Leonardo da Vinci improved a canal lock with hinged gates that close against each other.
The design used paired gates arranged so water pressure would press them together when the lock was filled. This created a tighter seal than a simple barrier and helped boats pass between waterways at different elevations.
Leonardo studied canal engineering in northern Italy, especially around Milan. His work was connected with plans for improving navigation and managing water levels in the canal network.
The paired gates are known as miter gates, a principle still associated with many navigation locks. Leonardo did not invent canals or every form of lock, but his drawings show a sophisticated understanding of hydraulic pressure and practical water transport.