Mast Head and Fractional Rigging
There are two variations on the standing rigging setup: Masthead and Fractional.
On masthead rigs, the attachment point for the sidestays (shrouds), forestay, and backstay (if they exist) is at the top of the mast.
On fractional rigs, only the backstay reaches to the top of the mast, whereas the attachment point for the sidestays and forestay is near the top of the mast but not all the way at the top. Tensioning the backstay will bend the mast, which provides an additional means of controlling the shape of the sail.
The strength of the mast material is relied upon to prevent it from flexing too much or breaking past the point of forestay and sidestay attachment.
See the animation and watch the sail flatten when the backstay is tensioned. The sail flattens because the midsection of the mast moves forward thus tightening the sail material.
