Ocean Surveillance Ships - T-AGOS

Description: Ocean surveillance ships have a single mission -- gather underwater acoustical data. The T-AGOS ships operate to support the anti-submarine warfare mission of the U.S. Navy's Atlantic and Pacific Fleets.

Features: T-AGOS ships are designed to tow an array of underwater listening devices to collect acoustical data. The ships also carry electronic equipment to process and transmit that data via satellite to shore stations for evaluation. The ships, listening devices and electronic equipment are all part of a system called the Surveillance Towed Array System, or SURTASS.

Victorious class ocean surveillance ships are built on a Small Waterplane Twin Hull, or SWATH, design for greater stability at slow speeds in high latitudes under adverse weather conditions.
Impeccable class ships have a hull form based on that of Victorious. Acoustic systems include an active low frequency towed array, which has a series of modules each of which houses two high-powered active transducers. These can be used with either mono or bi-static receivers.

Background: Oceanographic and hydrographic surveys, underwater surveillance, acoustic surveys and submarine support are just a few of the services these ships support. The ships are operated and maintained by civilian contractors. The Surveillance Towed Array Sensor is a linear array deployed on a tow cable. Information from the array is relayed via WSC-6 (SHF) satellite link to the shore. SURTASS patrols are 60 to 90 days in duration.

A contract for the first SWATH ship, T-AGOS 19, was awarded in November 1986, and options for the next three were exercised in October 1988. These ships have the same WSC-6 communications, links and operating procedures as the Stalwart class.

The keel for the first Impeccable class was laid down in February 1993. The ship was more than 60 percent completed when the shipyard encountered difficulties. The contract was sublet to Halter Marine in April 1995 to complete the ship. Impeccable was christened in November 2000 and will deliver to MSC in 2001.

Point of contact:
   Public Affairs Office
   Military Sealift Command
   914 Charles Morris Court SE
   Washington Navy Yard, D.C. 20398-5540
   (202) 685-5055 or www.msc.navy.mil

General Characteristics: Stalwart Class
Builder: Tacoma Boatbuilding, Tacoma, Wash.
Power Plant: Diesel-electric; 4 Caterpillar D 398 diesel generators, 3,200 hp, 2 motors, 1,600 hp; 2 shafts; bow thruster; 550 hp
Length: 224 feet
Beam: 43 feet
Displacement: 2,262 long tons (2,298.3 metric tons) full load
Speed: 11 kts (12.65 mph), 3 kts when towing array
Ships: No homeports assigned
   USNS Assertive (T-AGOS 9)
Crew: 18 mariners, 5 technicians and up to 15 Navy personnel

General Characteristics: Victorious Class
Builder: McDermott Marine, Morgan City, La.
Power Plant: Diesel-electric; 4 Caterpillar 3,512 diesel generators, 2 GE motors, twin screw 1,600 shaft hp; 2 bow thrusters; 2,400 hp
Length: 234.5 feet
Beam: 93.6 feet
Displacement: 3,396 tons (3,450.5 metric tons) full load
Speed: 10 kts, 3 knots when towing array
Ships: No homeport assigned
   USNS Victorious (T-AGOS 19)
   USNS Effective (T-AGOS 21)
   USNS Loyal (T-AGOS 22)
Crew: 19-22 mariners, 5 technicians and up to 15 Navy personnel

General Characteristics: Impeccable Class
Builder: Tampa Shipyard/Halter Marine, Pascagoula, Miss.
Power Plant: Diesel-electric; three diesel generators; 2 Westinghouse motors; 5,000 horsepower; twin screw shaft; 2 omni-thruster hydrojets; 1,800 horsepower
Length: 281.5 feet (85.8 meters)
Beam: 95.8 feet (29.2 meters)
Displacement: 5,370 long tons (5,456.18 metric tons) full load
Speed: 13 knots, 3 knots when towing
Ship: No homeport assigned
   Impeccable (T-AGOS 23)
Crew: 20 mariners, 5 technicians and up to 20 Navy personnel

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