German submarine U-181

German submarine U-181 was a Type IXD2 U-boat of the Nazi German Kriegsmarine during World War II. The submarine was laid down on 15 March 1941 at the AG Weser yard at Bremen as 'werk' 1021. She was launched on 30 December 1941 and commissioned on 9 May 1942 under the command of Kapitänleutnant Wolfgang Lüth. After training with the 4th U-boat Flotilla at Stettin, U-181 was attached to the 10th flotilla for front-line service on 1 October 1942, then transferred to the 12th flotilla on 1 November.

Operational history
Under Lüth's command she sailed on two long combat patrols in late–1942 and 1943, haunting the waters off South Africa and Mozambique and sinking 22 ships for a total of 103,712 tons, making Lüth the second most successful U-boat commander of the war (after Otto Kretschmer) and earning him promotion to Korvettenkapitän and the Knight's Cross of the Iron Cross with Oak Leaves, Swords and Diamonds. He went on to command the 22nd U-boat Flotilla.

On 1 November 1943 under the command of Fregattenkapitän Kurt Freiwald and part of the 12th U-boat Flotilla, U-181 sailed from her base in Bordeaux, France to Penang, Malaya (now Malaysia) in mid–1944, sinking four ships totalling 24,869 tons. On 1 October 1944 the U-boat was transferred to the 33rd U-boat Flotilla. She carried out only one patrol in the Indian Ocean, in 1944–1945, sinking a single ship of 10,198 tons.

After Germany's surrender in May 1945 the U-boat was taken over by Japan at Singapore and commissioned as I-501 on 15 July 1945. She surrendered to Allied forces there in August 1945, and was sunk on 12 February 1946 in the Strait of Malacca, in position 3.09722°N, 100.69722°W, by the British frigates HMS Loch Glendhu (K639) and HMS Loch Lomond (K437).