German submarine U-604 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II.She was laid down on 27 February 1941 by Blohm & Voss in Hamburg as yard number 580, launched on 16 November 1941 and commissioned on 8 January 1942 under Kapitänleutnant Horst Höltring (German Cross in Gold).