Re: [Paddlewise] Rollability

Nick wrote;

> Looking at the roll period from 90 degrees to 270 degrees ( Zero being
> upright) with the paddler hanging stiff does not strike me very relevant
to
> how easy the boat is to roll.

I agree and hope no one got the idea thta I looked at it that way.

 >The interesting part of rolling is going from
> 180 to 360 degrees. It is this portion of the rotation that is important,
> and the hardest part of the roll is typically from 270 to 360 degrees so
> determining the damping of the inverted boat (90 to 270) does not even
> address the section of the roll where most people (who know how to roll)
> fail.

I can't comment on this since I do not know where most people fail.

(SNIP)

>
> If the paddler is hanging stiff he would provide resistance. But as Bruce
> said, typically the paddler moves his body counter to the rotation of the
> boat, so instead of providing resistance to the roll, his body provides
> assistance, or at least very little resistance. The body drag is more of a
> factor during the setup, but this is not a factor of boat design.

Good point that I had not considered so maybe we can delete the body effect
on damping. On the other hand, maybe the fact that people don't use their
body that way contributes to their failure rate so maybe it does have a
negative impact on those who don't roll well.

> While inverted drag may contribute to how easily a boat rolls, it seems to
> me that the hardest part of the roll does not include the inverted
section.

Is the boat rotating at that point? If so it would seem that its shape
influences rotational drag.

> Why evaluate the whole chain when you can just look at the weakest link.

I misunderstood your original question. I thought you asked about rolling as
a dynamic phenomenon in its entirety and not rolling just when it got
difficult. Since I misunderstood I will respectfully bow out of the
discussion.

Cheers,

John Winters
Redwing Designs
Web site address http://home.ican.net/~735769


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