Leonardo da Vinci designed canal-lock systems to control water levels and help boats move between sections of a waterway.
A lock uses gates and a chamber. A boat enters the chamber, the gates close, and water is added or released until the boat reaches the level of the next canal section. Leonardo studied such mechanisms while working on Milan’s canals, especially the engineering problems involved in navigation, water control, and connecting waterways at different elevations.
Leonardo is often credited with improving the mitre-gate form of canal lock. Mitre gates meet at an angle and use water pressure to press the gates together, helping them resist the force of the water. The broader history of locks is older and involved earlier engineers, so Leonardo should not be described as the sole inventor of every canal-lock principle.
His canal studies show the close relationship between his artistic, scientific, and engineering work. He examined water as both a natural force and a resource that could be directed by carefully shaped structures.