German submarine U-523

German submarine U-523 was a Type IXC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 4 August 1941 at the Deutsche Werft yard in Hamburg as yard number 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.

Design
German Type IXC submarines were slightly larger than the original Type IXBs. U-523 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 shp 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-523 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
U-523 departed Kiel on 9 February 1943 and sailed out into the mid-Atlantic. On the morning of 19 March the 5,848 GRT American merchant ship Mathew Luckenbach, part of Convoy HX 229 en route to the UK from New York City, was hit by two torpedoes fired by GS U-527. 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.

Second 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.

Third and fourth 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.

Wolfpacks
U-523 took part in four wolfpacks, namely:
 * Burggraf (24 February – 5 March 1943)
 * Westmark (6 – 11 March 1943)
 * Stürmer (11 – 20 March 1943)
 * Seeteufel (23 – 30 March 1943)