Ictíneo II: The World’s First Powered Submarine That Ran On Chemicals

Jul 9, 2025

Before the age of steam, all early submarines relied on human muscle for propulsion. The first functional submarine, built by Dutch inventor Cornelius Drebbel in 1620, was rowed beneath the surface using oars. A century later, Russian autodidact Yefim Nikonov designed what is considered the first military submarine—also oar-powered. In America, David Bushnell’s Turtle, designed during the Revolutionary War, was a one-man submersible steered and propelled entirely by hand. Germany’s Wilhelm Bauer launched the Brandtaucher, the oldest surviving submarine today, which moved underwater thanks to a treadwheel. And of course, there was the historic Hunley—the first submarine to sink an enemy warship—powered by a hand-cranked propeller and doomed to sink three times itself.


A replica of Ictíneo II in Barelona. Credit: Wikimedia Commons

The shift from muscle to machine was anything but straightforward. Combustion engines needed fuel, and more critically, oxygen—something a submerged vessel couldn’t afford to spare. It was a Spanish visionary, Narcís Monturiol, who proposed a radical solution: a chemical engine that not only generated power but also released oxygen, paving the way for the world’s first truly air-independent submarine.

Monturiol was born in Figueres, Catalonia, and trained as a lawyer, but he was deeply drawn to utopian socialism, science, and technology. He was influenced by the ideas of thinkers like Étienne Cabet and became an advocate for peaceful progress through innovation. His political views led him to publish radical newspapers and pamphlets promoting feminism, workers’ rights, and pacifism, which repeatedly brought him into conflict with Spanish authorities.

To escape persecution for his beliefs, Monturiol fled to France, to a coastal town named Cadaqués, located just a few miles from Figueres. Monturiol's interest in underwater navigation came from a tragic accident he witnessed while watching coral divers in Cadaqués, which left one diver dead by drowning. Disturbed by the dangerous conditions faced by the workers, he set out to design a submarine that could allow people to safely explore and harvest resources from the ocean floor.

In 1857 Monturiol returned to Barcelona, where he organized the first commercial society in Spain dedicated to submarine navigation with a capital of 10,000 pesetas. In 1858 he presented his first submarine named Ictíneo or “fish-ship”.


Narcís Monturiol

Ictíneo I

The Ictíneo I was primarily constructed from olive wood, reinforced with oak and covered with a layer of copper to protect it from water pressure and marine organisms. It had a cigar-shaped hull approximately 7 meters (23 feet) long and 2.5 meters (8 feet) wide, designed to minimize resistance underwater.

The vessel featured a double hull—an innovative idea at the time. The inner hull was watertight and pressurized to accommodate the crew, while the outer hull functioned as a ballast tank system. By flooding or emptying the space between the two hulls, Monturiol could control the submarine’s buoyancy. Ictíneo I was powered entirely by human muscle. A hand crank turned a single propeller, allowing the vessel to reach speeds of around 2 knots.

The submarine was fitted with a primitive but effective life-support system. Chemical absorbers removed carbon dioxide from the air, and compressed oxygen was stored in tanks to extend underwater endurance. These were advanced features for a time when most submarines were little more than sealed boxes.


A replica of Ictíneo I in front of the Museu Marítim in Barcelona. Credit: Wikimedia Commons

Ictíneo I was successfully tested in Barcelona harbour, performing more than 50 dives, some lasting up to 2 hours long. It operated smoothly at depths of up to 20 meters (65 feet), proving Monturiol’s engineering concepts were sound.

In 1862, a cargo vessel collided with the submarine while it was docked in the port of Barcelona, completely destroying it. Monturiol was distraught, but the disaster only strengthened his resolve to build a larger submarine.

Ictíneo II

Launched in 1864, Ictíneo II was a revolutionary leap forward in submarine design. Unlike its hand-cranked predecessor, Ictíneo I, this new vessel was powered by a chemical engine, making it the first submarine in history capable of generating both propulsion and breathable oxygen while submerged.

Ictíneo II was larger and more refined than its predecessor. It measured around 14 meters (46 feet) in length and had a beam of about 2 meters (6.5 feet). Its hull was crafted from wood, reinforced with metal bracing, and coated with copper to prevent fouling. Like Ictíneo I, it had a double hull, with the outer hull serving as a ballast tank, while the inner hull maintained pressure and housed the crew.

What truly set Ictíneo II apart was its propulsion—it used a chemical steam engine. When operating underwater, the engine burned a mixture of zinc, manganese dioxide, and potassium chlorate. This chemical reaction produced heat to generate steam and, critically, also released oxygen, solving the twin challenges of underwater power and breathable air. When on the surface, the vessel could switch to a conventional coal-fired steam engine.

Monturiol's invention marked the first instance of air-independent propulsion, a technology not seriously revisited until 1940 when the German Navy tested a system employing the same principles, the Walter turbine, on the experimental V-80 submarine and later on the Type XVII submarines. The problem of air-independent propulsion was finally resolved with the construction of the first nuclear powered submarine, the USS Nautilus.


A scale model showing the interior of Ictíneo II. Credit: Australian National Submarine Museum

On 22 October 1867 the Ictíneo II made its first surface journey under steam power, averaging 3.5 knots (6.5 km/h) with a top speed of 4.5 knots (8.3 km/h). Two months later, on 14 December, Monturiol submerged the vessel and ran his chemical engine, but with a quite slow speed of 2.5 knots (4.6 km/h).

The Ictíneo II made almost 20 problem free demonstration drives. It could stay submerged for seven and a half hours and plunge to a depth of nearly 30 meters.

Despite its technical success, Ictíneo II faced a familiar problem— lack of funding and political support. Spain’s government, focused on military priorities, showed little interest in Monturiol’s peaceful invention. The submarine’s development bankrupted Monturiol’s company, and the vessel was eventually dismantled and sold for scrap in 1868. The ship's surface motor was removed to a textile factory, while the viewports ended up as bathroom windows.

In 1868 Monturiol returned to political life. A member of the Federal Party, he was a deputy in the Constituent Assembly of the First Spanish Republic (1873), and shortly afterwards became the director of Fabrica Nacional del Timbre (National Stamp Factory) in Madrid for a few months, where he implemented a process to speed up the manufacturing of adhesive paper. Monturiol's other inventions included a system for copying letters, a continuous printer, a rapid-firing cannon, a system to enhance the performance of steam generators, a stone cutter, a method for preserving meat, and a machine for making cigarettes.

Monturiol died in 1885, in Barcelona. He has been honoured on a postage stamp, and he has two monuments: one in Barcelona and other in Figueres, his native city.

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