Survey Ships - T-AGS

Description:Military Sealift Command's Special Missions program supports worldwide oceanographic programs with ships which perform acoustical, biological, physical and geophysical surveys. Ships such as USNS Silas Bent (TAGS 26), USNS Kane (TAGS 27) and USNS Bowditch (TAGS 62) gather data which provides much of the military's information on the ocean environment.

Oceanographic and hydrographic survey ships are used to study the world's oceans. The collected data helps to improve technology in undersea warfare and enemy ship detection. The oceanographic and hydrographic survey ships' multibeam, wide-angle precision sonar systems make it possible to continuously chart a broad strip of ocean floor. Two oceanographic ships survey the sea bottom and collect hydrographic data, charting three-fourths of the world's coastlines. USNS John McDonnell (TAGS 51) and USNS Littlehales (TAGS 52) make it easier for navigators to find their way along well-traveled and not-so-familiar shipping routes.

Features: The Silas Bent class of surveying ships were designed specifically for surveying operations. They have a bow propulsion unit for precise maneuverability and station keeping.

The John McDonnell class of survey ships carries 34-foot survey launches for data collection in coastal regions with depths between 10 and 600 m and in deep water to 4,000 m. A small diesel is used for propulsion at towing speeds of up to 6 knots. SIMRAD high-frequency active hull-mounted and side scan sonars are carried.

The Pathfinder class of survey ships have three multipurpose cranes and five winches plus a variety of oceanographic equipment including multibeam echo-sounders, towed sonars and expendable sensors.

Background: USNS John McDonnell (TAGS 51) was laid down Aug. 3, 1989, and USNS Littlehales (TAGS 52) on Oct. 25, 1989. McDonnell launched Aug. 15, 1980, Littlehales on Feb. 14, 1991.

The contract for the Pathfinder class of surveying ships was awarded in January 1991 for two ships with an option for a third which was taken up May 29, 1992. A fourth ship was ordered in Oct. 1994 with an option for two more. A fifth ship was ordered Jan. 15, 1997.

Point of Contact:
Office of Public Affairs
Military Sealift Command
Washington, DC 20398-5540
(202) 685-5055 or www.msc.navy.mil

General Characteristics, Silas Bent Class

Builders: American SB Co., Lorain/Christy Corp, Sturgeon Bay, Wis.
Power Plant: Diesel-electric; 2 Alco diesel generators; 1 Westinghouse/GE motor; 3,600 horsepower (2.69 MW); 1 shaft; cp prop; bow thruster; 350 horsepower (261 kW)
Length: 285.3 feet
Beam: 48 feet (14.6 meters)
Displacement: 2,550 to 2,843 tons (2,590.92 to 2,888.62 metric tons) full load
Speed: 15 knots when towing
Ships: No homeport assigned
USNS Silas Bent (T-AGS 26)
USNS Kane (T-AGS 27)
Crew: 31 civilians (12 officers) plus 28 scientists

General Characteristics, John McDonnell Class

Builder: Halter Marine Moss Point, Miss
Power Plant: 1 GM EMD 12-645E6 diesel; 2,500 horsepower (1.9 MW) sustained; 1 auxiliary diesel; 230 horsepower (172kW); 1 shaft
Length: 208 feet (63.4 meters)
Beam: 45 feet (13.7 meters)
Displacement: 2,054 tons (2,086.96 metric tons) full load
Speed: 12 knots (13.8 mph)
Ships: No homeport assigned
USNS John McDonnell (T-AGS 51)
USNS Littlehales (T-AGS 52)
Crew: 22 civilians plus 11 scientists

General Characteristics, Pathfinder Class

Builders: Halter Marine Moss Point, Miss
Power Plant: Diesel-electric; 4 EMD/Baylor diesel generators; 11, 425 horsepower (8.52 MW); 2 GE CDF 1944 motors; 8,000 horsepower (5.96 MW) sustained; 6,000 horsepower (4.48 MW); 2 Lips Z drives; bow thruster, 1,500 horsepower (1.19 MW)
Length: 328.5 feet (100.1 meters)
Beam: 58 feet (17.7 meters)
Displacement: 4,762 tons (4,838.42 metric tons) full load
Speed: 16 knots (18.4 mph)
Ships: No homeport assigned
USNS Pathfinder (T-AGS 60)
USNS Sumner (T-AGS 61)
USNS Bowditch (T-AGS 62)
USNS Henson (T-AGS 63)
USNS Bruce C. Heezen (T-AGS 64)
Crew: 28 civilians plus 27 scientists

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