German submarine U-1023 was a Type VIIC/41 U-boat of Germany's Kriegsmarine. She was commissioned on 15 June 1944 with Oberleutnant Wolfgang Strenger in command. U-1023 sank one ship and damaged one more for a total of 7,345 GRT and 335 tons. After the war she was sunk in Operation Deadlight. Of the 156 U-boats that surrendered to the allies at the end of the war, 116 were scuttled as part of Operation Deadlight. The Royal Navy carried out the operation, and planned to tow the submarines to three areas about 100 miles (160 km) north-west of Ireland and sink them. They intended to use 36 boats as practice targets for aerial attack. Submarines that were not used for target practice were to be sunk with explosive charges, with naval gunfire as a fall-back option if that failed. When Operation Deadlight began, the navy found that many of the U-boats were in poor condition from being moored in exposed harbours while awaiting disposal. These issues, combined with poor weather, sank 56 of the boats before they reached the scuttling areas, and those that did reach the area were generally sunk by gunfire rather than explosive charges. The first sinking took place on 17 November 1945 and the last on 11 February 1946.