German submarine U-904

German submarine U-904 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

She was ordered on 16 July 1942, and was laid down on 10 September 1942 at Flender Werke AG, Lübeck, as yard number 330. She was launched on 7 August 1943 and commissioned under the command of Leutnant zur See Detlev Fritz on 25 September 1943.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-904 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 SSW GU 343/38-8 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-904 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes or 26 TMA mines, 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 44 — 52 men.

Service history
On 4 May 1945, U-904 was scuttled at the U-boat base in Eckernförde.