The Axis war effort throughout the first half of the 1940s led to some incredible advances in submarine technology. That includes the anaerobic Walter turbine -- a newfangled engine that didn't need oxygen to work. Even more incredible, these discoveries were not entirely new, but in fact more than 60 years old -- the fruits of a Victorian-era engineer's labours during construction of the world's first powered submarine.
Built by Spanish nautical engineer Narcís Monturiol i Estarriol of Catalonia, Spain, the Ictineo II is widely considered the world's first "true" submarine. Unlike contemporary attempts such as the Ictineo I, USS Alligator or CSS Hunley, which were human-powered and required snorkels, the Ictineo II propelled itself using a unique combustion engine that worked underwater.
The vehicle's interior. Picture: public domain
The Ictineo II was constructed of olive wood, measured 14m long, more than 1.8m wide, and stood nearly 3m tall when out of the water. In the water, she displaced 46 tonnes while providing 28 cubic metres of interior room. Compared to the Hunley, which was 1.2m tall at its highest interior point, this thing was downright roomy.
Its propulsion system was a work of genius. In a closed system like that of a submerged vessel, a traditional combustion engine will quickly use up all of the available supply of atmospheric oxygen. So instead, Monturiol devised a solution that mixed zinc, manganese dioxide and potassium chlorate to create a chemical heat source hot enough to boil the water of an attached a steam furnace and generate power for propulsion. The reaction also generated enough oxygen to support a two-man crew (the rest of that "roomy" interior was actually filled up with equipment).
During the Ictineo II's maiden dive in May of 1865, she made it down to a depth of 30m -- the perfect level for her intended use: ferrying local coral divers down to their harvests. She would make 20 more successful dives over her three year demonstration career until 1867.
Unfortunately, finances were perpetually tight for the talented Spanish inventor -- Ictineo II was financed (and only barely) after Monturiol wrote an open letter to the people of Spain and Cube seeking 300,000 pesetas in public support. Unfortunately, Monturiol was never able to really capitalise on his invention. The sub was repossessed by creditors in 1867, dismantled, and sold for scrap while Monturiol died penniless and forgotten. It would be another 60 years and two World Wars before his contributions to naval technology were rediscovered.
Today, you can find recreations of both submarines in Barcelona, Spain. The Ictineo I stands outside the Marine Museum and its successor stands on display down near the harbor. [Scuttlefish - Wiki - Travelling Spain - Beyond Victoriana - Lowtech Mag]