Leonardo da Vinci designed a paddle boat with paddle wheels for movement on water.
His sketches show a vessel propelled by mechanical paddles rather than relying solely on wind or oars. Turning a crank would transfer motion through gears to paddle wheels, which would push against the water and move the boat forward. The arrangement resembles the principle later used by paddle steamers, although Leonardo’s design did not use a steam engine.
The proposal reflects Leonardo’s interest in applying rotary motion and gearing to transportation. A mechanically propelled boat could operate when wind conditions were poor and could reduce the dependence on large numbers of rowers. It was one of several water-related concepts in his notebooks, which also include canal engineering, locks, pumps, and methods for moving vessels.
Leonardo’s paddle boat is sometimes described loosely as a steamboat, but that wording is inaccurate. Steam power was not part of the original mechanism. The important feature is the use of paddle wheels driven by human mechanical effort. No evidence shows that Leonardo’s particular design was built and operated successfully during his lifetime.