What type of boat did Leonardo da Vinci sketch with paddle wheels for moving through water?

Leonardo da Vinci sketched a paddle-wheel boat designed to move through water using rotating paddles.

The concept used wheels fitted with boards or paddles that pushed against the water. Turning the wheels would produce forward motion, providing an alternative to ordinary oars or sails.

Leonardo’s watercraft studies were connected with his interest in canals, rivers, and mechanical power. Some versions appear to use human or mechanical effort to turn the wheels, but the surviving drawings do not establish that a finished powered boat was built.

A paddle-wheel boat is not the same as a propeller-driven ship. Paddle wheels push water with broad blades mounted around a wheel, while a propeller uses rotating helical blades. Leonardo explored both water movement and mechanical transmission, but this design is identified by its side or rear paddle wheels.