Leonardo da Vinci helped develop the canal lock as a mechanism for controlling water levels in navigation canals.
While locks existed before Leonardo, he studied and improved their engineering during his work in northern Italy. His designs included gates and chambers that allowed boats to move between sections of canal with different water levels. The lock chamber could be filled or emptied while keeping the vessel enclosed.
Leonardo is especially associated with improvements to the mitre lock, whose paired gates meet in a V shape pointing toward the higher water. Water pressure helps press the gates together when the higher-level side is behind them. This arrangement remains a fundamental lock principle.
Leonardo did not invent every form of canal lock from nothing. His importance lies in documenting, refining, and applying hydraulic designs. A sluice gate controls water flow, but a canal lock is the complete chamber system used to raise or lower boats.