Leonardo da Vinci proposed paddle wheels as a propulsion system for a boat.
His design used large rotating wheels fitted with paddles to push against the water and drive the vessel forward. The concept applied a familiar mechanical principle—turning rotational motion into thrust—to water transport.
Leonardo’s boat designs belong to his extensive studies of machines powered by people, animals, wind, and water. They were design proposals rather than a documented fleet of working vessels built by Leonardo himself.
The paddle-wheel concept should not be confused with a screw propeller. Paddle wheels push water with blades arranged around a wheel, while a screw propeller uses a rotating helical surface beneath or behind a vessel. Steam engines later made paddle-wheel boats practical on a large scale, but Leonardo’s proposal predates that technology.