Name U-81 Yard number 251 Commissioned 22 August 1916 Launched 24 June 1916 | Ordered 23 June 1915 Laid down 31 August 1915 Construction started 31 August 1915 Draft 4.02 m | |
Fate 1 May 1917 - Torpedoed W of Ireland at by HM Sub E54. 31 dead, seven survivors. Builder Friedrich Krupp Germaniawerft | ||
SM U-81 was one of the 329 submarines serving in the Imperial German Navy (Kaiserliche Marine) in World War I. U-81 was engaged in naval warfare and took part in the First Battle of the Atlantic.
U-81 had one 10.5 cm gun with 140-240 rounds. On 8 February 1917 she torpedoed the SS Mantola 143 nautical miles (265 km; 165 mi) off Fastnet, forcing her crew to abandon her. She then shelled the drifting hulk until being chased away by the Acacia-class sloop HMS Laburnum. Laburnum took the floating hulk under tow, but the line parted in the rough seas, and Mantola was left to sink, which she did on 9 February. She was torpedoed and sunk west of Ireland on 1 May 1917 by HMS E54; 31 of her crew died, there were seven survivors.
Design
German Type U 81 submarines were preceded by the shorter Type UE I submarines. U-81 had a displacement of 808 tonnes (795 long tons) when at the surface and 946 tonnes (931 long tons) while submerged. It had a total length of 229 ft 10 in (70.05 m), a pressure hull length of 182 ft 3 in (55.55 m), a beam of 20 ft 8 in (6.30 m), a height of 26 ft 3 in (8.00 m), and a draught of 13 ft 2 in (4.01 m). 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. It had two 1.7 m (5.6 ft) propeller shafts. It was capable of operating at depths of up to 50 metres (160 ft).
The submarine had a maximum surface speed of 16.8 knots (31.1 km/h; 19.3 mph) and a maximum submerged speed of 9.1 knots (16.9 km/h; 10.5 mph). When submerged, it could operate for 56 nautical miles (104 km; 64 mi) at 5 knots (9.3 km/h; 5.8 mph); when surfaced, it could travel 11,220 nautical miles (20,780 km; 12,910 mi) at 7 knots (13 km/h; 8.1 mph). U-81 was fitted with six 50 centimetres (20 in) torpedo tubes (one at the starboard bow and one starboard stern), twelve to sixteen torpedoes, and one 10.5 centimetres (4.1 in) deck machine gun. It had a complement of thirty-five (thirty-one crew members and four officers).