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ISLAND RESOURCES FOUNDATION SEARCHING FOR HISTORIC SHIPWRECKS: REPORT ON A MARINE ARCHAEOLOGICAL SURVEY OF CROWN BAY J ST. THOMAS J U.S. VIRGIN ISLANDS FINAL REPORT NOVEMBER, 1984 Prepared for The Virgin Islands Port Authority BY Dr. Edward L. Towle, Project Director Mr. J. Barto Arnold, III, Marine Archaeological Consultant With the Assistance of Project Staff: Mr. William Jones, Master Diver Mr. Andrew Fredebaugh, Support Diver Mr. Edward Trupp, Technician (Logistics) Ms. Sandra Tate, Technician (Administration) Ms. Judith Towle, Technician (Fiscal) Mr. Werner Wernicke, Engineer RED HOOK CENTER BOX 33, CHARLOTTE AMALIE, ST. THOMAS, U.S. VIRGIN ISLANDS 00802, (809) 775-6225 TABLE OF CONTENTS PAGE NO. 1.0 INTRODUCTION AND ABSTRACT ........... .................. 1 2.0 BACKGROUND INFORI.,1ATION................................ 3 2 II 1 The Location II • II II II II II II II II • II II II II • II II II II • II II II • II • II II II II II II II II • II 3 2.2 The Virgin Islands Port Authority Crown Bay Proj ect. II II II II,. II • II • II II II II •• II ••• II • II II II • II II II II II II II II II II II • 3 2.3 The Historical Setting ........................... 7 2.4 Environmental Parameters......................... 11 2.5 Archaeological Antecedants ....................... 12 3.0 RESEARCH DESIGN ....................................... 18 3.1 Re loca tion and Georeferencing.................... 18 3.2 Sub -Bottom Search Methods ........................ 20 4.0 PROJECT OPERATIONS SUM~4ARY ............................ 22 4.1 Chronology. II. II II II II II II II II. II II II II II. II II II. II II II. II II. II. II II II II II. II II 22 4 II 2 Staffing II II II •• II II II II • II •• II • II • II II II II II. II II II. II II II II II II II II II II II II II II 22· 4.3 Mobilization and Equipment ....................... 24 4.4 Anomaly Relocation and Positioning ............... 25 4.5 Anomaly Site Assessment .......................... 30 5.0 RESULTS AND CONCLUSIONS ............................... 35 5.1 Summary ...... e ••••••••••••••••••••••••••••••••••• 35 5.3 Detailed Anomaly Survey Data ..................... 38 6 . 0 REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 47 Figure Figure Figure Figure Figure Table Table Table Table Appendices II II II II II II II II " II II II II tI II II II II II II II II II II II II II II II II II II II ., II .. II II II II II II II 49.-.50 lA lB lC 2 3 4 5 1. 2 • 3. 4 . LIST OFFTGURES Location Map, St. Thomas, U.S. Virgin Islands .... 4 Location Map, Crown Bay .......................... 5 Location Map, 1981 Magnetometer Survey Anomalies. 15 Magnetic Anomaly Map - November 1984 ............. 23 Example of Anomaly Positioning ................... 29 Historical Dredge and Fill Activities Within Study Area....................................... 31 Sample Magnetometer Signatures (A,B,C,D & E) .. 44-4S-46 LIST OF TABLES Ranking of Magnetic Anomalies as to "f" 16 Potential Signl lcance .......................... . Shore Survey Station Georeference Loca tional Coordinates........................... 27 Crown Bay Magnetic Anomaly Georeference Loca tional Coordinates........................... 27 Magnetic Anomaly Survey Data Summary ............. 36 1 1.0 INTRODUCTION AND ABSTRACT Pursuant to its development plans for Crown Bay, which involved ceitain dredge and fill activities for Phases IIA and lIB of the original project scheme, the Virgin Islands Port Authroity arranged for a preliminary magnetometer! side scan sonar survey of Crown Bay, St. Thomas, to identify any submerged shipwreck sites which might have historic value. This task was carried out in February, 1981, by Tetra Tech, Inc. of Jacksonville, Florida, under contract to the Port Authority and under the direction of Mr. Erik Olsen, who was assisted by a professional marine archaeo- logist, Mr. J. Barto Arnold from Austin, Texas. Twenty-nine magnetic anomalies were identified in the study (Olsen, 1981), but nineteen were determined to be either modern debris or eliminated for other technical reasons, leaving ten possible high priority marine archaeo- logical sites that needed to be assessed as to their his- torical significance. The Island Resources Foundation was contracted in late July, 1984, to perform this task of relocating and evalu- ating each of the ten high priority magnetic anomalies re- ported previously by Tetra Tech. For those proving, upon inspection, to have significance, a salvage archaeological excavation effort was to be carried forward expeditiously prior to any dredging activity. Project mobilization commenced on 8 August; field work at Crown Bay started on 6 October, using a Geometrics Model 2 806A Proton Magnetometer to reloca,.te each anomalY' site and pinpoint the anomaly epicenter on the seabed. At the re- quest of the Port Authority three additional low priority sites in an area to be dredged were examined. Additionally, three new anomalies were found and investigated during the course of the survey work. Subsequent to relocation and inspection, ten promising sites were subjected to a pattern of sequential high pres- sure water jet probes penetrating up to sixteen feet of unconsolidated bottom sediments seeking evidence of the presence of a buried shipwreck. Test excavations using an air lift wer6 also carried out. All findings were negative, as no historical shipwreck sites were confirmed. Two anomaly areas proved to be geo- logical in origin, and all others were caused by modern ferrous objects -- mostly debris on the seabed or buried in the sandy harbor sediments. From a marine archaeological perspective, there appears to be no valid reason why the Port Authority cannot proceed to dredge the specified Crown Bay areas as scheduled. A dredge spoil area monitoring strategy for artifacts is recommended. 2.0 BACKGROUND INFORMATION 2.1 The Location 3 The project area is located adjacent to the Crown Bay Marine Freight Terminal along the southwestern portion of urbanized Charlotte Amalie, St. Thomas, Virgin Islands. The site is within the Crown Bay Harbor directly north of Water Island and east of Haypiece Hill and the former Submarine Base docking facilities at Little Krum Bay (Fig- ures lA and lB). 2.2 The Virgin Islands Port Authority Crown Bay Project The Virgin Islands Port Authority has proposed and received the necessary permits to expand the existing Crown Bay freight terminal facilities and provide deep water access to the cruise ship docking facilities presently under construction in the Crown Bay area. The project is a modi- fication of the jointly sponsored proposal by the Virgin Islands Port Authority and the U.S. Army Corps of Engineers in 1980. The U.S. Army Corps recommended in its feasibil- ity report that a terminal area for freight and cruise vessels be created in Crown Bay from fill material which would be dredged from Crown Bay Harbor to provide access to the terminal and increasing the depth of Gregerie Channel to 38 feet. It further recommended the development of new docking space and additional filled land to accommo- date freight and passenger ship service facilities. The expansion of Crown Bay port facilities was endorsed by the Virgin Islands Coastal Zone Management Program as CJ ffi ATLANTIC OCEAN (j('DUTCHCAP CAY NER BRASS I. SALT CAY ~ .. ,......... W .. E .S .. T CAY >:. c:::;t,.,. ...... . 0:( Adapted From: "Environmental Assess- ment Report/Crown Bay Port Facility Expansion STUDY AREA Q ~SABA ISLAND & Gregerie Channel· Improvement," (V.I. Port Authority, February 1983). by Island Resources Foundation November, 1984 SCALE IN MILES o 2 3 CARIBBEAN SEA ISLAND ~ ... .