Search & Recovery

The following is a list of various search and recovery projects that Williamson & Associates participated in over the years.


AHS Centaur, Brisbane, Australia

Search off the coast of Brisbane on the MV Seahorse Spirit for the Australian Hospital Ship Centaur, which was sunk by a Japanese submarine in 1943. Williamson provided the SM30 and AMS60 deep tow sonars and a crew of nine. In just five days, the Williamson team covered an area of 1080km2 in very steep terrain right on the continental shelf, in waters ranging from 250m to 3400m depth and with currents up to 4.5kts flowing through the survey area. Within that time six promising targets had been assessed and high resolution runs with the AMS 60 were run, determining one of the targets to be Centaur. December 12-20, 2009. The following month an ROV team confirmed the find to be AHS Centaur.

Picture A - AHS Centaur, Brisbane, Australia Picture B - AHS Centaur, Brisbane, Australia


a) Mosaic of the sidescan imagery draped over the bottom relief. The arrow points to the sonar target, showing where the Centaur lies on the sea floor.

b) Photo of Centaur’s hull, clearly displaying the hospital cross.


Deep Six shipwreck search, Atlantic Ocean

Williamson was hired by a commercial client to search for an historic shipwreck in the Atlantic in deep water. Nine Williamson personnel as well as the SM30 and AMS60 deep tow sonars were mobilized on the vessel Jean Charcot. 6930km2 were covered in 46 days with the SM30. A substantial list of targets was processed and analyzed. July 21- September 19, 2009.


ECO-OLAS shipwreck search, Panama

Search for historic shipwreck near Panama for a commercial client. Williamson provided a crew of eight personnel, the AMS60 deep tow sonar, a Benthos SIS-1624 Dual Frequency Sidescan Sonar, and two marine magnetometers on a local vessel and two small boats for shallow water operations. A list of targets was collected, processed, and assessed. April 29 – May 18, 2009.


HMAS Sydney/HSK Kormoran search, Indian Ocean

Williamson was contracted by the Finding Sydney Foundation to locate the heavy cruiser HMAS Sydney and the German raider HSK Kormoran. The pride of the Australian Navy, HMAS Sydney was attacked by the disguised raider and both ships were mortally wounded. The Kormoran was scuttled by her crew, and the Sydney later sunk from the damage in battle, with no survivors. Williamson provided seven personnel and mobilized the SM30 and AMS60 deep tow sonars on DOF Subsea’s Geosounder in Geraldton, Australia. The two wrecks were located and identified in 12 days of survey operations. March 5 – 18, 2008. An ROV team returned the following month and confirmed the identities of the two wrecks.

Picture A - HMAS Sydney/HSK Kormoran search, Indian Ocean Picture B - HMAS Sydney/HSK Kormoran search, Indian Ocean


a) Higher resolution image of HMAS Sydney. Frequency 60kHz. Range 375m. Damaged superstructure can be seen in acoustic shadow (appears as white).

b) X-turret on HMAS Sydney.


USS Grunion Search, Kiska, Aleutian Islands

Williamson  was hired by the family of the Commanding Officer of the lost WWII US submarine USS Grunion to search in waters off Kiska, Alaska.  The Williamson AMS 60 and SM 30 sidescan sonars,  two medium oceanographic winches and navigation and processing systems were mobilized on the FV Aquila in Seattle. A survey crew of seven joined in Dutch Harbor.  Over 250 square nautical miles  were searched. One target in 1000m water depth matched the size and shape of the Gato class submarine Grunion and also correlated with known information about the loss. Additionally several targets were identified as wrecks of sunken Japanese warships. All targets were assessed, positioned and provided to the client. August 6-24, 2006.  In 2007, an ROV search confirmed the wreck was indeed the USS Grunion.

Picture A - USS Grunion Search, Kiska, Aleutian Islands Picture B - USS Grunion Search, Kiska, Aleutian Islands


a) Higher resolution sonar image of USS Grunion. Frequency 60kHz. Range 150m.

b) Photo of the stern of USS Grunion with prop guards clearly visible.


