100-200 hp

A motorboat generally speaking is a vessel other than a sailboat or personal watercraft, propelled by an internal combustion engine driving a jet or a propeller. However, the International Regulations for Preventing Collisions at Sea defines it as any vessel propelled by machinery. more...

Since an oar is an example of a lever, one of the simplest machines, thus, a rowing boat is by definition a motorboat. 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.

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, 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 than 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 propellor 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 20th 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.

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