German submarine U-923

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 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-923 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, 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 54.51667°N, 10.3°W.