It works on the principle of ""Magnus Effect".
Irfan

"Punchy99" wrote in message
m...
Hello,

A few years ago I saw a brief thing on TV about a guy in the UK who
built a very cool sail for his catamaran or trimaman --can't remember
which one. It looked like a 15/20ft. tall cylinder where the mast
would normally be. You steered the thing pretty much like a car.

Does anyone know anything about this or the person who invented and
built it?

Any help would be greatly appreciated. Thanks in advance.