German submarine U-337

German submarine U-337 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

The submarine was laid down on 1 April 1941 at the Nordseewerke yard at Emden, launched on 26 March 1942, and commissioned on 6 May 1942 under the command of Oberleutnant zur See Kurt Ruwiedel.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-337 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 AEG GU 460/8-276 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-337 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, and a 2 cm C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.

FLAK weaponry
U-337 was mounted with two 2cm Flak C38 in a M 43U Zwilling mount with short folding shield on the upper Wintergarten. The M 43U mount was used on a number of U-boats (GS U-249, GS U-250, GS U-278, GS U-250, GS U-475, GS U-853, GS U-1058, GS U-1109, GS U-1023, GS U-1105, GS U-1165 and GS U-1306).

Service history
After training with the 5th U-boat Flotilla at Kiel, U-337 was transferred to the 6th U-boat Flotilla based at Saint-Nazaire in France for front-line service. After sailing from Kiel on 24 December 1942, the U-boat sailed north and then west into the Atlantic south of Iceland. Her last radio report, on 3 January 1943, gave her position as 63°N, -12°W. The U-boat was never heard from again. Its fate remains an unsolved mystery.

Previously recorded fate
A postwar assessment stated U-337 was sunk on 15 January 1943 southwest of Iceland by depth charges from a British Flying Fortress of No. 206 RAF. This attack was actually against U-632, inflicting no damage.