•. :p ~ ~ tS~:~HOMAS VICINITY MAP LONG PT. CD WEST GREGERIE CHANNEL @ EAST GREGERIE CHANNEL ~CK ISLAND c::::::- ST. CROIX MINGO CAY ~~ GRA~S CAY FIGURE I"A LOCATION MAP p .a .j:::. ~" :\ ~ I , . / j::e 3 gy 5 :7 fl·-·---' 53 'I' " J ',,- ! 59 40 59 " "-,,- 65 l' ! E."S !=J "" "- 15~., , " 46 hrd G 62 ~ ~-='~ --9 ...... ~Q> F/ G 4seE,. " 51 "v ~9 46 ~ (J 42 ~ 41 ..A. 36 "-'. fne 9,V S 42 3:', '" \ 21 \! 2:3 2,) "):) 3>3 43 ~ 43 G\ 19 48 (fl -...,0 n>1 Crown Bay Marine ArchaeologiGal Survey, st. Thomas, u.s. Virgin Islands LOCATION MAP Drawn by: W.W. Date: Nov. 1984 ~ L t t:") '"JJ Ul 6 approved by the Governor of the Virgin Islands and Secretary of the U.S. Department of Commerce in 1979. The present phase of the project is supported by a local Coastal Zone Permit Application CZT-47-83W submitted by the Virgin Islands Port Authority and a subsequent letter of conditional approval from E.E. Hatchette, Chairman, St. Thomas Coastal Zone Management Committee, addressed to Nr. J. Harding, Executive Director, Virgin Islands Port Author.ity, dated August 8, 1983. All parties acknowledged that dredging a 38 foot chan- nel and turning basin in Crown Bay posed the risk of pos- sible destruction of potential cultural resources in the form of historic shipwreck sites which might exist within and beneath the seabed sediments scheduled for removal to deepen the channel and provide fill material on shore. Therefore, the Virgin Islands Port Authority prepared and submitted to the Virgin Islands Coastal Zone Management and Virgin Islands Planning Office (Division of Archaeology and Historic Preservation), a marine archaeological plan outlining a protocol for a proper survey and assessment of the magnetic anomaly si teo documentation in the 1981 Tetra Tech study. The plan became the basis for the operational strategy employed by the Island Resources Foundation in carrying out the site surveys. 7 2.3 The Historical Setting Crown Bay, a small cove on the south shore of St. Thomas between Careen Hill (Frenchtown) and Little Krum Bay (the old U.S. Navy Sub-Base dock area), was originally known as Gregerie Bay (see Ro.hde map of 1822), after a prominent Grigri tree on its shore. This name, after spread- ing to embrace the adjacent entrances from the Caribbean Sea (East and West Gregerie channelsl, disappeared at its place of origin and was, in the mid-19th Century, replaced by the name Crown Bay (Maguire, 1925). In turn, this name is often now expanded to include the entire harbor, an- chorage and dock area west of Banana Point on Water Island and east of Haypiece Hill. (See Figure lB.) Maguire (1925) notes that Crown Bay was at that time a cable landing area, a feature reported forty-odd years later in the Virgin Islands chapter in "Sailing Directions for the West Indies," published by the U.S. Navy Hydro- graphic Office: Submarine cables are laid across West Gregerie Channel just southward of Little Krum Bay and just southward of Krum Bay. Cables are also laid between the northwestern extremity of Hassel Island and the mainland west-north~ westward. [Crown Bay] As the Tetra Tech consultants did previously (Olsen, 1981), we have examined the available historical carto- graphic, bathymetric, meteorological and narrative records in some detail seeking to establish a profile of maritime 8 usages and physical modifications within the Crown Bay study area. Some of the findings were instructive. For example, the old Keulen chart of 1719 shows "Gringri Bay" and IIWater Eyeland Haven" as having four principal anchorages near what we now call Grambokola Hill, Krum Bay and Hay- piece Hill and in Crown Bay itself. The Montargue chart of 1772 notes that "Gringri Bay" is "fur grose Schiffe," suggesting a major ship anchorage; and the Rohde chart of 1822 displays the preferred track for larger deep draft vessels sailing through East and West Gregerie Channels. The successive editions of the U.S. Coast and Geodetic Survey Chart #933 (1917, 1920, 1928, 1936, 1941, 1944, 1948, and 1965) are also instructive as is the U.S. Navy Hydrographic Office's Chart #977 of 1873, showing the chan- nel and harbor bathymetry and shoreline configurations prior to subsequent major dredge and fill operations. Much of the waterfront within the limits of the study area has been affected by major development activities within the last 50 or so years. As indicated in Figures IB and 4, major segments of the shoreline between Little Krum Bay and Careen Hill have been extended bayward by eitherbulkheading and backfilling or by filling alone. Correspondingly, various portions of the Crown Bay study area have been dredged as a source of fill, in order to eliminate hazards to navigation or to increase navigable depths. The 1941 and 1944 versions of U.S.C.& G.S. Chart #922 indicate that major wartime improvements to Little Krum Bay had been 9 completed within that time span. The facility was sub- sequently used as a submarine base and, to date, is still referred to locally as the "Sub-base." These charts like- wise indicate that between 1941 and 1944, a large rock or reef outcropping known as Gregerie Bank was removed from the northern end of West Gregerie Channel as a hazard to navigation to ships traversing between East and West Gregerie Channels. The former location of this geological feature is shown on Figure 4. Within the past decade, physical modifications to the Crown Bay/Little Krum Bay/West Gregerie Channel area shore- line and seabed have proliferated and usage levels by both large and small vessels seeking mooring sites, anchorages, dockage and support services has expanded rapidly. For example: • Whereas in 1974, there were only seven vessels (yachts and barges) moored or anchored in Elephant and Ruyter Bay on the north shore of Water Island (to the south of the main West Gregerie ship channel opposite Little Krum Bay), by 1981 it was 31 vessels, by 1983 it was 54 and in October of 1984, during the field work for this project, it exceeded 80 vessels . • Little Krum Bay (where the old U.S. Navy Docks were situated) has been filled,and a new Port Authority angled dock for cruise ship use is under construction . • Whereas in 1974, there was one marina (Shoreline), there are now three in the area. 10 • Dredging has taken place adjacent to the new Port Authority dock and elsewhere. • A major container-ship facility has been developed at the Crown Bay bulkhead. With all this recent expanded marine activity, and associated dock and bulkhead dredging and construction, it is inevitable that one will find a motley collection of ferrous (iron or steel) debris on the harbor bed -- vessel parts, abandoned vehicles, wire rope, old engine-block moorings, lost anchors, chain, etc. All this on top of, or intermixed with, U.S. Navy debris from the World War II period, and at least three runs of abandoned, heavy steel armored underwater telegraph, telephone or power cable, linking St. Thomas with Water and Hassel Islands, .are known to be buried in the Crown Bay and West Greger'ie Chan- nel sediments. In places, this old cable is cut, broken, twisted and the ends are looped back in convoluted coils. Historic shipwrecks in the area were listed by Towle (1976), and in the Tetra Tech report (Olsen, 1981), but the three documented coastal wreck sites now lie buried under the dredge spoil/fill areas at Crown Bay, Little Krum Bay and Krum Bay. A recently completed, even more comprehensive list of known historical shipwrecks completed by Mr. George Tyson for the Virgin Islands Planning Office's Division of Archaeology and Historic Preservation, adds no hew docu- mented historical shipwreck sites in the Crown Bay area (Mr. George Tyson, personal communication). 