Speed 15 k
Armament 4 5", 8 40mm
The third Proteus (AS-19) was laid down by the Moore Shipbuilding and Dry Dock Co., Oakland, Calif., 15 September 1941; launched 12 November 1942, sponsored by Mrs. Charles M. Cooke, Jr., and commissioned 31 January 1944, Capt. Robert W. Berry in command.
After shakedown off San Diego, she stood out of San Francisco 19 March for Midway to tend submarines of Submarine Squadron 20. She arrived 3 May, and operating there until 1 December completed 51 voyage repairs and 14 refits for submarines. She returned to Pearl Harbor 4 December, and on 5 February got underway for Guam where she completed 4 voyage repairs and 24 refits by 7 August.
Assigned to occupation duty after the end of the war Proteus rendezvoused with units of the 3rd Fleet and became the flagship of a 26 ship support group which steamed off the coast of Honshu until 26 August. On the 28th she anchored in Sagami Wan to begin supporting Submarine Squadron 20 as it demilitarized submarines, human torpedoes, torpedo carrying boats, and suicide boats at Yokosuka and other locations in the Sagami Wan-Tokyo Bay areas.
Also assigned to repair Japanese submarines, she remained until 1 November, when she headed home. Transiting the Panama Canal 6 December, she reached New London 16 December. A trip to the Canal Zone preceded cold weather operations with SubRon 8 at Argentia during November, after which she returned to New London. Decommissioned and placed in service 26 September 1947, she provided vital service to the submarine base at New London until January 1959. On the 15th she entered Charleston Naval Shipyard for conversion to a tender for the Polaris Fleet Ballistic Missile submarines, including the addition of a 44-foot section amidships.
Proteus recommissioned 8 July 1960, and after shakedown at Guantanamo Bay, she accomplished her first SSBN refit 20 January-21 February at New London. She then crossed to Holy Loch, Scotland arriving 3 March 1961. There for the next two years she completed 38 refits of Fleet Ballistic Missile submarines, for which she received the Navy Unit Commendation. Back at Charleston for overhaul in 1963, on 2 January 1964 she resumed operations at Holy Loch to provide support and refits to the Fleet Ballistic Missile submarines of Submarine Squadron 14.
On 24 February Proteus arrived at Rota, Spain to establish the second overseas replenishment site for Fleet Ballistic Missile submarines, returning to Holy Loch 12 April. On 29 June she put in at Charleston and on 16 October was enroute to Guam. Arriving Apra Harbor 29 November, she established the third overseas replenishment site for the Fleet Ballistic Missile submarines. She continued to operate at Apra Harbor and in the Pacific for the next five years, and remains with the Pacific Fleet into 1970.