German submarine U-551

German submarine U-551 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 21 November 1939 at the Blohm & Voss yard in Hamburg as yard number 527, launched on 14 September 1940, and commissioned on 7 November 1940 under the command of Kapitänleutnant Karl Schrott.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-551 had a displacement of 769 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two BBC GG UB 720/8 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-551 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, 220 rounds, and a 2 cm C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Service history
Attached to the 7th U-boat Flotilla, she first sailed from Kiel, Germany to Bergen, Norway, before commencing her first and only war patrol on 18 March 1941. She sailed to the waters south of Iceland, and there on 23 March, in position 62.61667°N, -16.78333°W, she was sunk by depth charges from the British anti-submarine warfare trawler HMT Visenda. All 45 hands were lost.