The first such boat was the Nordenfelt I, a 56 tonne, 19.5 metres (64 feet) vessel similar to Garret's ill-fated Resurgam, with a range of 240 kilometres (150 miles; 130 nautical miles), armed with a single torpedo, in 1885. Like Resurgam, Nordenfelt I operated on the surface by steam, then shut down its engine to dive. While submerged the submarine released pressure generated when the engine was running on the surface to provide propulsion for some distance underwater.