What Leonardo da Vinci design was a paddle-wheel boat intended to move without conventional oars?

Leonardo da Vinci designed a paddle-wheel boat intended to move without conventional oars.

His drawings show a vessel equipped with paddle wheels turned by human-powered mechanisms. The rotating paddles would push against the water and propel the boat forward. Leonardo studied several ways to transmit power through cranks, gears, and shafts, making the design an early example of mechanical marine propulsion.

The boat was not a steamship. Steam engines were developed much later, and Leonardo’s concept depended on people turning the mechanism. It also was not simply a normal rowboat: the propulsion came from rotating wheels rather than individual oars pulled through the water.

Paddle wheels were later used widely on riverboats and ships, especially during the nineteenth century. Leonardo’s design therefore anticipated a useful propulsion arrangement, although its human-powered form was limited by the strength and endurance of its operators. The surviving drawings document an idea, not a proven working vessel.