2.4 Environmental Parameters Crown Bay, along with St. Thomas Harbor and the en- tire south coast of the island has a tidal regime that is principally diurnal. The mean range is about 1/2 foot and the diurnal range is less than 1 foot. The mean level of the sea is 1 foot lower in April and May than at other periods of the year. The tidal currents in West Gregerie Channel and East Gregerie Channel set eastward on the flood and westward on the ebb at the junction of these two channels. The U.S. Navy Hydrographic Office reported that in 1958, a current of 2 or 3 knots was encountered in the vicinity of Little Krum Bay. This current was setting north-northwestward through East Gregerie Channel and southwestward through West Gregerie Channel. The wind was east-southeasterly at a velocity of 15 knots during the time of observation. It was also reported in 1961 that a 4-kno~westerly current was experienced in these channels. During the current marine archaeological survey, bot- tom and surface currents at anomaly sites E8, E9, 126 and E127 exceeded 3 knots in a southwesterly direction on five occasions when there were strong southeasterly winds com- bined with an ebb tide. Marker buoys with ten-pound anchors in 40 feet of water would not stay in place under the force of this current, which also prevented divers (wearing 30 lbs. of lead weights) from maintaining position on the bottom for the jet probe and air lift work during periods of 12 maximum flow. The steep magnetic gradients within the area, caused by local geological formations and conditions, rendered all magnetometer survey measurements less than optimal and subject to a masking effect, making interpretation of data more difficult and less indicative. Sedimentation rates in Crown Bay itself have been increasing as a consequence of adjacent shoreline and water- shed development. Present seabed depths (except where modified by dredging) are shallower, and overlying silt and sand sediment layers are thicker than in decades past. West Gregerie Channel, however, is characterized by deeper water, courser sandy sediments, and little evidence of cumulative sediment depositatio~ probably due to the scouring effect of the periodically fast flowing bottom currents moving southwestward towards the channel's seaward entrance west of Water Island. Visibility at the bottom rarely exceeded two meters during the project at all anomaly sites except those near the Sandy Point navigational beacon. Within the study area, living corals are present in quantity only near the Sandy Point beacon, along the northerly shore- line of Water Island, facing West and East Gregerie Channels, and, to a lesser degree, along the foot of Haypiece Hill, adjacent to anomaly 127. 2.5 Archaeological Antecedants Prior to 1981, only one underwater archaeological project had been conducted in the immediate Crown Bay area. 13 Albright (1975) reports the results of a shipwreck survey. He encountered difficult magnetometer survey conditions due to the geological conditions and the type of magneto- meter available at the time. Some years later, as a segment of its environmental impact assessment strategy regarding its proposed Crown Bay Development Project, the Virgin Islands Port Authority contracted with Tetra Tech in 1981 for a preliminary survey of Crown Bay to identify possible cultural resources in the area which might be affected by the project and as- sociated engineering and construction work. The Tetra Tech study was to include map studies, his- toric research, interviews with local divers and historians, marine geophysical remote sensing (i.e., magnetometer and side scan sonar surveys), and a limited amount of verifi- cation diving. It was assumed that historic shipwrecks or other kinds of underwater cultural resources, if identified, would need to be assessed for their significance during a later site test excavation phase. The on-site field research was carried out in Febru- ary of 1981, using a Geometrics Model G-806M Marine Proton Precission Magnetometer, in company with a Soltec Model VP-6723S dual channel strip chart recorder, and operating with a 200 foot streamer tow in sequential cross channel arcs with 50 meter spacing. A back-up side scan sonar survey, using a Klein Model 401 (100kHz), was also carried out with transects running normal to the channel axis (NE-SW), 14 covering approximately 150 meters per pass. The Tetra Tech report, dated April 1981 by Erik J. Olsen (with Mr. J. Barto Arnold of Texas as an archaeolog- ical consultant), identified, on the basis of the systematic magnetometer and side scan sonar survey, some ten priority sites out of twenty-nine magnetic anomalies (see Figure lC and Table 1). Bounce dives by Arnold and others to inspect these and other less promising "sites" resulted in little or no additional evidence as to the reason for the magnetic anomaly or the likelihood that the anomaly represented ship- wreck sites, let alone those with historical value, poten- tial, or significance. The magnetic anomalies could simply represent modern metalic relics (i.e., discarded junk), reflecting the U.S.Navy's heavy and extensive use of the area as a submarine base during World War II, or any number of other kinds of modern, non-historic,metal objects dis- carded in the Crown Bay harbor bed over time and now covered by even more recent marine and terrestrial sediments. Obviously, it would be prohibitively costly to inves- tigate every isolated ferrous object on the Crown Bay seabed; and, therefore, a practical compromise, leading to those sites with the highest probability of historical signifi- cance and based on the best available professional judgement and technology, was required. But since the real evidence lay buried beneath the surficial harbor bed sands and sediments deposited in years past, a second stage investigation was needed to relocate - - . &ItAIJIBOKOLA HILL ffi '1 I I I / \ \ \ I --'--I--o--~- SUB BASE 1 \ \. I \ \ i" I KRcM BAl" I r ~ 'o1J09m CAR£EN HILL BAY -.-.~ \ -~ ~ -.122 '·ZOO". ,~ ... , ' , , " I '-, ~, -L- V ·~·-"··'>.",-~·--7 :.;;.£~- SAILBOAT MOORING ',41'£04 ISLAND I ~ o BEGIN TltANIEeT • END TRANSECT * MAGNETIC ANOMALY EAST GR[G£RIC CHANNEL ..... LOCATIONS OF MA"Oft VESSELS -r- AFFECTING FIELD ,UftV[YS -FIGURe l-C LOCATION MAP ;l981_MAGNETOMETER SURVEY ANOMALIES , . ! Adapt.ed From: "Magnetometer Survey of Crown Bay .•• " . (Tetra Tech, April 1981) I"-'W .'"'" .... - ISLAND RESOUBCES FOUNDATION, 1984 I . I--' Ul 16 TABLE 1. CROWN BAY r~AGNETOMETER SURVEY, U. S. VIRGIN ISLANDS RANKING OF MAGNETIC ANOMALIES AS TO POTENTIAL SIGNIFICANCE 1 HIGH PRIORITY Cluster - E122, E123, E124 Cluster - E14, E121 E125 Cluster - E8, E9 E126 E127 LOW PRIORITY E120 E17 E15 Ell E12 El0 E4 DISREGARD E13 - modern bulkhead E16 - probably geological E7 - probably geological E6 - probably geological E5 - probably geological E3 - probably geological E2 - modern navigation buoy E1 - probably geological E18 - probably geological Cluster - E128 and E19 - significant cluster but lies outside dredging area E129 - probable cause identified as modern iron objects 1 A subjective analysis on the part of the project archeologist Extracted From: ;, Magnetometer Survey of Crown Bay " (Tetra Tech, April 1981). 17 and evaluate each of the ten alleged high priority sites by means of a sub-bottom probe test excavation activity. The procedures used in carrying out this task are reveiwed in the following sections. 