|Ordered:||20 January 1941|
|Builder:||DeSchiMAG AG Weser, Bremen|
|Laid down:||21 July 1942|
|Launched:||31 October 1942|
|Commissioned:||29 May 1943|
|Fate:||sunk by aircraft in position Coordinates:|
|Class and type:||Type IXC/40 submarine|
|Height:||9.60 m (31 ft 6 in)|
|Draught:||4.67 m (15 ft 4 in)|
|Test depth:||230 m (750 ft)|
|Complement:||4 officers, 44 enlisted|
|Commanders:||Oblt.z.S.d.R. Berthold Hashagen|
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-846 had a displacement of 1,144 tonnes (1,126 long tons) when at the surface and 1,257 tonnes (1,237 long tons) while submerged. The U-boat had a total length of 76.76 m (251 ft 10 in), a pressure hull length of 58.75 m (192 ft 9 in), a beam of 6.86 m (22 ft 6 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.67 m (15 ft 4 in). The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4,400 metric horsepower (3,240 kW; 4,340 shp) for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1,000 shaft horsepower (1,010 PS; 750 kW) for use while submerged. She had two shafts and two 1.92 m (6 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 18.3 knots (33.9 km/h; 21.1 mph) and a maximum submerged speed of 7.3 knots (13.5 km/h; 8.4 mph). When submerged, the boat could operate for 63 nautical miles (117 km; 72 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 13,850 nautical miles (25,650 km; 15,940 mi) at 10 knots (19 km/h; 12 mph). U-846 was fitted with six 53.3 cm (21 in) torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm (4.13 in) SK C/32 naval gun, 180 rounds, and a 3.7 cm (1.5 in) SK C/30 as well as a 2 cm (0.79 in) C/30 anti-aircraft gun. The boat had a complement of forty-eight.
U-846 was ordered in January 1941 from DeSchiMAG AG Weser in Bremen under the yard number 1052. Her keel was laid down on 21 July 1942. The U-boat was launched the following year on 17 February 1943. The following May she was commissioned into service under the command of Oberleutnant zur See der Reserve Berthold Hashagen (Crew 37) in 4th U-boat Flotilla.
After completing training, U-846 was transferred to 10th U-boat Flotilla and left Kiel for the North Atlantic on 4 December 1943. Joining groups Amrum and Rügen at the end of the month, returning without success to Lorient on 3 March 1944. U-846 left Lorient again on 29 April. During an air attack on 2 May she managed to shoot down one aircraft, Halifax 'H' of No. 58 Squadron RAF. The next day another aircraft attacked the U-boat without success, but early on 4 May a bomb hit from a Wellington, 'M' of 407 Squadron RCAF, sunk U-846 in position .