VI 0 Prototype steam propulsion submarine VIIA 1935 10 First practical post-World War I attack submarine VIIB 1936 24 Standard attack submarine in the early months of World War II VIIC 1938 568 Attack submarine "work horse" for the majority of World War II. VIIC (Flak) 1942 4 Special variant of Type VII which removed the deck gun and added extra anti-aircraft guns VIIC/41 1941 91 Upgraded attack boat with several additional offensive and defensive features as well as better diving ability. VIIC/42 1942 0 Project was cancelled in lieu of contracts for the Type XXI electrical attack boats VIID 1940 6 Mine layer submarine, few were produced VIIE 0 Early designs indicate this was to be a deep diving submarine VIIF 1941 4 Designed to be used as torpedo transport.