Since the Kriegsmarine had no bases in other parts of the world (although some U-Boats operated from Japanese bases in the
Pacific), the U-Boats depended on supply ships. After surface ships proved to be too vulnerable the idea of a supply submarine was born - the so called "Milchkuh" (Milkcow). Based on the successful Type VII design, the Type XIV could carry 4 spare torpedoes and over 400 ts of diesel fuel, while its own armamment consisted of anti aircraft guns only. The first of the 20 boats build was put into service in 1941 and they were useful for submarine operations in distant areas. But caused by their very bad maneuverability and diving speed, all were sunk by allied forces during the war.