Type U 81 submarine

Class overview
Builders	Germaniawerft, Kiel
Operators	Imperial German Navy
Preceded by	Type UE I
Succeeded by	Type U 87
Completed	6
Lost	4
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 (164 ft 1 in)
Complement	4 officers, 31 enlisted
Armament	4 × 50 cm (19.7 in) torpedo tubes (two bow, two stern); 12-16 torpedoes; 1 × 10.5 cm (4.1 in) SK L/45 deck gun;

Type 81 was a class of U-boats built during World War I by the Kaiserliche Marine.