German submarine U-735

German submarine U-735 was a Type VIIC U-boat built for the German Kriegsmarine for service during World War II. She served as a training boat preparing U-boat crews for service in the Atlantic Ocean. Her home base was Horten in Norway, from which she operated on short coastal patrols, practicing in fjords and channels for submarine warfare. A Type VIIC U-boat, U-735 was very useful for preparing sailors and officers for service in modern boats, as opposed to the new models usually used in training.

Commissioned at Christmas 1942 in Danzig after an exceptionally long building period, U-735 was given to Kptlt. Hans-Joachim Börner, who remained in command of the boat right up to her destruction exactly two years later, when he was killed on board his ship. Dispatched to Norway, Börner soon became an expert on the Norwegian seaways, and was able to train a large number of sailors on his practice missions from Horten.

On the 28 December 1944, RAF Bomber Command sought to eradicate the menace of submarines sailing from Norwegian bases, and launched a major raid on Horten. U-735 was anchored in the naval harbour at Horten. When the air raid alarm came at 21.30, U-735 eventually succeeded in leaving the harbour, having had trouble starting her diesels. At 23.30 NE of Horten she caught the full force of a bomb, sinking just outside the harbour, south of Mølen Island, with 26 men killed and ten missing, including her captain. Only one crew member survived, plus ten crew members who were on leave in Horten. She was the only U-boat to be lost in the attack. The wreck was rediscovered by a Royal Norwegian Navy sub-sea surveillance ship, Tyr in 1999. A high-resolution SAS image of the wreck made the cover of Sea Technology Magazine in June 2006, and another SAS image of U-735 is made available by the Norwegian Defence Reseasrch Establishment. Two other ships were also sunk in the air attack: MS Holmengraa and MS Nordvard (1925).