The ship was laid down under United States Maritime Commission (MC) Contract 3 June 1940 by the Federal Shipbuilding and Drydock Company of Kearny, New Jersey, MC hull 70, yard hull 175, and launched as Fred Morris on 2 November 1940, sponsored by Mrs. Fred Allain Morris.

Propulsion was a De Laval steam turbine driving a bronze, variable-pitch, three-bladed propeller 17 ft 6 in (5.3 m) in diameter.

[4] Assigned to the Asiatic Fleet as a submarine tender, she was anchored in Mariveles Bay, Philippine Islands, on 7 December 1941.

On 10 December 1941 she was slightly damaged during the Japanese air raid on the Cavite Navy Yard, when several bombs landed near her starboard side.

Remaining at Port Darwin through January 1942 Otus steamed to Java and Trincomalee, Ceylon, during February and the first part of March.

Arriving Mare Island Naval Shipyard 24 August, Otus underwent an extensive overhaul until 23 January 1943.

From September 1943 until December 1944 Otus served at four different sites in New Guinea furnishing tender services for escort vessels, minecraft, and amphibious craft as well as submarines.