ACCESS NUMBER: 73218 

STUDY TITLE: Study to Conduct National Register of Historic Places: Evaluations of 

Submerged Sites on the Gulf of Mexico Outer Continental Shelf 

REPORT TITLE: Study to Conduct National Register of Historic Places Evaluations of 

Submerged Sites on the Gulf of Mexico Outer Continental Shelf 

CONTRACT NUMBER: 1435-01-04-RC-73218 

SPONSORING OCS REGION: Gulf of Mexico 

APPLICABLE PLANNING AREAS: Central and Western Gulf of Mexico 

FISCAL YEARS OF PROJECT FUNDING: 2003; 2004 

COMPLETION DATE OF REPORT: July 2006 

COSTS: FY 2003: $85,230; FY 2004: $114,770; CUMULATIVE PROJECT COST: 

$200,000 

PROJECT MANAGER: C. Bond, R. Gearhart 

AFFILIATION: PBS&J 

ADDRESS: 6504 Bridge Point Parkway, Suite 200, Austin, Texas 78730 

PRINCIPAL INVESTIGATOR*: R. Gearhart 

KEY WORDS: Gulf of Mexico; marine archaeology; remote-sensing; National Register 

of Historic Places; shipwreck; MMS avoidance criteria; World War II; Spanish-American 

War; Civil War 

BACKGROUND: The MMS has regulatory responsibility for mineral exploration and 

development on the Gulf of Mexico Outer Continental Shelf (OCS). Part of that 

responsibility includes considering the effects of MMS-permitted undertakings on 

archaeological sites. Current Notices to Lessees require oil and gas operators to 

conduct geophysical survey of areas proposed for development and submit the data to 

qualified archaeologists for analysis. The archaeologist makes recommendations for 

every potentially significant magnetic and/or acoustic anomaly identified during survey. 

Industry operators typically avoid potential archaeological sites identified by the 

examining archaeologist. As a result, the MMS has amassed little information regarding 

the identification of these anomalies, which could potentially be of value in both 

eliminating extraneous, archaeologically insignificant sites from further concern and in 

refining the analytical methods used in selecting certain sites for avoidance in the future. 

While avoidance serves the purpose of protecting some cultural resources, historic and 

circumstantial evidence suggests that a substantial proportion of historic shipwrecks are 

missed by industry surveys. This study was conceived in order to address these issues. 
ACCESS NUMBER: 73218 

OBJECTIVES: (1) Evaluate the National Register of Historic Places eligibility of select 

submerged sites on the Gulf of Mexico OCS; (2) Assess the adequacy of current MMS 

avoidance criteria; (3) Assess industry compliance with government protective 

measures; (4) Apply lessons learned from study to eliminate archaeologically 

insignificant sites from further concern; and (5) Provide feedback useful for evaluating 

the effectiveness of the MMS historic preservation program. 

DESCRIPTION: Archaeological diver investigations and remote-sensing surveys were 

conducted at 14 known sidescan sonar targets. The targets were investigated over two 

separate field seasons in May 2004 and May 2005. Nine targets were visited in 2004 

and five in 2005. Remote-sensing data collected included close-order magnetic, high 

resolution sidescan sonar, and ROV video. Sub-meter accurate differentially corrected 

GPS positioning was recorded in conjunction with magnetic data and also embedded in 

sonar imagery. Survey line spacing was no greater than 30 feet (9.1 meters) and GPS 

and magnetic data were recorded at 1-second intervals. The sidescan sonar imaged 50 

meters (164 feet) to either side of its path and recorded constantly. Processing of 

remote-sensing data entailed the creation of magnetic contour maps and mosaic 

imagery for each site. The remote-sensing data enabled nautical archaeologists to 

accomplish objectives 2-5 above. Archaeological diver and ROV investigations were 

conducted at each site primarily to accomplish objective 1 above, but also to provide 

additional data to accomplish objective 3. 

SIGNIFICANT CONCLUSIONS: Three shipwreck sites, M/S Sheherazade; SS R.M. 

Parker, Jr.; and SS Castine, were recommended as eligible for listing on the National 

Register of Historic Places and the appropriate nomination forms were completed. 

At three shipwreck sites investigated, industry construction had occurred in the 

immediate vicinity. This construction was conducted under MMS avoidance measures 

tailored to each shipwreck site. While construction adhered to avoidance zones, PBS&J 

noted areas for improvement. Under current MMS survey requirements, avoidance of 

magnetic anomalies could better be accomplished through a variable-sized avoidance 

zone tailored to each anomaly perimeter rather than a set distance from a central point. 

