Submarine Snorkel

A submarine snorkel is a device that lets a submarine's engine run while the vessel stays submerged, drawing air down from above the surface through a tube so a diesel engine can keep operating without the submarine having to surface. The concept originated with Dutch naval engineers: the Royal Netherlands Navy experimented with such a system as early as 1938 aboard the submarines O-19 and O-20, in a design credited to Jan Jacob Wichers. After Germany captured the Dutch submarines O-25 and O-26 in 1940, the German Kriegsmarine adopted and refined the technology, first retrofitting it to U-boats in 1943 and building it into newer submarine classes during the war's final years.