German submarine U-173

German submarine U-173 was a Type IXC U-boat of Nazi Germany's Kriegsmarine during World War II.

She was laid down at the DeSchiMAG AG Weser yard in Bremen as yard number 1013, launched on 11 August 1941 and commissioned on 15 November with Fregattenkapitän Heinz-Ehler Beucke in command.

U-173 began her service career with training as part of the 4th U-boat Flotilla. She was reassigned to the 2nd flotilla for operations on 1 July 1942.

Design
German Type IXC submarines were slightly larger than the original Type IXBs. U-173 had a displacement of 1120 t when at the surface and 1232 t while submerged. The U-boat had a total length of 76.76 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 18.3 kn and a maximum submerged speed of 7.3 kn. When submerged, the boat could operate for 63 nmi at 4 kn; when surfaced, she could travel 13450 nmi at 10 kn. U-173 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.

First patrol
The boat departed Kiel on 15 June 1942, moved through the North Sea and negotiated the gap between Iceland and the Faroe Islands. She crossed the Atlantic Ocean and entered the Caribbean Sea. She entered Lorient, on the French Atlantic coast, on 20 September.

Second patrol
The submarine attempted the disruption of the Operation Torch landings (the invasion of North Africa) on 11 November 1942. She attacked convoy UGF-1 which was at anchor in Fedhala Roads. She hit three ships, sinking USS Joseph Hewes (AP-50) and damaging two more. One of the damaged vessels, the destroyer USS Hambleton (DD-455), was towed to nearby Casablanca where Seabees cut the ship in two, removed about 40 ft of hull, then joined the two halves together again; she survived the war.

A few days later and further north, U-173 torpedoed but did not sink USS Electra (AKA-4), on 15 November. This vessel also survived the war, not being broken up until 1974.

Loss
The boat was sunk by depth charges from the American destroyers USS Woolsey (DD-437), USS Swanson (DD-443), and USS Quick (DD-490) in the Atlantic Ocean off Casablanca (33.66667°N, -7.58333°W) on 16 November 1942. All fifty-seven hands were lost.