What kind of bridge did Leonardo da Vinci design to rotate for passing boats?

Leonardo da Vinci designed a revolving bridge that could rotate to let boats pass.

The bridge was intended to provide a fast crossing while also keeping a waterway open to navigation. Instead of being permanently fixed across the channel, it could pivot aside around a central support.

Leonardo’s notebooks show that he was interested in bridges that combined mobility with structural stability. His revolving design could be moved by mechanical means and was conceived as a practical solution for military or civil transport.

A revolving bridge differs from a drawbridge, which rises or folds upward, and from a pontoon bridge, which floats on boats or other buoyant supports. Leonardo’s design is notable for treating the bridge deck itself as a rotating structure.