible drill rigs are a common cause of 

damage and displacement to unburied pipelines during severe storm events. These same 

impacts can also result in damage to shipwrecks or potential shipwreck sites, but it is 

not possible to model every path along which a rogue anchor may be dragged on the 

seafloor. 
257 

6.1.4 Observations and Recommendations 

Despite almost 40 years of survey and regulation in the GOM, there are recognized 

complications in current survey requirements and avoidance zone strategies. Archaeological 

surveys are one small requirement in the overall permitting and planning process required of 

operators. A BOEM-provided checklist of well plan document requirements includes over 175 

different possible items, depending on the location and type of plan being submitted, not 

including the various state-specific requirements. Of these possible plan requirements, 

archaeology is mentioned only twice. Despite this relatively minor role of archaeology, in terms 

of plan documents and required actions, archaeological avoidance zones, like biological 

stipulations and safety issues, can significantly impact permit approval. It is essential that 

operators understand early on that the presence of an archaeological resource may require that 

they move their planned location in order to observe possible avoidance zones, for the protection 

of the resource and the safety of offshore personnel. In areas of anticipated resources, it is the 

operator’s responsibility to ensure that the survey design provides sufficient coverage to allow 

for possible re-routes and movement of proposed locations. When unanticipated discoveries are 

made, however, avoidance zones suggested by the operator’s contracting archaeologist could be 

revised by BOEM. Coordination between contracting and reviewing archaeologists before the 

official review can prevent some of this confusion. It is necessary for all archaeologists working 

with avoidance zone assignments to develop the zone sizes based on accurate understandings of 

the unique site formation processes acting on a site and the primary threats to site preservation. 

The World War II-era wrecks in this study measure between 121 and 152 m (400 and 500 ft) 

in length, with limited amounts of discrete material identified in the survey grid. These sites have 

been assigned 300-m (1,000-ft) avoidance zones, which are equal in size to those assigned to 

wrecks measuring as small as 15 m (50-ft) in length. As suggested by Enright et al. (2006:144), 

polygon type avoidances would be preferable to single point and radii in cases such as these. For 

example, the World War II wrecks have an average length to beam ratio of over 1:6, which 

creates ample distance between the perimeter of the avoidance zone and the sides of the hull, but 

significantly less distance between the avoidance zone perimeter and the bow and stern areas. 

This practice has not been adopted in the GOM, likely because of the difficulty of expressing this 

data to operators; however, the South Carolina strategy detailed in Section 6.1.1 may be a 

relatively straightforward way to implement a version of polygon or oval avoidances in the 

GOM. 

The results of this study did not provide any quantitative data to support or challenge the 

effectiveness of BOEM-mandated avoidance zones. Ultimately, the operator is responsible for 

ensuring that their activities do not impact any known or potential sites. Because impacting a site 

can result in expensive mitigation measures and possible civil penalties, it is in the operator’s 

best interest to ensure that avoidance zones are adhered to during primary construction activities 

and also during ancillary activities conducted by subcontractors. The most effective way to avoid 

site damage is to place installations well outside the avoidance zones. When well locations are 

selected, the location should exceed the recommended avoidance zone provided by BOEM, with 

the understanding that successful wells, as discussed above, are accompanied by ancillary 

installations. If the well is installed the minimum distance specified by the avoidance, the 

placement of subsequent pipelines, manifolds, or platforms will be limited due to the need to 

maintain the avoidance zone, and risk possible inadvertent site impacts. For pipeline routes, it is 
258 

necessary to ensure that the survey corridor width is adequate to account for any necessary reroutes to the pipeline that may be required if targets or anomalies are located along the proposed 

route. Operators and regulators should also be aware that real-world operating conditions may 

require anchor patterns to differ from pre-planned designs, and these may result in anchors 

extending beyond the extents of a survey grid designed to meet minimum requirements. 

 No avoidance criteria can predict or protect against all potential threats to a site. During 

installation, sites can be avoided by vessels, anchors, and the actions of offshore personnel, but 

post-installation industry presents few threats to submerged archaeological resources. The 

greatest industry-related threats to shipwreck sites occur in charted mudflow zones, areas in close 

proximity to platforms (due to associated vessel traffic and potential damage from the structure 

impacting the site), and drifting or dragged anchors moving across the site. The most practical 

way to protect sites against impacts related to future infrastructure is to ensure that the location is 

selected in consideration of the current avoidance zone and potential placement of subsequent 

installations. 

6.2 FURTHER RESEARCH

6.2.1 Historic Research 

The GOM is home to some of the oldest known shipwrecks in the Western Hemisphere, but 

its shipwrecks are often overshadowed by those in the Atlantic and Caribbean regions. As 

demonstrated in this study, many wrecks in the GOM are relatively modern in origin. Modern 

wrecks, however, represent the unique culture of the Gulf Coast. Although the wrecks of oil and 

gas industry vessels and fishing boats may not excite today’s archaeologist, these vessels are 

intrinsically tied to the culture of the region and are reflected in all parts of daily life. Because of 

the prevalence of museum-quality examples (such as those housed at the Louisiana State 

Museum and the Center for Traditional Louisiana Boatbuilding), the modern offshore wrecks 

were not interpreted as historically significant, but future archaeologists or historians may have 

questions about these industries and their place in U.S. culture. Offshore oil and gas exploration 

represents significant and rapid technological innovations; in fewer than sixty years, oil and gas 

wells moved from just out of sight of land to ultra deepwater. 

The World War II-era wrecks identified as part of this study represent a time of intense 

innovation. Refrigerated cargo compartments and the transition from steam to oil are just some 

examples of changes within global shipping represented by these wrecks. Each was a unique 

vessel with its own story, but all ended as casualties of German incursion into U.S. waters. Their 

histories highlight both military and civilian responses to the attack on shipping. It cannot be 

overlooked that while tankers and commercial vessels were targeted by German U-boats, the 

smaller fishing craft and trawling vessels operating in the GOM went largely ignored. 

Historical research conducted for this study was extensive; it encompassed numerous 

archival institutes and uncovered previously unpublished documents, such as the plans for J.A. 

Bostwick. Despite this, a wealth of information is available on each of the study sites and 

additional research could prove valuable. For instance, Heredia was built in Belfast, Ireland. 
259 

Although museums and archival collections in Belfast were contacted, an onsite trip would be 

necessary to properly search for information, such as plans for Heredia. Because of the number 

of study sites, this was not deemed a priority. Future studies could benefit by limiting the number 

of sites investigated, which would result in more extensive and in-depth research on fewer 

wrecks. 

6.2.2 Long-term Monitoring 

Today, the shipwrecks of the GOM, both the modern and the historically significant, function 

as artificial reefs on the seabed. As such, these wrecks are independent laboratories at which a 

number of different experiments can be conducted. Part of this study was to identify the 

processes impacting each site, but more can be done. The initial contract solicitation read, 

“Sediment cores will be collected at each site in order to conduct sedimentary analysis of the 

local area.” A contract clarification was issued which stated, “At a minimum, sediment type and 

size analysis should be completed to address site formation and sedimentation rates. However, 

the offeror is encouraged to propose additional analysis of sediment cores.” While sediment 

cores can provide information about sediment type, consolidation, plasticity, water content, etc., 

this data does not provide any information about sediment movement, including accretion, 

erosion, compaction, mass transport, and scour. To use this data for these purposes, 

oceanographic modeling that accounts for factors, such as currents, waves, seafloor slope, and 

morphology, is necessary. Even then, this data represents only a model and is not a replacement 

for direct empirical data specific to each site. To address sediment movement at an individual 

site, including deposition, scour, and reworking, empirical data at the shipwreck sites should be 

obtained with on-site measurement tools to accurately record current flow over and around the 

wreck, tidal currents, seasonal fluctuation of water chemistry, and sediment accretion rates at 

different places on site. Collected using current meters, erosion pins, sediment traps, or other 

meters, these data sources would provide more detailed information about the interrelated 

processes that impact the individual shipwreck site. Because of the complexity of these 

interrelated processes, a study of this type would require intensive investigation and long-term 

monitoring to obtain sufficient data. The present study, limited in time and budget, did not have 

the resources to do this, but did collect baseline data and develop interpretations of site 

conditions which can be tested and expanded upon by future studies. The present results 

illustrate conditions on a multitude of wrecks, any of which could form the basis of unique and 

meaningful research questions regarding in-depth site formation processes, either through longterm study or comparison of two sites. A multiyear intensive study that looks at a limited number 

of sites (two to four) or an ongoing monitoring program at a single site would be more effective 

in examining natural site formation processes. 

6.2.3 Core Analysis 

Based on the results of this study, geophysical data appears to show higher rates of sediment 

movement than are suggested by hurricane sediment transport modeling or disturbance events as 

identified in the radioisotope data. The radioisotope analysis was implemented in an attempt to 

determine the age of sediments at the sites and, therefore, to be a proxy for sediment accretion 

and erosion rates. Linear accumulation rates (LAR) could be calculated for five of the six sites. 

Although not a goal of the research design, results from this study indicate that the wrecking 
260 

event may cause severe enough seafloor disturbance to influence the radioisotope count and 

therefore provide a date range for the wrecking event. The coring and sampling strategy utilized 

by the current study was not sufficient to fully test this hypothesis, which may be a viable study 

in and of itself. 

