German submarine U-23 (1936)

German submarine U-23 was a Type IIB U-boat of the Nazi German Kriegsmarine, built in Germaniawerft, Kiel. She was laid down on 11 April 1936 and commissioned on 24 September.

Career
At 4:45 am on 4 October 1939, U-23 scored one of the Kriegsmarine's early successes of the war when she torpedoed and sank with gunfire, the merchant ship Glen Farg about 60 mi south-southwest of Sumburgh Head (southern Shetland). One person died, while 16 survivors were picked up by HMS Firedrake (H79) and landed at Kirkwall the next day.

In 16 patrols U-23 sank seven ships for a total of including two warships, as well as damaging a warship and an auxiliary warship.

Over the course of her service with the Kriegsmarine, U-23 had ten commanding officers, the most famous of whom was Kapitänleutnant Otto Kretschmer, who went on to become the top scoring U-boat ace. After service in the Atlantic with the 1st U-boat Flotilla, U-23 served as a training boat with the 21st U-boat Flotilla from July 1940 until September 1942. U-23 was then refitted and transported overland to the Black Sea port of Konstanza, Romania, with the 30th U-boat Flotilla until September 1944.

Fate
U-23 was scuttled by her crew on 10 September 1944, off the coast of Turkey in the Black Sea at position 41.18333°N, 30°W to prevent her capture by the advancing Soviets.

On 3 February 2008, The Daily Telegraph newspaper reported that U-23 had been discovered by Selçuk Kolay, a Turkish marine engineer, in 160 ft of water, three miles from the town of Agva.