De Marssumermolen, Marssum 57 cogs. This drives the "wallower" (31 cogs) at the top of the "upright shaft". At the bottom of the "upright shaft" there are two "crown wheels"' The upper "crown wheel", which has 17 cogs drives an Archimedes' screw. The axle of the Archimedes' screw is diameter and long. This screw is used to pump water into the polder. The lower "crown wheel", which has 43 cogs, drives a gearwheel with 38 cogs on the axle of an Archimedes' screw, which is used to drain the polder. The axle of the screw is diameter and long. The screw is diameter.
SS Archimedes 1836 patent. Following the ship's entry into service, the propeller would subsequently undergo a number of modifications, the most important of which were an alteration to a double threaded/half turn format, and a division of the original 360° screw into two separate blades. The propeller had the unusual feature of being fully retractable in order to reduce drag when the ship was under sail—a task that took about 15 minutes. "Archimedes" made her maiden voyage, from London to Sheerness near the mouth of the Thames, commencing 2 May 1839. On the 15th, she commenced her first sea voyage, from Gravesend