18 3.0 RESEARCH DESIGN 3.1 Relocation and Georeferencing The scope of work to be done in the anomaly testing phase was defined by the Virgin Islands Port Authority. The anomalies listed in the high priority section of the 1981 Tetra Tech report were selected for further investi- gation. We are referring to the magnetic anomalies here, as the side scan sonar anomalies from 1981 were not promis- ing in this regard. The approach to the problem, that is a magnetometer re-survey and a follow-up anomaly investigation~utilizes a standard method. The magnetometer is an electronic in- strument which measures the strength of the earth's mag- netic field. Ferrous (iron) artifacts present on a historic shipwreck site, such as anchors, cannons, chains, spikes, and nails, and other forged or cast- iron hardware, cause a change of the gradients in the earth's field. The distur- bance is known as an anomaly and is recorded by the magne- tometer. Of course, similar anomalies are caused by modern ferrous debris. The magnetometer survey has, in recent years, proved to be a very useful tool in both underwater and land archaeology. References include Breiner 1965; Arnold 1975, 1976, 1977, 1981, and 1982; Arnold and Clausen 1975; Arnold and Weddle 1978; and Murphy 1980 and 1983. The techniques selected for the present project included preliminary or rough relocation using shore-based surveyor's transits sited at known locations and with known baseline 19 distances between them. Angular arcs from known baselines and intersecting lines of bearing were established in pairs for each position at which a given anomaly had been located on a survey track during the initial 1981 survey. Employing a radio-telephone link between the magnetometer tow boat and the two shore survey stations, a position buoy would be placed at the point of intersection. Then, towing the magentometer sensor a measured distance behind a survey ves- sel, both north-south and east-west, crossing transects would be run on the mark and buoys dropped to bracket the anomaly area. The center of the anomaly or area of highest readings which is located closest to the anomaly cause would then be defined by as many passes with the magnetometer sensor or "fish" as needed. The next step would be to send down a diver for an initial inspection tb see if there were any readily visible or obvious seabed surface indications for the anomaly cause, i. e., debris. If not, the survey vessel would then be anchored slightly downwind of the anomaly marker buoy and the magnetometer sensor supported . . by a float then moved slowly in arcs over the anomaly by a dinghy or surface swimmer to precisely pinpoint the center of the anomaly, which would be buoyed. All five previously installed, temporary buoys would be removed at this time, and the seabed beneath the new anomaly epicenter buoy-marked with a five foot piece of one-half inch steel or aluminum rod flagged with several feet of flat, brightly colored vinyl surveyor~ tape to make the marker rod more visible and 20 easier to relocate. This was a necessary back-up site marker in case the buoy on the surface (a) drifted; (b) was stolen; or (c) was cut off by the propellors of passing boats at night. In the case of a cluster of anomalies, preliminary position bouys were placed on each anomaly and transects run to establish the relationship and to determine whether the initial readings were two recordings of the same large anomaly or separate anomalies or dispersed clusters of numerous smaller anomalies. 3.2 Sub-Bottom Search Methods Once all target anomaly sites are relocated, marked, visually inspected by divers and the magnetometer data analyzed, one then commences a laborious process of jet probing and a test airlift excavation at each site for which there is no visible or demonstrable cause of the anomaly, such as a major piece of ferrous debris, a nearby steel dock or bulkhead, or a dominant geological feature. This phase of the assessment requires a rather large work barge positioned sequentially over each site with a four point moor and carrying two low pressure, high volume air compressors (150 psi @ 11 to 15 cubic feet per minute each), one surge tank, one high pressure water pump (.500 gallons per minute), one fifteen foot long galvanized steel, two inch jet probe pipe, plus all necessary pressure guages, hoses , valves, manifolds , dive gear, (both SCUBA and a Desco, or equivalent, full face mask) .and a s'urface-to-diver, two- 21 way communication system. Each site is then submitted to a series of twenty or more high pressure water jet probing efforts using the 15 foot pipe which is repeatedly jetted into the seabed at two meter intervals along a north, south, east, and west axis from the seabed site marker to determine both point of refusal and texture and location of any subsurface artifact. The diver reports the probe depth at each probe hole via the diver-to-surface intercom, and they are plotted. Once a buried target object is located, a diving team excavates a test hole through the overlying sediments with an air lift to find out what it is -- more modern debris or pos- sibly the remains of an old wooden vessel or shipwreck. Any historic wreck site located in this manner would be briefly investigated by additional test air lift excava- tions to determine its age, condition and significance. Any further work necessary would be carried out in a sub- sequent phase of the investigation requiring different equipment and support systems. Since no shipwrecks were located during the course of examining the various anomaly sites, there is no point in summarizing here the research design for a salvage archae- ology effort prior to dredging that would have been used in the event of a "find" and positive determination of its historical significance. 22 4.0 PROJECTOPERATIONSSUlvIMARY 4.1 Chronology This project was carried out by the Island Resources Foundation (IRF) under a contract with the Virgin Islands Port Authority (VIPA), dated 31 July, 1984. The Notice to Proceed was received 8 August, 1984, and, following a sched- uled sixty-day logistic planning and mobilization phase to assemble and test equipment, the IRF research team moved to the staging site at the new, partially completed, cruise ship dock at the Sub-base on the 5th of October, with two tons of equipment, one leased work barge, the IRF research vessel (Odyssey), four dinghies and outboard engines, six radio communication systems, and one support vehicle. The leased magnetometer arrived from Texas on the 5th_ of Oc- tober, and the consulting marine archaeologist the following day. Field work commenced on Sunday, October 7th and con- tinued for 23 consecutive days. Demobilization, data analysis and report preparation required another 30 days. The port Authori ty vessel ,Lady pleasant (skippered by Chip Gerard) , was made available for the initial phase of the magnetometer work from 7 October to 13 October. 4.2 Staffing The survey team consisted of the following: Project Director: Dr. Edward L. Towl~ - maritime his- torian, marine resource planner, skipper of Odyssey, marine archaeologist, certified diver. Consulting archaeologist; Mr. J, Barto Arnold, M.A. - State 23 Marine Archaeologist (Texas), certified by the Society of Professional Archaeologists in Marine Archaeology and Marine Archaeological Surveying, staff director for the Texas Antiquities Committee, certified diver (on site: 10/6 to 10/14/84). Master Diver: Mr. William Jones - PADI Instructor, commercial diver, Coast Guard Ocean Operator Captain's License, 20 years experience as diver, dive shop operator, welder, mechanic. Support Diver: Mr. Andrew Fredebaugh - commercial diver, certified PADI. Project Engineer: Mr. Werner Wernicke, P.E., M.A. - surveyor, cartographer. Proj ect Technician: Mr. Edw:ard Trupp - IRF Facili t.ies Manager, diver/surface support specialist, mechanic. The administrative and technical support team consisted of the following: Project Secretary: Fiscal Manager: Electronics: Ms. Sandra R. Tate Ms. Judith A. Towle Mr. Stuart Setterfield. Total person days expended was 220. Total diver bottom time was 105 hours. Two persons were stationed on site, one at the staging area and one on the work barge 24 hours a day for the duration of the field work. All SCUBA tank filling, refueling, preventative naintenance and data logging was done in the evening during the field operations. 