steamboat

A steamboat is a boat that is propelled primarily by steam power, typically driving propellers or paddlewheels. Steamboats sometimes use the prefix designation SS, S.S. or S/S (for 'Screw Steamer') or PS (for 'Paddle Steamer'); however, these designations are most often used for steamships.

The term ''steamboat'' is used to refer to smaller, insular, steam-powered boats working on lakes and rivers, particularly riverboats. As using steam became more reliable, steam power became applied to larger, ocean-going vessels.

Background

Limitations of the Newcomen steam engine

Early steamboat designs used Newcomen steam engines. These engines were large, heavy, and produced little power, which resulted in an unfavorable power-to-weight ratio. The Newcomen engine also produced a reciprocating or rocking motion because it was designed for pumping. The piston stroke was caused by a water jet in the steam-filled cylinder, which condensed the steam, creating a vacuum, which in turn caused atmospheric pressure to drive the piston downward. The piston relied on the weight of the rod connecting to the underground pump to return the piston to the top of the cylinder. The heavy weight of the Newcomen engine required a structurally strong boat, and the reciprocating motion of the engine beam required a complicated mechanism to produce propulsion.

Rotary motion engines

James Watt's design improvements increased the efficiency of the steam engine, improving the power-to-weight ratio, and created an engine capable of rotary motion by using a double-acting cylinder which injected steam at each end of the piston stroke to move the piston back and forth. The rotary steam engine simplified the mechanism required to turn a paddle wheel to propel a boat. Despite the improved efficiency and rotary motion, the power-to-weight ratio of Boulton and Watt steam engine was still low.

High-pressure steam engines

The high-pressure steam engine was the development that made th