What type of boat did Leonardo da Vinci design with paddle wheels for moving along water?

Leonardo da Vinci designed a paddle-wheel boat intended to move through water using mechanical paddles.

His sketches show paddle wheels mounted along the sides of a boat and connected to cranks or gearing. Turning the mechanism would rotate the paddles and push water backward, producing forward motion. The arrangement resembles the principle later used by paddle steamers, although Leonardo’s proposal relied on human power rather than a steam engine.

The design reflects Leonardo’s broader interest in reducing the effort needed for transport. Gears could coordinate the motion of several paddles, and a crew could operate the cranks. The sketches do not establish that a full-size working boat was built or tested.

A paddle-wheel boat is not the same as a galley, which is propelled mainly by oars, or a modern propeller vessel, which uses a screw rotating underwater. Leonardo’s watercraft studies also included ideas for canals, locks, and other hydraulic machines.