Paddle Wheel

A paddle wheel is a form of waterwheel fitted with a ring of paddles around its rim, mounted at the side or stern of a vessel and turned by a steam engine to propel it through the water, and it served in the nineteenth century as an early alternative to sail and oar power that let ships operate independently of the wind. The paddle steamer proved a significant but comparatively brief chapter in marine propulsion, giving way once the screw propeller demonstrated greater efficiency: in an 1845 tug-of-war trial the screw-driven HMS Rattler pulled the paddle steamer HMS Alecto backward at 2.5 knots, a decisive demonstration that the propeller delivered more thrust for less weight and fuel than the paddle wheel, and shipbuilders turned to propeller propulsion soon after.