What Leonardo da Vinci machine used paddles to help propel a boat?

Leonardo da Vinci’s paddle-powered boat concept was a paddle-wheel boat.

Leonardo studied boats propelled by rotating paddle wheels. In his designs, mechanical power turned wheels fitted with paddles, pushing against the water and moving the vessel forward. The concept aimed to replace or supplement conventional oars and could allow propulsion from inside the boat.

Leonardo’s hydraulic studies included canals, locks, pumps, and water-lifting machines. A paddle-wheel boat fit into this broader interest in converting mechanical motion into useful movement on water. His sketches explored the arrangement of the wheels and the mechanisms that might drive them.

The design was not a steam-powered paddle steamer. Steam engines were developed much later, and Leonardo’s proposals relied on human or mechanical power. Nor was it a screw-propelled vessel: a paddle wheel pushes water with blades mounted around a rotating wheel, while a propeller uses helical blades on a shaft.