What type of bridge did Leonardo da Vinci design to swing aside and clear a waterway?

Leonardo da Vinci designed a revolving bridge that could swing aside to clear a waterway.

His bridge concept used a pivoting structure supported so that it could rotate away from the channel. This would let boats pass without requiring the entire bridge to be dismantled or lifted vertically. Leonardo’s notebooks often combine structural ideas with mechanisms for moving them efficiently.

The revolving bridge was proposed as a rapid military bridge. A movable crossing could help an army cross a river and then be turned aside, making the route less useful to an approaching enemy. Leonardo described the idea while developing practical engineering proposals for patrons.

The design is not the same as a drawbridge, whose deck normally rises or folds upward. Nor is it a pontoon bridge, which floats on boats or other buoyant supports. Leonardo’s key feature was horizontal rotation around a pivot.