Those that glance over Leonardo da Vinci drawings and notes in the corner of library archive sections, or hear of his life at the back of history classrooms, will be aware of his desire to fill the sky – his bird-shaped ornithopter, or “aerial screw” which later became the design behind the modern helicopter – but few knew of his fascination for the world below the waves. An underwater army, clad in leather diving suits and set to march along the Venetian seabed to thwart any incoming invasions by sea, was an unmade da Vinci design that may have inspired the invention of the first scuba equipment – 300 years after his death.

The diving suit

Looking like a post-apocalyptic nuclear suit. This dive design was the suit of nightmares. © Wikimedia Commons

Looking like a post-apocalyptic nuclear suit, this dive design was the suit of nightmares. © Wikimedia Commons

Da Vinci’s drawings, which are ruffled with age and purposefully ambiguous (many believe that his notes were left incoherent so as to confuse those who wish to sinisterly “misuse” his designs), depict a diver outfitted in an apparent post-apocalyptic nuclear suit. It’s the suit of nightmares. 

With a leather cloth, a protective face mask and goggles, the suit was attached to a long snorkel made of bamboo which ran up to the water’s surface. Da Vinci’s designs and inventions were made famous for being ahead of their time, and his breathing apparatus was one such example. Attaching the bamboo pipes together with sheepskin cloth to give them the flexibility to bend, da Vinci accounted for the effect of water pressure on the sheepskin “connectors” by placing large springs inside the cloth pipes to hold them open. This allowed the whole snorkel to bend and not collapse under pressure.

A page from the Codex Arundel, featuring one of da Vinci's sketches of a diving apparatus. © Leonardo da Vinci/Public Domain

A page from the Codex Arundel, featuring one of da Vinci’s sketches of a diving apparatus. © Leonardo da Vinci/Public Domain

The snorkel was attached to a hollow cork diving bell on the surface, with a specialised cap on top to stop any water getting in. Da Vinci’s design also allowed the diving bell to be pulled underwater, turning it into a compressed-air diving system. Surface air could also be delivered to the diver from the people above with a bellow. An alternate drawing shows his diver breathing from makeshift air bladders, which is vaguely reminiscent of the later-developed oxygen supply tanks. Interestingly, both drawings had the diving soldiers carrying urine collection bottles in order to remain underwater for an extended period of time.

Another element of the da Vinci scuba gear design was to have an air balloon fitted to the face mask that could be regulated by a valve, enabling the diver to inflate or deflate the chamber to surface or sink in the water.

A forgotten army

Perhaps unsurprisingly, the Venetian Army was not impressed with da Vinci’s presentation of what seemed a radical invention, and his weapon of war – his underwater army – never properly surfaced. Instead, it was left to future generations to be inspired by da Vinci’s design and turn it into a breathing apparatus used passionately by millions.