Leonardo da Vinci designed a paddle boat that used rotating paddle wheels for propulsion.
The concept replaced the physical work of individual oarsmen with mechanical paddles driven by cranks and gears. Turning the mechanism would make the paddles push against the water and move the boat forward.
Leonardo explored the design as part of his broader interest in hydraulics, machines, and transportation. His drawings show how mechanical power could be transferred from a person operating the mechanism to the water-moving paddles.
This design should not be confused with a modern steam-powered paddle steamer. Leonardo’s boat relied on human mechanical effort, not an engine. The idea also differs from a conventional rowboat, whose oars move through the water independently.