6.2.4 Local Knowledge 

Interviews with Cappy Bisso, C.J. Christ, and Avery Munson provided a great deal of 

information and also indicated that many of these wrecks have been investigated previously by 

multiple teams of avocational divers. Interviews also revealed that the identities of many of these 

wrecks have been known for some time. Some of this information has been published, but some 

has not. Charter captains, fishermen, and shrimp trawlers are well known as sources of 

information about offshore hangs, obstructions, and wreck locations. Some of these informants 

may be willing to share their knowledge of the shipwrecks of the GOM, and such interviews 

could provide invaluable data and perspective. Veterans of World War II, and especially 

survivors of German U-boat attacks in the GOM, could provide previously undocumented 

information on the war in the GOM, about which many Americans outside of the region are 

unaware. 

6.2.5 The Future of Shipwrecks on the OCS 

Shipwrecks are a non-renewable resource, and, as such, are protected by both state and 

federal laws. Collectively, they represent the intangible heritage of a nation, but individually they 

represent stories of culture, trade, travel, economics, innovation, and, ultimately, loss. Each 

vessel investigated in this study represents the history and culture of the GOM region. BOEM 

has a role in protecting the nation’s historically significant submerged cultural resources for the 

enjoyment and education of future generations. Avoidance zones enforced by BOEM help to 

protect the sites against anthropogenic or human-made impacts resulting from its permitted 

actions, which present the most immediate threats to the sites, as identified by the results of this 

study. Site formation processes identified as part of this study indicate that the sites are relatively 

stable, even in light of recent extreme storm events and hurricanes. While these examples of 

history are often out of sight, they should never be out of mind. 
261 

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Appendix A 

 

M/V Nikola Boat Diagram and Geophysical Equipment 

Specifications 
284 
285 

EZNAV NAVIGATION SYSTEM 

EZNav Geophysical is a comprehensive system for the control of most types of geophysical 

surveys and site investigations. Used in conjunction with the microprocessor-controlled SSC 03 

event controller, EZNav produces event timing independent of the PC clock or operating system 

timing restrictions. Like all EZNav software versions, this is designed to be as simple to use in 

the field as possible, while retaining the capabilities necessary to get the job done. EZNav 

Geophysical is the easiest tool for all types of offshore geophysical survey. With EZNav 

Geophysical, it is easy to use controls, configure, store and recover data connect devices, use 

with AutoCAD DXF files, send contact closures, run lines or go from point to point or integrate 

with Nobeltec ECDIS. 

EZNav GEOPHYSICAL SPECIFICATIONS 

Key 

Features 

Wizards to aid setup of key parameters such as geodetics and offsets. 

 Single directory structure for all setup and data for each project, resulting in easy 

import and export from the ship. 

Interfaces to most industry standard sonar and magnetometer recording systems. 

Supports up to 16 channels of I/O including dual GPS, offset telemetry and USBL 

Accurate twin event generation channels, based on distance down line, distance 

traveled or time. 

Flexible, simple line control, or point to point navigation. 

DXF support for background graphics and line import.

For Gulf of Mexico work, import of MMS platform, block and pipeline databases.

Dedicated helmsman’s display with line or chart graphics.

Nobeltec ENC support for line and data export, including 3D depth data displays 

and radar overlays.

User friendly tools for quality control and survey operations such as: on screen 

measurement, geodetic conversions, GPS and Gyro comparison. 

Comprehensive data logging options for events and all offsets.

Post mission software to edit and/or convert data to Excel or DXF formats. 
286 

QPS QINSY SURVEY 

QINSy is a hydrographic software suite capable of producing almost final results and images 

for real time quality control. The system makes use of a project template database which contains 

all survey configuration parameters pertinent to the project. QINSy supports most of the world’s 

datums and projections, multiple units and geoidal models used world-wide. Together with realtime depth measurements, sound velocity profiles, tide levels, RTK height, etc,. QINSy 

calculates in real time final footprint positions and images this on the various displays. QINSy 

key technology is based on collection, visualization and storage of large volumes of navigation, 

depth and other sensor data, producing almost final result in real time. 

QPS QINSy Specifications 

Key 

Features

Real-time calculation of footprint positions and DTM production 

 Combination of ring buffers and PPS provide a proven accuracy of 1msec. 

Storage of Raw sensor data enables total replay of performed survey in-office with 

different settings if required 

Total Propagated Uncertainty (error budget) calculation in real-time for on-line data 

clipping 

Multilayer sounding grid used for online imaging of DTM, layer difference ,etc. 

Imaging of project using 2D and 3D imaging techniques together with flexible 

alpha numerical information displays 

2D/3D XYZ Data Cleaning (line by line method) with 3D Grid Display (including 

3DS Object Support) 

All incoming and outgoing data is stamped with an UTC time label 

Also 

Includes 

Complex Tidal Reduction Models 

 Digital Chart Display (ENC) Support 

Enhanced Multilayer Navigation Display 

Extensive Filter Methods (on-line and post process) 

Heading sensors 

Pipeline Detection and Eventing 

Position Navigation Systems (GNSS) 

Sound Velocity Management/Modeling with Sound Velocity Profiler Support (File 

input and on-line). 

Surface Navigation Systems 

Tide Gauge Support (File input and on-line) 

USBL and LBL Support 

X-Section View and Profile Display 
287 

VERIPOS LD2 INTEGRATED MOBILE POSITIONING UNIT/VERIPOS 

ULTRA POSITIONING SERVICE 

The Veripos Ultra service is a precise positioning service designed to deliver decimeter level 

position accuracy, globally. The service is based around Precise Point Positioning (PPP)- a 

technique where all GPS system errors are removed or minimized by direct calculation, precise 

modelling or estimation. The positioning service is received through the LD2 Integrated Mobile 

Positioning Unit which uses a compact high-gain omni-direction antenna and works with an LBand input within the range 1225 to 1559 MHz. 

Veripos Specifications 

LD2 

Integrated 

Mobile 

Positioning 

Unit 

Features 

Input Voltage: 90v to 265v AC 

Consumption: 20W 

Onboard PC/104 Processor: 300 MHz Geodeprocessor, 64 Mb SDRAM, 64Mb 

 Linux Operating System 

Veripos L-band Frequency input 1525 to 1559MHz 

 Data rates 600, 1200, 2400, 4800 baud 

Receiver: Magellan 3011 HF/MF dual channel receiver 

Ultra 

Positioning 

Service 

Process type: Precise Point Positioning 

Orbit and clock corrections: JPL 

Observations used: L1/L2 carrier phase 

Availability: worldwide 

HP satellites: Inmarsat 25E, 98W, 109E, AORE, AORW, IOR 

LP satellites: Inmarsat POR 

Data format: Proprietary 

Typical correction update 30 seconds 

Typical latency: 2 seconds 

Normal horizontal accuracy: 10cm (95%) 

Normal vertical accuracy: 20cm (95%) 

Co-ordinate reference frame: ITRF05 
288 

CODA DA ACQUISITION SYSTEM 

The Coda DA is a digital data acquisition system that can accept input from sidescan sonar, 

subbottom profiler, boomer or archived analogue data. CODA systems are designed to meet 

Minerals Management Service requirements for digital data recording in a standardized format 

for both seismic and sonar systems. This system also reduces processing and reporting time. 

CODA DA TECHNICAL SPECIFICATIONS 

System Triggers Channels Serial Interfaces Additional 

DA 1 2 2 SSS or SBP 19” rack- f i

INPUTS & OUTPUTS 

Analogue inputs Adjustable input-range analogue inputs compatible with all 

analogue sidescan sonar outputs and sub-bottom profilers 

including direct hydrophone connection. Improved low voltage 

performance. 

Trigger inputs & 

outputs 

Standard TTL input & output. Up to 2 independent/asynchronous 

triggers. 

Navigation & fix 

data 

Multiple serial ports for NMEA compatible navigation data and 

other proprietary format navigation, fix and annotation strings. 

Network 2 Ethernet interfaces (1 x 1Gb, 1 x 10/100Mb) for data transfer 

and interface to digital sonars. 

DATA RECORDING 

Recording devices Internal hard disk, external hard disk (via USB 2.0 or IEEE 1394), 

DVD RAM and remote network devices. Automatic continuous 

recording switch-over. Raw or processed data recording and 

copying. Post-acquisition data back-up to DVD-R and CD-R 

disks. 

Recording formats CODA, SEGY, XTF, QMIPS 

DISPLAY MODES 

Sonar Vertical and horizontal scrolling waterfall, A-scan/oscilloscope, 

dual or single channel. 

Sub-bottom User-defined seismic zoom windows, left/right, up/down, scroll 

directions. 

Navigation On screen real-time nav. updates, track plot, corrected nav, 

navigation smoothing, speed correction etc. 

PROCESSING 

Sidescan Real-time sonar gain correction and colour palette display 

enhancement facilities, cross-track smoothing, speed correction. 

Extensive real-time and post-processing modules including 

Pipeline Inspection, Mosaicing and GeoKit interpretation tools. 
289 

Sub-bottom Extensive real-time signal processing and gain correction for subbottom profiler together with display enhancement facilities. 

User-defined depth and time based filters and gain controls. 

Stacking, auto seabed tracking, speed correction. Extensive post 

processing modules for reprocessing and interpretation. Supports 

heave sensor input for real-time heave correction. 

