The Skipjack class of United States Navy nuclear attack submarine was the replacement for the Skate class. This class was named after its lead ship, the USS Skipjack (SSN-585). A new design from the keel up, they were the first submarines to use a nuclear reactor in an Albacore hull: a round hull with a single shaft. Placement of the bow planes on the sail greatly reduced flow noise at the bow-mounted sonar. Deep-diving and high speed capabilities were the result of HY-80 construction and the new S5W reactor. The first Skipjack class was authorized in the FY 1956 new construction programmed with the first of the class commissioned in April 1959. Each hull cost around $40 million. The hull of USS Scorpion (SSN-589) was laid down twice as the original hull was redesigned to become the first US ballistic missile submarine USS George Washington (SSBN-598). Also, the material for building USS Scamp (SSN-588) was diverted into building USS Patrick Henry (SSBN-599) which delayed her progress. Skipkacj Class Submarine The Skipjack class was not fitted with aft torpedoes because of the sharply tapering sterns. Two mk 45 ASTOR torpedoes with low yield tactical nuclear weapons were deployed on some of the boats. The Skipjack class was also the fastest submarines in the United States Navy until the Los Angeles class submarine entered service. The class also had their engine rooms (except for the reactor and steam turbines) duplicated to minimize total breakdown possibilities. The Skipjack class submarines were withdrawn from service in the late 1980s and early 1990s except for Scorpion, which sank on 5 June 1968 in the south west Azores, while returning from a Mediterranean deployment. HMS Dreadnought, the United Kingdom's first nuclear submarine, was built using Skipjack as a basis, differing primarily in having a British-designed hull.
