"Steve Firth" wrote in message
...
Paul Cassel wrote:

Steve Firth wrote:
Bill wrote:


Umm well we can, water can be made to flow up hill on a slope.

http://www.livescience.com/environment/060329_water_uphill.html

No, it can't. The water is propelled by steam. It's not flowing, it's
boiling.

And steam makes a frictionless cushion so it should be shooting
downhill. There was also another URL which you have conveniently snipped
from your reply.

And water vapor goes up to make clouds all without the help of scientists or
steam.

Gravity does not exist at the LaGrangian point.

Oil droplets could go up or down under the control of Milliken.

If one accelerates toward the earth at the correct rate the gravitational
field disappears.

Photons do not change speed due to acceleration in the earth's gravitational
field. They change colour.

Electrons can exist in large, dense clusters without repelling each other.

A clock runs at two different rates for two observers travelling at
different speeds.

In spite of all these wonders there still ain't no such thing as a free
lunch.



Also no matter how you turn your boat in a calm, the wind is always
directly on your nose.

If you're not moving how can the wind be on your nose?

"toad" wrote in message
oups.com...
On 14 Oct, 16:52, Andy Champ wrote:
toad wrote:
Care to explain why a windmill which is capable of powering itself
forward against it's own drag can only do it with a true wind? How
does it know if the wind it is 'feeling' is true or not, it has no
concept of true wind which is merely the wind speed and direction at
an arbitary stationary point.

There will be a level of gearing low enough somewhere, so that the
boat can wind itself forward against the winch.
Even so, if the true wind is zero you get no excess of power whatever
you do.

How does the windmill know the wind is not true wind? It has no
concept of 'true' wind, it lives exclusively in apparent wind.

Assume the windmill direct into wind concept works:

You can take your windmill cart, put it on another cart and tow it at
20kts. It sees 20kts and will move forwards along its cart. If you
stop the cart and blow 20kts at the windmill cart it will move
forwards at exactly the same speed.


In other words there is some spare energy left over to drive the cart
forwards after the energy required to hold the windmill in equilibrium
with the wind is expended. In my example above that spare energy is
used to drive the cart forwards but in your example of the windmill on
the foredeck that surplus energy can be used to save petrol.

Now we both accept that idea is laughable so you have to explain why
it's not laughable when the wind blowing is caused by nature.

...but most importantly, why oh why oh why doesn't someone just post
the mathmatical proof, the last time this came up I said I'd leave the
thread 'till proof turned up and none did. Odd that.

http://www.boatdesign.net/forums/showthread.php?t=14182

Reality beats proof.

Umm well we can, water can be made to flow up hill on a slope.

http://www.livescience.com/environment/060329_water_uphill.html

No, it can't. The water is propelled by steam. It's not flowing, it's
boiling.

And steam makes a frictionless cushion so it should be shooting
downhill. There was also another URL which you have conveniently snipped
from your reply.


"Bill" wrote:
And water vapor goes up to make clouds all without the help of scientists or
steam.


Nice backpedal.
You really urped on that one "Bill."


Gravity does not exist at the LaGrangian point.


Yes it does. Gravity always exists. At a LaGrange point, the gravity
of one mass is cancelled by the mass of another. So gravity has no
effect on free bodies at a LaGrange point, but gravity still exists.


Oil droplets could go up or down under the control of Milliken.


Wrong again. Oil droplets could appear to go up or down under his
telekinetic control.
"Seems" is not the same as "is" no matter how much it appears to be.


If one accelerates toward the earth at the correct rate the gravitational
field disappears.


Nope. It is cancelled out by the acceleration (the "correct rate"
happens to be 32 ft/sec/sec, or about 1 g.... how difficult is it to
figure this out?) but gravity never "disappears."


Photons do not change speed due to acceleration in the earth's gravitational
field. They change colour.


An energy effect nontheless. Does a net change in energy always cause
a change in velocity and only a change in velocity? There are other
forms of energy.



A clock runs at two different rates for two observers travelling at
different speeds.


No they don't. They run at different rates relative to the observers.

In other words, "Bill" you flunked the physics test and you don't know
as much as you think you do.


In spite of all these wonders there still ain't no such thing as a free
lunch.

Got that one right.... the 1/2 pt extra credit doesn't save your grade
though.

DSK

Wilbur Hubbard wrote:

"Stephen Trapani" wrote in message
...
If the apparent wind, say, decreases *any* resistance by, say lifting
the boat a fraction, or changing the effective hull shape that is
hitting the water, then NORDHAVN's statement is technically correct.

Poppycock! NORDHAVN's statement is fiction. Pure fiction! Had they said
light air instead of dead air they would have been correct on any point
of sail other than with the wind dead ahead but they didn't say that.
They said dead air which means NO WIND. No wind will always cause the
apparent wind to be from dead ahead when motoring ahead and this dead
ahead wind can't impart any forward force to the boat because it can
only shake the sails around and cause drag on the sails and rigging
which slows the boat.

Any chance they have some type of special rigging or innovative hull
shape to make what they are saying true? Ever seen what a dead air wind
dead ahead can do for an airplane?

Stephen

"Bill" wrote in message
...

"toad" wrote in message
oups.com...
On 14 Oct, 16:52, Andy Champ wrote:
toad wrote:
Care to explain why a windmill which is capable of powering itself
forward against it's own drag can only do it with a true wind? How
does it know if the wind it is 'feeling' is true or not, it has no
concept of true wind which is merely the wind speed and direction at
an arbitary stationary point.

There will be a level of gearing low enough somewhere, so that the
boat can wind itself forward against the winch.
Even so, if the true wind is zero you get no excess of power whatever
you do.

