What kind of boat did Leonardo da Vinci sketch with rotating paddle wheels for propulsion?

Leonardo da Vinci sketched a paddle-wheel boat powered by rotating wheels.

The design used paddle wheels mounted along the sides of a boat. Cranks and gears would transfer the effort of operators to the wheels, pushing against the water and moving the vessel forward. Leonardo’s studies of this type of craft belong to his broader investigations of mechanics, water flow, and transportation.

The boat was not a steam-powered vessel. Its propulsion depended on human effort, and the design predates practical steam navigation by centuries. Leonardo explored several watercraft concepts because canals and rivers were important transport routes in Renaissance Italy, especially around Milan.

Leonardo’s paddle-wheel boat is often described as an early ancestor of later paddle steamers, but the resemblance is limited to the use of rotating paddles. Later vessels used engines to provide continuous power, while Leonardo’s proposal relied on people operating the mechanism. The sketch therefore demonstrates an early mechanical approach to marine propulsion rather than a working modern ship.