 "Antares" was originally built under Shipping Board contract as the steel-hulled freighter Nedmac, and constructed by the American International Ship Building Corp.; acquired by the Navy on 14 November 1921 under the terms of Executive Order No.3570 (29 October 1921) which authorized her transfer from the Shipping Board, she was renamed Antares and classified as a "miscellaneous auxiliary", AG-10.She was commissioned at the Philadelphia Navy Yard on 23 February 1922, Lieutenant Commander Howard E. Pinkham, USNRF, in command.