The U-boat Type VII was a German submarine built before WWII. It could conduct a war in the Atlantic. A total of 704 Type VII series U-boats were ever built. It kept to be the backbone of the German U-boat force until the end of the war. Relying on Admiral Karl D?nitz?s ?wolfpack? tactics, many ace commanders and their crew operated their U-boats to gain outstanding victories during WWII. ?