Errol (AG-133) was built in 1944 by Wheeler Shipbuilding Corp., Whitestone, Long Island, New York, for the U.S. Army as USAT FS-274; acquired by the Navy 3 April 1947; and commissioned 9 July 1947. She was reclassified AKL-4 on 31 March 1949.
From September to December 1949 she was overhauled at Pearl Harbor, the only interruption to her constant operations in the Pacific.
Transfer to Department of the Interior
She was decommissioned 31 July 1951, and lent to the U.S. Department of the Interior for similar duty the same day. On 29 January 1952 her transfer to the Department of the Interior was made permanent.