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A motorboat, speedboat, or powerboat is a boat which is powered by an engine. Some motorboats are fitted with inboard engines, others have an outboard motor installed on the rear, containing the internal combustion engine, the gearbox and the propeller in one portable unit.
An inboard/outboard contains a hybrid of a powerplant and an outboard, where the internal combustion engine is installed inside the boat, and the gearbox and propeller are outside.
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. The v-drive has become increasingly popular due to the wakeboarding and wakesurfing sports.
Motorboats vary greatly in size and configuration, from the 4-meter, open center console type to the luxury mega-yachts capable of crossing an ocean.
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 boat powered by a petrol engine only came about in the latter part of the 19th century with the invention of the internal combustion engine.
The earliest boat to be powered by a petrol engine was tested on the Neckar river by Gottlieb Daimler and Wilhelm Maybach in 1886, when they tested their new "longcase clock" engine. It had been constructed in the former greenhouse (converted into a workshop) in Daimler's back yard. The first public display took place on the Waldsee in Cannstatt, today a suburb of Stuttgart, at the end of that year. The engine of this boat had a single cylinder of 1 horse power. Daimler's second launch in 1887 had a second cylinder positioned at an angle of 15 degrees to the first one, and was known as the "V" type.
The first successful motor boat was built by the Priestman Brothers in Hull, England, under the direction of William Dent Priestman. The company began trials of their first motorboat in 1888. The engine was powered with kerosene and used an innovative high-tension ignition system. The company was the first to begin large scale production of the motor boat, and by 1890, Priestman's boats were successfully being used for towing goods along canals.
Another early pioneer was Mr. J. D. Roots, who in 1891 fitted a launch with an internal combustion engine and operated a ferry service between Richmond and Wandsworth along the River Thames during the seasons of 1891 and 1892. 
The eminent inventor Frederick William Lanchester recognized the potential of the motorboat and over the following 15 years, in collaboration with his brother George, perfected the modern motorboat, or powerboat. Working in the garden of their home in Olton, Warwickshire, they designed and built a river flat-bottomed launch with an advanced high-revving engine that drove via a stern paddle wheel in 1893. In 1897, he produced a second engine similar in design to his previous one but running on benzene at 800 r.p.m. The engine drove a reversible propeller. An important part of his new engine was the revolutionary carburettor, for mixing the fuel and air correctly. His invention was known as a wick carburettor, because fuel was drawn into a series of wicks, from where it was vaporized. He patented this invention in 1905.
Daimler Company began production of motor boats in 1897 from its manufacturing base in Coventry. The engines had two cylinders and the explosive charge of petroleum and air was ignited by compression into a heated platinum tube. The engine gave about 6 horse-power. The petrol was fed by air pressure to a large surface carburettor and also an auxiliary tank which supplied the burners for heating the ignition tubes. Reversal of the propeller was effected by means of two bevel friction wheels which engaged with two larger bevel friction wheels, the intermediate shaft being temporarily disconnected for this purpose. It wasn't until 1901 that a safer apparatus for igniting the fuel with an electric spark was used in motor boats.
Interest in fast motorboats grew rapidly in the early years of the 20th century. The Marine Motor Association was formed in 1903 as an ofshoot of the Royal Automobile Club in 1903. Motor Boat & Yachting was the first magazine to address technical developments in the field and was brought out by Temple Press, London from 1904. Large manufacturing companies, including Napier & Son and Thornycroft began producing motorboats.
The first motorboating competition was established by Alfred Charles William Harmsworth in 1903. The Harmsworth Cup was envisioned as a contest between nations, rather than between boats or individuals. The boats were originally to be designed and built entirely by residents of the country represented, using materials and units built wholly within that country.
The first competition, held in July 1903, at Cork Harbour in Ireland, and officiated by the Automobile Club of Great Britain and Ireland and the Royal Victoria Yacht Club, was a very primitive affair, with many boats failing even to start. The competition was won by Dorothy Levitt in a Napier launch designed to the specifications of Selwyn Edge. This motorboat was the first proper motorboat designed for high speed. She set the world's first Water Speed Record when she achieved 19.3 mph (31.1 km/h) in a 40-foot (12 m) steel-hulled, 75-horsepower Napier speedboat fitted with a 3-blade propeller. As both the owner and entrant of the boat, "S. F. Edge" was engraved on the trophy as the winner.
An article in the Cork Constitution on 13 July reported "A large number of spectators viewed the first mile from the promenade of the Yacht Club, and at Cork several thousand people collected at both sides of the river to see the finishes." Levitt was then commanded to the Royal yacht of King Edward VII where he congratulated her on her pluck and skill, and they discussed the performance of the motorboat and its potential for British government despatch work.
The acknowledged genius of motor boat design in America, was the naval architect John L. Hacker. His pioneering work, including the invention of the 'v-hull' and the use of dedicated petrol engines revolutionized boat design from as early as 1908, when he founded the Hacker Boat Co. In 1911, Hacker designed the ‘Kitty Hawk’, the first successful step hydroplane which exceeded the then-unthinkable speed of 50 mph and was at that time the fastest boat in the world. The Harmsworth Cup was first won by Americans in 1907. The US and England traded it back and forth until 1920. From 1920-1933, Americans had an unbroken winning streak. Gar Wood won this race eight times as a driver and nine times as an owner between 1920 and 1933.
- http://media.daimler.com/dcmedia/0-921-1303725-1-1303019-1-0-0-0-0-1-11694-614318-0-1-0-0-0-0-0.html?TS=1302091862634 Daimler AG homepage on Daimler Gedächtnis Stätte in English
- Reuß, H.-J. Automobil und Motorschiff haben dieselben Wurzeln. In: Hansa, issue 2/2011, p. 20–21, Schiffahrts-Verlag Hansa, Hamburg 2011, ISSN 0017-7504
- "Catalogue of the naval and marine engineering collection in the London Science museum". Her Majesty's Stationery Office.
- Bernard B. Redwood. "A Short History of Motor Boating".
- "Where it all began!".
- The British International Harmsworth Trophy
- Hydroplane History, From Rowboats to Roostertails – A Brief History of Unlimited Hydroplane Racing,  by Fred Farley, APBA Unlimited Historian
- Hydroplane History – Duby Looks Back 25 Years , One speed record that still stands by Larry Paladino
- Scarf and Goggles, Dorothy Levitt – The Fastest Girl on Water. Profile of Levitt's Motor Yachting races.
- The Penny Illustrated Paper and Illustrated Times (London, England),Saturday, November 17, 1906; pg. 309; Issue 2373. The Sensational Adventures of Miss Dorothy Levitt, - Champion Lady Motorist of the World. Available at British Library, British Newspapers,  Search for Dorothy Levitt
- Autosport, The Nostalgia Forum, Historical Research, Complete transcription of The Penny Illustrated Paper and Illustrated Times (London, England), Saturday, November 17, 1906; pg. 309; Issue 2373. The Sensational Adventures of Miss Dorothy Levitt, - Champion Lady Motorist of the World
The dictionary definition of motorboat at Wiktionary