"Edgar" wrote in message
. ..

"Scout" wrote in message
news
One would think that the sheer volume of air would make its efficient
use
a
non-issue. Unless the point is the area of the cross-section of air
available to a given size boat is limited. If that makes any sense.
Scout

The energy availabe to a sailboat is only limited by the area of sail you
put up to catch it and you do not have to worry about extracting all the
energy from the moving air because there is so much of it and it is free.
You want more energy? Hoist a bigger sail.
In a turbine or any motor that requires fuel you have paid for the fuel
that
creates the energy and the fuel you have on board is limited in quantity
so
of course you have to extract every last bit of energy from it by any
available means.

Edgar, that's pretty much what I was trying to say. By increasing the sail
size, you increase the area of the cross-section of air available. But given
the restriction of a limited (practical) sail square footage, I would
imagine it a benefit to capture more of the available energy using the
concept proposed by the Italians, per Gilligan. Not sure if it's worth the
effort, but it might be.
Scout