World War II, 1944–1945

Midnight completed conversion for Navy use on 28 March and was assigned to the Service Force, Pacific Fleet. That same day, she was towed out of San Francisco, California, on her way to the Central Pacific. After a stop at Pearl Harbor, she continued her voyage and arrived in Majuro Lagoon on 4 May. For the next five months, she served at Majuro and Eniwetok. During that time, she was renamed Trefoil on 10 June 1944.

On 5 October, Current (ARS-22) towed her out of Eniwetok and on to Ulithi where she arrived on 16 October. She remained there for ten months on duty with Service Squadron 8. In August 1945, she was towed from Ulithi to Leyte in the Philippines where she arrived on 28 August. Trefoil remained there until 9 November, when she was towed out for Guam in the Mariana Islands. The barge reached Apra Harbor on 16 November.^[1]

Post-war activities, 1945–1948

Trefoil served at Guam for the remainder of her Navy career. Early in 1946, she was chosen as one of the support ships for "Operation Crossroads", the atomic bomb tests conducted at Bikini Atoll that summer. However, soon thereafter, that decision was rescinded and another made to dispose of her. Action on that decision was also deferred, and she was used to house Stockton-Pollack employees building a drydock in Apra Harbor. Her reprieve ended in September 1947 when she was determined to be in excess of the needs of the Navy.

Disposal

On 28 May 1948, the barge was turned over to the Foreign Liquidations Commission of the United States Department of State for disposal, and she was sold to the Asia Development Corporation of Shanghai, China. Her name was struck from the Naval Vessel Register on 22 December 1948. The barge, however, remained at Apra Harbor because she was impounded due to a dispute over ownership of the vessel between the Asia Development Corporation and Moellers, Limited, of Hong Kong. Resolution of the dispute and final disposition of the barge is unknown.