Leonardo da Vinci improved the mitre lock, a canal-gate mechanism for controlling water levels and moving boats between different elevations.
A mitre lock uses two gates that meet at an angle pointing upstream. Water pressure pushes the gates together, helping them seal when the lock chamber contains higher water. Leonardo studied and refined canal engineering while working in northern Italy, where waterways were important for transport, irrigation, and trade.
Leonardo’s designs included detailed work on lock gates, channels, and water control. In Milan, he was involved with canal projects connected to the Naviglio system. His engineering notebooks show careful observation of flow, resistance, and the practical problems of operating locks.
Leonardo did not invent every part of canal-lock technology. His contribution was to analyze and improve mechanisms already developing in Renaissance hydraulic engineering. A mitre lock is not the same as a sluice gate, which controls water flow without forming a navigable chamber.