A motorboat is a vessel propelled by an internal combustion engine driving a jet pump or a propeller. The International Regulations for Preventing Collisions at Sea defines a "power driven vessel" as any vessel propelled by machinery and even a sailboat while it has an engine running (i.e. under power) is technically a power driven vessel. A speedboat is a small motorboat designed to move quickly, used in races, for pulling water skiers, as patrol boats, and as fast-moving armed attack vessels by the military. Even inflatable boats with a motor attached which may be serving as a high speed patrol boat or as a plodding pedestrian dinghy providing transport to and from a mooring buoy are motorboats.

There are three popular variations of powerplants: inboard, inboard/outboard, and outboard. If the engine is installed within the boat, it's called a powerplant; if it's a removable module attached to the boat, it's commonly known as an outboard motor.

An outboard motor is installed on the rear of a boat and contains the internal combustion engine, the gear reduction (Transmission), and the propeller.

An inboard/outboard contains a hybrid of a powerplant and an outboard, where the internal combustion engine is contained inboard and the gear reduction and propeller are outside.

A purely inboard boat contains everything except a shaft and a propeller inside the vessel. There are two configurations of an inboard, v-drive and direct drive. A direct drive has the powerplant mounted near the middle of the boat with the propeller shaft straight out the back, where a v-drive has the powerplant mounted in the back of the boat facing backwards having the shaft go towards the front of the boat then making a 'V' towards the rear.

Motorboats vary greatly in size and configuration, from the 4-meter, open Boston Whaler type to the luxury mega-yachts capable of crossing an ocean.

History

Although the Screw propeller had been added to an engine (steam engine) as early as the 18th century in Birmingham, England by James Watt, the petrol engine only came about in the later part of the 19th century, at which point Frederick William Lanchester recognised the potential of combining the two components to create the first all British powerboat, tested in Oxford England the powerboat was born. Late in that same period fishermen in San Francisco were being transforming their feluccas into early versions of the Monterey clipper, also known locally as put-puts.