German Type Mittel U submarine

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

SM U-86, a Mittel U submarine
Class overview
Builders	AG Weser, Bremen Germaniawerft, Kiel Kaiserliche Werft, Danzig Bremer Vulkan, Vegesack
Operators	Imperial German Navy
Preceded by	Type U 66
Completed	46
General characteristics
Displacement	808 tonnes (795 long tons)(surfaced) 946 tonnes (931 long tons) (submerged) 1,160 tonnes (1,140 long tons) (total)
Length	70.60 m (231 ft 8 in) (overall) 55.55 m (182 ft 3 in) (pressure hull)
Beam	6.30 m (20 ft 8 in) (overall) 4.15 m (13 ft 7 in) (pressure hull)
Draught	4.02 m (13 ft 2 in)
Propulsion	2 hp × 2,400 hp (1.5 kW × 1,789.7 kW) (surfaced) 2 hp × 1,200 hp (1.5 kW × 894.8 kW) (submerged)
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 mi (9,750 nmi; 18,060 km) (surfaced) 56 mi (49 nmi; 90 km) (submerged)
Complement	39 men
Armament	16 torpedoes (4/2 in bow/stern tubes) 105mm deck gun with 220 rounds 88mm deck gun

Mittel U U-boats carried 16 torpedoes and had various arrangements of deck guns. Some had only one 88mm gun while others had a single 105mm gun - but most had both originally. In 1917 some of the boats were refitted with a single 105mm gun.

They carried a crew of 39 and had excellent seagoing abilities with a cruising range of around 11,220 miles. Many arrangements from the Mittel U were also seen on the World War II Type IX U-boats when their design work took place 20 years later.

Between 1915 and 1919 46 were built, amongst them U-88 with Walther Schwieger as commander and U-103 with Claus Rücker.