What type of bridge did Leonardo da Vinci design to swing aside and let boats pass?

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

Leonardo’s bridge concept was a rapid military bridge, but its rotating structure also provided a practical way to clear a waterway. The bridge could pivot around a support, allowing traffic on the water to continue without dismantling the crossing. Counterweights and a winch were part of the broader mechanical idea.

The design was associated with Leonardo’s work for Ludovico Sforza in Milan during the late 15th century. He proposed bridges that could be moved, assembled, and transported more easily than permanent masonry crossings. A revolving bridge offered both mobility and control in a military or canal setting.

This invention is sometimes confused with Leonardo’s self-supporting bridge, which was designed to lock together from wooden beams without nails or rope. The revolving bridge instead depends on a pivoting motion. Neither design is known to have survived as a Leonardo-built original, but both show his focus on portable engineering.