24 4.3 Mobilization and Equipment All mechanical and electronic systems to be employed on the project were not only assembled but tested during this phase. This included three communication systems (to link diver to surface and the work barge and two vessels to base and the two surveyors moving from station to station), plus two low pressure and one high pressure air systems, the'high pressure water pump jet probe system, the air lift system, navigation and georeferencing systems, and the vessel support system (two survey boats, one barge and four dinghies). A hurricane contingency plan was developed, as was an injured diver evacuation plan. Fortunately, neither was needed. A critical compressor and engine spare-parts inventory was developed, and se~eri separate pDrtahle dock lockers built to keep equipment both organized, orderly and secure. Critical items like the sextant, hand-bearing compass, head- phones, dive-tank guage, wire cutters, and other key tools were acquired in pairs in order to have a redundant spare on site and to avoid delays in the event of a breakdown or loss of an item. :Marker buoys were made up during the mobilization phase of the project. Five site visits were conducted by project staff to plan the deployment of vessels and equipment under varying conditions of weather and for the various sequential or routine tasks -- magnetometer seirch, anomaly site marking, diver surveys, jet probing air lift excavation, buoy re:: trieval, barge relocation, refueling, etc. 25 All of this advance planning enabled us to carry out 23 straight days of field work without a major breakdown or delay. With five persons and a leased barge, boat and magnetometer on site, each lost day would have cost in excess of $1,000.00 and unnecessarily delayed the project-- a situation which we sought to avoid as the Port Authority's contracted dredge was arriving in early November. 4.4 Anomaly Relocation and Positioning Under the direction of the consulting archaeologist, Mr. J. Barto Arnold, the Geometries Magnetometer was, after calibration and adjustment (7 October, 1984) to local geo- magnetic conditions, deployed in a towed search mode for the entire first week of field work [7-13 October), seeking to relocate, reconfirm and fi~oy each target anomaly. More or less simultaneously, the shore-based "posi- tioning" crew, under the direction of Mr. Werner Wernicke, was re-establishing six "base" stations (not one of the base station marks used during the Tetra Tech survey survived the passage of time). Once the base reference stations were shot in and baselines established (see Table 2), angles were calculated and swung for each anomaly site, and the ves- sel towing the magnetometer directed by radio along a re- verse line of bearing to an intersett point with the second surveyor's line of site when a marker buoy was dropped on signal via VHF or CB radio from the second shore-based transit operator. Sequential towed magnetometer transects at right angles, generally east-west and north-south, over 26 the newly marked site were then. run and the anomaly brack- eted witJl.: four more marker buoys. The center of the anom- aly was then established by making sufficient additional passes through the bracket~d area withth~ magnetometer sensor to pinpoint and mark the corrected epicenter of the anomaly. A temporary bottom Cseahed) marker made from steel re-bar flagged with surveYor's tape was driven into the sedi- ment with a sledge hammer directly beneath the new epicenter buoy. At this point in time, the bracket buoys were removed, a cursory bottom inspection sweep made by SCUBA divers, noting visible ferrous debris (large ite~s were buoyed) , and the entire team would then shift its attention and strategy to the next 1981 anomaly location and repeat the entire operation. All ten high priority anomaly sites (plus three others requested by the Port Authority) were relocated and inspec- ted in this manner during the first seven days of field work. Two sites, however, E14 and E12, which were determined to begealogical, and siteE13~_ which was caused by an adja- cent bulkhead with sheet stzel piling, were not marked the same way., as epicenters could not be established. The locational results of this first relocation phase of the work are summarized in Table 2 and Table 3 and displayed in Figures 2 and 3. Water depthi involved and prior major modifications to the study area by dredge and fill activities are 27 TABLE 2. Shore Survey Station Georeference Locationa1 Coordinates (see Figures 2 and 3 for sites). STATION N E A 185,117 1,014,350 B 184,916 1,015,958 C 183,571 1,013,415 C-1 183,571 1,012,906 C-2 183,757 1,013,415 D 183,153 1,012,418 ********** TABLE 3. Crown Bay Magnetic Anomaly Georeference Locationa1 Coordinates (see Figure 2 and 1981 Tetra Tech Report). ANOMALY NUMBER N E E122 184,518 1,014,362 E123 184,382 1,014,209 E124 184,545 1,014,040 E14 184,018 1,014,464 E121 183,948 1,014,695 E125 183,255 1,014,282 E8 183,300 1,013,364 E9 183,185 1,013,610 E126 182,600 1,013,439 E127 182,948 1,013,000 E17 184,785 1,014,520 E10 184,760 1,014,189 E13 184,970 1,014,363 N.B. Anomaly Numbers E8, E9, 124, 125 and 127 were plotted incorrectly in the Figures used in the 1981 Tetra Tech Report to the Virgin Islands Port Authority. Figures 2 and 3 of this Report shows them at their corrected location. The coordinates in both instances are the same. '~'''''''''' ,- F ILL II -- ... --... __ --'" '" ;. ." ---- ., -- ........ 28 '" ~' ~ o ~ ;. CAR E EN H' L L lit··· ./"... "-. I • o o (u n der,construct ion) / • ". 1ll.Q.QQ. / * .. v) SUB BAS E FILL ·/' /" j'" ~ ~ i" " . C-2 " I I J ~ " V /"'.:" ~.,uo-,-",--,-,,,_c o ~~ (} ,. :; '\ ) \ \. ". ""- ~ ~ \ '\ ~\CJ \ HAYPIECE ) " j \ HILL J: ------- '00 '% J / I ~~ j) ..J .. r··../'· * 127 * 126 ~ -',--.-""--._/. 9 ~ SCA L E IN FEET 2~**b 200' '460 / ~B 17 \ 124 1.f,2 ~ ¥ 123 ¥ ~5 KEY * " . J1 121 ~ I:):fN'6 .. _ ... _ ... --..... .. EAST G REGERIE CHANNEL /"'-'" ~.,---,.----... /- ", . . 1~ ~ Magnet Ic Anomal ies{1g81 and 1984) o S h 0 re Sur ve y S tat i <>(' S /. WAn. ( J' OS,"., , \ BN,·6 Navigation Beacon No.6 . " f, F;gme.2. I\._ ... ~ r ISLAND RESOURCES FOUNDATION ~ ; .r"I\...-... -.J~";; 1-- .. /' ::-;.=-=~~~rIC j' -~I i 182.990 Crown Bay Marine Archaeological Survey, st. Thomas. U.S. Virgin Islands M.i\GNETIC ANOMALY MAP Drawn by: W. W. .~: . Date: Nov_. 1984", ~j SUB BASE NEW Fill / o a /' .. /" /' /----.... "'" /,., ~ ~. ""-..J ( "" 0\ g ~ , ; ~~ 8,\, _\ ~\a '\ H 'kY PIE C E H') '" J ~ \~a Jill /) I , 0 • 00 • ~. i .. (,·J ~. /' ~ ... ",--._/ ~ .. J .. ~ .. ../. Fill (u n d eLconstruct ion) ( 24 *' * 9 ~ 127 * 126 ~ SCALE HI: FEET 29 '111 1\ ~ ~. ~ o CAREEN Hill 'I: ... --... ---.... - tA ~ .•• ---- ••• . "" .... ~ -- 1 ' .. # ---... "'-. '. " . ...... "") l.a5...Q.Q.O. j /; ~' 123 ¥ ~2 ~B '" _ ... _ ... --....... .. 21 .* EAST yBIl'6 G REGERIE CHANNEL VI KEY . ~ Magnet ic ,Anomalles(1981 and 1984) o S h 0 re Sur Ii e y S tat i O\f' s BN:6 Na·vigalion Beacon No.6 r ... -......, /.~/ •• \ 183.000 :r'"'''''~''' { ... f W ATE R I S l AND \ !