Leonardo da Vinci designed a miter lock for canals to manage changes in water level.
His canal-engineering work included improvements to lock gates used on the Naviglio di San Marco in Milan. Miter gates meet at an angle that points toward the higher water level. Water pressure then pushes the two gates together, helping them seal the passage when the lock is closed.
Leonardo did not invent the canal lock itself. Earlier locks existed in Europe, but his drawings and engineering work refined mechanisms for navigation and water management. Canal locks allow boats to move between sections of water at different elevations without requiring a continuous level route.
A miter lock differs from a simple sluice gate. A sluice controls water flow through an opening, while a lock chamber and its gates raise or lower boats. Leonardo’s canal studies also involved irrigation, water power, and transport, so they formed part of a broader body of hydraulic engineering rather than a single isolated invention.