Leonardo da Vinci designed miter-lock gates for controlling water levels in canals.
A miter lock uses two gates that meet in a V shape, with the point directed toward the higher water level. Water pressure then helps press the gates together and seal the opening. Leonardo studied this arrangement while working on canal and hydraulic-engineering problems in northern Italy.
Canal locks allow boats to move between stretches of water at different elevations. Gates isolate a chamber, and changing the chamber’s water level lets a vessel rise or descend. Leonardo’s interest included improving the movement of boats around Milan and connecting waterways more efficiently.
Leonardo did not invent every principle of canal locking, and the terminology can cause confusion. A sluice gate regulates flow through an opening, while a miter lock is a paired gate system used as part of a navigable lock chamber.