German submarine U-777

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 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two Garbe, Lahmeyer & Co. RP 137/c double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-777 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, (220 rounds), one 3.7 cm Flak M42 and two twin 2 cm C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.

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 53.85°N, 8.16667°W. One crewman was killed.

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 GS 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.