2. Ictineo II
Narcís Monturiol, a Spanish inventor, and political activist after he witnessed in 1857 the drowning death of a coral diver built Ictineo II Estarriol. The sub was, therefore, his way of ensuring there was an underwater vehicle that would increase worker safety. This was a pioneering sea craft widely known today as the world’s first engine-powered submarine.
The Ictineo II had a double hull and featured four pump-operated ballast tanks and a system of weights that gave the 46-foot vessel a remarkable stability. Monturiol made an anaerobic steam engine that relied on a chemical reaction to create heat and oxygen that propelled the sub. It made a successful dive in 1867. It was later sold for scrap because of funding problems.