Sailing Upwind

Modern sail boats have more in common with airplanes than ancient ships. How do you design a sideways flying airplane? I have always found this a fascinating topic so I was very happy to see an article about the physics of sailing by Bryon Anderson a couple of months ago in Physics Today.

This image from Anderson's article demonstrates something profoundly unintuitive about sailing. Sailing downwind is not the fastest direction.




Not everything sails on water though. A land yacht called the Greenbird has just broken the wind-powered vehicle world record. The Rochelt Musculair sails through the air, flys, solely on human power.

These examples lead us to a paragon of design that has yet to prove its mettle, the BMW Oracle 90, a truly devastating machine. It is at the center of the America's Cup controversy. The controversy not withstanding this yacht is something to be in awe of: the BMW Oracle 90 is the size of a baseball infield, it has a mast taller than the statue of liberty (that is 48 meters, the Statue of Liberty is 46 meters not including the pedestal), and is one of the fastest sailboats created by man (what is the fastest?) . Please watch this video and behold.