The was an article in Popular Mechanics (maybe Popular Science) more than 30
years ago, I think, about a home brew inventor in Australia (maybe New
Zealand) who had developed a wind powered boat that did just this.
IIRC he had started with a keel boat that had been split down the middle and
a section added to give greater beam. He could vary the pitch of the
windmill blades according to conditions, and the power from it went to a
large slow turning and efficient propeller.
He could power dead upwind, and boat speed was about the same regardless of
wind direction.
Future plans were to mount the system on a catamaran with the prop located
between the hulls about where the bow waves converged.

"Wilbur Hubbard" wrote in message
anews.com...
"Capt.Bill" wrote in message
...
http://www.windvinder.com/index.php?id=14&L=1


Nobody's seen it because it doesn't exist. It is a pipe dream. Notice on
the site there are no photographs of it in action. Just drawings. It can't
work. You cannot harness enough wind power with a windmill on a boat to
make the entire untethered vessel proceed directly upwind. It isn't going
to happen because it defies the laws of physics.

Wilbur Hubbard