PHYSICAL 

Description 19" rack-mountable system - 1U, slim-line ruggedized industrial 

Dimensions 17" wide x 1.75" high x 14" deep (19" wide x 1.75" x 14" deep 

Power 100-240 Volts AC 

Processor Pentium M 1.8GHz or better 

Memory 512Mb as standard 

Hard Disk 300 gigabyte 

Display Compatible with single or dual screens (optional) 
290 

EDGETECH 4200-FS (SP) 100/ 410 KHZ SIDE SCAN SONAR 

The EdgeTech 4200 Series Side Scan Sonar System provides a unique advantage over 

conventional dual frequency side scan systems by combining EdgeTech’s Full Spectrum and 

MulitPulse technologies into one unit. The 4200 Series uses EdgeTech's Full-Spectrum chirp 

technology to deliver wide band, high energy transmit pulses, coupled with high-resolution and 

superb signal to noise ratio echo data. The 4200 Series sets new standards in the industry for 

seafloor mapping by integrating key performance and safety features, the dual mode feature 

along with EdgeTech’s Secondary Recovery System, Standard Heading, Pitch & Roll, optional 

Depth, Magnetometer interface and Acoustic responder for accurate towing positioning 

4200-SP SPECIFICATIONS 

Frequency (dual 

simultaneous) 

100 / 400 kHz 

Horizontal Beam Width 100 kHz – 1.5°, 400 kHz – 0.4° 

 Optional CW Pulse Short 100 kHz – 100us, 410 kHz – 30us 

Operating Range (max) 100 kHz: 500 meters/side; 400 kHz: 120 meters/side 

Towing Speed (max safe) 12 knots 

Towing Speed * 4.8 knots 

Towfish Material Stainless Steel 

Towfish Diameter 11.4 cm. (4.5 inches) 

Towfish Length 125.6 cm. (49.5 inches) 

Weight (in air) 30 kg (66 lbs.) 

Weight (in sea water) 18 kg (40 lbs.) 

Operating Depth (max) 1000 m 

Tow Cable Type Coaxial 

Options Pressure, Temperature, Magnetometer, USBL Acoustic 

Tracking System, Acoustic Responder, Depressor and 

Custom Sensors 

* Meets NOAA Shallow Water Survey Specification- Min 3 pings on a 1-meter target at 100 

m range. 
291 

EDGETECH 3200-XS CHIRP SUB-BOTTOM PROFILING SYSTEM 

The SB-216S tow fish operates from 2-16 kHz and utilizes special design transmitters with 

low Q wideband characteristics, best suited for “chirp” transmissions. At least two hydrophones 

are installed in the tow vehicle to reduce acoustic scattering from the sides. This results in a 

narrower across track beam pattern. Preserved in the output of the Full Spectrum chirp 

processing is the signal phase. This phase information is also recorded to the mass storage 

device. This phase information is required for sub-surface sediment classification. Phase is used 

to determine if the impedance is increasing or decreasing. The system separates the Full 

Spectrum signal processing and the signal amplifier out into separate housings. This lets a user 

interface to his own or a third party topside display processors such as the CODA 50, for 

command, control, display, printing and data storage. 

SPECIFICATIONS 

Towfish model SB-216S 

Frequency range 2 - 16 kHz 

Pulses (user selected) 2-16 kHz, 2-12 kHz, 2-10 kHz 

Vertical resolution 

(depends on pulse selected) 

6 - 10 cm 

Penetration (typical) in coarse calcareous 

sand(meters) in clay (meters) 6 

80 Beam width 17° - 24° 

Size (cm) 105L x 67W x 40H 

Weight 76 kg 

Calibration Each system is calibrated for reflection 

Cable requirements 3 shielded twisted pairs (5 used) 

Maximum Towfish Operating Depth 300 m (1,000 ft)

Optimum tow height 3 to 5 m above seafloor 

Tow Speed 3-4 knots optimal, 7 knots maximum safe 

Options Integrated depth sensor, 4 kW amplifier, 

USBL acoustic tracking system 
292 

R2 SONIC BROADBAND MULTIBEAM ECHOSOUNDER 

The Sonic 2024 Broadband Multibeam Echosounder system networks the modules, and 

embeds the processor/controller in the sonar head. With a wide operating frequency band, the 

user has unparalleled flexibility in trading off resolution and range and controlling interference 

from other active acoustic systems. Commands are transmitted through an Ethernet interface to 

the Sonar Interface Module which supplies power to the sonar heads, synchronizes multiple 

heads, time tags sensor data, and relays data to the applications workstation and commands to the 

sonar head. Features include: 60 kHz wideband signal processing, 150-m range, embedded 

processor/controller. 

System Specifications 

Frequency 200 kHz – 400 kHz

Beamwidth, across track 0.5°

Beamwidth, along track 1.0°

Number of beams 256

Swath sector Up to 160°

Max Range setting 500 m

Pulse Length 10 μs – 1ms

Pulse Type Shaped CW

Depth rating 100 m

Operating Temperature 0° C to 40° C

Storage Temperature -30° C to 55° C

Electrical Interface

Mains 90-260 VAC, 45-65 Hz

Power Consumption < 50 W

Uplink/Downlink 10/100/1000 Base-T Ethernet

Data Interface 10/100/1000 Base-T Ethernet

Sync In, Sync Out TTL

GPS 1PPS, RS-232

Auxiliary Sensors RS-232

Deck Cable Length 15 m

Mechanical

Receiver Dim (LWD) 480 x 109 x 190 mm

Receiver Mass 12 kg

Projector Dim (LWD) 273 x 108 x 86 mm

Projector Mass 6 kg

Sonar Interface 280 x 170 x 60 mm

Module Dim (LWH) Sonar 3 kg
293 

ODOM ECHOTRAC DF MK III DIGITAL PRECISION DUAL FREQUENCY 

ECHO SOUNDER &TSS CMS25 MOTION SENSOR 

The MK III Echotrac is recorded at 24/200 kHz and interfaced into a TSS Compact Motion 

Sensor. The CMS25 allows for real-time heave compensation of the sounder data and can 

provide heave data in analogue and digital format. 

ECHO SOUNDER SPECIFICATIONS 

AC power 110 or 220 VAC 

Number of channels 2 

Agile Frequency Board Broadband 

Channel 1:Broadband High Frequency Board 100 kHz to 1MHz 

Channel 1:Broadband Low Frequency Board 3-50 kHz 

Channel 2:Broadband Low Frequency Board 3-50 kHz 

Channel 2:Broadband High Frequency Board 100 kHz to 1 MHz 

TSS CMS25 MOTION SENSOR 

Accuracy Heave: ±5cm or 5% whichever is greater

Roll & Pitch for ±30° Vessel Motion: 

+0.25° 

Range Heave: ±10cm Pitch and Roll: ±30° 

Resolution 1cm; Digital - 0.01°; Analogue - 12 bit 

Bandwidth 0.05 to > 10Hz 

0 to > 10 Hz 

Update rate Digital - Up to 200Hz 

Analogue - Up to 500Hz 

Power 10 - 36V dc, <6.5W 

Velocity input 

packet formats 

NMEA 0183 (requires VTG & GLL or 

GGA); TSIP: Doppler Speed Log 

Heading input 

packet formats 

NMEA 0183; SGB; Robertson, Sperry 

LR40/60 

Depth rating 3000m standard 

Up to 6000m optional 

Tilt Operating +45° any plane; Transit - No limit 

Yaw immunity 10° per second with 30° roll & pitch 

Available outputs formats Standard TSS and other manufacturer’s 

data strings in addition to a user configurable menu can be viewed and 

selected with DMSView for Windows. 
294 

SBE 19PLUS V2 SEACAT PROFILER CONDUCTIVITY, TEMPERATURE 

AND PRESSURE RECORDER WITH RS-232 INTERFACE 

The SBE 19plus V2 SEACAT Profiler is designed to measure conductivity, temperature, and 

pressure in marine or freshwater environments at depths up to 7,000 m (22,900 ft). 

 

General Specifications

Measurement Range 

Conductivity 0 to 7 Siemens/meter (0-70 mmho/cm) 

Temperature -5 to +35° C 

Pressure 0 to full scale – 2000/3000/6000/10,000/15,000 psia 

A/D inputs 0 to +5 volts 

Initial Accuracy 

Conductivity 0.0003 S/m (0.003 mmho/cm)

Temperature 0.001° C 

Pressure 0.015% of full scale 

A/D inputs 0.005 volts 

Typical Stability 

Conductivity 0.00004 S/m (0.0004 mmho/cm)

Temperature 0.0002° C 

Pressure 0.0015% of full scale

A/D inputs 0.001 volts 

Resolution (at 24 Hz) 

Conductivity 0.00004 S/m (0.0004 mmho/cm)

Temperature 0.0002° C 

Pressure 0.001% of full scale 

A/D inputs 0.0012 volts 

Time Response (1) 

Conductivity 0.065 second

Temperature 0.065 second

Pressure 0.015 second

A/D inputs 5.5 Hz 2-pole Butterworth Low Pass Filter

Master Clock Error Contribution (2) 

Conductivity 0.00005 S/m 

Temperature 0.00016° C 

Pressure 0.3 dbar (for 6800m [10,000 psia] pressure sensor) 
295 

SEA SPY OVERHAUSER MAGNETOMETER 

The Marine Magnetics SeaSPY is the latest and most accurate magnetometer on the market 

today. This system addresses the limitations associated with other marine magnetometers; such 

as orientation restrictions, sensor realignment, time and temperature drift and poor absolute 

accuracy. The SeaSPY magnetometer measures the ambient magnetic field using a specialized 

branch of nuclear Magnetic Resonance technology, applied specifically to hydrogen nuclei. The 

SeaSPY sensor is entirely omni directional. The amount of signal produced by the sensor is 

completely independent of magnetic field direction and optimized to work around the world. No 

matter what the magnetic field strength is, the SeaSPY sensor will continue to provide a strong 

signal and accurate data. 

