 German submarine U-3521

German submarine "U-3521" was a Type XXI U-boat (one of the ""Elektroboote"") of Nazi Germany's "Kriegsmarine", built for service in World War II.She was ordered on 6 November 1943, and was laid down on 24 September 1944 at F Schichau GmbH, Danzig, as yard number 1666.