Pochtovy was a submarine built for the Imperial Russian Navy

Imperial Russian Navy

The Imperial Russian Navy refers to the Tsarist fleets prior to the February Revolution.-First Romanovs:Under Tsar Mikhail Feodorovich, construction of the first three-masted ship, actually built within Russia, was completed in 1636. It was built in Balakhna by Danish shipbuilders from Holstein...

. The boat was designed by Drzewiecki

Stefan Drzewiecki

Stefan Drzewiecki was a Polish scientist, journalist, engineer, constructor and inventor, working in Russia and France....

 and built at the Metal Works St Petersburg in 1908. She was funded by Public subscription.

This ship's machinery was a novel attempt at Air Independent Propulsion (AIP) using gasoline engines with oxygen supplied by pressurised cylinders. Forty-five cylinders containing 350 cubic feet (9.9 m³) of air at 2500 psi could give the boat a 28 nautical miles (51.9 km) submerged range. The exhaust gasses were vented via perforated pipe under the keel. The system proved reliable in trials but condensation problems and the tell-tale wake produced by the exhaust resulted in no further development and the boat was stricken in 1913.