SEA SPY SPECIFICATIONS 

Operating Zones No Restrictions 

(SeaSPY will perform exactly according to spec throughout the 

entire range) 

Absolute Accuracy 0.1nT 

Sensor Sensitivity 0.01nT 

Counter Sensitivity 0.001nT 

Resolution 0.001nT 

Dead Zone NONE 

Heading Error NONE 

Temperature Drift NONE 

Power Consumption 1W standby, 3W maximum 

Timebase Stability 1ppm, -45°C to +60°C 

Range 18,000nT to 120,000nT 

Gadient Tolerance Over 10,000nT/m 

Sampling Range 4Hz-0.1Hz 

External Trigger By RS-232 

Communications Rs-232, 9600bps 

Power Supply 15VDC or 100-240VAC 

Operating Temperature -45°C to +60°C 

Operating Depth 300 m 

Temperature Sensor -45°C to +60°C, 0.1 step 
296 

Towfish 

Length 124 cm (49 inches) 

Diameter 12.7 cm (5 inches 

Weight in air 16 kg (35 lbs) 

Weight in water 2 kg (4.4 lbs) 
Appendix B 

 

Geophysical Survey Post-Plots 
Map B-1. Survey post-plot. S

2

ite 380, repor

98 

ted wooden wreck, South Pelto area.
Map B-2. Survey post-plot. S

2

ite 433, proba

99 

ble R.W. Gallagher, Ship Shoal area.
Map B-3. Survey post-plot. Sit

3

e 386, probab

00 

le Heredia, Ship Shoal area.
Map B-4. Survey post-plot. Sit

3

e 373, probab

01 

le Cities Service Toledo, Ship Shoal area. 
Map B-5. Survey post-plot. S

3

ite 15488, un

02 

identified wreck, High Island area. 
Map B-6. Survey post-plot. Sit

3

e 15366, unid

03 

entified wreck, Galveston, Texas, area. 
Map B-7. Survey post-plot, S

3

ite 389, proba

04 

ble J.A. Bisso, South Timbalier area.
Map B-8. Survey post-plot. S

3

ite 369, USS 

05 

Hatteras, Galveston area.
Appendix C 

 

Tabulated Magnetic Anomalies 
309 

SITE 380 MAGNETIC ANOMALIES 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR

HT 

(FT) 

SIGNATURE nT 

DURATION 

(FT.) 

1 UNKNOWN 1A 7.4 13 D 14 107 

2 UNKNOWN 1A 6.7 13 - 5 38 

3 PIPELINE 3 10.2 15 D 194 596 

4 UNKNOWN 4 4.7 11 D 9 80 

5 UNKNOWN 5A 5.3 11 D 6 75 

6 PIPELINE 5A 9.7 11 D 372 346 

7 PIPELINE 6 9.1 14 D 204 1110 

8 UNKNOWN 6 7.7 13 D 15 109 

9 PIPELINE 7 8.7 12 D 961 848 

10 UNKNOWN 8 9.9 12 + 6 74 

11 UNKNOWN 8 8.8 11 D 53 293 

12 PIPELINE 8 7.7 11 D 315 511 

13 PIPELINE 10 6.6 10 D 830 912 

14 UNKNOWN 10 8 10 D 17 91 

15 UNKNOWN 10 9.9 12 - 9 76 

16 UNKNOWN 11 7.1 10 D 37 237 

17 PIPELINE 11 5.8 11 D 2907 384 

18 PIPELINE 12 5.8 9 D 3453 484 

19 UNKNOWN 12 6.9 10 - 9 61 

20 UNKNOWN 12 7.2 10 D 252 137 

21 UNKNOWN 12 8.5 10 - 4 68 

22 PIPELINE 15 4.9 9 C 187 347 

23 UNKNOWN 16 6.4 9 D 40 105 

24 PIPELINE 101 7.5 6 + 312 324 

25 PIPELINE 102 7.4 10 + 183 165 

26 UNKNOWN 102 7.1 10 + 0 38 

27 PIPELINE 103 7.2 7 - 681 301 

28 PIPELINE 104 7.1 7 D 2087 506 

29 UNKNOWN 104 9.7 6 - 10 50 

30 PIPELINE 105 7 10 - 1722 514 

31 PIPELINE 106 6.9 5 - 597 364 

32 UNKNOWN 107 10.5 10 D 10 150 

33 PIPELINE 107 6.8 13 D 161 444 
310 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR

HT 

(FT) 

SIGNATURE nT 

DURATION 

(FT.) 

34 PIPELINE 108 6.7 14 + 190 313 

35 UNKNOWN 108 5.4 15 - 4 59 

36 PIPELINE 109 6.7 16 - 211 220 

37 PIPELINE 110 6.7 11 + 164 195 

38 UNKNOWN 110 5 12 + 15 75 

39 PIPELINE 111 6.7 8 + 304 315 

40 UNKNOWN 111 7.1 9 C 89 154 

41 UNKNOWN 112 4.7 13 D 7 98 

42 UNKNOWN 112 6.3 10 D 20 92 

43 PIPELINE 112 6.6 10 + 256 169 

44 UNKNOWN 112 7.2 9 D 6 57 

45 PIPELINE 113 6.5 16 D 66 296 

46 UNKNOWN 114 6 10 - 19 80 

47 PIPELINE 114 6.4 11 - 314 194 

48 UNKNOWN 114 8.4 8 D 37 132 

49 UNKNOWN 115 10.3 10 D 10 64 

50 PIPELINE 115 6.3 15 D 226 316 

51 UNKNOWN 116 8.9 11 - 6 67 

52 PIPELINE 116 6.3 14 + 282 322 

53 UNKNOWN 117 6.9 16 - 5 72 

54 PIPELINE 117 6.2 17 + 139 242 

55 UNKNOWN 118 8.1 11 D 98 183 

56 PIPELINE 118 6.2 12 D 78 437 

57 PIPELINE 119 6.2 11 - 1073 400 

58 UNKNOWN 119 8.4 7 - 2 31 

59 UNKNOWN 119 8.7 7 D 5 44 

60 PIPELINE 120 6.1 9 - 414 278 

61 UNKNOWN 120 6.4 8 D 65 46 

62 UNKNOWN 120 8.5 5 - 8 61 

63 PIPELINE 121 6 13 - 199 358 

64 PIPELINE 122 5.9 9 - 287 256 

65 UNKNOWN 122 9.5 9 D 33 112 

Shaded cells represent anomalies located in close proximity to the reported location of #380.
311 

SITE 433 MAGNETIC ANOMALIES 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT 

DURATION 

(FT.) 

1 UNKNOWN 4 6.3 45 + 14 34 

2 UNKNOWN 5 9.4 18 - 315 205 

3 UNKNOWN 6 6 16 D 8 58 

4 UNKNOWN 7 8.8 9 + 3 107 

5 UNKNOWN 8 7.6 13 + 3 33 

6 UNKNOWN 104 8 11 D 28 148 

7 UNKNOWN 104 9.6 9 + 9 49 

8 UNKNOWN 201 7.7 11 + 10 64 

9 UNKNOWN 202 5.8 11 + 48 24 

10 UNKNOWN 202 7.8 16 - 51 111 

11 UNKNOWN 208 8.3 16 D 153 153 

12 UNKNOWN 209 8.2 14 - 157 220 

13 UNKNOWN 210 8.1 12 + 10 99 

14 UNKNOWN 212 5.3 11 - 5 38 

15 UNKNOWN 212 4.8 12 D 3 52 

16 UNKNOWN 302 7.4 8 D 27 49 

17 UNKNOWN 304 9 36 - 9 104 

18 WRECK 1 7.6 11 - 16 1607 

19 WRECK 2 7.3 9 D 41 2225 

20 WRECK 3 6.3 4 D 260 2008 

21 WRECK 4 7.1 36 D 12761 1619 

22 WRECK 5 7.2 13 D 504 1742 

23 WRECK 6 7.5 12 D 80 2107 

24 WRECK 7 7.4 11 + 22 937 

25 WRECK 103 6.9 12 D 221 1847 

26 WRECK 201 5.3 11 + 199 1556 

27 WRECK 202 5.3 16 + 354 1605 

28 WRECK 203 5.4 15 + 1152 1687 

29 WRECK 204 5.4 30 D 25138 1554 

30 WRECK 205 5.5 33 D 63512 1453 

31 WRECK 206 5.8 34 D 11426 1247 

32 WRECK 207 5.9 40 - 1045 1333 

33 WRECK 208 6.2 18 D 458 1434 

34 WRECK 209 6.3 19 - 232 1268 

35 WRECK 210 5.3 10 D 124 1323 
312 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT 

DURATION 

(FT.) 

