De Westermolen, Kollumerpomp of the upright shaft. At the bottom of the upright shaft is the "crown wheel", which has 41 cogs, drives a gearwheel with 42 cogs on the axle of the Archimedes' screw. The axle of the Archimedes' screw is diameter. The screw is diameter . It is inclined at 16.7°. Each revolution of the screw lifts of water. The Archimedes' screw that pumped water into the polder has been removed. "De Westermolen" is open on Friday mornings. It is also open on Saturday mornings if there is enough wind to work the mill. De Westermolen, Kollumerpomp De Westermolen is a
SS Archimedes the Archimedes' screw, named after Archimedes of Syracuse who lived in the 3rd Century BC. It was not until the 18th century however, and the invention of the steam engine, that a practical means of delivering effective power to a marine screw propulsion system became available, but initial attempts to build such a vessel met with failure. In 1807, the world's first commercially successful steam-powered vessel, Robert Fulton's "North River Steamboat", made its debut. As this vessel was powered by paddlewheels rather than a propeller, the paddlewheel thereby became the "de facto" early standard for steamship propulsion. Experimentation with screw