Information about her early career is largely absent, but by the 1920s, news reports revealed that the ship was sailing on the North Atlantic.

[3] West Arrow was inspected by the 13th Naval District of the United States Navy after completion and was assigned the identification number of 2585.

[4] One early mention of West Arrow in contemporary news accounts is found in The Washington Post, which reported in February 1921 that the cargo ship had delivered 742 "milch cows" to Bremen as a gift from American farmers from Texas and Kansas.

[7] By March 1926, West Arrow was sailing for American Diamond Lines[Note 2] in New York – Rotterdam service on a U.S. government-subsidized mail route.

[11] On 24 March 1938,[12] Black Osprey was sailing in a dense fog off St. Catherine's Point on the Isle of Wight when she struck the 311 GRT British cargo ship Chagford, which sank within five minutes.

After the fog lifted, the Chagford survivors were transferred to a fishing vessel that landed the crewmen, and Black Osprey resumed her Rotterdam – Philadelphia journey.

As a result, American Diamond was unable to continue its Dutch route, and chartered the eight vessels it employed in that service (which included Black Osprey) to other U.S.

[16] Black Osprey was one of several chartered to the Isthmian Line,[17] and made voyages in the Pacific, calling at ports such as Singapore and Honolulu in 1940.

[17] The USMC granted the permission,[20] and Black Osprey was sold to the Ministry of War Transport for operation by the Cairn Line of Newcastle-upon-Tyne, for about $50 per deadweight ton, or around $440,000.

[21] After falling behind in the convoy, Black Osprey was torpedoed by U-96 under the command of Fregattenkapitän Heinrich Lehmann-Willenbrock at 02:27 on 18 February south of Iceland, near position 61°18′N 18°6′W / 61.300°N 18.100°W / 61.300; -18.100.