The Hase (Polish Hare) was the prototype of the German miniature submarine of World War II. The block was armed with one torpedo. Probably only one copy of this ship was made. The Hase was designed as a modernized and improved version of the Marder miniature submarine, which was first used in combat in August 1944. Hase was almost certainly built and tested at the turn of 1944-1945. Compared to its predecessor, the Hase was lengthened, but kept the diameter of the case (533 mm). An attempt to use Walter's system, which uses hydrogen peroxide for propulsion, was a novelty. However, during the tests, the new engine, like larger underwater installations, caused significant problems and turned out to be ineffective. Finally, mainly due to problems with the power plant, Hase's development was stopped very quickly.