Chevron Post Katrina & Rita Assessment

Williamson was prime contractor to Chevron USA for a variety of tasks in the Gulf of Mexico following Hurricanes Katrina and Rita. The Williamson AMS 120 and SM 30 sidescan sonars, an SAIC Edgetech FS 4200 dual frequency sidescan sonar, two SeaSpy magnetometers, two winches, a surface and USBL nav system, coring equipment, a Phantom ROV and processing systems were mobbed on the Ocean Services 175 foot RV Davidson. Most work was performed for the Typhoon TLP platform Root Cause Analysis team which was investigating the loss of that rig.  Additional MMS related tasks were conducted for Southern Natural Gas and other Chevron business units. RV Davidson was mobbed from 3 October until 13 January.  MV Stannard Tide was employed as a Chase Boat from December 9 to 18. A total of 31 Williamson employees and contactors worked on this project. GEMS Inc. did the final reporting for the five independent MMS reports and for the Typhoon rig debris assessment. Over 1200 individual small targets were positioned, assessed and correlated with other sidescan targets and ROV video. The 30 kHz SM 30 sonar proved particularly useful in locating buried targets and pipeline sections. October 2005 to January 2006.


SubSea Resources Plc. Shipwreck Search

Searching English Channel for 1850s steam packet in water depths of about 120 meters. Employed  SM 30 sidescan sonar and six Williamson personnel from 165 foot vessel Aquitaine Explorer.  Eighty plus wrecks located with the sonar. All targets assessed, positioned and provided to client. August 1 to September 1, 2005.


Discovery Channel Inc.

Search from 165 foot vessel June T for wreckage of Navy cruiser USS Indianapolis which was sunk east of the Philippines in the last days of World War II. Williamson provided SeaMARC 1A sidescan sonar, B1 winch with 10,000 meters of 0.68" cable, navigation and processing systems and six personnel. A large target in several pieces in the center of the probability zone was located.  A subsequent ROV expedition did not find a target. Water depths 2500-4000 meters. May 28 to July 2, 2000.


Howland Landing  LLC

Search for Amelia Earhart’s Airplane northwest of Howland Island, Central Pacific from the 165 foot vessel June T. Williamson provided SeaMARC 1A sidescan sonar, B1 winch with 10,000 meters of  0.68" cable, navigation and processing systems and six personnel. Two good targets worth a return visit located but not pursued due lack of time. Water depths 5000-5500 meters. November 9 to December 23, 1999.


Israel Ministry Of Defense

Subcontractor to Nauticos, Inc. for search for lost Israeli submarine INS Dakar; Mediterranean Sea off Crete using EDT 185 foot vessel Flying Enterprise. Williamson provided AMS 60 sidescan sonar, B1 winch with 9000m 0.68" cable, processing equipment and five personnel.  Located Dakar after 15 days at 2900 meters water depth.  Job was from 27 April to 7 June 1999.


Oregon State University

Search and recovery of lost oceanographic instrument package 11 nm off Newport, Oregon from 80 meters water.  Waverly sidescan and Phantom ROV from OSU 185 foot R/V Wecoma.  September 1998.


Commercial Client

Shipwreck Search, Eastern Atlantic for an old Spanish vessel in water depths of 800 to 2000 meters. Employed  SeaMARC 1A sidescan sonar, deep oceanographic winch with 6000m  0.68" cable and seven Williamson personnel from French 165 foot vessel Abeille Supporteur.  Seventeen wrecks located with sonar and ID'd with an ROV. June 1992.  


U.S. Coast Guard and P&I Club

Container/Arsenic Barrel Search off Cape May New Jersey.  Williamson was project manager for the sonar search, location and encapsulated recovery of 320 thirty gallon barrels of arsenic trioxide     which had been lost from the vessel Santa Clara during a storm in January 1992.  The SeaMARC 1A was employed from the 190 foot vessel Cannon Tide to search a 37 mile by 1400 meter swath of the Santa Clara's track off the New Jersey coast to locate any missing barrels. A pipeline laybarge with two work class ROVs from Sub Sea International of Belle Chasse, Louisiana was used to individually pluck the arsenic barrels from the seabed and deposit them in a larger drum in a 20 drum rack. When a rack was filled, the drums were overfilled with cement, and the rack was lifted to the surface and transported ashore to a landfill. All pertinent EPA, USCG and OSHA regulations and procedures were followed. An EPA deadline for depositing all arsenic drums in a South Carolina landfill was met with one day to spare. March 29 to May 10, 1992.


