What Leonardo da Vinci design used paddle wheels to propel a boat?

Leonardo da Vinci designed a paddle boat propelled by paddle wheels.

His marine engineering studies included boats that used mechanical paddles rather than relying only on wind or oars. In the proposed arrangement, rotating mechanisms transferred motion to paddles that pushed against the water and moved the vessel forward.

The design reflects Leonardo’s interest in adapting familiar mechanical principles to transportation. It was a concept preserved in drawings and notes, not a documented powered boat that he successfully launched. Renaissance engineers often explored such ideas because controllable mechanical propulsion could operate when wind conditions were poor.

Leonardo’s paddle boat should not be called a steamship. Steam engines were developed centuries later. It was also not a submarine: the design was intended for surface travel and used paddles to generate thrust in the water.