Leonardo da Vinci’s paddle boat used rotating paddle wheels to move through water.
Leonardo sketched paddle-wheel boats in the fifteenth century, exploring how mechanical power could replace or assist rowing. His designs used wheels fitted with projecting paddles that pushed against the water as they turned. A system of gears and cranks was intended to transmit power from people operating the mechanism to the wheels.
The idea was not a steam-powered boat. Leonardo had no compact engine capable of supplying continuous mechanical power, so the proposed craft depended on human operators. It also differed from later paddle steamers, which used engines to drive side wheels or a stern wheel.
Leonardo’s work belongs to a long history of attempts to improve water transport with mechanical propulsion. The drawings are valuable because they show him applying gears, shafts, and rotational motion to a practical transportation problem. Whether a particular Leonardo paddle boat was built or tested is uncertain, so it is safest to describe it as an early paddle-propelled boat concept.