On 15 Oct, 16:20, "Bill" wrote:
"toad" wrote in message

The guy who built the windmill boat could be a lying crackpot. I have not
seen one with my own eyes so your point is valid.

You wouldn't have to lie. Natural wind isn't all in one direction. You
could be steaming ahead in your windmill boat on the components of the
wind that are not directly on the nose and really believe yourself to
be sailing upwind. Pyro actually posted a picture of his cart working
- but in the photo he was blowing downwards on it. He wasn't lying, he
realy did think it was going upwind, he just didn't have a handy head
protractor!

It's also worth noting that some of the windmill craft identified in
the course of this 'debate' as craft that could sail directly into
wind turn out to be incapable of going direct into wind!

It's a futile to debate this in words. We need figures. It will be
resolved one day when somebody who genuinely knows (as opposed to
guessing based on gut feeling and justifying it with wordy posts using
analogies) simply posts the worked formula to prove it one way or the
other.

You only have to look at the Conundrum thread to realize just how much
of a pinch of salt you have to take with armchair physicists on usenet!