/ \ f' Figure-:3. ..~ - I ISLAND RESOURCES FOUNDATION- n • Crown Bay Marine Archaeological Survey, St. Thomas, U.S. Virgin Islands 182.00Q EXAMPLE OF ANOMALY POSITIONING Drawn by: W.W. Date: Nov. 1984 30 portrayed in Figure 4. 4.5 Anomaly Site Assessment For this phase of the project, the magnetometer was shifted from the highly maneuverable towing vessel CLady Pleasant) to a more stable, self-propelled work barge, approximately 12 feet by 30 feet,with an enclosed deck house and flat working-deck area capable of serving as a tethered diver support platform while also carrying a rather heavy load of air compressors, water pumps, hoses, dive tanks, air lifts, marker buoys, mooring anchors and anchor rodes, chain, radios, fuel containers, and the magnetometer plus 200 feet of armored cahle attached to the sensing head. The work barge was positioned directly over a given anomaly site and secured in place by four,45 pound anchors, each with a 16 foot heavy chain (3/8 inch) leader and 200 feet of anchor rode in order to keep the steel anchors and chain as far from the barge and study area (a 44 meter diameter circle) as possible so as to not influence the magnetometer sensor. Each anchDr was provided with buoyed retrieval line to facilitate barge repositioning to the next anomaly site. Once the work barge was in position on a site, the next step involved deployment of the magnetometer sensing head suspended 10 to 15 feet above the bottom on a line to a large surface float and wi th a tether line (15 feet), which enabled a diver using an aTuIninum SCUBA tank to tow the sensing head in sequential sweeps or arcs over the bottom at varying distances from the barge. The radius of the 7 .', 9 ib" .. II 42 49 45 45 s 47 ,,~ 2·S; 47 36 .' 23 ; ... 52 (. - 2~ .. ·· ······~o S 46 .•.... .' 63 47 ;52 " 60 621' 57 ... e:. s 57 61 -..N 59 38 54 V 37 59 ~ ~ \ , ...... : ... :.::3.~.::, "45 33 32 38 .. ~ ... ~56 43 58 36 38 "Y 38 43 I.l' ...... 41 38 \29 ..... 47 44 C\ 33·.\ "l) 40 ' ~ 46 " 31 25; S Co ~42 52 46 :n Co 51 J' ., .. 52 47 S 41 40 4 . BASE MAP-USCSGS #933 (1928) Adapted From: "Mag-netometer Survey of Crown Bay ..• " (Tetra Tech, April 1981). FIGURE 4 HISTORICAL DREDGE AND FILL ACTIVITIES WITHIN STUDY AREA ...• 31 s U I- 32 arc was determined by adjusting the length of the sensing head cable. This process enabled the team to select the best spot to use as the focal point for the jet probing and test air lift excavation to follow. Two difficulties with the tactic should be noted. First, it had to be done in four separate stages (i.e., for each 90 degrees of arc) because with a four-point barge mooring system, the magnetometer cable would foul on the anchor lines if a full circle sweep was attempted. Second, with the sensing head closer to the seabed, it was more sensitive to smaller ferrous bottom surface debris, and in sites with an irregular bottom contour, there was a risk of damaging the head if it were to touch bottom. During this operation, the towing diver could not ~ee the head as his 15 foot tether line put him beyond the range of visibility because of turbidity levels in the area. This 15 foot distance was necessary, however, because of the steel in the diver's air tank valve and regulator. (This could be overcome by building a tank valve and regu- lator system entirely out of bronze and non-magnetic stain- less steel similar to the old U.S. Navy two hose regulators.) The next stage followed the high pressure water jet probe procedure described in Section 3.2 of this report. A diver, wearing 30 pounds of lead weights and a Desco Full Face Mask with free flow air supply from the low pressure C150psi) air compressor (11 CFM) on the barge, drilled (j etted) a sequence of holes in the seabed with a 33 heavy-walled, one-and-one-half inch, 15 foot piece of gal- vanized steel pipe that was linked by hose to a high pressure, high volume, 7 horsepower, 3" Peabody and Barnes water pump (500 gallons/minute) stationed on the work barge. Starting at the "center point" and using a wrist compass for direction, the diver would jet the pipe into the seabed six times with two meter spacing between holes, following a line of bearing first to the east and then repeating the process to the north, south and west of the center point. The jet probe was driven to point of refusal and the probe depth and hole bottom texture reported to the surface via the intercom for each probe hole. When necessary, after an immediate surface team analysis of the "pattern," the diver would be instructed from the surface to diiv...e additional probe holes. The average number of probe points per site was 25 and the average depth approximately eight feet [minimum was two feet and maximum was 16 feet). The third stage of anomaly site assessment involved Ca) selecting a test location, and (b) deploying a stan- dard three inch air lift with a 15 CFM air supply, and ec) deploying a SCUBA equipped diver and observer, and Cd) ex- cavating a test pit seeking any indication of a shipwreck, isolated artifacts or the nature of the sub-bottom "point of refusal" (i.e., bedrock, coral encrusted rock, coral or consolidated calcareous sediments). Upon completion of these three activities, all sur- viving buoys were retrieved, bottom markers removed, and 34 the work barge repositioned on the next site. During this site assessment activity, we had a work barge mooring line severed twice by passing vessels, lost 36 buoys to either currents, theft, or vessel traffic, and had numerous verbal complaints from passing vessels about "blocking" the channel, despite the fact we were displaying the day marker for electronic survey work. Also, on numerous occasions passing small craft ignored our large, prominently displayed, "diver in the water" flag. 35 S.D'RESULTS ANDCONCLUSTONS 5.1 Summary Magnetometer readings, sub-bottom jet probe data, diver observations and test air lift excavation findings for each anomaly site are summarized in Table 4 and reported on in detail in the following segment of this report. In sum, there was no indication of any historical or modern shipwreck remains, whether intact or dispersed, at any of the 13 sites investigated by the anomaly site as- sessment strategies employed. These findings do not, however, imply, nor should the reader infer, that there are no culturally and historically significant shipwrecks in the larger Crown Bay area. Some may lie outside the study area as defined by the previously established list of priority anomalies identified by the Tetra Tech sweep survey strategy. A truly old wreck -- say from the eighteenth century -- might well by now be irrev- ocably entombed in the hard consolidated coral substrate beneath the sediment layer and, therefore, essentially be unsalvageable. We found no evidence of such a possibility, however. The most logical explanation for the absence of ship- wreck sites lies in the nature of Crown Bay and its relative shallowness, its short reaches, its semi-closed, elongated and therefore protected configuration, and its proximity to populated areas. Virtually any ship wrecked by storm action but not totally destroyed by the grounding process TABLE 4. .Magnetic Anomaly Survey Data Summary Anomaly Number Cluster - E122 E123 E124 Cluster - E14 E121 E12S Cluster - E8 E9 E126 E127 E17 EIO El3 Anomaly strength 1981 Survey -S20y -128y - 69y -30y, +20y -17y +lOOy, -90y +40y +160y +90y -210 -26 +SO -S20y Maximum strength on Initial Relocation 1984 -60y -65y -80y +75y +14y, -lly +lOOy -45y -16Sy -3Sy, -SOy +12y +SOOy Maximum Strength on Pinpointing center prior to Probing and Test Excavation -90y -7Sy -80y +80y -lSy, +lOy +120y -6Oy -sOy -30y Average water Depth (fee~ 28 25 21 32 30 29 42 38 40 12 12 COMMENTS E122, E123 and E124 were caused by buried abandoned broken cables, see Figure S. Disturbed area of over 100 geological gradients. Prob- ably not caused by man-made objects. See Figure S. Steel pipe, modern vessel wreckage, plus apparent buried rock ledge with sharp geological gradient. possible distant readings on pipe and H-beam just to north. E9 was caused by a tangle of discarded steel reinforcing rod partially buried in the seabed. Modern ferrous debris includ- ing a large pipe and a large triangular piece of steel plate were found. Two crossing submarine cables were found. Closely spaced associated anomalies- mooring debris. Modern ferrous debris--big coil of wire rope and heavy steel wire box. Part of very large anomaly from modern bulkhead. Island Resources Foundation l\'T,..V'f7.o.TY'I 'h.o.,..... 