Leonardo da Vinci’s underwater breathing device was designed as a diving suit.
Leonardo’s notes from the early 16th century describe equipment for a person working beneath the surface. The concept included a mask, breathing tubes, and an air supply arrangement, along with a suit intended to protect the diver. It is generally associated with studies made for underwater operations in Venice, although the historical purpose and intended construction remain uncertain.
The design was not a modern scuba system. It did not have a compressed-air cylinder, regulator, buoyancy compensator, or the carefully controlled gas supply required for safe deep diving. Long flexible tubes would also have created serious problems with air flow and water pressure.
Leonardo reportedly worried that such equipment could be used for secret attacks on ships, so he did not fully publicize every detail. His drawings nevertheless show an early attempt to solve underwater breathing and mobility as linked engineering problems.