What are the Sails of a sail boat?

Strictly speaking, a boat's sails serve to catch the wind, propelling the boat forward. They can be adjusted in a number of ways using things like sheets, halyards, topping lifts, cunninghams, and other lines. Sails are generally adjusted based on what direction the boat is facing relative to the wind, how windy it is, and how fast you want to go. Many small boats have two sails. The larger of these sails is generally called the mainsail. It is to the rear of the mast and is attached to the boom. In the average two-person skipper/crew setup, one of the skipper's duties is to control the mainsail. This is achieved via the main sheet, which is pulled in or let out based on how close (or far from) heading upwind the boat is. In general, the closer you are to upwind, the more the sails should be pulled in. The smaller of the two sails is generally called the jib. The crew controls the jib via the jib sheets, which are adjusted in nearly the same way as the main sheet. In addition, some small sailboats are equipped to fly a spinnaker. This sail is sometimes also called a chute because it looks like a parachute when full. The spinnaker is flown only when going downwind or nearly downwind, and is controlled by both the skipper and crew.