Catamarans, often called 'cats' in boating circles, are twin-hulled watercraft noted for their speed and stability in open water. Many long-distance sailing races are won by catamarans, although traditional boat designers haven't always embraced their unorthodox features. Catamarans can be powered by sails placed forward or by engines mounted in the central rear.

The first catamarans were designed and sailed by affluent fishing tribes working in the Indonesian area of the Indian ocean. 'Catamaran' is an anglicized pronunciation of the Tamil word kattumaram, literally translated as logs tied together. Instead of using the traditional single-hulled design of a canoe, the first catamarans utilized two separate pontoons held apart by a single deck and diagonal strapping, with a sail mounted on the forward section of the deck. Eventually, the speed and maneuverability of these early catamarans would prove useful in the defense of Indonesian trade routes.

Modern catamarans are still considered to be among the fastest sailing boats available. Typically, catamarans use deep v-shaped hulls to cut through the water, creating a phenomenon known as planing. Catamarans running at full speed may only have a few inches of the hulls remaining in the water. Because their hulls are generally thinner than those of monohull boats, catamarans are also noticeably lighter. The stability of two hulls and a central deck eliminates the need for additional ballast.

This is not to say that catamarans are easier to sail than other sailboat designs. Pilots often have to lean out of the opposite hull in order to counterbalance the boat during a turn. Catamarans have a tendency to capsize if the sails are not reversed in time. Pilots cannot always follow a straight course while steering catamarans -- a series of zig-zags may be required.

Powered catamarans can be very large indeed, with some top-end models rivaling yachts and small cruise ships. Military ship designers are also creating fortified catamarans for use as swift-moving transporters. Small sail-powered catamarans can be purchased for a few thousand US dollars, while luxury models may run into the hundreds of thousands of dollars. Special trailers may be required to transport catamarans over standard roadways, since the boat must be tilted to meet load width regulations. Storage slips on the water may also be difficult to obtain because of the boat's wider dimensions.