At 19.13 hours on 26 Feb, 1942, the unescorted Mamura (Master P. Dobbenga) was torpedoed by U-504 about 230 miles off the coast of Florida. One torpedo hit the engine room, while a second detonated in the bow. The tanker was immediately ablaze and broke in two. The U-boat had fired the torpedoes from a distance of 400 meters and had to avoid the burning gasoline by diving. After surfacing eight minutes later, the stern section sank, while the bow was still visible. None of the 49 crew members, 35 of them Chinese, survived.