motorboating, sport of navigating a motor-powered vessel on the water. It is done on either fresh- or saltwater and may be competitive or recreational. The first successful motorboat traveled (1887) a few yards on the Seine River in Paris. As the internal-combustion engine was improved, the motorboat became a practical means of transportation and motorboating became a popular sport. In 1903 the Harmsworth Trophy Race, one of the sport's most prestigious international competitions, was inaugurated in Great Britain. In the following year the Gold Cup Race, the premier U.S. competition, was first held.

Motorboating did not become widely popular until after World War II. Since then, however, it has grown tremendously, as greater affluence, increased leisure time, and mass production made it possible for more and more people to own motorboats. By 1996 there were estimated to be 12 million such boats in U.S. waters, and calls were increasing for stricter licensing and training of operators.

The smaller motorboats, traditionally called runabouts, range from 10 to 22 ft (3–6.7 m) in length; cabin cruisers, often equipped with facilities for cooking, dining, and sleeping, may be from 20 to 60 ft (6.1–18.3 m) long. The larger and more luxurious cabin cruisers are often called yachts.

Recreational boats are generally powered by a gasoline or diesel engine that turns a submerged propeller located behind the boat. Engines may be of either the outboard or inboard type. Outboard engines, generally found in smaller boats, are mounted at the back of the craft, which is steered by rotating the engine. The larger inboard-type vessels have their engine in the middle of the boat and are steered with a wheel-controlled rudder; the engine is attached to the propeller by a drive shaft beneath the craft. Certain classes of racing boats are jet-powered and are able to attain speeds of 250 mph (402 kph). The fastest propeller-driven racing boats can travel about 175 mph (282 kph).

See J. West, Modern Powerboats (1970); N. E. Fletcher and J. D. Ladd, Family Sports Boating (1972); E. A. Zadig, The Complete Book of Boating (1972).