USS Proteus (AS-19) was a Fulton-class submarine tender built during World War II. Like most tenders, it had the same type of propulsion system as the ships/boats it was designed to tend and maintain - in this case, 12 diesel engines and electric motors driving two shafts. It was decommissioned after the war in 1947, but then converted to a ballistic missile submarine tender and recommissioned in 1960. The conversion involved inserting a 44-foot long hull section midships, along with a gantry crane for moving the missiles between the ship and submarines alongside. It served in this role until 1992.