How does the windmill know the wind is not true wind? It has no
concept of 'true' wind, it lives exclusively in apparent wind.

Assume the windmill direct into wind concept works:

You can take your windmill cart, put it on another cart and tow it at
20kts. It sees 20kts and will move forwards along its cart. If you
stop the cart and blow 20kts at the windmill cart it will move
forwards at exactly the same speed.


In other words there is some spare energy left over to drive the cart
forwards after the energy required to hold the windmill in equilibrium
with the wind is expended. In my example above that spare energy is
used to drive the cart forwards but in your example of the windmill on
the foredeck that surplus energy can be used to save petrol.

Now we both accept that idea is laughable so you have to explain why
it's not laughable when the wind blowing is caused by nature.

...but most importantly, why oh why oh why doesn't someone just post
the mathmatical proof, the last time this came up I said I'd leave the
thread 'till proof turned up and none did. Odd that.

http://www.boatdesign.net/forums/showthread.php?t=14182

Reality beats proof.



I'm surprised that the fact that this (windmill boat sailing directly
upwind) is viable isn't intuitively obvious to more people. A sailboat
tacking upwind is an airscrew blade (the sail(s)) driving a waterscrew blade
(the keel), operating in their respective mediums. There is no inherent
difference between the back-and-forth motion of the conventional sailboat to
the rotary motion of the 'windmill' type boat.

Another mental experiment would be to think of a very wide catamaran with a
side-to-side track on which runs a car which holds the mast and sail above
and a centerboard sticking into the water below. Both are angled and a
mechanism in the 'car' causes both to change angle towards the center of the
catamaran when either end is reached. The 'car' effectively 'tacks' back and
forth on it's track while the catamaran moves straight ahead into the wind.

On 15 Oct, 05:33, "John Smith" x@y wrote:
"Bill" wrote in message

...







"toad" wrote in message
roups.com...
On 14 Oct, 16:52, Andy Champ wrote:
toad wrote:
Care to explain why a windmill which is capable of powering itself
forward against it's own drag can only do it with a true wind? How
does it know if the wind it is 'feeling' is true or not, it has no
concept of true wind which is merely the wind speed and direction at
an arbitary stationary point.

There will be a level of gearing low enough somewhere, so that the
boat can wind itself forward against the winch.
Even so, if the true wind is zero you get no excess of power whatever
you do.

How does the windmill know the wind is not true wind? It has no
concept of 'true' wind, it lives exclusively in apparent wind.

Assume the windmill direct into wind concept works:

You can take your windmill cart, put it on another cart and tow it at
20kts. It sees 20kts and will move forwards along its cart. If you
stop the cart and blow 20kts at the windmill cart it will move
forwards at exactly the same speed.

In other words there is some spare energy left over to drive the cart
forwards after the energy required to hold the windmill in equilibrium
with the wind is expended. In my example above that spare energy is
used to drive the cart forwards but in your example of the windmill on
the foredeck that surplus energy can be used to save petrol.

Now we both accept that idea is laughable so you have to explain why
it's not laughable when the wind blowing is caused by nature.

...but most importantly, why oh why oh why doesn't someone just post
the mathmatical proof, the last time this came up I said I'd leave the
thread 'till proof turned up and none did. Odd that.

http://www.boatdesign.net/forums/showthread.php?t=14182

Reality beats proof.

I'm surprised that the fact that this (windmill boat sailing directly
upwind) is viable isn't intuitively obvious to more people.

Intuitively it does seem obvious. As do all the best perpetual motion
machines. It's only when you think about it that the flaws become
apparent and you start to look around to look for the figures. ...and
there are none. The last time this came up we had a 300 post argument
fest and still nobody was able prove it worked.

As for reality beats proof. FFS. There was a photo of a perpetual
motion machine in the daily mail a few weeks back.

On 14 Oct, 17:18, "Bill" wrote:

Read this about lift:

http://home.hccnet.nl/m.holst/LiftDrag.html

Particularly the part about "by definition lift does NOT do work".

What force do you think does work against gravity to allow aeroplanes
to ascend?

Ian

On 14 Oct, 23:07, (Steve Firth) wrote:

If you're not moving how can the wind be on your nose?

Motoring?

What you wrote before was "If one is motoring in a calm on a flat
millpond then there is an
apparent wind equal to the speed of the boat from dead ahead."

You then seemed to claim that by changing course this apparent wind
could be made to do useful work.

Ian

On 14 Oct, 19:14, (Steve Firth) wrote:
toad wrote:
How does the windmill know the wind is not true wind? It has no
concept of 'true' wind, it lives exclusively in apparent wind.

Most amusing that you call me a troll for pointing out that this also
applies to motor sailers.

But you seem to be claiming that a sail can produce forward force from
a headwind. It's obvious how a windmill might do that, but a
sail ... ?

Ian

On 15 Oct, 07:09, toad wrote:

Intuitively it does seem obvious. As do all the best perpetual motion
machines. It's only when you think about it that the flaws become
apparent and you start to look around to look for the figures. ...and
there are none. The last time this came up we had a 300 post argument
fest and still nobody was able prove it worked.

Toad, my dear fellow, please don't make an arse of yourself over this
yet again. Windmill powered sailing boats which can go directly upwind
have been built many times. Details have been given here - have you
been to see the one in the Scottish Maritime Museum yet?

As I recall, your main failure to understand came from thinking that
there was only a windmill involved, so it case you have forgotten,
please remember that all these designs use a PROPELLOR IN THE WATER
COUPLED TO THE WINDMILL.

Ian