What Leonardo da Vinci invention used a paddle wheel to move a boat against a river current?

Leonardo da Vinci designed a paddle-wheel boat intended to move against a river current.

Leonardo’s notebooks contain several watercraft concepts, including boats propelled by paddle wheels. Turning paddles pushed against the water and produced forward motion, offering an alternative to rowing or relying on wind. Some designs used human power transmitted through cranks and gears.

The concept reflects Leonardo’s interest in improving transport on rivers and canals. A mechanically driven boat could potentially travel in conditions where a sailing boat was limited by wind direction. However, the drawings do not establish that Leonardo built a full-scale, practical vessel.

This invention is distinct from Leonardo’s diving devices, which focused on underwater activity. It is also different from a modern steamboat: Leonardo’s paddle-wheel concepts relied on human-powered mechanical transmission rather than an engine or steam pressure.