spreader

thumb|Line art drawing of crosstrees.

Crosstrees are the two horizontal spars at the upper ends of the topmasts of sailing ships that are used to anchor the shrouds from the topgallant mast. They may also be mounted at the upper end of the topgallant to anchor the shrouds from the royal mast (if fitted). Similar transverse spars remain on steamship and motor vessel masts to secure wire antennae or signal flag halyards. In modern sailing vessels, spreaders serve the same purpose.