1 Q RLl tN 0\ 37 was accessible for either scavenging or salvage. In cen- turies past, ships driven ashore and considered unsalvag- able were, after stripping, customarily burned in order to salvage the iron or bronze fittings and fastenings, which could be recycled. Vessels that sank or foundered at an- chor or when moored "in the stream" in areas like Crown Bay and East or West Gregerie Channels were sometimes raised, if only for their salvage value. If they could not be raised, grappling hooks and/or black powder (and later dynamite) were often used to break or blow them apart to make sal- vaging cannon, stores and cargo easier or to eliminate them as hazards to other vessels transiting or using the area as an anchorage. This Project has established that for the 13 magnetic anomaly target sites and their individual environs to a radius of 12 meters Capproximately 80 feet), no identifiable evidence of an historic shipwreck exists on or in the un- consolidated seabed sediments, nor is there any assemblage of singular isolated historical artifacts suggesting the possible presence of such a shipwreck in the immediate area. It is concluded, therefore, that based on these find- ingsthedredging activity at Crown Bay, as proposed by the Virgin Islands Port Authority, offers no threat or risk to any marine archaeological site that might have cultural or historical significance. Crown Bay has a history of maritime usage, but it is 38 most unlikely that we will ever be able to learn much about those sailors and ships of yesteryear from historical evi- dence derived from a well preserved shipwreck site in the Bay. What we do know now, however, as a result of this project is that no potentially valuable historic wreck site is likely to be destroyed in the process of dredging the area. 5.2 Detailed Anomaly Survey Data Clus tar EIZ2,EI23,andET2 4 These anomalies were recorded in the 1981 survey as -520y, -128y, and -69y,respectively, in strength and looked like the best possibility for a historic wreck site. Upon relocation and inspection, all three anomalies appear to have been caused by convoluted lengths of heavy steel- armored underwater (telegraph?) cable mostly buried in the bottom sediments. Maguire (1925) reports this area of Crown Bay as a telegraph cable landing site. The difference in the initial survey strength of the anomaly at -520y, and the -60y strength recorded in the relocation survey is accounted for by the fact that it is generally difficult if not impossible to completely replicate the position and direction of the original vessel and sensor. The magneto- meter signatures achieved during the relocation process were quite sufficient to define the anomaly area and guide the divers to the correct locale £or the jet probing and test air lift excavation at each site. Prohe depths at all three sites ave~aged just under four feet to hard 39 consolidated coral. . Twenty-five probe holes were jetted at each site on a north/south and east/west axis with two meter spacing between probe locations. These and test air lift excavations produced no evidence of any buried ship- wrec~ and no artifacts were recovered. ClusterE14andET2l E14 was originally recorded as a dipolar anomaly of -30y, and +20y, and E12l was -17y. After numerous tran- sects, it was determined that these anomalies were distant readings on a disturbed area of geological anomalies (E12, E13, and EI6). This is the area (Gregerie Bank) from which a pinnacle of rock had been removed by blasting and dredg- ing as a hazard to navigation in the 1940~. (See Figure 5.) Jet probing attempts were tinsuccessful at both sites as the sediment overburden was less than three feet in depth at the locations tested. Moderate levels of miscellaneous ferrous surface debris were also observed,but no large ob- jects were noted. E125 This was a dipolar anomaly of +lOOy and -908y which proved both elusive and difficult to relocate due to the presence of numerous moored o;r anchored sailboats in the area and the hidden presence of an apparently massive sedi- ment covered rock ledge or ridge of hard coral, which bi- sected the site and which may account for part of the anom- aly signature. To the west and south of the anomaly center, our jet probe regularly penetrated the sandy overburden 40 from 10 to 15 fee~ but to the north and east the point of refusal rarely exceeded two feet of penetration before hard bottom was reached. Modern vessel debris and a semi-buried length of steel pipe were observed on the seabed and may also account for or contribute to the anomaly signature recorded. Twenty-five jet probe holes were driven on a standard x-y axis with two meter spacing, and one test air lift excavation was undertaken with no positive indications of the presence of a shipwreck buried in the deeper sediments. Clus ter E8andE9 In the original survey, E8 was a -40y anomaly and E9 a +160y anomaly. At the positions indicated, we found associated broad, weak -13y, +14y, and -lly anomalies. Found nearby to the north of E8 was a very large piece of heavy-walled steel pipe ahout 12 inches in diameter and 20 feet in length which produced a large -200y anomaly on one run and a large dipolar -lOOy and +145y anomaly on another. Near E9 and again to th_e north was found a large steel H- beam about 2 feet x 1-1/2 feet x 20 feet in length which produced a +380y anomaly. E8 and E9 could be distant read- ings on the large steel pipe and H-beam (see Figure 5), or the causes of those anomalies might have been shifted or removed since 1981. E8 is located near the new dock,and it is noted that there has heen dredging in front of the dock to get fill during the dock's construction. ".,. At E8, twenty-one jet probe holes were driven in the 41 bottom (2 meter spacing on an x-y axi~with an average penetration of only 4 feet to the point of refusal (con- solidated coral confirmed by an air lift test excavation). Obviously, the remaining (post dredging) sediment layer appears to be too thin to hide a buried shipwreck at this location. Probing at E9, which is only 200 feet to the south- east of E8, resulted, after 21 holes and our test air lift excavation, in the finding of a tangled mass of discarded, bent 1/2" reinforcing rod and assorted wire rope which produced the anomaly. Penetration of the probe at this site averaged ten feet in the well sorted,course, sandy sediments. The southwesterly flowing currents at E9 general- ly exceeded three knots. No ev,idence of a shipwreck was found at either anomaly sites E8 or E9. E126 This anomaly measured +90y on the original survey and -45y was recorded on resurvey. In the area there was scattered ferrous debris,including a triangle of heavy steel pIa te, 3 feet on a side, and two large joined steel pipes of 8" in diameter