36 WRECK 211 6.4 19 - 76 1253 

37 WRECK 212 6.5 12 - 43 1128 

38 WRECK 301 5.6 6 D 949 1617 

39 WRECK 302 5.9 9 D 9402 1237 

40 WRECK 303 5.8 34 D 25628 1435 

41 WRECK 304 6 37 D 9816 1078 

42 WRECK 305 5.8 36 C 10402 1200 

43 WRECK 306 5.8 41 C 6456 1020 

44 WRECK 307 6.1 41 - 6284 1364 

45 WRECK 308 6.3 14 D 641 1337 

46 WRECK 309 5.6 16 D 273 1334 

47 WRECK 310 6.5 16 D 123 1378 

48 WRECK 311 5.4 11 D 61 1533 

49 UNKNOWN 101 4.7 9 D 64 65 

50 WRECK 101 6.8 11 - 30 1090 

51 WRECK 102 6.8 9 D 1207 1693 

52 WRECK 401 6.3 11 - 1173 1729 

53 UNKNOWN 402 4.9 15 + 12 30 

54 WRECK 402 6.7 13 - 1706 1469 
313 

SITE 386 MAGNETIC ANOMALIES 

ANOMALY

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

1 UNKNOWN 3 4.7 17 + 11 157 

2 UNKNOWN 4 9.4 17 + 5 39 

3 UNKNOWN 6 5.3 10 D 26 79 

4 UNKNOWN 6 6.7 10 - 27 37 

5 UNKNOWN 6 7.4 16 - 94 23 

6 UNKNOWN 6 7.6 18 + 121 47 

7 UNKNOWN 7 4.4 15 - 15 15 

8 UNKNOWN 7 4.6 12 C 8 48 

9 UNKNOWN 7 5.3 13 - 62 145 

10 UNKNOWN 7 5.4 12 - 9 71 

11 UNKNOWN 8 8.7 11 D 19 77 

12 UNKNOWN 403 6.8 13 + 43 23 

13 UNKNOWN 404 5.6 15 + 25 66 

14 UNKNOWN 404 5.7 14 + 8 23 

15 UNKNOWN 407 8.9 5 D 14 41 

16 UNKNOWN 407 6.3 12 - 29 29 

17 UNKNOWN 408 5.9 13 + 22 60 

18 UNKNOWN 409 6 8 - 13 29 

19 UNKNOWN 504 8.1 14 - 10 84 

20 UNKNOWN 504 5.5 15 - 215 40 

21 UNKNOWN 601 7 16 - 3 93 

22 UNKNOWN 601 10.4 18 D 12 69 

23 WRECK 4 7.6 18 D 25 1387 

24 WRECK 5 7.6 17 D 4778 1311 

25 WRECK 6 7.7 9 C 1335 1435 

26 WRECK 7 8.1 5 D 47130 1505 

27 WRECK 401 6.6 10 D 30 1043 

28 WRECK 402 6.5 13 + 53 983 

29 WRECK 403 6.5 12 + 134 1312 

30 WRECK 404 6.4 9 D 346 1295 

31 WRECK 405 6.2 28 + 2797 1567 

32 WRECK 406 6.2 32 C 6714 1587 

33 WRECK 407 6.5 9 - 355 1043 

34 WRECK 408 6.5 13 - 141 1206 

35 WRECK 409 6.7 9 D 60 1149 
314 

ANOMALY

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

36 WRECK 410 6.7 14 + 29 1057 

37 WRECK 411 6.7 14 D 19 1385 

38 WRECK 501 5.8 10 - 24 777 

39 WRECK 502A 5.8 14 - 45 790 

40 WRECK 503 5.8 13 - 88 756 

41 WRECK 504 5.9 18 - 267 711 

42 WRECK 505 6 32 - 3221 806 

43 WRECK 506 6 35 D 11856 734 

44 WRECK 507 5.9 28 D 15327 1170 

45 WRECK 508 6 29 D 11907 1213 

46 WRECK 509 6.1 29 D 1943 1164 

47 WRECK 510 6.1 11 - 205 1343 

48 WRECK 511 6.2 15 - 74 1228 

49 WRECK 512 6.3 7 - 35 979 

50 UNKNOWN 101 8.8 14 - 9 145 

51 UNKNOWN 101 6.3 15 D 17 124 

52 UNKNOWN 102 8.6 16 + 9 47 

53 WRECK 102 7.9 16 - 25 952 

54 UNKNOWN 103 5.5 10 D 5 59 

55 WRECK 103 8.4 11 - 62 1000 

56 UNKNOWN 104 10.5 10 D 11 84 
315 

SITE 373 MAGNETIC ANOMALIES 

ANOMALY 

NO. SOURCE LINE FIX

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

1 UNKNOWN 2 7.7 11 D 13 67 

2 UNKNOWN 3 7 18 - 30 139 

3 UNKNOWN 4 5.4 16 + 16 42 

4 UNKNOWN 4 6.7 16 + 154 44 

5 UNKNOWN 4 6.9 15 + 30 44 

6 UNKNOWN 6 6.5 11 D 36 74 

7 UNKNOWN 102 10.2 12 D 8 56 

8 UNKNOWN 102 8.3 29 D 5 56 

9 UNKNOWN 103 5.1 9 + 22 43 

10 UNKNOWN 103 5.6 10 D 15 150 

11 UNKNOWN 103 8 11 D 6 36 

12 UNKNOWN 103 8.8 11 D 25 64 

13 PIPELINE 104 5.4 12 + 404 153 

14 UNKNOWN 104 5.2 11 + 69 72 

15 UNKNOWN 104 5 11 D 15 51 

16 UNKNOWN 201 5.9 11 + 16 93 

17 UNKNOWN 202 5.9 10 D 48 149 

18 UNKNOWN 204 7.5 14 - 18 50 

19 UNKNOWN 208 6 14 + 22 46 

20 UNKNOWN 6A 5 26 + 162 78 

21 UNKNOWN 309 7.5 11 - 18 52 

22 WRECK 2 6.6 12 - 31 1594 

23 WRECK 3 6.7 18 - 128 1372 

24 WRECK 4 6.7 18 C 6617 1819 

25 WRECK 5 7 13 - 900 1526 

26 WRECK 6 7 11 - 125 1227 

27 WRECK 7 7.1 12 - 28 1448 

28 WRECK 101 7.5 12 + 26 1610 

29 WRECK 102 7.4 30 D 50870 782 

30 WRECK 103 7.1 11 + 393 1036 

31 WRECK 201 5.6 11 - 123 1249 

32 WRECK 202 5.7 10 - 243 1101 

33 WRECK 203 5.7 10 - 463 978 

34 WRECK 204 5.8 12 - 1219 1482 

35 WRECK 205 6.1 24 D 6185 1672 
316 

ANOMALY 

NO. SOURCE LINE FIX

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

36 WRECK 206B 5.6 29 D 55938 1141 

37 WRECK 207A 5.8 26 D 54106 1123 

38 WRECK 208 6 14 - 2536 1375 

39 WRECK 209 6 16 - 813 926 

40 WRECK 210 6 15 - 335 1117 

41 WRECK 211 6 15 - 183 1222 

42 WRECK 212 6.1 13 - 99 1217 

43 WRECK 301 6.1 13 + 1407 996 

44 WRECK 302 6.1 14 + 2320 822 

45 WRECK 303A 5.8 29 D 51614 997 

46 WRECK 304B 5.9 28 C 55408 900 

47 WRECK 305 5.9 32 C 40808 1202 

48 WRECK 306A 6.1 28 C 9281 953 

49 WRECK 307 6 27 C 34754 1032 

50 WRECK 308A 5.9 14 D 1695 954 

51 WRECK 309 5.9 12 + 335 857 

52 WRECK 310 6 12 + 174 1040 

53 WRECK 311 5.8 12 + 85 1015 
317 

SITE 15488 MAGNETIC ANOMALIES 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

1 UNKNOWN 4 4.5 10 + 2 53 

2 UNKNOWN 4 5.3 10 + 2 73 

3 WRECK 4 7 10 C 21 462 

4 WRECK 5 6.9 11 D 26 399 

5 PIPELINE 6 6 13 D 348 1045 

6 PIPELINE 7 8.6 13 D 548 848 

7 PIPELINE 101 8.1 11 + 160 208 

8 PIPELINE 102 8.5 12 + 520 334 

9 PIPELINE 103 8.8 9 + 1036 340 

10 UNKNOWN 103 7.9 9 + 12 56 

11 UNKNOWN 103 7.2 9 + 4 88 

12 PIPELINE 104 9.2 11 - 270 202 

13 UNKNOWN 203B 5.5 10 + 3 129 

14 UNKNOWN 203B 7.5 10 + 2 121 

15 UNKNOWN 204A 7.4 12 + 5 96 

16 WRECK 205A 6 14 D 30 438 

17 WRECK 206C 6.1 10 D 642 491 

18 WRECK 207D 6.1 7 - 6259 607 

19 UNKNOWN 207D 6.9 7 + 5 31 

20 WRECK 208B 5.8 12 - 14 354 

21 PIPELINE 211B 5.2 12 C 101 329 

22 UNKNOWN 212B 8.7 12 - 18 20 

23 PIPELINE 212B 5.5 11 D 1204 698 

24 PIPELINE 301 7.1 15 D 116 288 

25 PIPELINE 302 7.3 16 D 138 229 

26 UNKNOWN 303 6.2 17 - 11 294 

27 PIPELINE 303 7.3 17 - 1291 241 

28 WRECK 304 6.2 16 D 77 544 

29 PIPELINE 304 7.4 17 + 962 342 

30 WRECK 305 6.2 18 D 3727 497 

31 PIPELINE 305 7.4 17 - 694 245 

32 WRECK 306A 6.1 18 - 639 295 

33 PIPELINE 306A 7.4 18 D 36 354 

34 PIPELINE 307 7.4 16 C 43 194 

35 WRECK 307 6 16 - 92 394 

36 PIPELINE 308 7.5 14 - 471 201 
318 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

37 WRECK 308 6 14 - 14 337 

38 PIPELINE 309 7.5 16 + 73 291 

39 UNKNOWN 309 5.9 15 + 3 73 

40 PIPELINE 310 7.6 17 - 261 162 

41 PIPELINE 311 7.6 14 - 115 180 
319 

SITE 15366 MAGNETIC ANOMALIES 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

