Commissioned as a secret weapon by the commander of submarines in May of 1944, the midget submarine "Beaver" was designed, built and handed over to the troops in six weeks time only. The mini-submarine was propelled by one fuel- and one electric engine. The speed when surfaced was 5,8km/h and 4,7km/h submerged. The first time she went into action was in a combat unit of Admiral Heye in the night of 29th to 30th August 1944. Altogether 18 Beaver submarines took part in this attack in which a landing craft as well as a Liberty-transport ship were sent to the bottom. In spirit of these achievements technical problems prevented the Beaver from meeting the expectations that had been placed in her. But few of the totally 325 units built have been preserved.
The specimen on exhibit in the Technik Museum Speyer was discovered in 1976 when a shipping channel was dreged out near Rotterdam in the Netherlands.