Re: [Paddlewise] chine and stability

From: 735769 <735769_at_ican.net>
Date: Fri, 17 Nov 2000 08:32:32 -0500
Matt wrote:



>Imagine we make two ramps in the shape of a stability curve to roll a ball
bearing up and over. The front side of the curves are identical but one then
drops straight down to zero at its peak and the other falls away like most
static stability curves do. Question: Which ball will reach the (ground)
zero point on the back side the quickest (if you were to roll it over both
ramps equally hard and with plenty of momentum to easily make it over the
hump)?

If the velocity of the ball were sufficiently high so that the ball would
lose contact with the curve after reaching the maximu then you are
absolutely right. Are you saying that all capsizes result from this kind of
rotational velocity?


(SNIP)


John wrote:
>>>I don't have any data to support "meaningless" and would suggest that if
peope can sense the stability of the boat then it probably exceeds
"meaningless". What do they sense if not the boat?<<<<

>That's my point, how many of us can sense the stability of the backside
once
our momentum has put us there and into the virtual freefall we call a
capsize.

Are you saying that if you can't sense the righting force it doesn't exist?

John wrote:
>>>>>That is, boat righting
arm plus weight shift plus paddle forces.  The greater the righting moment
contributed by the boat after the maximum the less on needs of the other two
to right the boat.<<<<

>While I can't disagree with anything you say here it is essentially
irrelevant because that little righting component is so small compared with
the righting moment that you can generate with your paddle blade that it
would be inconsequential. In other words, it won't make the difference
(whether you capsize or not) once in a thousand times.

What science do you have to support "irrelevant"?



Thanks to Matt for all the information  he dug up that supports my arguments
by providing the various aspects of stability and how one quantifies them.
Unfortunately none of them relate to a measure of how one "feels" about
stability.

Cheers,

John Winters



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Received on Fri Nov 17 2000 - 05:53:02 PST

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