Re: [Paddlewise] Group Paddling - folders stability

Ralph wrote;

(SNIP)

>> Only if the hard-shell does not have reserve buoyancy or a pod or sea
sock.
>> The flotation in concert with the shape provides stability. So far I
have
>> seen no support for the argument stability have seen a number of studies
on
>> this topic and performed some myself with no suggestion that the hull
>> materials have any unique properties.
>
>I am not sure I agree.  I have paddled hardshells that were half filled
>with water in the cockpit area while having bulkheads and waterproof
>compartments on the ends fore and aft.

This provides a good example of what I spoke about regarding apples and
fruits of another color. The stability in a flooded boat largely depends
upon athwartships flotation. The point I tried to make had to do with how
boatsa with similar floatation had similar stability in the flooded sate
regardless of hull materials. End tanks etc. do not add appreciably to
flooded stability particularly with large free surface effects in the
cockpit area. My discussion had to do with whether construction  materials
affected flooded stability (I am not sure they do to any noticeable degree)
not whether the location of buoyancy affected flooded stability for that
should I take as a given..

>
>Which bring me to something, John, that you said in your early posting,
>the one I kidded you were using to press you shameless attack on wearing
>life jackets (when not killing babies or signing suicide pacts) :-).
>You said "Many paddlers achieve this
>result by packing their boats with waterproof bags along the interior
>sides
>of their rigid boats."  I have never seen anyone do that in a
>hardshell.

Perhaps this has to do with ignorance. I do this on my boats when I do not
have a sea sock or pod. I use a multitude of small gear bags. Some boats,
may lack enough beam for this kind of thing but foam sheathing glued to the
hull sides to reduce volume also works. Reducing the floodable volume in
the boat ios the objective. I doubt if most paddlers understand or consider
the effects of free surface in their boats.  Most production boats don't
come with methods to attach side bags, sea socks, or pods and that seems to
me a serious omission.

Of course, if one uses a sea sock or pod the internal bags become
redundant.

I cannot say why builders of hardshells fail to recognize the importance of
flooded stability. As Ralph points out, all they need do is look at folders
to see them in use and apply the same principle.

Please don't call internal buoyancy bags sponsons. Sponsons attach to the
outside of the boat. Buoyancy bags and tanks attach inside.

Cheers,
John Winters
Redwing Designs
Specialists in Human Powered Watercraft
http://home.ican.net/~735769/



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