The most common type of small to midsize sailboat is the sloop. The rig is one mast and two sails. The mainsail is a tall, triangular sail mounted to the mast at its leading edge, with the foot of the sail along the boom, which extends aft from the mast. The sail in front, called the jib or sometimes the head sail, mounts on the forestay between the bow and the masthead, with its trailing corner controlled by the jibsheet.
These tall triangular sails are called the Bermuda rig, or sometimes the Marconi rig, named for their development more than two centuries ago in Bermudan boats. Because of the physics of how force is generated by wind blowing past a sail, tall thin sails generally have more power when the boat is sailing into the wind. This is why most sailboats today have a Bermuda rig.