and 2 -feet and 5 feet in length. Jet probing 21 holes to an average sediment penetra- tion depth of 9 feet produced no evidence of a buried ship- wreck or other explanationfortlie anomaly at the site (save for the ferrous debris on the seahed surface). E126 may also be caused in part by' the kriown presence of a burried, long abandoned, old armored subrnarinetelephone cable to 42 Water Island which we were not able to find due to the small size of the cable and the proximity of four large steel water barges moored adjacent to the site which seri- ously affected the magnetometer sensor, masking smaller anomalies in the area. E127 E127 was originally' recorded as a -200y anomaly. On resurvey, a very confused magnetic situation of mUltiple anomalies in a broad area was recorded including a maximum -165y reading. The cause of this anomaly was found to be two (crossing), heavy 2" diameter steel armored power or telephone cables. Power cahlesare not generally laid straight, but instead snake across th~ bottom so there is sufficient slack to pick them up to the surface ftir repair if needed. Secondly,these abandoned cables have been cut and the ends dragged about by being snagged by boat anchors or dredges or whatever, resulting in a very complex and convoluted anomaly. Therefore, anomaly site El27 Cand associated anom- alies E7, E4J and other new ones to the west of E127 are not a shipwreck, but are quite definitely abandoned under- water power or telephone cable. In t he area of E127, fourteen ()4) jet probe test hoTes were run and hedrock or hard coral was encountered less than two to six feet from the harbor b~d surface. Seventy-five feet west-southwest of E127, there is a crossing of two cables on the seabed. One end of one of these extends nearly' 200 feet in a 43 northerly direction (355 0 Magnetic) and another more than 300 feet in a southwesterly direction (approximately 230 0 Magnetic). Other cable pieces are present in the area (where the sediment base is too shallow to contain a major wreck) and clearly account for the numerous small magnetic anomalies in the general area. E17 Recorded as a -26y anomaly on the original survey, this proved to be a small area of assuciated anomalies -- -35y, and -SOy being the largest readings. Diver investigation, 20 probe holes and one test excavation produced no evidence of a shipwreck and simul- taneously documented extensive scattered modern ferrous debris in the slick clay and mud bottom sediments which are found in this area. Th~ major anomaly was caused by a cluster of old chain and engine parts -- perhaps an aban- doned mooring buried in the mud. El0 This was originally recorded as of,50y in strength and on resurvey of,12y. Two items of modern ferrous debris were found on the surface, a twisted coil of 1" diameter wire rope, and a 2-1/2 ft. x 3 ft. x 4 ft. strong-box-like structure made of heavy steel wire mesh (definitely hot a fish pot) . E13 E13 was recorded as a -520y reading on the nearby modern steel and concrete bUlkhead. Reinvestigation conclusively confirmed this finding. 45 FIGURE5C E124 Armored steel cables southwest of E124. FIGURE 5D i il. E8 and E9 Signatures showing the massive signature of heavy steel sheet piling bulkhead in the new-Port Authority dock (southeast corner), now covered ~ith steel rein- forced concrete cap. ***** ,- ., 44 FIGURE SA E17 Illustrates an anomaly (-30y, +2Sy) against a larger background signature. FIGURESB E122 and 123 ***** Note disturbed area between these anomaly signatures - resulting from an extended area of abandoned, tangled broken, submarine cable largely buried in the soft sediment. FIGURE SE E8 and E9 Area FIGURE SF 46 Anomaly signature of a large steel pipe on the seabed near E8 and E9. ***** ***** 47 6.0 REFERENCES Albright, Alan B. Proton Magnetometer Survey of Marine Archaeological Sites in the Virgin Islands. Caribbean Research Institute, College of the Virgin Islands, St. Thomas, U.S. Virgin Islands. 1975 Arnold, J. Barto III. A marine archaeological application of automated data acquisition and processing. Newsletter of Computer Archaeology, 11(1}:5-11. 1975 Anunderwa ter archaeological magneto- meter sur~ieY'andsitetestexcavationproject off Padre Island, Texas. Texas Antiquities Committee Publication 3. Austin, Texas. 1976 1977 underwater site test excavations off Padre Island> Texas. Texas Antlqul tles Comml.ttee Publication 5. Austln, Texas. 1976. A marine archaeological magnetometer survey in the Galveston, Texas area. In Underwater archaeology; the challenge before us: the proceedlngs of the Twelfth Conference on Underwater Archaeology, Gordon P. Watts, Jr., ~d. pp. 209-217. Fathom Elght, San Marino, California. 1981. A Matagorda Bay Magnetometer Survey and Site Test Excavation ProJect. Texas Antlqultles Commlttee Publlcat10n 9. Austln, Texas. 1982. and Carl J. Clausen. A magnetometer sur- vey with electronic positioning control and ca1culator- plotter system. International Journal of Nautical Archaeology, Vol.4:Z6-40. 1~75. and Robert S. Weddle. The nautical arch- eology of Padre Island: the Spanish sh:rpwYecks of 1554. Academlc Press, New York. 1918 Breiner, Sheldon. Applications manual for portable magneto- meters. Geometrics. Palo Alto, California. 1973. McGuire, J.W. Geographic Dictionary of the Virgin Islands of the United States. U.S. Department of Commerce, U.S. Coast and Geodetic Survey, Special Publication No. 103. 1925. 48 References (Continued) Murphy, Larry. Survey Methodology: specific site survey, Biscayne National Honument,1980. U.S. Department of the Interior, National Park Service, Southwest Cultural Resources Center, Submerged Cultural Resources Unit, Santa Fe, New Mexico. 1980. -----r~~----., Ed. Submerged Cultural Resources Inventory, Shipwreck Survey, Poitit Reyes National Seashore and Point Reyes-Farallon Islands National Marine Sanctuary. Phase I-- Reconnaissance, Sections I and II, 1982. U.S. Department of the Interior, Submerged Cultural Resources Unit, Santa Fe, New Mexico. 1983. Olsen, Erik J. Magnetometer Survey of Crown Bay, St. Thomas, U.S. Virgin Islands. Prepared for the Virgin Islands Port Authority (TC-3462). Tetra-Tech, Inc., Jacksonville, Florida. 1981. Towle, E.L., Marx, R., and Albright, A. Shipwrecks of the Virgin Islands: An Inventory (1523-1825). Second edition. Island Resources Foundation, St. Thomas, U.S.V.I. 1976. U.S. Naval Oceanographic Office. Sailing Directions for the West Indies (Chapter II Virgin islands, H.O. 22). Washington, D.C. 1968. Virgin Islands Port Authority. Environmental Assessment Re- port, Crown Bay Port Expansion and G~egerie Channel Improvement. St. Thomas, U.S.V.I. 1983 CROWN BAY ANOMOLY TESTING Magnetometer Survey Parameters Geometrics 806A Proton Precision Mag. 250' tow system. Mag. Serial No. 9066 APPENDIX I Soltec Dual channel strip chart recorder (VP-6723S) Cycle time l/sec.; Sensitivity ly Tuning - Coarse 37-45; Fine 3 Scale (strip chart) 0-99y (red pen) 0-999Y (black pen) Chart speed 4cm/min Vessel speed 4~ - 5 knots (one engine dead slow) Estimated 8-9' depth for sensor Distance behind vessel of sensor - 76~·.ft. Background field strength 40400-40500y + Typical noise level - 1-2y Survey vessel: LADY PLEASANT, 31' fiberglass, twin diesel JBA/srt 10/11/84 50 APPENDIX II CROWN BAY MARINE ARCHAEOLOGICAL SURVEY NEW ANOMALIES - OCTOBER 1984 Anomaly (New) Pipe near E8 H-beam near E9 Annored cable SW of E124 Anomaly strength 1981 Survey Maximum Strength on Initial Location 1984 -200y; -lOOy,+145y +380y +70y COMMENTS Large pipe -~ ~bout 20 feet long and 12 inches :in di- ameter. Large H-beain about 2 feet.J{ 1-1/2 feet x 25 feet. Cable -- broken, looped and coiled