German submarine U-903

German submarine U-903 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 25 August 1942 at Flender Werke AG, Lübeck, as yard number 329. She was launched on 17 July 1943 and commissioned under the command of Oberleutnant zur See Hans Hellmann on 4 September 1943.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-903 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-903 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
On 5 May 1945, U-903 was scuttled in the Gelting Bay near Gelting. She was later raised and broken up in 1947.