SM U-81

History
German Empire
Name:	U-81
Ordered:	23 June 1915
Builder:	Germaniawerft, Kiel
Yard number:	251
Laid down:	31 August 1915
Launched:	24 June 1916
Commissioned:	22 August 1916
Fate:	1 May 1917 - Torpedoed W of Ireland at 51°33′N 13°38′W / 51.550°N 13.633°W / 51.550; -13.633Coordinates: 51°33′N 13°38′W / 51.550°N 13.633°W / 51.550; -13.633 by HM Sub E54. 31 dead, seven survivors.
General characteristics
Displacement:	808 t (795 long tons) surfaced 946 t (931 long tons) submerged
Length:	70.06 m (229 ft 10 in) (o/a) 55.55 m (182 ft 3 in) (pressure hull)
Beam:	6.30 m (20 ft 8 in) (oa) 4.15 m (13 ft 7 in) (pressure hull)
Height:	8.00 m (26 ft 3 in)
Draught:	4.02 m (13 ft 2 in)
Installed power:	2 × 2,400 PS (1,765 kW; 2,367 shp) surfaced 2 × 1,200 PS (883 kW; 1,184 shp) submerged
Propulsion:	2 shafts, 2 × 1.70 m (5 ft 7 in) propellers
Speed:	16.8 knots (31.1 km/h; 19.3 mph) surfaced 9.1 knots (16.9 km/h; 10.5 mph) submerged
Range:	11,220 nmi (20,780 km; 12,910 mi) at 8 knots (15 km/h; 9.2 mph) surfaced 56 nmi (104 km; 64 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged
Test depth:	50 m (160 ft)
Complement:	4 officers, 31 enlisted
Armament:	6 × 50 cm (19.7 in) torpedo tubes (four bow, two stern) 12-16 torpedoes 1 × 10.5 cm (4.1 in) SK L/45 deck gun
Service record
Part of:	Imperial German Navy IV Flotilla 18 October 1916 – 1 May 1917
Commanders:	Kptlt. Raimund Weisbach 22 August 1916 – 1 May 1917
Operations:	4 patrols
Victories:	30 ships sunk 88,483 GRT 2 ships damaged 3,481 GRT

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.

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. She had a total length of 70.06 m (229 ft 10 in), a pressure hull length of 55.55 m (182 ft 3 in), a beam of 6.30 m (20 ft 8 in), a height of 8 m (26 ft 3 in), and a draught of 4.02 m (13 ft 2 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).

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, 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 11,220 nautical miles (20,780 km; 12,910 mi) at 8 knots (15 km/h; 9.2 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 cm (4.1 in) SK L/45 deck gun. She had a complement of thirty-five (thirty-one crew members and four officers).

...
Wikipedia