(AO‑119: dp. 21,880; l. 524'; b. 68'; d. 30'; s. 16.5 k.; cpl. 52; a. none; cl. Mission Buenaventura; T. T2‑SF‑A2)
A merchant name retained. A Franciscan mission in California founded in 1771.
Mission San Antonio was laid down on 15 January 1944 under a Maritime Commission contract by Marine Ship Corp., Sausalito, Calif.; launched 8 April 1944; sponsored by Mrs. Marian McClure; and delivered 24 May 1944.
Chartered to Los Angeles Tanker Operators Inc., on her delivery date for operations, she spent the remainder of the war carrying vital fuel products to our forces in the western Pacific. She was returned to the Maritime Commission on 30 April 1946 and laid up in the Maritime Reserve Fleet at Mobile, Ala.
Acquired by the Navy on 22 October 1947, she was placed in service with the Naval Transportation Service as Mission San Antonio (AO‑119). After 1 October 1949, she was under the operational control of the new Military Sea Transportation Service as USNS Mission San Antonio (T‑AO‑119). She served with MSTS until 22 November 1954 when she was returned to the Maritime Administration and laid up in the Maritime Reserve Fleet, at James River, Va.
Reacquired by the Navy on 6 July 1956, she was placed in service with MSTS until 16 December 1959, when she was returned to the Maritime Administration and laid up in the Maritime Reserve Fleet at Beaumont, Tex.
Her stay in the Reserve Fleet was short for on 9 June 1960, Mission San Antonio was reacquired by the Navy and placed in service with MSTS on the same date. She served faithfully until 11 January 1965, when she was once again returned to MARAD and laid up in the Maritime Reserve Fleet at James River, Va. Struck from the U.S. Naval Register in the same date, she was sold to Transwestern Associate 9 June 1965, for conversion to a bulk carrier. She was renamed Transartic, but was reacquired by MARAD on 27 August 1965. She was resold to Hudson Waterways Corp. on 24 January 1966 for conversion into a combination train ferry and containership. Transartic was renamed Seatrain San Juan in September 1966. Into 1969, she has carried cargo between the east and west coasts of the United States and occasionally to Vietnam.