File:US Army hospital ship USAHS Shamrock in port, circa 1943-1946 (NH 103128).jpg

English: The U.S. Army hospital ship USAHS Shamrock in port, circa 1943-1946.

Shamrock was originally the Ward Line (New York & Cuba Mail Steam Ship Co.) passenger ship SS Havana, commissioned in 1907. Initially taken over by the U.S. Army for wartime service as USAT Havana, she was acquired by the U.S. Navy on 19 July 1917 and converted to a hospital ship. Commissioned as USS Comfort (AH-3) on 18 March 1918, she was laid up at the Mare Island Navy Yard in 1919, stricken on 26 May 1924 and sold on 1 April 1925.
The former hospital ship was repurchased by the Ward Line in 1927, who refitted her and placed her back in service on the Havana route under her original name of Havana. In January 1935, Havana grounded on a reef north of The Bahamas and remained there for three months. After being refloated and repaired, she was placed back in service as SS Yucatán in June. In 1940 the ship was removed from passenger service to be converted into a freighter. After capsizing in port in 1941, the ship was again refloated and renamed SS Agwileon.

Under a bareboat charter by the United States Maritime Commission, Agwileon carried civilian technicians and advisors to Sierra Leone for the U.S. Army. In November 1942, the ship was taken over by the Army as USAT Agwileon and converted to a troopship, making one trip in that capacity. In June 1943, the ship was selected for conversion to an Army hospital ship, and was renamed USAHS Shamrock. Operating locally in the Mediterranean for most of her career, the ship had transported almost 18,000 patients by September 1944. The ship was converted for use in the Pacific Theatre, but not before the war ended. The ship was placed in reserve in February 1946, and was scrapped in February 1948.