De Kievit, Menaldum of the "upright shaft" there are two "crown wheels" The upper "crown wheel", which has 35 cogs drives an Archimedes' screw via a "crown wheel". This screw was used to pump water into the polder. The lower "crown wheel", which has 35 cogs, drives a gearwheel with 32 cogs on the axle of an Archimedes' screw, which was used to drain the polder. The axle of the screw is diameter and long. The screw is diameter. It is inclined at 10°. Each revolution of the screw lifts of water. "De Kievit" is open to the public at any time it
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