Leonardo da Vinci’s paddle-boat invention used a large wheel and paddles to propel a boat. His sketches show a vessel in which rotating paddles would push against the water, replacing the repeated action of oars.
The concept belongs to Leonardo’s broader work on water engineering, where he studied currents, canals, locks, pumps, and machines for moving vessels. A paddle wheel can convert rotary motion into forward thrust because its blades push water backward as the wheel turns.
Leonardo’s drawing was a proposed mechanism, not evidence that he built a successful powered boat. Paddle wheels later became important in working boats and steamships, especially during the 18th and 19th centuries. The idea should not be confused with the twin-hulled boat design already associated with Leonardo or with a screw propeller, which moves a vessel through a rotating underwater screw.