Hi

"Drew Dalgleish" skrev i en meddelelse
...
Jaques Cousteu had a boat like that in the late 80s. The wind somehow
spun the cylinder which turned a propellor. The boat was able to sail
directly into the wind but didn't perform as well as sail on other
points.


Now these sails work without any propellor. By rotating the cylinder a more
dense vaccum on one side of the cylinder is created , ------ quite a few
know about these types of "sails" and the first ones was tested out just
after W.W.1 and acturly when well constructed they are as good as
tradisional sails, but the weight of the cylinder and different other issues
concerning strength made it into an idear reinvented each 20 year.
They work, but it is a common misunderstanding, that the rotating cylinder
need drive a propellor ------ this is not the force that work with a
rotating cylinder sail.
P.C.