Leonardo da Vinci studied canal locks to control water levels between sections of a waterway.
His work on canals in northern Italy included designs for lock gates and mechanisms that made navigation possible where waterways had different elevations. A lock works by enclosing a boat in a chamber, then raising or lowering the water level before opening the opposite gate.
Leonardo is often credited with improving the mitre lock, whose two gates meet at an angle pointing upstream. Water pressure helps press the gates together when the chamber is filled. His canal engineering was connected with projects around Milan, including improvements to navigation routes.
Leonardo did not invent the general idea of a lock from nothing; earlier forms existed. His importance lies in studying, refining and documenting practical canal mechanisms with unusually detailed engineering drawings.