A masting sheer, sheers, shears or masting crane is a specialised shipyard crane, intended for placing tall masts onto large sailing ships. "Sheers" is an old name for a fixed crane formed by one or two wooden beams, fixed at the base and supported by ropes. As sheers are not required to move, they were often constructed as masonry towers, with wooden jib structures atop them. Few have survived intact, but some of the towers remain, having now lost their jibs.