Leonardo da Vinci designed a miter lock for canals, using two angled gates that meet in a V shape.
A miter lock has gates whose edges meet at an angle pointing toward the higher water level. Water pressure pushes the gates together, helping them resist the force of the water when the lock is closed. This arrangement became a key feature of canal engineering.
Leonardo is credited with improving canal-lock designs in Milan, especially for waterways connected with the Naviglio di Martesana. His work addressed the practical problem of moving boats between sections of canal with different water levels.
Leonardo did not invent every principle of canal locks from nothing, and earlier forms existed in Europe. His importance lies in refining mechanisms and documenting engineering solutions. The term “miter lock” describes the gate arrangement, not a particular Leonardo-built machine.