SS Archimedes SS Archimedes SS "Archimedes" was a steamship built in Britain in 1839. She is notable for being the world's first steamship to be driven by a screw propeller. "Archimedes" had considerable influence on ship development, encouraging the adoption of screw propulsion by the Royal Navy, in addition to her influence on commercial vessels. She also had a direct influence on the design of another innovative vessel, Isambard Kingdom Brunel's , then the world's largest ship and the first screw-propelled steamship to cross the Atlantic Ocean. The principle of moving water with a screw has been known since the invention of
Archimedes number Archimedes number In viscous fluid dynamics, the Archimedes number (Ar) (not to be confused with Archimedes' constant, π), named after the ancient Greek scientist Archimedes is used to determine the motion of fluids due to density differences. It is a dimensionless number defined as the ratio of external forces to internal viscous forces and has the form: where: When analyzing potentially mixed heat convection of a liquid, the Archimedes number parametrizes the relative strength of free and forced convection. When Ar » 1 natural convection dominates, i.e. less dense bodies rise and denser bodies sink, and when Ar « 1