The T-1 class submarines were a pair of submarines built for the United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 in the early 1950s for use in training submarine personnel and testing submarine equipment. Both submarines of the class served in these roles for over 19 years.

Design and construction

The T-1-class were among the smallest operational submarines ever built for the United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

. The first unit was planned as an experimental auxiliary submarine with hull number

Hull classification symbol

The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration use hull classification symbols to identify their ship types and each individual ship within each type...

 AGSS-570, but instead was built as the training submarine USS T-1 with hull number SST-1. Her sister ship

Sister ship

A sister ship is a ship of the same class as, or of virtually identical design to, another ship. Such vessels share a near-identical hull and superstructure layout, similar displacement, and roughly comparable features and equipment...

, USS T-2, was planned as SST-2 from the beginning.

Both submarines were constructed by the Electric Boat

Electric boat

While a significant majority of water vessels are powered by diesel engines, with sail power and gasoline engines also remaining popular, boats powered by electricity have been used for over 120 years. Electric boats were very popular from the 1880s until the 1920s, when the internal combustion...

 Division of the General Dynamics

General Dynamics

General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...

 Corporation at Groton

Groton, Connecticut

Groton is a town located on the Thames River in New London County, Connecticut, United States. The population was 39,907 at the 2000 census....

, Connecticut

Connecticut

Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...

, in 1952-1953.

Service history

Both submarines entered service in 1953 and were renamed in 1956, T-1 becoming USS Mackerel (SST-1) and T-2 becoming USS Marlin (SST-2). Both operated primarily in Florida

Florida

Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

 and Caribbean

Caribbean

The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

 waters to train submarine personnel, serve as targets for sonar

Sonar

Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...

 and antisubmarine warfare training, and test submarine equipment. They were decommissioned

Ship decommissioning

To decommission a ship is to terminate her career in service in the armed forces of her nation. A somber occasion, it has little of the elaborate ceremony of ship commissioning, but carries significant tradition....

 simultaneously in a combined ceremony in 1973.

USS Mackerel (SST-1), ex-USS T-1, ex-AGSS-570

, planned as AGSS-570, was commissioned as T-1 (SST-1) in October 1953 and decommissioned in January 1973. A highlight of her career was testing of equipment for the NR-1 Deep Submergence Craft

NR-1 Deep Submergence Craft

The Deep Submergence Vessel NR-1 was a unique United States Navy nuclear-powered ocean engineering and research submarine. It was built by the Electric Boat Division of General Dynamics at Groton, Connecticut. It was launched on January 25, 1969, completed its initial sea trials August 19, 1969,...

 in 1966-1967. Mackerel was sunk as a target in 1978.

USS Marlin (SST-2), ex-USS T-2

was commissioned as USS T-2 (SST-2) in November 1953 and decommissioned in January 1973. Donated as a museum ship

Museum ship

A museum ship, or sometimes memorial ship, is a ship that has been preserved and converted into a museum open to the public, for educational or memorial purposes...

 in August 1973, she was assigned on 20 August 1974 to go on display at Freedom Park in Omaha

Omaha, Nebraska

Omaha is the largest city in the state of Nebraska, United States, and is the county seat of Douglas County. It is located in the Midwestern United States on the Missouri River, about 20 miles north of the mouth of the Platte River...

, Nebraska

Nebraska

Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

.