SS Coamo was an American Steam passenger ship built in 1925. In January 1942 she was time chartered as US Army transport.
On 1 December 1942, the Coamo (Master Nels Helgesen) left the convoy MKF-3 about 150 miles west of Ireland on orders of the British Admiralty and proceeded independently when on route from Gribraltar for New York. At 20.18 hours on 2 Dec, 1942, U-604 fired one torpedo from 800 yards at the Coamo, which was proceeding at 17.5 knots. The torpedo struck under the bridge and caused her to sink in about five minutes.
The ship had eleven officers, 122 crewmen, 37 armed guards and 16 US Army passengers on board. None of the 186 people on board survived the sinking. This was the greatest single loss of a merchant crew on any US Flag merchant vessel during the Second World War.