A vessel with paddle wheels usually driven by the earliest forms of steam propulsion. The type which has two, one on either side mounted amidships, was known as a side-wheeler; the other, where a single paddle wheel is mounted at the stern, was known as a stern-wheeler. They were powered by reciprocating engines, though in the USA they often had a walking beam engine.
Various forms of man-operated paddle-wheel boats were in use long before the introduction of any kind of power, both in China and later in Europe. With the development of steam propulsion in the latter half of the 18th century various experiments were made in Europe to apply it to paddle wheels. The first to make a practical success of powering a boat in this way was a French engineer, the Marquis de Jouffroy d'Abbans (1751–1832). His 1776 experiment with a 13-metre (43-ft) boat on the Doubs River failed, but in 1783 his paddle steamer Pyroscaphe, with a displacement of 182 tons, was propelled against the current on the river Saône for fifteen minutes before it disintegrated. Another pioneer, the American John Fitch (1743–98), after a successful trial of a 14-metre (45-ft) paddle steamer in 1787, built a larger one the next year which ran regularly between Philadelphia and Burlington, NJ, though it was not large enough to be economically viable. The same year, in England, Patrick Miller also launched a steamboat. This was powered by an engine made by William Symington which drove a paddle between two hulls, and in 1802 William Symington produced the Charlotte Dundas. The first paddle steamer in Europe to run a regular commercial service for passengers was the 13-metre (43-ft 6-in.) Comet which, from 1812, plied between Glasgow and Greenock. Other early paddle steamers such as the Clermont, Savannah, Enterprize, Great Western, and Sirius, all contributed to the slow transition from sail to steam.
The earliest powered paddle wheels carried six or more fixed floats, and some, like those fitted to the Savannah, could be dismantled and carried on deck when not in use. By about 1840 most paddle wheels were fitted with a feathering device in which radial rods mounted on an eccentric moved the floats in turn so that as they entered the water and left it they remained nearly upright, thereby gaining more propulsive power and causing less wash. In the early days of the 19th century there were also many experiments in the arrangement and shape of the floats, from single paddles to multiple shutters, all aimed at increasing the wheel's efficiency and reducing the shocks as the floats struck the water. Many variations of these ideas in model form can be seen in the Science Museum, South Kensington, London. Up to the end of the paddle steamer era, however, the traditional wheel with feathering floats was almost universal.
For the first fifty years of steam propulsion at sea the paddle steamer had few rivals. But shipowners were well aware of some of its disadvantages. One was the danger of broken paddle shafts and damaged engines when the ship rolled heavily in bad weather. Another was the varying effect in speed and coal consumption between a deeply laden cargo vessel, whose wheels would be well immersed, and one which was in ballast, when the wheels would have little grip of the water. For warships, too, paddle wheels proved far too vulnerable to enemy gunfire or collision, which hastened the introduction of the propeller.
Subjects: Maritime History.