German submarine U-23 (1936)

U-9, a typical Type IIB boat
History
Nazi Germany
Name:	U-23
Ordered:	2 February 1935
Builder:	Germaniawerft, Kiel Galați shipyard, Romania
Yard number:	553
Laid down:	11 April 1936
Launched:	28 August 1936
Commissioned:	24 September 1936
Fate:	Scuttled 10 September 1944, off the coast of Turkey in the Black Sea
General characteristics
Class and type:	IIB coastal submarine
Displacement:	279 t (275 long tons) surfaced 328 t (323 long tons) submerged
Length:	42.70 m (140 ft 1 in) o/a 27.80 m (91 ft 2 in) pressure hull
Beam:	4.08 m (13 ft 5 in) (o/a) 4.00 m (13 ft 1 in) (pressure hull)
Height:	8.60 m (28 ft 3 in)
Draught:	3.90 m (12 ft 10 in)
Installed power:	700 PS (510 kW; 690 bhp) (diesels) 410 PS (300 kW; 400 shp) (electric)
Propulsion:	2 shafts 2 × diesel engines 2 × electric motors
Range:	1,800 nmi (3,300 km; 2,100 mi) at 12 knots (22 km/h; 14 mph) surfaced 35–43 nmi (65–80 km; 40–49 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth:	80 m (260 ft)
Complement:	3 officers, 22 men
Armament:	3 × 53.3 cm (21 in) torpedo tubes 5 × torpedoes or up to 12 TMA or 18 TMB 1 × 2 cm (0.79 in) anti-aircraft gun
Service record
Part of:	Kriegsmarine: 1st U-boat Flotilla 21st U-boat Flotilla 30th U-boat Flotilla
Identification codes:	M 01 984
Commanders:	Eberhard Godt Hans-Günther Looff Otto Kretschmer Heinz Beduhn Heinrich Driver Kurt Reichenbach-Klinke Ernst-Ulrich Brüller Ulrich Gräf Rolf-Birger Wahlen Rudolf Arendt
Operations:	16
Victories:	Seven ships sunk for a total of 11,179 GRT Two warships sunk for a total of 1,410 tons One auxiliary warship of 1,005 GRT damaged One warship of 56 tons damaged Three ships declared a total loss for a total of 18,199 GRT

German submarine U-23 was a Type IIB U-boat of Nazi Germany's Kriegsmarine, built in Germaniawerft, Kiel. She was laid down on 11 April 1936 and commissioned on 24 September.

German Type IIB submarines were enlarged versions of the original Type IIs. U-23 had a displacement of 279 tonnes (275 long tons) when at the surface and 328 tonnes (323 long tons) while submerged. Officially, the standard tonnage was 250 long tons (250 t), however. The U-boat had a total length of 42.70 m (140 ft 1 in), a pressure hull length of 28.20 m (92 ft 6 in), a beam of 4.08 m (13 ft 5 in), a height of 8.60 m (28 ft 3 in), and a draught of 3.90 m (12 ft 10 in). The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of 700 metric horsepower (510 kW; 690 shp) for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of 460 metric horsepower (340 kW; 450 shp) for use while submerged. She had two shafts and two 0.85 m (3 ft) propellers. The boat was capable of operating at depths of up to 80–150 metres (260–490 ft).

The submarine had a maximum surface speed of 12 knots (22 km/h; 14 mph) and a maximum submerged speed of 7 knots (13 km/h; 8.1 mph). When submerged, the boat could operate for 35–42 nautical miles (65–78 km; 40–48 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 3,800 nautical miles (7,000 km; 4,400 mi) at 8 knots (15 km/h; 9.2 mph). U-23 was fitted with three 53.3 cm (21 in) torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a 2 cm (0.79 in) anti-aircraft gun. The boat had a complement of twentyfive.