Likewise with sidescan sonar targets, protection would better be afforded through an 

avoidance zone tailored to the margins of a target. This would account for such factors 

as vessel size and variable GPS accuracy. Position estimates from surveys conducted 

in deeper water can vary significantly due to necessarily longer sensor layback. 

Increasing avoidance zones proportional to the increase in sensor layback during 

surveys conducted in relatively deeper water could counteract this problem. Avoidance 

zones additionally would offer an added measure of protection against collision were 

industry work vessels required to honor avoidance zones as strictly as construction 

impacts, especially at shallower sites. Aside from the direct impact resulting from the 

construction of industry facilities, an indirect impact exists during the construction phase 

– lay barge anchoring. PBS&J noticed a lay barge anchor spread implemented during 

the construction of a pipeline immediately adjacent to an MMS avoidance zone 

crisscrossed the zone numerous times. As water depths decrease and/or anchor 
ACCESS NUMBER: 73218 

cables lengthen the potential to impact exposed or shallowly buried shipwrecks 

increases. Requiring lay barge anchor spreads to honor avoidance zones as strictly as 

the anchors themselves could prevent unintentional damage to sites. 

On the Gulf of Mexico OCS many shipwreck sites are afforded a high level of protection 

due to their discovery, while buried wooden hulls located in relatively shallow water may 

be eluding detection during industry surveys. These wrecks represent potentially the 

largest class of shipwrecks on the OCS and are marked by relatively small magnetic 

anomalies and by ambiguous to nonexistent sonar targets. To fill this archaeological 

gap would require a reduction of remote-sensing survey line spacing, revised 

methodology for processing and analyzing data, and new selection criteria. A 

combination of the three would better allow the nautical archaeologist to both identify 

potential shipwrecks and eliminate archaeologically insignificant debris items. 

STUDY RESULTS: Close-order magnetic data, high resolution sidescan sonar 

imagery, ROV video footage, and diver investigative data were collected at fourteen 

known sidescan sonar targets over two field sessions. Diver and ROV site 

investigations and historical research allowed identification of most of these targets and 

an assessment of National Register of Historic Places eligibility status. One site, the 

USS Hatteras (41GV68), had previously been identified and was visited as part of an 

ongoing monitoring effort. Of the remaining targets nine were identified as shipwrecks 

and four were not relocated. Four of the shipwrecks, M/S Sheherazade; R.M. Parker, 

Jr.; SS Castine; and Caribe No. 500, are historic vessels. Research conducted at 

various libraries and archives resulted in the creation of detailed historical narratives for 

these vessels, with the exception of the Caribe No. 500. Three shipwrecks are modern 

and the remaining two remain unidentified. 

Remote-sensing data processing entailed the creation of magnetic contour maps and 

mosaic imagery of each located site. This data allowed PBS&J to assess compliance 

with government protective measures at three shipwreck sites. Along with previous 

PBS&J remote-sensing work, data from this study provided the means to draw 

significant conclusions concerning the current level of protection afforded shipwrecks on 

the Gulf of Mexico OCS. Moreover, PBS&J was able to devise alternate survey, 

processing, and analysis options designed to improve discovery and protection of 

shipwrecks on the Gulf of Mexico OCS.

STUDY PRODUCT(S): Enright, J.M., R. Gearhart, D. Jones, J.J. Enright. 2006. Study 

to conduct national register of historic places evaluations of submerged sites on the Gulf 

of Mexico OCS. A final report by PBS&J for the U.S. Dept. of the Interior, Minerals 

Management Service Gulf of Mexico OCS Region, New Orleans, LA. Contract No. 

1435-01-04-RC-73218. MMS OCS Study 2006-036. 147 pp. + 1 not for public 

disclosure appendix. 

Enright, J.M. Sheherazade National Register of Historic Places registration form. A 

nomination by PBS&J for the U.S. Department of the Interior, Minerals Management 

Service Gulf of Mexico OCS Region, New Orleans, LA. 
ACCESS NUMBER: 73218 

Enright, J.M. R.M. Parker, Jr. National Register of Historic Places registration form. A 

nomination by PBS&J for the U.S. Department of the Interior, Minerals Management 

Service Gulf of Mexico OCS Region, New Orleans, LA. 

Jones, D. Castine National Register of Historic Places registration form. A nomination 

by PBS&J for the U.S. Department of the Interior, Minerals Management Service Gulf of 

Mexico OCS Region, New Orleans, LA. 

*P.I.’s affiliation may be different than that listed for Project Manager.