In January 1942 five German Type IX U-boats, essentially unmolested by U.S. air and naval forces who were unprepared for anti-submarine warfare, began hunting merchant ships off the east coast of North America. Many of their brazen attacks were on the surface and close to shore.

Throughout 1942, successive waves of Type IX and Type VII submarines (eventually refueled at sea by Type XIV “milk cow” tanker submarines) sank more than 310 U.S. ships off the East Coast, Gulf of Mexico and the Caribbean Sea.

In mid-1942, with improved training, equipment and the institution of an interlocking convoy system off the American coast and in the Caribbean Sea, the number of successful U-boat attacks dropped off in those areas. The main focus of U-boats attacks then shifted to the North Atlantic convoy system.