1 UNKNOWN 1 7.8 17 D 8 80 

2 WRECK 4 7.5 19 - 34 397 

3 WRECK 5 7.5 12 - 7 461 

4 UNKNOWN 101 6 13 - 243 158 

5 WRECK 102 7.3 18 + 28 328 

6 WRECK 204 6.1 19 + 8 361 

7 WRECK 205 6.1 18 + 47 312 

8 WRECK 206 6.1 19 + 5135 642 

9 UNKNOWN 207 5.1 10 D 28 62 

10 WRECK 207 6 10 - 28115 591 

11 UNKNOWN 208 5.2 9 + 40 89 

12 WRECK 208 6 9 - 27 579 

13 UNKNOWN 209 6.5 19 D 8 104 

14 WRECK 303 5.8 15 - 9 354 

15 WRECK 304 5.9 16 - 25 415 

16 WRECK 305 5.9 18 - 299 508 

17 WRECK 306 5.9 17 D 2687 477 

18 WRECK 307 5.8 17 - 119 368 

19 UNKNOWN 308 6.3 18 D 10 47 

20 WRECK 308 5.8 17 - 11 286 

 
320 

SITE 389 MAGNETIC ANOMALIES 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

1 UNKNOWN 2 5.6 15 - 3 51 

2 UNKNOWN 2 7 15 D 8 58 

3 WRECK 3 8.9 15 + 2 1158 

4 WRECK 4 7.1 16 - 111 460 

5 WRECK 5 7.3 15 - 17 654 

6 UNKNOWN 7 4.7 14 + 4 59 

7 UNKNOWN 8 5.6 12 + 3 56 

8 WRECK 103 7.2 16 + 6 300 

9 WRECK 202 5.9 14 - 7 627 

10 WRECK 203 6.3 14 + 226 606 

11 UNKNOWN 203 6.2 15 + 16 38 

12 WRECK 204 6.2 17 - 210 389 

13 WRECK 205 6.2 17 - 972 482 

14 UNKNOWN 206 5.2 17 + 22 75 

15 WRECK 206 6.3 19 D 9831 486 

16 UNKNOWN 206 7.2 18 + 20 89 

17 UNKNOWN 207 5.2 14 - 17 65 

18 WRECK 207 6.3 16 D 2160 504 

19 UNKNOWN 207 7.2 15 - 47 59 

20 UNKNOWN 208 7 13 - 55 66 

21 WRECK 208 6.1 13 D 2634 565 

22 UNKNOWN 208 5.1 13 - 8 87 

23 WRECK 209 6.1 13 C 329 634 

24 WRECK 210 6.1 12 - 64 636 

25 WRECK 211 6.3 16 - 11 633 

26 WRECK 212 6.3 16 - 5 609 

27 UNKNOWN 212 7.2 16 + 2 30 

28 UNKNOWN 301 6.2 14 D 9 121 

29 WRECK 302 6.2 12 + 3 449 

30 WRECK 303 6.2 12 + 8 484 

31 UNKNOWN 303 7.4 12 + 7 55 

32 WRECK 304 6.1 14 + 33 464 

33 WRECK 305 4.6 15 + 4 51 

34 WRECK 305 6.1 16 + 113 646 

35 WRECK 306 6.1 14 + 766 878 
321 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION 

(FT.) 

36 WRECK 307 5.9 15 - 7758 874 

37 WRECK 308 5.9 19 - 1049 837 

38 UNKNOWN 308 5.5 19 D 87 136 

39 WRECK 309 6.1 15 D 26 657 

40 WRECK 310 6.2 16 D 11 868 
322 

SITE 236 MAGNETIC ANOMALIES 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION

(FT.) 

1 UNKNOWN 1 6.7 14 + 10 106 

2 UNKNOWN 3 6.3 13 - 15 51 

3 UNKNOWN 3 6.9 15 - 2 24 

4 WRECK 4A 7.2 14 - 11 785 

5 UNKNOWN 4A 7.1 16 + 5 23 

6 UNKNOWN 4A 6.3 13 D 4 77 

7 UNKNOWN 5 8.2 16 + 4 28 

8 WRECK 5 7.1 15 D 14641 819 

9 UNKNOWN 6 6.8 15 D 11 52 

10 WRECK 6 7.3 16 - 35 592 

11 UNKNOWN 8 9.8 9 D 40 172 

12 UNKNOWN 102 6.7 14 - 4 49 

13 WRECK 103 7.6 14 D 47 1054 

14 UNKNOWN 201 5.6 6 - 9 37 

15 UNKNOWN 201 5 6 D 15 72 

16 UNKNOWN 202 5.1 8 + 7 45 

17 WRECK 203 6.2 10 - 7 626 

18 UNKNOWN 204 7.4 8 D 5 47 

19 UNKNOWN 204 7.1 9 D 12 51 

20 WRECK 204 6.2 8 - 24 694 

21 UNKNOWN 204 5.9 8 - 4 29 

22 UNKNOWN 204 5.4 7 D 4 59 

23 WRECK 205 6.2 7 - 42 581 

24 WRECK 206 6.2 7 D 79 855 

25 WRECK 207 6.2 11 D 323 696 

26 WRECK 208 6.4 16 D 6935 693 

27 WRECK 209 6.3 11 D 19216 789 

28 UNKNOWN 209 7.4 12 D 18 79 

29 WRECK 210 6.3 14 - 1760 878 

30 WRECK 211 6.1 13 D 10362 947 

31 WRECK 212 6.3 13 - 497 761 

32 WRECK 213 6.2 11 - 83 520 

33 UNKNOWN 301 4.4 14 D 20 59 

34 UNKNOWN 301 5.3 13 - 3 33 

35 WRECK 302A 6.5 12 - 8 852 
323 

ANOMALY 

NO. SOURCE LINE FIX 

SENSOR 

HT(FT) 

SIGNATURE nT DURATION

(FT.) 

36 WRECK 303 6.3 18 + 24 848 

37 UNKNOWN 303 5.6 18 D 12 59 

38 WRECK 304 6.5 17 + 78 830 

39 WRECK 305 6.5 18 + 251 870 

40 UNKNOWN 305 6 18 - 52 101 

41 WRECK 306 6.5 16 + 1175 978 

42 WRECK 307A 6.3 10 C 11352 879 

43 WRECK 308A 6.4 10 C 16253 835 

44 UNKNOWN 308A 5.5 10 + 11 43 

45 WRECK 309 6.6 17 C 6839 935 

46 WRECK 310 6.5 16 C 106 823 

47 WRECK 311 6.6 15 D 37 926 
Appendix D 

 

Supplemental Maps 
326

Map D-1. Reported location of U-boat victims in the north central GOM (based on coordinates from Rohwer 1983). 
327

Map D-2. Comparison of reported locations of designated study sites and World War II-eratankers. 
328

Map D-3. Ge

Ge

rman grid systerman U-boat acc

m map showing

ounts (Rowher 1

 reported locatio

983). A. R.W. Ga

ons of World Wa

llagher, B. Here

ar-II-era study sit

dia, C. Cities Ser

tes, b

vice 
329

Map D-4. Locations of study sites and datums in relation to 2005 hurricanes (hurricane tracks from NOAA). 
330

Map D-5. Locations of study sites and datums in relation to 2008 hurricanes (hurricane tracks from NOAA). 
Appendix E 

 

Supplemental Documents 
SITE 433 R. W. GALLAGHER
335

Figure E-1. General arra

(Courtesy of A

ngement and

very Munso

 outboard pr

n). 

ofile plans for Hull 4306 (duplicate plans were made for Hull 4307-R.W. Gallagher) 1936 (last rev
336

.

Figure E-2. Engineering plans for Hulls 4306-4309 (R.W. Gallagher–Hull No. 4307) 1936. Courtesy of William A. Baker Collection, MIT Mu
337

Figure E-3. L

S

ist of Hull Nos. 4

teel Collection, B

305-4312 speci

ox 170, Hagley M

fications, built at 

useum & Librar

Bethlehem Spar

y. 

row’s Point, Maryland Shipyard. Acce
Figure E-4. War 

(USM

shipping adm

C 1942b). 

inistration re

338 

quisition time charter for R.W. Gallagher 1942, p.1 
Figure E-5. W

(U

ar Shipping A

SMC 1942b)

dministratio

. 

339 

n requisition time charter for R.W. Gallagher 1942, p.2 
Figure E-6. W

(U

ar Shipping 

SMC 1942b

Administratio

). 

