Mainsail

[2] The modern Bermuda rig uses a triangular mainsail aft of the mast, closely coordinated with a jib for sailing upwind.

[3] Before Nathanael Greene Herreshoff's invention of sail tracks and slides in the 1880s, mainsails were limited in height.

This meant a traditional mainsail could be raised no higher than the first point a rope or wire was required to keep the mast upright.

Further mainsail area (and height) was obtained by adopting a gaff rig.

A mainsail may be fixed to the boom via slugs, cars, or a bolt-rope, or may be "loose-footed," meaning it is only attached at the tack and clew.