Hellmuth Walter

Walter began training as a machinist in 1917 in Hamburg and in 1921 commenced studies in mechanical engineering at the Technische Hochschule in Charlottenburg (now Technische Universität Berlin). He left before completing these studies, however, in order to take up a position at the Stettiner Maschinenbau AG Vulcan, a major shipyard. Walter's experience with marine engines here led him to become interested in overcoming some of the limitations of the internal combustion engine. He reasoned that an engine powered by a fuel source already rich with oxygen would not require an external supply of oxygen (from the atmosphere or from tanks). This would have obvious advantages for powering submarines and torpedoes.

Research suggested that hydrogen peroxide was a suitable monopropellant fuel—in the presence of a suitable catalyst it would break down into oxygen and steam at high temperature. The heat of the reaction would cause the oxygen and steam to expand, and this could be used as a source of pressure. Walter also realised that another fuel could be injected into this hot mixture of gases to provide combustion and therefore more power. He patented this idea in 1925.

Entrepreneur

After working for some time at the Germaniawerft shipyard in Kiel, Walter branched out on his own in 1934 to form his own company, Hellmuth Walter Kommanditgesellschaft (HWK, or Walter-Werke), to further research and development of his ideas. That same year, he made a proposal to the Oberkommando der Kriegsmarine (OKM – Naval High Command) suggesting that a submarine powered by one of these engines would have considerable speed advantages over the conventional combination of diesel engine(s) for surface running and electric motor(s) while submerged. The proposal was met with much scepticism, but Walter persisted, and in 1937 showed his plans to Karl Dönitz, who was able to assist in obtaining a contract to produce a prototype. Construction started in 1939 on a small research submarine designated the V-80. When it was launched in 1940, the submarine demonstrated a top speed of 23 knots submerged, twice that of any submarine in the world at the time. Despite these spectacular results, problems with the production, supply, and safe handling of hydrogen peroxide prevented wide-scale implementation of Walter's revolutionary engine. In the end, only a handful of German Type XVII submarines were built using this engine, and none saw combat.

Post-war career

The end of the war saw all of his research materials confiscated by the British military and Walter and his colleagues taken to the UK to work for the Royal Navy. With Walter's co-operation, one of the German submarines using his drive, the U-1407 was raised from where it had been scuttled and re-commissioned as HMS Meteorite. The Royal Navy constructed two more submarines using AIP engines before abandoning research in this direction in favour of nuclear power.

Allowed to return to Germany in 1948, Walter worked for the Paul Seifert Engine Works. In 1950 he emigrated to the United States and joined the Worthington Pump Corporation of Harrison, New Jersey, eventually becoming vice president of research and development. In 1956 he founded the company Hellmuth Walter GmbH in Kiel, and in 1967 constructed a civilian submarine, STINT, with Walter propulsion.