Re: [Paddlewise] Slamming

From: <rdiaz_at_ix.netcom.com>
Date: Fri, 12 Mar 1999 23:45:41 -0800
> Larry Bliven wrote:
> 
> > i've read that the acceleration of water in breaking ocean waves reaches a
> > maximum of about 10 G. Continued slamming of ocean going boats can cause
> > fatigue problems... perhaps failure.
> >
> > so i wonder, what design forces are used for developing kayaks? is there any
> > real consideration beyound folks tossing them off of roof tops to see if
> > they survive...

I hope I am not starting a holy war but I doubt that any hardshell
manufacturer would want to drop a nice fiberglass kayak off of a factory
roof.  The gelcoat would break off in pieces and scatter like the
contents of a large spilled package of Chiclets.  Artistic patterns of
stress fractures would radiate across the hull, et al.

I once was helping a friend empty water from his kevlar kayak by turning
it upside down and lifting alternate ends.  As we were turning it back
upright, my hand slipped on the slick surface and I dropped it from just
knee level.  That's where I got the Chiclets imagery re the gelcoat.

On the other hand I have dropped one of my folding kayaks from the
moderately high roof of my mini-van.  No damage aside from a slight
buffed mark on the hull where it hit the concrete surface of the parking
lot.  The wooden frame was just fine.  One or two of the longerons (thin
long pieces running the length of the boat) popped out of their holders
on the crossribs and just had to be pushed back into place.

BTW, Nautiraid I know does drop its boats from the factory roof to see
what happens. Nothing.

I think the same would be true of any skin boat.  There is a lot to be
said about wood and wooden frames made up of parts that flex and give to
absorb impact.  Same with soft yielding skins instead of rigid
surfaces.  Aluminum tubing frame parts also have lots of resilency and
will flex enough to absorb punishment.

Someone related a true story that I wrote up in my newsletter of several
of his folding boats being picked up by a twister and dashed against
some concrete posts.  Again just some scrapes on the skin from the
rubbing on the rough surface.  

Can things break on one.  Of course.  But you have fairly easy repair or
you can always replace the individual piece.

ralph diaz    



 
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Ralph Diaz . . . Folding Kayaker newsletter
PO Box 0754, New York, NY 10024
Tel: 212-724-5069; E-mail: rdiaz_at_ix.netcom.com
"Where's your sea kayak?"----"It's in the bag."
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Received on Fri Mar 12 1999 - 20:43:41 PST

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