Type U 23 submarine

Class overview
Builders	Germaniawerft, Kiel
Operators	Imperial German Navy
Preceded by	Type U 19
Succeeded by	Type U 27
Completed	4
Lost	2
General characteristics [1]
Displacement	669 t (658 long tons) surfaced 864 t (850 long tons) submerged
Length	64.70 m (212.3 ft)
Beam	6.32 m (20 ft 9 in)
Draught	3.45 m (11 ft 4 in)
Propulsion	2 shafts 2 × Germania 6-cylinder two stroke diesel motors with 1,800 PS (1,320 kW; 1,780 shp) 2 × SSW double Motordynamos with 1,200 PS (880 kW; 1,180 shp) 450rpm surfaced 330 rpm submerged
Speed	16.7 knots (30.9 km/h; 19.2 mph) surfaced 10.3 knots (19.1 km/h; 11.9 mph) submerged
Range	9,910 nmi (18,350 km; 11,400 mi) at 8 knots (15 km/h; 9.2 mph) surfaced 85 nmi (157 km; 98 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged
Test depth	about 50 m (160 ft)
Complement	4 officers, 31 men
Armament	4 × 50 cm (19.7 in) torpedo tubes (2 each bow and stern) 6 torpedoes 1 × 8.8 cm (3.5 in) SK L/30 gun

Type U 23 was a class of U-boats built during World War I by the Kaiserliche Marine. Four Boats were ordered from Germaniawerft on 18 March 1911.^[2]

Type U 23s had an overall length of 64.70 m (212 ft 3 in) The boats' beam was 6.32 m (20 ft 9 in), the draught was 3.45 m (11 ft 4 in). The boats displaced 669 tonnes (658 long tons) when surfaced and 864 t (850 long tons) when submerged.^[1]

Type U 23s were fitted with two Germaniawerft 6-cylinder two-stroke diesel engines with a total of 1,800 metric horsepower (1,324 kW; 1,775 bhp) for use on the surface and two SSW double-acting electric motors with a total of 880 kW (1,196 PS; 1,180 shp) for underwater use. These engines powered two shafts, which gave the boats a top surface speed of 16.7 knots (30.9 km/h; 19.2 mph), and 10.3 knots (19.1 km/h; 11.9 mph) when submerged. Cruising range was 9,910 nautical miles (18,350 km; 11,400 mi) at 8 knots (15 km/h; 9.2 mph) on the surface and 85 nautical miles (157 km; 98 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged.^[1] Diving depth was 50 m (164 ft 1 in).

The U-boats were armed with four 50 cm (20 in) torpedo tubes, two fitted in the bow and two in the stern, and carried six torpedoes. All boats received one 8.8 cm (3.5 in) SK L/30 deck gun. The boats' complement was 4 officers and 31 enlisted.^[1]

• Gröner, Erich; Jung, Dieter; Maass, Martin (1991). German Warships 1815–1945, U-boats and Mine Warfare Vessels. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
• Herzog, Bodo (1993). Deutsche U-Boote : 1906 - 1966 [German U-boats : 1906 - 1966] (in German). Erlangen: Müller. ISBN 9783860700365.
• Möller, Eberhard; Brack, Werner (2004). The Encyclopedia of U-Boats. London: Chatham. ISBN 1-85367-623-3.
• Rössler, Eberhard (2001). The U-boat: The evolution and technical history of German submarines. London: Cassell & Co. ISBN 0-304-36120-8.