Global Diving

Search for Sunken 60 foot Yacht Prime Time in Puget Sound.  Based on missing yacht and story of one survivor, planned and executed search for missing yacht in vicinity of Bainbridge Island. Located yacht in 750 feet depth and took ROV videotapes for customer.  Used EG&G 262 sonar and Phantom D2HD ROV. May 1992.


Washington State Department of Transportation

I-90 Bridge survey of sunken bridge sections, bridge anchors and cables, Lake Washington, Seattle. AMS 60 sidescan sonar, Waverly 100 kHz and Klein 50 kHz sidescan sonars and QMIPS image processing system from DOT boat.  December 1990-June 1991.


U.S. Navy, NOAA, USGS and EPA

Search for radioactive waste drums off Farallon Islands, California from 205 foot MV Farnella. Employed SeaMARC 1A Deep Towed 30 kHz sidescan sonar. Data were collected in a 190 sq km area around the radioactive waste sites in water depths to 3300m on swath widths of 5, 2, 1 and 0.5 km. Many barrels were detected. SeaMARC 1A with seven Williamson personnel.  USGS has published several articles about this project and the utility of the 30kHz in barrel searches. July 1990


Canadian Air Force

Search and locate wreckage of Canadian Air Force CF-18 jet off Vancouver Island in 4800 meters depth. Williamson provided the SeaMARC 1A sidescan sonar and six personnel to survey from the Canadian 226 foot research vessel John P. Tully. The aircraft had entered the water in a vertical dive causing significant debris field dispersal; the largest piece of wreckage was the nose wheel assembly.  June 1990


Lockheed Space & Missiles Company

Search for wreckage of a Trident C-4 and a Trident D-5 missile off Cape Canaveral. Used SeaMARC 1A 30 kHz sidecan sonar, AMS 150 sidescan sonar, DOE Phantom HD2D ROV and Harbor Branch submersibles variously from 204 foot RV Seward Johnson and 168 foot RV Edwin Link from Harbor Branch Oceanographic Institute and the 176 foot RV Liberty Star, a booster recovery vessel owned by NASA.  Job was in ten separate underway periods from May 20, 1988 to 17 August, 1989 covering search and recovery phases for the missile debris. Seabed recovery work by the Harbor Branch Sea-Link submersibles.  Max water depth was 2600 feet. Over 1200 targets assessed for position and size. All major components desired for Lockheed post loss analysis were found and recovered.  At end of the program, Williamson & Associates, Inc. received a Letter of Commendation from Admiral Ken Malley, Director of Navy Strategic Programs.  Sep 1988 – October 1989.


Columbus America Discovery Group

Search for gold-laden SS Central America, sunk in a hurricane off Charleston in September 1857. Employed SeaMARC 1A and nine Williamson personnel from the 165 foot vessel Pine River to search a 1500 square nautical mile area (an area larger than the state of Rhode Island).  Several wrecks were found during a search in June and July 1986. In September of 1987, SeaMARC was employed on the 225 foot Nicor Navigator to search an adjacent 500 square mile area. More wrecks were found and additional data was collected on some of the 1986 wrecks. After data analysis, in 1988 the more promising wrecks were visited with an ROV, definitively finding Central America. The gold was recovered over the next several years amid several court battles over ownership of the treasure. The story is partially told in the book "Ship of Gold" by Gary Kinder (Atlantic Monthly Press, 1998).  With the treasure originally reputed to be possibly worth a billion dollars, it is worth noting that the investors who backed the several sonar and ROV expeditions have yet to be repaid. 


Submerged Offshore Platform Superstructure

In another search and recovery project we use the AMS-120 to document the remaining submerged superscructure of an offshore platform in the Gulf of Mexico. Click the image to see details.