German submarine U-923

U-570 Type VIIC submarine that was captured by the British in 1941. This U-boat is almost identical to U-923.
History
Nazi Germany
Name:	U-923
Ordered:	6 June 1941
Builder:	Neptun Werft AG, Rostock
Yard number:	510
Laid down:	21 February 1942
Launched:	7 August 1943
Commissioned:	4 October 1943
Fate:	Sunk on 9 February 1945
General characteristics
Class & type:	Type VIIC submarine
Displacement:	769 tonnes (757 long tons) surfaced 871 t (857 long tons) submerged
Length:	67.10 m (220 ft 2 in) o/a 50.50 m (165 ft 8 in) pressure hull
Beam:	6.20 m (20 ft 4 in) o/a 4.70 m (15 ft 5 in) pressure hull
Height:	9.60 m (31 ft 6 in)
Draught:	4.74 m (15 ft 7 in)
Installed power:	2,800–3,200 PS (2,100–2,400 kW; 2,800–3,200 bhp) (diesels) 750 PS (550 kW; 740 shp) (electric)
Propulsion:	2 shafts 2 × diesel engines 2 × electric motors
Speed:	17.7 knots (32.8 km/h; 20.4 mph) surfaced 7.6 knots (14.1 km/h; 8.7 mph) submerged
Range:	8,500 nmi (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph) surfaced 80 nmi (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth:	220 m (720 ft) Crush depth: 250–295 m (820–968 ft)
Complement:	4 officers, 44–52 enlisted
Armament:	5 × 53.3 cm (21 in) torpedo tubes (four bow, one stern) 14 × torpedoes or 26 TMA mines 1 × 8.8 cm (3.46 in) deck gun (220 rounds) various AA guns
Service record
Part of:	23rd U-boat Flotilla (Training) 4 October 1943 – 9 February 1945
Commanders:	Oblt.z.S. Heinz Frömmer 4 October 1943 – 9 February 1945
Operations:	No patrols
Victories:	None

German submarine U-923 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

She was ordered on 6 June 1941, and was laid down on 21 February 1942 at Neptun Werft AG, Rostock, as yard number 510. She was launched on 7 August 1943 and commissioned under the command of Oberleutnant zur See Heinz Frömmer on 4 October 1943.

Design

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-923 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged. She had a total length of 67.10 m (220 ft 2 in), a pressure hull length of 50.50 m (165 ft 8 in), a beam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two SSW GU 343/38-8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).

The submarine had a maximum surface speed of 17.7 knots (32.8 km/h; 20.4 mph) and a maximum submerged speed of 7.6 knots (14.1 km/h; 8.7 mph). When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph). U-923 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes or 26 TMA mines, one 8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and an anti-aircraft gun. The boat had a complement of between 44 — 52 men.

Service history

U-923 sunk 9 February 1945, in the Bay of Kiel in the Baltic Sea after striking a British air-laid mine. The crew of 48 were all lost.

The wreck is located at .