|Ordered||6 November 1943|
|Builder||Blohm & Voss, Hamburg|
|Laid down||8 December 1944|
|Launched||31 March 1945|
|Commissioned||24 April 1945|
|Fate||Run aground on 5 May 1945|
|Class and type||Type XXI submarine|
|Length||76.70 m (251 ft 8 in) (o/a)|
|Beam||8 m (26 ft 3 in)|
|Height||11.30 m (37 ft 1 in)|
|Draught||6.32 m (20 ft 9 in)|
|Complement||5 officers, 52 enlisted|
|Sensors and |
German submarine U-2551 was a Type XXI U-boat of Nazi Germany's Kriegsmarine during World War II. The Elektroboote submarine was laid down on 8 December 1944 at the Blohm & Voss yard at Hamburg, launched on 31 March 1945, and commissioned on 24 April 1945 under the command of Kapitänleutnant Gerhard Schaar.
U-2551 was a brand new, high technology electric boat which could run constantly submerged rather than having to surface to recharge her batteries every day the way submarines until that point had had to do. However, these advanced vessels were introduced to the Kriegsmarine only late in 1944, much too late to influence the Battle of the Atlantic, and too late for many of them to serve in an offensive capacity at all.
With the end of the war near, training on U-boats had dropped to a minimum due to lack of fuel, falling morale and the effectiveness of allied attacks on U-boat construction and preparation. The exception to this were the new Type XXI boats, which continued to train in the Baltic Sea.
Like all Type XXI U-boats, U-2551 had a displacement of 1,621 tonnes (1,595 long tons) when at the surface and 1,819 tonnes (1,790 long tons) while submerged. She had a total length of 76.70 m (251 ft 8 in) (o/a), a beam of 8 m (26 ft 3 in), and a draught of 6.32 m (20 ft 9 in). The submarine was powered by two MAN SE supercharged six-cylinder M6V40/46KBB diesel engines each providing 4,000 metric horsepower (2,900 kilowatts; 3,900 shaft horsepower), two Siemens-Schuckert GU365/30 double-acting electric motors each providing 5,000 PS (3,700 kW; 4,900 shp), and two Siemens-Schuckert silent running GV232/28 electric motors each providing 226 PS (166 kW; 223 shp).
The submarine had a maximum surface speed of 15.6 knots (28.9 km/h; 18.0 mph) and a submerged speed of 17.2 knots (31.9 km/h; 19.8 mph). When running on silent motors the boat could operate at a speed of 6.1 knots (11.3 km/h; 7.0 mph). When submerged, the boat could operate at 5 knots (9.3 km/h; 5.8 mph) for 340 nautical miles (630 km; 390 mi); when surfaced, she could travel 15,500 nautical miles (28,700 km; 17,800 mi) at 10 knots (19 km/h; 12 mph). U-2551 was fitted with six 53.3 cm (21.0 in) torpedo tubes in the bow and four 2 cm (0.79 in) 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.
U-2551 was deliberately run aground by her crew on 5 May 1945 in a bay named Solitüde of the suburb of Flensburg named Mürwik in N. Germany. Post-war, she was destroyed by the Royal Navy on 23 July 1945, and the wreck broken up.