340 

n requisition time charter for R.W. Gallagher 1942, p.3 
Figure E-7. Degaussing installation report fo

341 

r R.W. Gallagher 1942, p.1 (Bureau of Ordnance). 
Figure E-8. Degaussing 

Ordnance).

installation r

 

342 

eport for R.W. Gallagher 1942, p.2 (Bureau of 
Figure E-9. Degaussing installation repor

343 

t for R.W. Gallagher 1942, p.3 (Bureau of Ordnance). 
Figure E-10. Degaussing installation repo

344 

rt for R.W. Gallagher 1942, p.4 (Bureau of Ordnance). 
Figure E-11. Por

194

t director’s re

2b). 

port arming 

345 

merchant vessels for R.W. Gallagher 1942, p.2 (OCNO 
Figure E-12. Por

194

t director’s re

2b). 

port arming 

346 

merchant vessels for R.W. Gallagher 1942, p.3 (OCNO 
Figure E-13. Por

(OC

t director’s m

NO 1942f). 

aterial repor

347 

t for Armed Guard Unit for R.W. Gallagher 1942, p.4 
Figure E-14. R.W

of, 

. Gallagher

pg. 1 (Kraem

(Tk), Wreck N

er 1944, cour

348 

o. 628, Dete

rtesy of J. Ave

rmination of 

ry Munson C

depth of wate

ollection). 

r above the wreck 
Figure E-15. R.

wr

W. Gallagher

eck of, pg. 2 

 (Tk), Wreck

(Kraemer 194

349 

 No. 628, D

4, courtesy o

Determination 

of J. Avery M

of depth of 

unson Collec

water above 

tion). 

the 
SITE 386 HEREDIA
352 

Figure E-16. Timeta

Image 

ble cover from Scourtesy of Bjorn

tates Steamship 

 Larsson. 

Company highlighting General Pershing and her sister 
353

Figure E-17. Timetable 

of Bjorn La

pages from State

rsson. 

s Steamship Company, showing drawing of General Pershing, 1932. Im
354 

Figure E-18. Pages 

Image 

of timetable from

courtesy of Bjorn

 States Steams

 Larsson. 

hip Company, illustrating cabin plans for the Genera
355 

Figure E-19. Page of timeta

Bjorn Larsson.

ble from States Steamship Company, illustrating cabin plans for the General Liners, 193
Figure E-20. Imag

the 

Soci

e of Heredia

charter to S

iety. 

 in Portland

tates Steams

356 

, Oregon, De

hip Service

cember 23, 

. Image cou

1932, upon c

rtesy of the 

ommenceme

Oregon Hist

nt of 

orical 
Figure E-21. P

1

ort director’s

942a). 

 report armi

357 

ng merchant vessels for Heredia 1942, p.2 (OCNO 
Figure E-22. Po

19

rt director’s m

42d). 

aterial repo

358 

rt for Armed Guard Unit for Heredia 1942, p.1 (OCNO 
Figure E-23. Arm

194

ed Guard C

2, p.2 (OCNO

enter report o

 1942e). 

359 

f materials furnished to Armed Guard Units for Heredia
Figure E-24. Letter

mena

of the

 to the Chief

aces to navig

e J. Avery Mu

 of Naval Ope

ation, p.1. U.

nson Collecti

360 

erations, Hyd

.S. Navy Dep

on. 

rographic Of

artment, Bur

fice, regardin

eau of Ships

g the remova

 1944. Court

l of 

esy 
Figure E-25. Le

of 

Co

tter to the C

menaces to

urtesy of the

hief of Naval 

 navigation,

 J. Avery Mun

361 

Operations, 

 p.2. U.S. N

nson Collectio

Hydrographic

Navy Depart

on. 

 Office, rega

ment, Burea

rding the rem

u of Ships 

oval 

1944. 
Figure E-26. Lette

men

the J

r to the Chie

naces to navig

J. Avery Muns

ef of the Bure

gation, p.2. O

son Collection

362 

au of Ships, N

Office of the C

n. 

Navy Departm

hief of Naval

ent, regardi

l Operations 1

ng the remov

944, Courte

al of 

sy of 
SITE 373 CITIES SERVICE TOLEDO
365

Figure E-27. J. A. Bostwic

Company Arc

k outboard p

hive. 

rofile plan, Hull No. 445, Harlan and Hollingsworth Corp., Wilmington, Delaware, 1916. Courtesy o
367

Figure E-28. J. A. Bos

Steel Com

twick profile 

pany Archive

and deck pla

. 

ns, Hull No. 445, Harlan and Hollingsworth Corp., Wilmington, Delaware, 1916. Courte
369

Figure E-29. J. A. Bostw

Steel Comp

ick stern fram

any Archive

e and rudde

. 

r plans, Hull No. 445, Harlan and Hollingsworth Corp., Wilmington, Delaware, 1916. Cou
Figure E-30. Wa

194

r Shipping A

2, p.1 (USMC

dministration

 1942e). 

371 

 requisition time charter for Cities Service Toledo
Figure E-31. W

19

ar Shipping 

42, p.2 (USM

Administratio

C 1942e). 

372 

n requisition time charter for Cities Service Toledo
Figure E-32. W

1

ar Shipping 

942, p.3 (US

Administratio

MC 1942e). 

373 

n requisition time charter for Cities Service Toledo
Figure E-33. Por

(OC

t director’s re

NO 1942c). 

port arming 

374 

merchant vessels for Cities Service Toledo 1942, p.2 
Figure E-34. Po

(O

rt director’s r

CNO 1942c)

eport arming

. 

375 

 merchant vessels for Cities Service Toledo 1942, p.3 
Figure E-35. Por

p.1 

t director’s m

(OCNO 1942

aterial report

g). 

376 

 for Armed Guard Unit for Cities Service Toledo 1942, 
Figure E-36. Po

19

rt director’s 

42, p.2 (OCN

material rep

O 1942g). 

377 

ort for Armed Guard Unit for Cities Service Toledo
SITE 389 J. A. BISSO
Figure E-37. Photograph of J. A. Bisso, da

381 

te unknown. Courtesy of William “Cappy” Bisso. 
Figure E-38. Pho

Ver

J. A

“Ca

otograph of J

rso inscribed 

A. Bisso alon

appy” Bisso. 

J. A. Bisso, f

“McDermott 8

ngside Sunke

382 

far right, repo

800 ton Derri

en American 

ortedly on the

ick #9 Bisso 4

 Tideland Ri

e job it was 

00 ton derri

ig #101.” Co

on when it s

ck Cairo with

urtesy of Wi

sank. 

h Tug 

illiam 
SITE 236 USS HATTERAS
385

Figure E-39. Drawing of the

Museum, New

 engine for St. 

port News, Virgin

Mary’s, Hull No.ia. 

 41, date unknown, from the Harlan & Hollingsworth 
Figure E-40. Paul A. Clo

the Hattera

utier and Fra

s site. Cover 

386 

ank E. Vandi

image, Rice 

ver shown w

University Re

ith artifacts r

view, 1976. 

ecovered from 
Figure E-41. Ir

C

&

on ball, show

orpus Christi

& Heritage Co

wn from abo

i Museum of S

ommand Unde

387 

ove, recovere

Science and 

erwater Archa

ed from USS

History. Imag

aeology Branc

S Hatteras si

ge courtesy o

ch, Departme

ite, housed a

of the Naval H

ent of the Nav

at the 

History 

vy. 
Figure E-42. Iron

Chr

Her

 ball, side v

risti Museum

ritage Comma

view, recover

m of Science 

and Underwa

388 

red from USS

and History

ater Archaeolo

S Hatteras si

y. Image cou

ogy Branch, D

ite, and hous

urtesy of the

Department o

sed at the C

e Naval Histo

of the Navy. 

Corpus 

ory & 
Appendix F 

 

Water Quality and Radioisotope Tables 
391 

Figure F-1. Salinity measurements compared by depth of sample. 

Figure F-2. Salinity measurements displayed west (left, Site 236) to east (right, Site 380). 

 

‐40

‐30

‐20

‐10

0

30.5 31 31.5 32 32.5 33 33.5 34 34.5 35

Depth below sea level (meters)

Salinity (ppT) by Depth

29

30

31

32

33

34

35

236 15366

no. 2

15366

no. 1

15488

no. 2

15488

no. 1

322 15326 373 386 433

no. 2

433

no. 1

389 380

Salinity (ppT)

Salinity (ppT) by Longitude
392 

Figure F-3. Salinity measurements displayed by distance offshore. 

Figure F-4. Averaged pH values compared by depth of sample. 

 

30.5

31

31.5

32

32.5

33

33.5

34

34.5

35

0 10 20 30 40 50

Salinity (ppT)

statute miles

Salinity (ppT) by Distance Offshore

‐40

‐30

‐20

‐10

0

7.000 7.200 7.400 7.600 7.800 8.000 8.200 8.400

Depth below sea level (meters)

Measured pH values

pH by Depth
393 

Figure F-5. Averaged pH values displayed by longitude west (Site 236) to east 

(Site 380). 

Figure F-6. Averaged pH values displayed by distance offshore. 

 

7.000

7.200

7.400

7.600

7.800

8.000

8.200

pH (ppT)

pH by Longitude

7.000

7.200

7.400

7.600

7.800

8.000

8.200

8.400

0 10 20 30 40 50

pH (ppT)

statute miles

pH by Distance Offshore (statute miles)
394 

Figure F-7. Averaged DO measurements compared by depth of sample. 

