Leonardo da Vinci designed canal-lock mechanisms to control water levels and movement in waterways.
During his work in northern Italy, Leonardo studied canals, river navigation, and hydraulic engineering. His designs included arrangements of gates that could isolate a section of water and allow boats to move between different levels. Such systems made canals more useful in regions where changes in elevation would otherwise block navigation.
A canal lock is different from a sluice gate. A sluice controls the flow or level of water, while a lock uses a chamber between gates to raise or lower boats. Leonardo is often associated with improvements to mitre-gate lock designs, especially through his engineering work connected with Milan.
Leonardo did not invent every element of canal-lock technology. Earlier locks existed in Europe, but his notebooks document sophisticated refinements to gates, channels, and hydraulic control.