Sailing was once a hobby of the rich, but the availability of free time and more cash to the "average" person has made sailing one of the most popular forms of recreation. Sailboats may be handcrafted or factory built in all sizes from day-sailers and other boats less than 11 ft (3.4 m) long to the dinghy, larger single-masted sailboats, two-masted boats called yawls, and large yachts. Yachts are patterned after historic sailing vessels called brigantines, cutters, clipper ships, and schooners. Boats used for racing are specially designed for speed and manoeuvrability, while sailboats of all sizes that have onboard quarters for passengers and crew and sturdier in design with more details for comfort. Many sailboats also carry inboard or outboard diesel-powered motors in the event they are becalmed (motionless from lack of wind) or their sailors simply want a speedier return to port.
Of course, the sailboat is distinguished from other craft by its sails. A sail is simply a piece of fabric that is used to catch the wind to drive the boat across the water. Most modern sails are made of Dacron, a polyester fibre. Because the fabric is heated to meld the fibres together, the wind cannot escape through pores like those in woven cloth, and the surface has a very low friction factor. Polyester sails are also lightweight with a little stretch.
Sails fall into two major categories and then into many subclasses. The two major categories are square and triangular sails. Square sails are mounted across the main axis of the boat to use the wind pressure to power the boat. The wind strikes only the back, or after side, of square sails. Triangular sails follow the same axis as the boat, with foresails at the front or bow of the ship and aft sails at the rear or stem. Both sides of triangular sails are used for forwarding motion, and they can be adjusted to make the best use of the wind’s force.