German submarine U-46 was a Type VIIB U-boat of Nazi Germany's Kriegsmarine during World War II.

The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two BBC GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged.

[1] U-46 was ordered on 21 November 1936 and laid down on 24 February 1937 at Friedrich Krupp Germaniawerft, Kiel, becoming yard number 581.

She set out from Kiel on her first war patrol on 19 August 1939 in the North Sea, returning on 15 September.

[2] On 13 April 1940 during the battles around Narvik, Norway U-46 was depth charged and severely damaged by British destroyers supporting HMS Warspite.

[2] Sohler eventually commanded U-46 for six war patrols, but failed to score any successes against enemy shipping.

Endrass had been Günther Prien's First Officer aboard U-47 when they had infiltrated Scapa Flow and sunk the battleship HMS Royal Oak.

He was immediately successful, on 6 June U-46 scored her first kill, the armed merchant cruiser Carinthia.

Endrass claimed that Captain Eric Jones and his crew "lost their heads completely" at the shot across the bows from his U-boat.

The crew of Luimneach abandoned ship and Endrass sank her with gunfire, as he had no torpedoes remaining.

Following an inquiry on 4 March 1941, Dönitz concluded that the U-boat acted correctly in sinking an abandoned ship.

[2] Her next patrol took her from Kiel on 12 February 1941 to St. Nazaire where she arrived on 4 March after 21 days at sea, during which she had not attacked any ships.