Paddle wheel ship

A paddle steamer is a steamship or riverboat powered by a steam engine that drives paddle wheels to propel the craft through the water.

In antiquity, paddle wheelers followed the development of poles, oars and sails, where the first uses were wheelers driven by animals or humans.

Modern paddle wheelers may be powered by diesel engines. But for their role as tourist attractions and small pedal-powered paddle boats, paddle propulsion has been largely superseded by the screw propeller and other marine propulsion systems that have a higher efficiency, especially in rough or open water.

The paddle wheel is a large steel framework wheel. The outer edge of the wheel is fitted with numerous, regularly-spaced paddle blades (called floats or buckets). The bottom quarter or so of the wheel travels underwater. An engine rotates the paddle wheel in the water to produce thrust, forward or backward as required. More advanced paddle wheel designs feature feathering methods that keep each paddle blade closer to vertical while in the water to increase efficiency. The upper part of a paddle wheel is normally enclosed in a paddlebox to minimise splashing.

There are two types of paddle wheel steamer, a sternwheeler with a single wheel on the rear, and a sidewheeler with one on each side. Both were used as riverboats in the United States. Some still operate for tourists, for example on the Mississippi River.

Although the first sternwheelers were invented in Europe, they saw the most service in America, especially on the Mississippi. The Enterprise was built at Brownsville, PA in 1815 as an improvement over the less efficient side wheelers. The second sternwheeler built, the Washington of 1816, had two decks and served as the prototype for all subsequent steamboats of the Mississippi, including those made famous in Mark Twain's book Life on the Mississippi.

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