The USS Grayback (SS/SSG/APSS/LPSS-574) was a prominent submarine of the United States Navy, serving as the lead vessel of her class. Laid down on July 1, 1954, at Mare Island Naval Shipyard in California, she was launched on July 2, 1957, and commissioned on March 7, 1958. Initially designated as an attack submarine, she was swiftly converted into a guided-missile submarine (SSG-574) later that year, becoming the first to carry the Regulus II sea-to-surface missile, though the program was canceled in December 1958, leaving her equipped with four Regulus I missiles for operational deterrent missions. Grayback was a substantial vessel, with modifications during her conversion that included an increased sail height by ten feet, additional tanks, and the capacity to carry 67 troops and SEAL Swimmer Delivery Vehicles (SDVs). Her length was extended by 12 feet to accommodate these modifications. The submarine was equipped for nuclear missile deployment, and her primary mission was deterrence during the Cold War. She conducted nine patrols, spending over 20 months at sea and logging more than 130,000 miles, primarily operating out of Pearl Harbor and visiting ports such as Yokosuka, Adak, and Pearl Harbor itself. Throughout her service, Grayback participated in testing, missile exercises, and deterrent patrols, including her first patrol from September to November 1959. She underwent a significant modification in February 1960 to simplify her missile launching system. Her operational history includes a notable incident on August 27, 1963, when a fire caused by a short circuit resulted in the loss of a crew member and some propulsion issues, but she returned to service after repairs. In 1972, Grayback supported Operation Thunderhead, deploying Navy SEALs into North Vietnamese waters during the Vietnam War. After a second conversion in 1968 to serve as an amphibious transport (LPSS-574), she was used to carry troops and SDVs, and in 1982, a diving accident resulted in five Navy divers' deaths. Grayback was decommissioned on January 15, 1984, in Subic Bay and was ultimately sunk as a target in April 1986. Her service marked a significant phase in Cold War naval deterrence, especially as part of the first nuclear missile submarine patrols.

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