Snorkel:Monturiol had successfully resolved the two basic obstacles presented to submarine inventors: air supply and mechanical power. In fact, he devised an early form of anaerobic (air-independent) propulsion only to be repeated in the 1940s with the Walter turbine in Germany, and finally with the first atomic submarine, the USS Nautilus.The Ictíneo II was the first of its kind providing its own oxygen, without surfacing regularly or using a snorkel, as seen on the Nautilus. Perplexing is the reality that Monturiol, never having patented his ideas, is absent in many maritime records of the progression of submarines.On account of all the machinery in the vessel, only 2 men could fit in the submarine originally designed for a crew of 20. The Ictíneo II made almost 20 problem free demonstration drives. It could stay submerged for eight hours and plunge to a depth of 50 meters. Monturiol calculated that the maximum possible depth was 500 meters, but chose not to take the risk of diving to this depth.In 1868, shortly after its launch, the groundbreaking Ictíneo II was seized by the shipyard and scrapped, together with her predecessor. The reason? Monturiol could not pay the bills.