Type VII U-boat

The Type VII is a class of medium-sized German submarines built for Nazi Germany's Kriegsmarine from 1935 to 1945, developed from earlier German First World War submarine designs and from the Finnish Vetehinen class, and built specifically to hunt merchant shipping along the North Atlantic convoy routes that supplied Britain and, later, the Allied invasion of Europe. More Type VII boats were built than any other submarine class in history, and the type formed the backbone of Germany's submarine fleet throughout the war, fighting the core of the prolonged Battle of the Atlantic against Allied convoys and their escorts. The class evolved through several improved variants over the war, from the original VIIA through the much more numerous VIIB and VIIC models, the deeper-diving, reinforced-hull VIIC/41, and specialized minelaying and torpedo-resupply versions, reflecting continuous wartime modification as Allied anti-submarine tactics and technology improved.