German submarine U-122 (1939)

German submarine U-122 was a Type IXB U-boat of Nazi Germany's Kriegsmarine that operated during World War II.

She was ordered on 15 December 1937 and was laid down on 5 March 1939 at DeSchiMAG AG Weser, Bremen, becoming yard number 954. She was launched on 20 December 1939 and commissioned under her first and only commander, Korvettenkapitän Hans-Günther Looff on 30 March 1940.

Design
Type IXB submarines were slightly larger than the original Type IX submarines, later designated IXA. U-122 had a displacement of 1051 t when at the surface and 1178 t while submerged. The U-boat had a total length of 76.50 m, a pressure hull length of 58.75 m, a beam of 6.76 m, a height of 9.60 m, and a draught of 4.70 m. The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4400 PS for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1000 PS for use while submerged. She had two shafts and two 1.92 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 18.2 kn and a maximum submerged speed of 7.3 kn. When submerged, the boat could operate for 64 nmi at 4 kn; when surfaced, she could travel 12000 nmi at 10 kn. U-122 was fitted with six 53.3 cm torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm SK C/32 naval gun, 180 rounds, and a 3.7 cm SK C/30 as well as a 2 cm C/30 anti-aircraft gun. The boat had a complement of forty-eight.

Service history
She carried out two combat patrols with the 2nd U-boat Flotilla. On her first foray in May 1940, she transported an 88 mm Flak (anti-aircraft gun) with ammunition, some bombs, 90 cbm (some 750 oilbbl) of fuel for aircraft and some motor oil to Trondheim during the Norwegian campaign. On 23 May she encountered an enemy submarine in the North Atlantic, but neither boat attacked each other. She sank a single ship during her career, the SS Empire Conveyor (5911 GRT) on 20 June 1940.

She was declared missing with all hands after 22 June 1940 between the North Sea and the Bay of Biscay. She may have collided with the vessel San Felipe on 22 June, or been sunk by depth charges from the corvette HMS Arabis (K73) on 23 June.

Some Dutch and Polish authors suggest that U-122 was sunk after being rammed by the submarine ORP Wilk on 20 June soon after midnight. The first officer of Wilk reported in his memoirs ramming a surfaced U-boat while it was attempting to dive. This version was often disputed and an alternative theory states that Wilk instead rammed and sank the Dutch submarine O-13, or most probably, a minefield protector buoy rather than a submarine. Moreover, the U-122 sank the SS Empire Conveyor during the day following the Wilk's collision, and she was too far away then, and reported her position for the last time on 21 June.