Leonardo da Vinci’s miter lock was a canal-lock design using two gates that met in a V shape to control water levels.
Leonardo worked on canal engineering in northern Italy, including projects connected with Milan. A miter lock has two gate leaves arranged so their point faces the higher water. Water pressure pushes the leaves together, helping them seal the chamber. Opening and closing the gates allows boats to move between different water levels.
Leonardo did not invent canal locks, which had earlier examples in Europe and China. His contribution was the refinement and application of lock engineering, including designs that improved navigation around changes in elevation. The miter-gate principle remains familiar in modern canals.
This invention is sometimes confused with a dam or a simple sluice. A lock is different because it raises or lowers boats inside a chamber rather than merely releasing water.