Rotor Ship

A Rotor ship, also known as a Flettner ship, is a ship designed to use the Magnus effect for propulsion. The Magnus effect is a force acting on a spinning body in a moving airstream, which acts perpendicularly to the direction of the airstream. German engineer Anton Flettner was the first to build a ship which attempted to tap this force for propulsion.

Invention

Flettner's spinning bodies were vertical cylinders; the basic idea was that thanks to the Magnus effect, small motors powering a ship via rotating cylinders could propel it more efficiently than if they had driven a conventional propeller. These types of propulsion cylinders are now commonly called Flettner rotors.

His first idea was to produce the propulsion force by using a belt running round two cylinders. Later Flettner decided that the cylinders would be better rotated by individual motors. Flettner applied for a German patent for the rotor ship on 16 September 1922.

Assisted by Albert Betz, Jacob Ackeret and Ludwig Prandtl, Flettner constructed an experimental rotor vessel, and in October 1924 the Germaniawerft finished construction of a large two-rotor ship named "Buckau". The vessel was a refitted schooner which carried two cylinders (or rotors) about 15 metres high and 3 metres in diameter, driven by an electric propulsion system of convert|50|hp|abbr=on power.

Voyages

Following completion of its trials, the "Buckau" set out on her first voyage in February 1925, from Danzig to Scotland across the North Sea. The rotors did not give the slightest cause for concern in even the stormiest weather, and the rotor ship could tack (sail into the wind) at 20-30 degrees, while the vessel with its original sail rig could not tack closer than 45 degrees to the wind.

On 31 March 1926, the "Buckau", now renamed "Baden Baden" after the German spa town, sailed to New York via South America, arriving in New York harbor on 9 May.

The rotor system was less efficient than conventional engines. Flettner turned his attention to other projects and the rotors were dismantled. "Baden Baden" was destroyed in a Caribbean storm in 1931.

Uses today

The University of Flensburg is developing the "Flensburg catamaran" or "Uni-cat Flensburg", a rotor-driven catamaran.

The German wind-turbine manufacturer Enercon launched and christened its new rotor-ship E-Ship 1 on the 2nd of August 2008. The ship will be used to transport turbines and other equipment to locations around the world.

Stephen H. Salter and John Latham recently proposed the building of 1500 robotic rotor-ships to mitigate global warming. The ships would spray seawater into the air which some believe may increase global dimming. [ [http://news.bbc.co.uk/2/hi/programmes/6354759.stm Stephen Saltner and John Latham's cloud-seeding Flettner vessels] ] [ [http://www.see.ed.ac.uk/~shs/Global%20warming/Flettner%20ship Index of /~shs/Global warming/Flettner ship ] ]

See also

* Turbosail
* Wingsail

References

External links

* [http://www.tecsoc.org/pubs/history/2002/may9.htm Center for the Study of Technology article]
* [http://physics.kenyon.edu/EarlyApparatus/Miscellaneous/Rotor_Ship/Rotor_Ship.html Photograph of "Baden Baden" in NY harbour]
* [http://www.enercon.de/www/en/nachrichten.nsf/41657424de23a0b8c1256ed10041a39f/a0be583a3be1bcddc125749b0029b7a4?OpenDocument# Enercon press release for the launch of E-Ship 1]