Leonardo da Vinci designed a paddle boat powered by mechanical paddles.
The concept used rotating paddles to push against the water and propel the vessel forward. A crew member would operate a mechanism connected to the paddles, transferring motion from a crank or wheel to the water. Leonardo explored the idea as part of his studies of transport and mechanical power.
A mechanically propelled boat could move independently of wind, which would make it useful on rivers and in calm conditions. However, Leonardo's design was not a steamship and did not use an engine in the modern sense. Its energy came from human operation.
This invention is sometimes confused with Leonardo's naval weapons and underwater designs. The paddle boat was a surface vessel intended for propulsion, while his diving equipment addressed underwater breathing and his ship studies included military engineering.