Paddlewheel
As the first successful steam engines were developed in the 1700s, many inventors wondered how these new machines could be harnessed to drive boats. The problem was to transfer the motion of the engine to some device that would propel the boat. Several odd arrangements were tried, like mechanical oars and mechanical duck feet. It was natural for many early inventors to try paddlewheels. They took their inspiration from water wheels, which spun around under the power of running water. If paddles were attached to a boat and made to spin in such a way that they dug into the water, they might provide forward motion.
The Chinese were using paddlewheels on ships as early as the eighth century, and by the twelfth century large numbers of paddlewheel ships plied the Yangtze River. The wheels on these boats were powered by human muscle--some of the largest required as many as 200 separate wheels. Paddlewheels were first combined with a mechanical power source in the United States and Europe in the late 1700s. An American engineer, John Fitch, built a steamboat in 1788 that had stern paddles that moved like ducks' feet, and operated a ferry service with this boat between Philadelphia and Burlington, New Jersey, beginning in 1790. Fitch continued to improve the paddlewheels until they resembled a more modern configuration.
Two other American inventors, Samuel Morey and Oliver Evans, also introduced vehicles with paddlewheels in the late 1700s. While Morey designed a steamboat with paddlewheels, Evans used paddlewheels to power a strange amphibious vehicle. He built this vehicle--a floating, steam-driven dredge--at the request of the city of Philadelphia to dig and clear out the harbor area. It could move on land with wheels, switching to a paddlewheel for river travel.
Meanwhile, in Great Britain, William Symington built a steam tugboat to replace the horses that towed barges on an English canal. Symington's boat, called the Charlotte Dundas, was 58 feet (18 m) long, with a small steam engine driving a stern paddlewheel. Symington put his vessel into service in 1788. Robert Fulton built perhaps the best-known early steamboat, the Clarmont.. As early as 1779, Fulton had experimented with paddlewheel boats, and shortly after his return from Europe in the early 1880s, he began building the Clarmont. Completed in 1807, it became the first commercially successful steam-driven vessel when it quickly earned back its entire initial cost of $20,000. By the 1850s, luxurious paddlewheel boats were commonplace on waterways such as the Mississippi River, where countless passengers ferried between Louisville, Kentucky and New Orleans, Louisiana on a journey of a few days.
Isambard Kingdom Brunel, a brilliant English engineer, brought the paddlewheel ship to its zenith with the Great Western,, launched in 1838. Designed to cross the Atlantic to New York from the terminus of Brunel's Great Western Railway at Bristol, England, the Great Western was an enormous oaken ship with a massive hull; at the time of its launch it was the largest steamboat in the world. It made the Atlantic crossing 67 times, the quickest of these at 12 days and six hours.
But Brunel abandoned paddlewheels for his next (and larger) ship, the Great Britain. As more and more steamboats were built, the use of paddles came under critical fire. It was true that paddles made of wood were easy to repair and cheap to replace--all that needed to be done was to turn the wheel over until the damaged portion was above the water line. Though the paddle pulled the boat ahead as it entered the water, it also offered drag on its upward swing to clear the water. In addition, paddles did not work very well at sea, because as boats pitched from side to side, their paddles would lift completely out of the water, making them useless for propulsion. Engineers such as Brunel turned to the screw propeller for these reasons. It provided a powerful and efficient thrust, and remained underwater even in rough weather. Once the power and reliability offered by the screw propeller was established, the use of paddlewheel waned.
Though the paddlewheel has long since been replaced as a means of propulsion, paddlewheel boats have not entirely disappeared. The aesthetic value of these majestic ships makes them fashionable as tourist attractions in some parts of the United States.
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