German submarine U-3523

German submarine U-3523 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 7 October 1944 at F Schichau GmbH, Danzig, as yard number 1668. She was launched on 14 December 1944, and commissioned under the command of Oberleutnant zur See Willi Müller on 23 January 1945.

Design
Like all Type XXI U-boats, U-3523 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 of 8 m, and a draught 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-3523 was fitted with six 53.3 cm torpedo tubes in the bow and four 2 cm C/30 anti-aircraft guns. She could carry twenty-three torpedoes, or seventeen torpedoes and twelve mines. The complement was five officers and fifty-two men.

Sinking
U-3523 had been sailing on the surface with U-534 and U-3503 just north of the cease-fire line when it was sunk by depth charges from a British B-24 Liberator of 86 Squadron/G RAF about 10 nmi north of Skagen Horn, in the Skagerrak on 6 May 1945. All 58 crewmen were lost.

The wreck was thought to be located at 57.86667°N, 10.81667°W, however, in April 2018, it was found by Sea War Museum Jutland, Thyborøn, 9 nmi further west. The wreck lies at a depth of 123 m. The entire fore part of the boat is buried in the seabed while its stern rises 20 m above the bottom.