The Ictíneo II, more than twice the length of the Ictíneo I, was launched between 1864 (with human power) and 1867 (with steam power). It became the first combustion engine driven submarine in the world.
The thinking at the time was that it was almost impossible to run a steam engine underwater because it would use up all the oxygen and convert the inside of the ship into an oven. To overcome this, Monturiol invented a chemical furnace based on a reaction between potassium chlorate, zinc and manganese dioxide - a process that produced enough heat to boil water to run the steam engine. To complement this ingenuity, the reaction gave off oxygen as a by-product.
The Ictíneo II was equipped with arms to retrieve objects from the sea floor. According to other sources, Monturiol regarded the submarine as a tool for exploring the underworld of the deep sea and as a passenger transportation device.
When his search for independant funding proved unsuccessful, Monturiol attempted to sell his invention to the military. He mounted a cannon onto the Ictíneo II in a last effort to attract investment from Madrid, but the Spanish monarchy regarded the wooden fish with apprehension and was not prepared to invest any money into it. In other countries at the time, military factions saw little potential in submarines - their use went against their understood etiquette of war in those times.
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.
Ironically, only 30 years later, the Spanish fleet was annihilated by America in the dispute over Cuba, and with it Spain lost the final remnants of its 400 year old world empire. The Spanish vessels were infinitely inferior to their American enemy. Speculatively, an army of submarines may have been able to change the course of history.
Monturiol died in 1885, penniless and forgotten.