SM U-88[Note 1] was a Type U 87 submarine built for the Imperial German Navy (Kaiserliche Marine) in World War I. U-88 was engaged in the naval warfare and took part in the First Battle of the Atlantic.
U-88 is most notable for sinking and taking with her Kapitänleutnant Walther Schwieger, responsible for sinking the RMS Lusitania when he was commander of U-20. The submarine came to an end on 5 September 1917 when she struck a British mine and sank in the North Sea north of Terschelling at 53°57′N 4°55′E / 53.950°N 4.917°E / 53.950; 4.917. Everyone on board U-88 was killed.[1]
Type U 87 submarines were preceded by the shorter Type U 81 submarines. U-88 had a displacement of 757 tonnes (745 long tons) when at the surface and 998 tonnes (982 long tons) while submerged.[2] She had a total length of 65.80 m (215 ft 11 in), a pressure hull length of 50.07 m (164 ft 3 in), a beam of 6.20 m (20 ft 4 in), a height of 9.35 m (30 ft 8 in), and a draught of 3.88 m (12 ft 9 in). The submarine was powered by two 2,400 metric horsepower (1,800 kW; 2,400 shp) engines for use while surfaced, and two 1,200 metric horsepower (880 kW; 1,200 shp) engines for use while submerged. She had two propeller shafts. She was capable of operating at depths of up to 50 metres (160 ft).[2]
The submarine had a maximum surface speed of 15.6 knots (28.9 km/h; 18.0 mph) and a maximum submerged speed of 8.6 knots (15.9 km/h; 9.9 mph).[2] When submerged, she could operate for 56 nautical miles (104 km; 64 mi) at 5 knots (9.3 km/h; 5.8 mph); when surfaced, she could travel 11,380 nautical miles (21,080 km; 13,100 mi) at 8 knots (15 km/h; 9.2 mph). U-88 was fitted with four 50 centimetres (20 in) torpedo tubes (two at the bow and two at the stern), ten to twelve torpedoes, one 10.5 cm (4.1 in) SK L/45 deck gun, and probably one 8.8 cm (3.5 in) SK L/30 deck gun. She had a complement of thirty-six (thirty-two crew members and four officers).[2]