German submarine U-3504

German submarine U-3504 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 30 June 1944 at F Schichau GmbH, Danzig, as yard number 1649. She was launched on 15 August 1944, and commissioned under the command of Kapitänleutnant Karl-Hartwig Siebold, on 23 September 1944.

Design
Like all Type XXI U-boats, U-3504 had a displacement of 1621 t when at the surface and 1819 t while submerged. She had a total length of 76.70 m (o/a), a beam length of 8 m, and a draught length of 6.32 m. The submarine was powered by two MAN SE supercharged six-cylinder M6V40/46KBB diesel engines each providing 4000 PS, two Siemens-Schuckert GU365/30 double-acting electric motors each providing 5000 PS, and two Siemens-Schuckert silent running GV232/28 electric motors each providing 226 PS.

The submarine had a maximum surface speed of 15.6 kn and a submerged speed of 17.2 kn. When running on silent motors the boat could operate at a speed of 6.1 kn. When submerged, the boat could operate at 5 kn for 340 nmi; when surfaced, she could travel 15500 nmi at 10 kn. U-3504 was fitted with six 53.3 cm torpedo tubes in the bow and four 2 cm anti-aircraft guns. She could carry twenty-three torpedoes or seventeen torpedoes and twelve mines. The complement was five officers and fifty-two men.

Fate
U-3504 was scuttled on 2 May 1945, at Wilhelmshaven, as part of Operation Regenbogen. The wreck was later raised and broken up.