Leonardo da Vinci designed canal-lock mechanisms to raise or lower boats between waterways at different levels.
A canal lock uses gates and a chamber. A boat enters the chamber, the gates close, and water is added or released until the boat reaches the level of the next section. Leonardo studied and improved such hydraulic arrangements while working on canal projects in northern Italy.
His interest in locks was connected with attempts to improve navigation around Milan. Leonardo’s notebooks contain detailed observations about water flow, gates, channels, and mechanisms for controlling water.
Leonardo did not invent the basic idea of a lock from nothing; earlier forms of canal locks already existed. His importance lies in studying, refining, and documenting hydraulic engineering, including designs intended to make navigation more efficient.