History
Nazi Germany
Name	U-312
Ordered	5 June 1941
Builder	Flender Werke, Lübeck
Yard number	312
Laid down	10 April 1942
Launched	27 February 1943
Commissioned	21 April 1943
Fate	Surrendered on 9 May 1945, sunk as part of Operation Deadlight on 29 November 1945
General characteristics
Class and 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	230 m (750 ft) Crush depth: 250–295 m (820–968 ft)
Complement	4 officers, 40–56 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) 2 × twin 2 cm (0.79 in) C/30 anti-aircraft guns
Service record[1][2]
Part of:	8th U-boat Flotilla 21 April – 30 November 1943 6th U-boat Flotilla 1 – 31 December 1943 11th U-boat Flotilla 1 January – 31 August 1944 13th U-boat Flotilla 1 September 1944 – 8 May 1945
Identification codes:	M 13 550
Commanders:	Kptlt. Kurt-Heinz Nicolay 21 April 1943 – 1 December 1944 Oblt.z.S. Friedrich-Georg Herrle 2 December 1944 – 31 January 1945 Oblt.z.S. Jürgen von Gaza 1 February – 9 May 1945
Operations:	8 patrols: 1st patrol: a. 23 January – 4 February 1944 b. 7 – 29 February 1944 2nd patrol: 15 March – 12 April 1944 3rd patrol: 29 April – 13 May 1944 4th patrol: 7 September – 2 October 1944 5th patrol: a. 17 October – 8 November 1944 b. 5 – 8 December 1944 6th patrol: a. 14 December 1944 – 4 January 1945 b. 7 – 10 March 1945 7th patrol: 12 March – 9 April 1945 8th patrol: a. 16 April – 8 May 1945 b. 9 May 1945 c. 12 May 1945 d. 15 – 19 May 1945
Victories:	None

German submarine U-312 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 10 April 1942 at the Flender Werke yard at Lübeck as yard number 312, launched on 27 February 1943 and commissioned on 21 April under the command of Oberleutnant zur See Kurt-Heinz Nicolay.

During her career, the U-boat sailed on eight combat patrols, but sank no ships. She surrendered on 9 May 1945 and was sunk as part of Operation Deadlight on 29 November 1945.^[1]

She was a member of eight wolfpacks.

Design

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-312 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.^[3] 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 Garbe, Lahmeyer & Co. RP 137/c 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).^[3]

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).^[3] 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-312 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and two twin 2 cm (0.79 in) C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.^[3]

Service history

After training with the 8th U-boat Flotilla, U-312 was transferred to the 6th flotilla, for front-line service on 1 December 1943.^[1] She made the short voyage from Kiel in Germany to Bergen in Norway in the first half of January 1944.

First, second and third patrols

She left Bergen on 23 January 1944 and travelled through the north Norwegian Sea and southwest of Bear Island, arriving in Hammerfest on 29 February.

Her second patrol was similar to the first, sailing through the Norwegian, Greenland and Barents Seas. She docked at Narvik on 12 April 1944.

The boat sortied for a third time from Narvik on 29 April 1944. She arrived back at that port on 13 May and moved to Trondheim.

Fourth and fifth patrols

Her fourth foray was relatively uneventful, starting and finishing in Narvik.

The submarine's fifth patrol was only notable for clearing the North Cape and passing east of Murmansk.

Sixth, seventh and eighth patrols

Patrol number six was slightly different in that it took her as far as the northern Scottish coast, arriving there on 24 December 1944.

The boat was now based at Kilbotn, from whence she sailed on her seventh and eighth patrols.

Surrender and fate

Following the German capitulation, U-312 was moved, first from Kilbotn to Narvik, then to Skjomenfjord before arriving at Loch Eriboll in Scotland on 19 May 1945 in preparation for Operation Deadlight. She was finally transferred to Lisahally and sunk on 29 November by the guns of HMS Onslow.^[4]