History
Nazi Germany
Name	U-777
Ordered	20 January 1941
Builder	Kriegsmarinewerft Wilhelmshaven
Yard number	160
Laid down	5 June 1943
Launched	25 March 1944
Commissioned	9 May 1944
Decommissioned	22 November 1944
Fate	Sunk in air raid on 15 October 1944, raised on 22 November 1944 Scuttled on 5 May 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 1 × 8.8 cm (3.46 in) deck gun (220 rounds) 1 × 3.7 cm (1.5 in) Flak M42 AA gun 2 × twin 2 cm (0.79 in) C/30 anti-aircraft guns
Service record
Part of:	31st U-boat Flotilla 9 May – 15 October 1944
Identification codes:	M 17 108
Commanders:	Oblt.z.S. Günter Ruperti 9 May – 15 October 1944
Operations:	None
Victories:	None

German submarine U-777 was a German Type VIIC U-boat built in World War II, launched on 25 March 1944, and commissioned on 9 May, by its sole commander, Oberleutnant zur See Günter Ruperti.

Design

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-777 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.^[1] 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).^[1]

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).^[1] 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-777 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), one 3.7 cm (1.5 in) Flak M42 and two twin 2 cm (0.79 in) C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.^[1]

It underwent training with the 31st U-boat Flotilla, but did not participate in any patrols during its five-month career of active service. It was destroyed at 20:02 hours on the night of 15/16 October 1944, during a British air raid on Wilhelmshaven, Germany, at position 53°51′N 08°10′E / 53.850°N 8.167°E / 53.850; 8.167. One crewman was killed.^[2]

Other notes

• Despite the fact that many other U-boats lost men due to accident, disease and various other causes, the crew of U-777 did not suffer any casualties until she was destroyed and was sunk.
• The commander of the ship, Günter Ruperti, also commanded U-3039 during World War II, by which time he had been promoted to Kapitänleutnant. He commanded U-3039 from March 1945 until May 1945, taking up his post only about five months after U-777 was sunk.