USS Skylark, a 1735-ton Penguin class submarine rescue ship, was built at Charleston, South Carolina. Begun as the fleet tug Yustaga (ATF-165), she was redesignated ASR-20 and renamed Skylark in late 1945. Launched in March 1946 and completed a few months later, the ship was placed in reserve and not commissioned until March 1951. Based at New London, Connecticut, throughout her active career, Skylark periodically deployed to other locations along the U.S. Atlantic coast and in the Caribbean area during her first decade of service. Beginning in January 1962, she began a pattern of regular tours in the Mediterranean and also operated in support of ballistic missile submarine activities at Holy Loch, Scotland. In 1963 and 1968, she assisted in the searches for the lost submarines USS Thresher (SSN-593) and Scorpion (SSN-589). Decommissioned in June 1973, Skylark was sold to Brazil, in whose navy she served under the name Gastao Moutinho until about 1988.