[1] It was built in 1918 by Union Iron Works, San Francisco, Calif., under a United States Shipping Board contract.

Challenger cleared San Francisco 9 October 1918 for Mejillones and Antofagasta, Chile, where it loaded nitrates.

Sailing on to deliver its cargo at Pensacola, Fla., 11 December, Challenger was next ordered to New Orleans to load cotton and steel for the French government.

After a voyage in January and February 1919 carrying cargo to France to supply the Army of Occupation, Challenger returned to Baltimore, Md.

On 17 May 1942 while serving with American-South African Line during World War II, it was torpedoed and sunk by the German submarine U-155.