The USS Seawolf (SSN-575) was a pioneering nuclear-powered submarine of the United States Navy, notable for being the second nuclear submarine and the only US vessel built with a liquid metal cooled (sodium), beryllium-moderated reactor, designated S2G. Laid down on September 7, 1953, by Electric Boat in Groton, Connecticut, she was launched on July 21, 1955, and commissioned on March 30, 1957. Her design was a variant of the Nautilus (SSN-571), featuring a double-hull configuration, twin screws, a stepped sail, and an unusual bow shape due to her top-mounted BQR-4 passive sonar array. Seawolf's initial propulsion utilized a sodium-cooled LMFR reactor, which proved problematic due to leaks and maintenance complexity. Consequently, her reactor was replaced between December 1958 and September 1960 with a standard pressurized water reactor (S2Wa), similar to Nautilus, after the original sodium system was sealed in a containment vessel and sunk in deep Atlantic waters. Throughout her service, Seawolf engaged in various operational activities including NATO exercises, independent patrols, and covert missions. She participated in the search for the lost USS Thresher in 1963 and was part of the world's first nuclear task force during a Mediterranean deployment in 1964. Her operational history included multiple deployments along the East Coast, the Caribbean, and the Pacific, where she was tasked with trailing Soviet submarines, retrieving seabed test weapons, and tapping Soviet communications cables. Significantly, Seawolf was extensively modified from 1971 to 1973 into a "special project platform," enhancing her capabilities for covert intelligence operations. Despite ongoing technical issues, including reactor scrams and fires, she maintained a vigorous operational schedule, setting endurance records such as remaining submerged for 89 consecutive days. Decommissioned on March 30, 1987, and later dismantled through the Navy's recycling program in 1997, USS Seawolf remains a notable vessel for her experimental reactor design and contributions to early nuclear submarine development.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.