Figure F-8. Averaged DO values displayed west (left, Site 236) to east (right, Site 380). 

 

‐40

‐30

‐20

‐10

0

6.600 6.700 6.800 6.900 7.000 7.100 7.200 7.300 7.400 7.500 7.600

Depth below sea level (meters)

Measured DO (mg/L)

DO (mg/L) by Depth

6.200

6.400

6.600

6.800

7.000

7.200

7.400

7.600

236 15366

no. 2

15366

no. 1

15488

no. 2

15488

no. 1

322 15326 373 386 433

no. 2

433

no. 1

389 380

DO (mg/L)

DO (mg/L) by Longitude
395 

Figure F-9. Averaged DO measurements displayed by distance offshore. 

6.600

6.700

6.800

6.900

7.000

7.100

7.200

7.300

7.400

7.500

7.600

0 10 20 30 40 50

DO (mg/L)

statute miles

DO (mg/L) by Distance Offshore
396 

Table F-1 

Radiochemical and Porosity Data for Site 433 

Sample 

Depth 

(cm) 

xs Pb210 xs err Ra226 Ra err Cs-137 Cs err Porosity 

75% 

porosity 

consolidated 

depth 

0–1 1.54 0.82 1.28 0.22 0.08 0.09 0.75 0.59 

1–2 1.74 0.81 1.20 0.09 0.03 0.08 0.59 

2–3 0.34 0.67 1.42 0.10 0.05 0.07 0.59 2.08 

3–4 0.64 0.76 1.45 0.32 0.00 0.00 0.59 3.86 

4–5 0.53 0.71 1.36 0.20 0.00 0.08 0.61 5.63 

5–7 0.34 0.66 1.28 0.02 0.00 0.00 0.62 7.37 

7–9 0.00 0.69 1.66 0.18 0.00 0.08 0.64 9.90 

9–11 0.10 0.66 1.35 0.16 0.00 0.00 0.53 13.16 

19–21 1.11 0.79 1.14 0.39 0.00 0.00 0.65 16.74 

No activity reported for remaining samples, taken at depths of 29–31, 39–41, 49–51, 59–61, 

and 69–71 cm 

Table F-2 

Radiochemical and Porosity Data for Site 373 

Sample 

Depth 

(cm) 

xs Pb210 xs err Ra226 Ra err Cs-137 Cs err Porosity 

75% 

porosity 

consolidated 

depth 

0–1 2.95 0.95 1.20 0.07 0.00 0.00 0.84 0.39 

1–2 3.75 0.95 1.24 0.15 0.05 0.08 0.82 1.21 

2–3 3.37 0.78 1.30 0.21 0.13 0.06 0.81 2.10 

3–4 5.13 1.22 1.63 0.52 0.00 0.00 0.83 2.96 

4–5 4.55 1.05 1.57 0.24 0.00 0.08 0.80 3.85 

5–7 5.03 1.04 1.20 0.15 0.00 0.00 0.80 5.31 

7–9 3.93 1.03 1.46 0.30 0.05 0.09 0.75 7.44 

9–11 4.24 0.94 1.29 0.04 0.01 0.08 0.75 9.76 

19–21 3.18 0.99 1.47 0.20 0.00 0.00 0.75 21.38 

29–31 3.00 0.93 1.36 0.31 0.24 0.08 0.68 34.50 

39–41 5.66 1.05 1.15 0.03 0.10 0.08 0.73 48.01 

49–51 4.98 1.03 1.16 0.14 0.16 0.08 0.72 60.58 
397 

Table F-3 

Radiochemical and Porosity Data for Site 15488 

Sample 

Depth 

(cm) 

xs Pb210 xs err Ra226 Ra err Cs-137 Cs err Porosity 

75% 

porosity 

consolidated 

depth 

0–1 4.66 1.04 1.06 0.12 0.24 0.09 0.86 0.33 

1–2 3.90 1.05 1.24 0.33 0.00 0.10 0.86 1.01 

2–3 2.37 0.89 1.11 0.24 0.00 0.00 0.83 1.77 

3–4 1.47 0.81 0.88 0.22 0.00 0.00 0.77 2.74 

4–5 3.06 0.98 1.02 0.11 0.10 0.10 0.79 3.78 

14–16 3.52 0.97 1.22 0.14 0.00 0.00 0.78 14.35 

24–26 4.56 1.06 1.29 0.31 0.07 0.09 0.74 25.52 

34–36 4.27 1.03 1.11 0.24 0.08 0.09 0.78 36.66 

44–46 4.45 0.99 1.27 0.15 0.05 0.08 0.75 47.65 

54–56 4.95 1.09 1.29 0.29 0.00 0.00 0.74 59.60 

64–66 4.54 1.02 1.45 0.17 0.01 0.08 0.72 72.19 

Table F-4 

Radiochemical and Porosity Data for Site 15366 

Sample 

Depth 

(cm) 

xs Pb210 xs err Ra226 Ra err Cs-137 Cs err Porosity 

75% 

porosity 

consolidated 

depth 

0–1 5.70 1.21 1.04 0.17 0.00 0.11 0.85 0.37 

1–2 5.34 1.12 1.32 0.08 0.07 0.09 0.85 1.09 

2–3 4.37 1.16 1.06 0.20 0.00 0.00 0.83 1.85 

3–4 3.44 1.01 1.07 0.12 0.05 0.10 0.83 2.66 

4–5 3.21 0.94 1.02 0.32 0.00 0.00 0.84 3.47 

14–16 6.03 1.34 1.36 0.43 0.14 0.11 0.80 12.66 

24–26 5.88 1.09 1.15 0.15 0.12 0.08 0.79 22.38 

34–36 2.76 0.74 0.80 0.04 0.00 0.07 0.56 36.85 

44–46 4.76 0.88 1.18 0.19 0.14 0.06 0.77 51.83 
398 

Table F-5 

Radiochemical and Porosity Data for Site 389 

Sample 

Depth 

(cm) 

xs Pb210 xs err Ra226 Ra err Cs-137 Cs err Porosity 

75% 

porosity 

consolidated 

depth 

0–1 1.93 0.72 0.82 0.27 0.00 0.00 0.62 0.40 

1–2 2.16 0.71 1.10 0.22 0.12 0.07 0.65 1.24 

2–3 1.77 0.87 1.58 0.41 0.00 0.00 0.53 2.12 

3–4 0.63 0.57 0.76 0.12 0.00 0.00 0.49 3.02 

4–5 0.62 0.44 0.81 0.09 0.00 0.00 0.46 3.95 

14–16 2.28 0.80 1.00 0.37 0.00 0.00 0.53 14.18 

24–26 3.52 0.84 1.72 0.24 0.07 0.06 0.78 24.57 

34–36 4.27 1.01 1.56 0.20 0.04 0.09 0.77 35.82 

44–46 1.77 0.75 1.49 0.17 0.03 0.07 0.63 47.32 

Table F-6 

Radiochemical and Porosity Data for Site 236 

Sample 

Depth 

(cm) 

xs Pb210 xs err Ra-226 Ra err Cs-137 Cs err Porosity 

75% 

porosity 

consolidated 

depth 

0–1 6.15 1.23 1.25 0.17 0.11 0.1 0.88 0.31 

1–2 6.00 1.19 1.28 0.24 0.1 0.09 0.85 0.97 

2–3 4.42 1.03 1.31 0.32 0.02 0.08 0.83 1.73 

3–4 4.37 0.87 0.99 0.27 0.04 0.06 0.82 2.56 

4–5 3.38 0.92 1.24 0.11 0.06 0.08 0.81 3.45 

5–7 2.46 0.77 0.8 0.16 0 0 0.63 5.53 

7–9 0.93 0.73 1.06 0.18 0 0 0.69 8.58 

9–11 4.60 1.13 1.25 0.33 0.07 0.09 0.76 11.12 

19–21 3.61 0.96 1.38 0.43 0.07 0.07 0.74 22.82 

29–31 0.42 0.52 1.13 0.2 0.02 0.05 0.64 36.94 

39–41 0.78 0.72 1.11 0.23 0.01 0.08 0.68 52.13 

49–51 0.32 0.63 1.05 0.14 0 0 0.61 67.8 

59–61 0.50 0.67 0.84 0.3 0.05 0.07 0.48 87.09 
Appendix G 

 

Core Logs 
401 
402 
403 
404 
405 
406 
407 
408 
409 
410 
411 
412 
The Department of the Interior Mission

As the Nation’s principal conservation agency, the Department of the Interior 

has responsibility for most of our nationally owned public lands and natural 

resources. This includes fostering the sound use of our land and water 

resources; protecting our fish, wildlife, and biological diversity; preserving the 

environmental and cultural values of our national parks and historical places; 

and providing for the enjoyment of life through outdoor recreation. The 

Department assesses our energy and mineral resources and works to ensure 

that their development is in the best interests of all our people by encouraging 

stewardship and citizen participation in their care. The Department also has a 

major responsibility for American Indian reservation communities and for 

people who live in island communities. 

The Bureau of Ocean Energy Management Mission 

The Bureau of Ocean Energy Management (BOEM) promotes energy 

independence, environmental protection, and economic development through 

responsible, science-based management of offshore conventional and 

renewable energy.