Manatee was laid down 28 August 1943 by the Bethlehem Sparrows Point Shipyard, Inc. of Sparrows Point, Maryland as a Maritime Commission type (T3-S2-A3) tanker hull with a cargo capacity of 146,000 barrels, under Maritime Commission contract (MC hull 724); launched 18 February 1944; sponsored by Mrs. Paul V. McNutt; and commissioned 6 April 1944 with Lieutenant Commander Joseph B. Smyth in command.