The ‘Biber’ (’Beaver’) was the third one-man midget submarine type. It could be transported by road or by specially equipped ‘mother’ submarines and proved to be quite successful in 1944-45.
The best of all the German World War II midget submarines was the two-man 15.2-tonne (15-ton) ‘Seehund‘ (’Seal’), the only type which was truly capable of operating independently.
Given their almost complete lack of success, it comes as something of a surprise to discover the extent of the German Navy’s midget submarine programme. At least six different types of craft were produced in considerable numbers – certainly over 1500 in total – from 1943 (the programme was behind those of Britain, Italy, and especially Japan). The first types would more accurately be called semi-submersibles, for they all ran with their upper surfaces barely awash, the solitary crewman being able to see out through ports in the vestigial conning tower which enclosed his head. The first constructed was known as the ‘Hecht’ (Tike’); it was battery-powered and really little more than a manned torpedo with a detachable warhead. An improved model, the ‘Neger’ (’Negro’) had a petrol engine, and carried an underslung torpedo. It worked well enough, but its solitary crewman had to breathe oxygen, and was thus restricted in what he could do. Two larger one-man types, the ‘Molch’ (’Salamander’) and the ‘Marder’ (’Marten’), were slightly more practical, with recirculating air supplies. The former carried two underslung torpedoes, and was used with some success against Allied shipping in the Scheldt in late 1944 and 1945. The ‘Marder’ carried just one torpedo but could submerge completely in order to attack.
The next step was to produce a true submersible, a proper submarine in miniature. The first attempt resulted in a single-seater experimental vehicle called the ‘Hai’ (’Shark’), powered by a petrol engine and batteries, which could make 20 knots for two hours on its electric motor. The ‘Hai’ was developed into the one-man ‘Biber’ (’Beaver’), which displaced 3.04 tonnes (3 tons) and carried two torpedoes slung beneath the hull; a later version of the ‘Biber’ was capable of carrying a second crewmember. Over 300 were built and used with a measure of success in the Scheldt Estuary and off Murmansk in the convoy assembly area. The ‘Biber’ could be transported by road or by air as well as by specially modified conventional submarines.
The most successful of the German midget submarines was the two-man ‘Seehund’ (’Seal’). This was much bigger at 15.2 tonnes (15 tons) displacement, and had jettisonable auxiliary fuel tanks, which gave it a range of around 800km (500 miles). It could make 8 knots on the surface and 6 knots submerged. The ‘Seehund’ also gained some success in the mouth of the Scheldt. Unconfirmed reports from German sources claim that it also operated against merchant shipping in the Thames estuary and off Margate.
