German submarine U-73 was a Type VIIB U-boat of Nazi Germany's Kriegsmarine during World War II.

She was laid down by Vegesacker Werft, Germany as yard number 1 on 5 November 1939, launched on 27 July 1940 and commissioned on 30 September of the same year under Kapitänleutnant (Kptlt.)

The submarine was powered by two MAN M 6 V 40/46 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.

Her route took her the length of the North Sea, through the 'gap' separating the Faroe and Shetland Islands, north-west toward Iceland, then south and west.

[citation needed] Her next victim was SS Empire Endurance on 20 April, southwest of Rockall; also lost when this ship went down were two launches which were being carried as deck cargo: ML-1003 and M-1037.

203 Squadron RAF about 50 nautical miles (93 km; 58 mi) north northwest of Derna in Libya on 22 March 1942.

On 11 August 1942 she sank the aircraft carrier HMS Eagle during Operation Pedestal (supplying Malta).

[7] U-73 was depth-charged during an unsuccessful attack on Operation Torch (the invasion of French North Africa) troopships on 7 November.

She sank the 7,200-ton American Liberty ship SS Arthur Middleton from the convoy UGS 3 on 1 January 1943[10] 3 nautical miles (5.6 km; 3.5 mi) off Oran.

[11] The Brinkburn exploded with such force that damaged food cans and two 75 mm shells, still in their transit boxes, were found on the U-boat's bridge.

Patrol number thirteen took U-73 to Sicily; she reached the Straits of Messina (between the island and the Italian mainland),[12] on 19 August 1943.

[14] Hull turbulence made the U-boat's hydrophones ineffective at the speed U-73 was leaving the area, so she was unaware of the destroyers until Woolsey's pattern of depth charges exploded below the submarine at 18:39.

[15] All ballast tanks were blown to bring U-73 to the surface as inflowing water exceeded pumping capacity.