USS Marlin (SST-2), originally USS T-2 (SST-2), was a T-1-class training submarine in commission from 1953 to 1973. She was the second submarine of the United States Navy to be named for the marlin, a large game fish. Except for the first 25 early development pre-World War I submarines, she was one of the smallest operational submarines ever built for the U.S. Navy.
Renamed Marlin on 15 May 1956, the submarine deployed to Guantanamo Bay for services to the Fleet Training Group in January 1956, July and August 1958, March 1960, and December 1961. In March 1963, Marlin participated in the National Defense Industrial Association (NDIA) demonstration.
From 1963, Marlin performed mainly target duty for both surface and air antisubmarine units at the Fleet Sonar School at Key West.
Marlin and her sister ship Mackerel were decommissioned on 31 January 1973 in a dual ceremony at Naval Station Key West. Both also were stricken from the Naval Vessel Register that day.
On 15 August 1973, the U.S. Navy donated Marlin for use as a museum ship. On 20 August 1974, she was assigned for display as a memorial submarine in Freedom Park at the Greater Omaha Marina at 2000 North 25th Street, in Omaha, Nebraska.
^The Dictionary of American Naval Fighting Ships[1] and NavSource[2] both state that Marlin was commissioned in 1953 and never served in a non-commissioned status. However, a Welcome Aboard program[3] providing the ships history states the ship was "placed in service on 29 November" before moving to her "present home port of Key West, Florida", but also includes pages from after she became a museum in Nebraska. The status "In Service" was often used in this period for training ships, in particular Naval Reserve destroyers and ocean escorts, and is still used for yard and district craft.[4]