(Freighter: dp. 12,185; l. 423'9"; b. 54'0"; dph. 29'9"; dr. 24'0" (mean); s. 11.5 k.; cpl. 88; a. 1 6", 1 6-pdr.)
Westchester—a single-screw, steel-hulled cargo vessel built as War Ally under a United States Shipping Board contract at Portland, Oreg., by the Northwest Steel Co.—was launched on 5 December 1917; acquired by the Navy on 9 August 1918; designated Id. No. 3122; and commissioned at Norfolk, Va., on the same day, Lt. Comdr. Thomas W. Sheridan. USNRF, in command.
Assigned to the Naval Overseas Transportation Service, Westchester got underway on 27 August from Newport News with general Army cargo and a deck load of 25 trucks. Arriving in New York two days later, she joined a convoy bound for Europe. She reached Le Havre, France, on 15 September and moved on to Davenport, England, before discharging her cargo.
Westchester was at sea, heading for the United States, when the armistice ended World War I. She made port at Newport News on 15 November, loaded 7,800 tons of Army cargo for shipment to France, and stood out of Hampton Roads on 19 December. She lost a propeller blade a few days out, however, and was obliged to put back into Norfolk for repairs. She set out on 3 January 1919, but another propeller casualty forced Westchester into New York eight days later.
Her third attempt to reach France succeeded, though, and she made port at Quiberon, France, on 2 March. With a return cargo of Army ordnance material, she set sail on 23 March. Arriving at New York on 7 April, Westchester discharged her cargo and was decommissioned on 25 April 1919. Returned to the Shipping Board, she remained in the custody of that agency until abandoned in 1933