What type of lock did Leonardo da Vinci design to improve canal gates?

Leonardo da Vinci designed a miter lock to improve canal gates.

A miter lock uses two angled gate leaves that meet in a V shape pointing upstream. Water pressure pushes the leaves together, helping the closed gates resist the force of the water. Leonardo used this principle in canal engineering, where boats and water levels had to be managed efficiently.

His work on canals in northern Italy included studies of locks, gates, water flow, and excavation. The miter-gate principle was not a simple door lock and should not be confused with a household security lock. It is part of water navigation engineering, allowing vessels to pass between stretches of canal at different levels.

Leonardo’s canal designs demonstrate that his inventions extended beyond flying machines and weapons. He treated water as a mechanical system that could be measured, directed, and controlled. The basic miter-gate arrangement remains recognizable in later canal infrastructure.