Leonardo da Vinci designed a miter lock to help boats change water levels.
Leonardo worked on canal engineering in northern Italy and improved the concept of a chamber lock with inward-pointing gates. When the gates meet at an angle pointing upstream, water pressure helps press them closed. This arrangement is known as a miter lock and became an important feature of canal navigation.
Leonardo’s canal work is especially associated with the Naviglio di San Marco in Milan. His designs helped boats bypass differences in elevation that would otherwise obstruct continuous travel. A lock works by admitting or releasing water inside a chamber, raising or lowering a boat to the level of the next canal section.
Leonardo did not create the entire principle of canal locks from nothing, and earlier locks existed in Europe and Asia. His contribution was the refinement of mechanisms, gates, and water-control details. The miter-lock principle remains recognizable in modern canals, although today’s gates and operating systems are much larger and more standardized.