Leonardo da Vinci improved the canal lock by using hinged miter gates.
A navigation lock lets boats move between waterways at different elevations. Leonardo’s design used pairs of gates that met in a V shape, with the point facing the higher water. Pressure from the water helped press the gates together and seal the entrance.
He applied the idea while working on canal projects in northern Italy, including plans connected with Milan. Miter gates were not wholly invented by Leonardo; earlier canal engineers had used related forms. His importance lies in refining and documenting a practical arrangement for controlling water levels.
A lock is not the same as a dam or a sluice. A lock encloses a chamber and changes its water level so vessels can rise or descend. Leonardo’s engineering drawings addressed both navigation and the management of water flow.