Date: Thu, 05 Nov 1998 14:18:00 -0600
From: "Wolfgang Brinck" <wolfgang.brinck@hksystems.com>
To: baidarka@lists.intelenet.net
Subject: Re: baidarka FOLDABLES AND STIFFNESS
I've had some more thoughts since my previous reply, so here it goes:
If I knew how to weld aluminum, I'd be tempted to weld up some tubes into a fairly
rigid frame and cover it with skin just to see how a more rigid kayak would compare
to a looser lashed kayak.
I did lash a baidarka fairly loosely once and have since relashed it tightly. Come
to think of it, performance wasn't all that different. Of course, the ribs are
sitting loose in their mortises in any case and it is the skin that does a lot of
the work of holding the parts together.
It is instructive to take a baidarka frame before it is skinned and twist it, shake
it and bend it and to watch the internal motion of the parts relative to each other.
I don't know what I've learned from all this other than that what goes on is fairly
complex. Also, the shape of the frame changes quite a bit when stress is put on it.
This is where the skin comes in; by tightly enclosing the frame it limits how much
it can change its shape.
Wolfgang
Stefano Moretti wrote:
> Wolfgang Brinck wrote:
> >
> > I would like to re-iterate that a baidarka built to a more or less traditional
> > design, even one that uses aluminum tubing is more flexible than a hard shell
> > boat. So my point was that even if you go for maximum stiffness in a skin on
> > frame boat, it will still be plenty flexible. Making it intentionally more
> > flexible by lashing it loosely or by leaving the skin slack will not create a
> > better boat.
>
> This message is cristal clear.
>
> My point however was slightly different:
>
> how much flexibility is good enough ?? How flexible can a boat be
> without performing as an inflatable canoe (it floats but speed is on the
> very low side) ?
>
> If this degree of "adequate" flexibility can be expressed with a figure
> from 1 to 100, just to have a term of comparison in the foldable world ,
> how much would you rate klepper aerius double and feathercraft k-light
> ?? And where would you put a multi chined traditional version as the
> awesome one depicted in your book.
>
> Thanks to anybody willing to share his much needed experience (first
> hand better) in this venture of mine.
>
> Stefano, looking forward to start a very traditional wooden frame
> baidarka