SS-417 Tench
A total of 144 Tench (SS-417) class submarines were ordered during 1943-46. They had improved machinery and ballast tank arrangements and stronger hull than the Gato (SS-212) and Balao (SS-285) classes though were very similar in design. Six (SS-429 thru 434) were cancelled in July 1944, two more (SS-427 and 428) in August 1945, and a further 105 were cancelled in January 1946 (SS-491 thru 562 and 437 thru 474). The first hull was laid down in August 1943 and the program continued up through the end of the war. Most of this class was built at Portsmouth Naval Shipyard (23 boats); Cramp, Electric Boat, and Boston Naval Shipyard each built one.
The pressure hull consisted of 7/8-in high tensile steel. There were eight waterproof compartments in addition to the conning tower. They were equipped with four engine rooms, diesel-electric reduction gear, one auxiliary generator, four electric motors generating 5480 hp when submerged driven by two 126-cell batteries. Submerged endurance was 48 hours at 2 knots. Cruising range was 11,000 miles on the surface at 10 knots with 118,510 gallons of diesel fuel. Patrol duration was 75 days.
Thirty of the original 144 submarines of this class saw commissioned service; eighteen served during World War II. Four had their construction suspended and were completed to the GUPPY (Greater Underwater Propulsion Program) specification. The GUPPY I program meant streamlining exterior hull surfaces, increasing battery capacity, removal of deck guns, and compartment rearrangements whereas the GUPPY II program added a snorkel system that allowed the diesel engines to be operated while the boat was at periscope depth.
The class was removed from service 1963-75 as newer submarines were commissioned into the US Navy. Tigrone (SS-419) was the last boat of this class in commission; she decommissioned in June 1975. Three Tench class submarines were donated to become museums.
