Leonardo da Vinci helped improve the miter lock by using hinged gates in canal engineering. A miter lock uses two gates that meet at an angle, allowing water pressure to help hold them closed when the lock chamber is full.
Leonardo worked on water-management projects in Milan and studied canals, rivers, locks, and irrigation. His contributions are especially associated with the navigable canal system around Milan, where locks allowed boats to move between stretches of water at different elevations. The lock principle itself predates Leonardo, so he should not be described as its sole inventor.
A navigation lock works by admitting or releasing water from a chamber. A boat enters, the gates close, and the water level is changed until it matches the next section of canal. This makes it possible to overcome a change in elevation without a boat being dragged over a rapid or lifted by a crane.
The term “miter lock” identifies the angled meeting of the gates. It is more specific than “canal lock,” which describes the broader structure rather than this particular gate arrangement.