U-557 was a Type VIIC U-boat built for the Nazi German Kriegsmarine for service during World War II. She was laid down on 6 January 1940, launched on 22 December 1940 and commissioned on 13 February 1941. Oberleutnant Ottokar Paulssen was in command throughout her career. For her first three war patrols her 2nd Watch Officer was Herbert Werner, who later wrote the memoir of U-boat service, "Iron Coffins". She sank six merchant ships and one warship, a total of almost over four patrols. She was rammed and sunk by mistake by an Italian torpedo boat on 16 December 1941 west of Crete.