Leonardo da Vinci improved canal navigation with a miter lock, a hinged gate system used in waterway locks.
Leonardo is credited with improving the miter gate, whose two gates meet at an angle pointing upstream. Water pressure then helps press the gates together, creating a strong seal. This made it possible to control water levels between sections of a canal.
His work is associated especially with canal projects around Milan, where locks were essential for moving boats through changes in elevation. The principle was not created from nothing by Leonardo, but his designs refined mechanisms and practical arrangements for canal engineering.
A lock is different from a dam: it raises or lowers boats between water levels while retaining a navigable route. Leonardo’s canal studies also included gates, water flow, and construction methods, showing his interest in applying mechanical ideas to infrastructure as well as weapons.