s were slightly larger than the original German Type IX submarines, later designated IXA. U-122 had a displacement of when at the surface and while submerged. The U-boat had a total length of, a pressure hull length of, a beam of, a height of, and a draught of. The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to. The submarine had a maximum surface speed of and a maximum submerged speed of. When submerged, the boat could operate for at ; when surfaced, she could travel at. U-122 was fitted with six torpedo tubes, 22 torpedoes, one SK C/32 naval gun, 180 rounds, and a SK C/30 as well as a 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 with ammunition, some bombs, 90 cbm 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 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 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 memoiries 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 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.
