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Stephen Trapani

wrote:
On Sun, 14 Oct 2007 14:17:54 +0100, Andy Champ
wrote:

Steve Firth wrote:
Wilbur Hubbard wrote:

It's good to see a
Brit is the first to insert his foot into his mouth.
Ah no, that would have been you, as usual, Craptain. I bet you think
that ice yachts can't reach 146mph either.
Wilbur seems to have it right this time. Either the article is
misquoted, very badly written, or just plain wrong.

An apparent wind from dead ahead can add nothing but a force directly
astern.

The case where a true wind from ahead can be used to drive a windmill
that can drive a propeller to propel the vessel is different; but this
requires a true wind.

BTW ice yachts cannot make 146mph *directly* upwind.

Andy

This is got to be one of the stupidest threads I have ever read.
Anyone who has ever been in a boat motoring directly into the wind
knows that the sail produces no forward force. I can only assume that
the individuals who argue otherwise have never been a boat under those
conditions.

The advertisement never claimed to impart forward force going directly
into the wind. All they claimed was that they could somehow decrease the
load on the motor or increase the efficiency of the system. Even the
slightest lift on the hull could produce this, a heel to a more
effecient hull shape could also do it.

We can't tell if it's true with this boat because we don't really know
what they are talking about, but it seems very very possible, though
almost surely the effect will be trivial. So the advertisement is
probably true.

Stephen