German submarine U-523

German submarine U-523 was a Type IXC U-boat of the Nazi German Kriegsmarine during World War II. The submarine was laid down on 4 August 1941 at the Deutsche Werft yard in Hamburg as 'werk' 338. She was launched on 15 April 1942, and commissioned on 25 June under the command of Kapitänleutnant Werner Pietzsch. After training with the 4th U-boat Flotilla in the Baltic Sea, the U-boat was transferred to the 10th flotilla for front-line service on 1 February 1943.

1st patrol
U-523 departed Kiel on 9 February 1943 and sailed out into the mid-Atlantic. On the morning of 19 March the 5,848 ton American merchant ship SS Mathew Luckenbach, part of Convoy HX-229 en route to the UK from New York, was hit by two torpedoes fired by GS U-527. The crew of eight officers, 34 crewmen and 26 armed guards (the ship was armed with one 4 in gun, one 3 in gun, and eight 20 mm guns) abandoned ship in three lifeboats and two rafts, and were picked up later by USCGC Ingham (WHEC-35). Around 20:00 that evening, U-523 discovered the drifting wreck of the Mathew Luckenbach and hit her with a single torpedo, sinking the ship within seven minutes. The U-boat arrived at her new home port of Lorient, in occupied France, on 16 April 1943 after 67 days at sea.

2nd patrol
U-523 sailed from Lorient on 22 May 1943, but on the 24th, still in the Bay of Biscay, she was bombed by a British Whitley medium bomber of No. 10 Squadron RAF. The U-boat was severely damaged and was forced to return to Lorient.

3rd and 4th patrols
U-523 sailed from Lorient briefly on 1 August 1943, for a voyage lasting only three days, before setting out once more on 16 August, and headed south-west.

The U-boat was sunk on 25 August, west of Vigo, Spain, in position 42.05°N, -18.03333°W, by depth charges from the destroyer HMS Wanderer (D74) and the corvette HMS Wallflower (K44). Seventeen of U-523's crew were killed and 37 survived the attack.