What type of boat did Leonardo da Vinci design using paddle wheels for propulsion?

Leonardo da Vinci designed a paddlewheel boat using rotating wheels for propulsion.

His studies of watercraft included mechanisms in which paddle wheels pushed against the water, allowing a vessel to move without relying solely on oars or sails. The arrangement transferred motion from a human-powered mechanism to the wheels, making it an early concept related to later paddle steamers, although Leonardo’s design did not use a steam engine.

The boat is sometimes labeled a steamboat in popular retellings, but that description is misleading. Leonardo was exploring mechanical propulsion, not documenting a working steam-powered vessel. His drawings combine naval architecture with gears, cranks, and other machine elements.

As with many of Leonardo’s engineering projects, the surviving material is mainly design work rather than evidence of a completed prototype. The importance of the idea lies in recognizing that paddle wheels could convert rotary motion into forward movement through water.