Re: [Paddlewise] Slamming

From: John Winters <735769_at_ican.net>
Date: Sat, 13 Mar 1999 09:37:06 -0500
I have done the calculations using Lloyd's standards and most sea kayaks
(and canoes) get over designed due to stiffness requirements. In other
words a boat designed to have only enough strength for slamming loads would
not have enough rigidity to maintain its shape.

Of course, I assumed a properly constructed boat. Not all builders get the
hull/deck joints right etc. so what one boat does should not suggest that
all boats will do the same.

Like ships, the biggest danger to sea kayaks is impact with something hard.
Anecdotal evidence can be found to support the magical qualities of any
material but no one can really calculate how strong "strong" should be
since no one really knows the magnitude of potential loads.

I suspect most reputable builders produce boats suitable for the intended
use. If you want more, then I am sure you can find a builder that can
supply it. As for dropping boats off the roof, I have done one
manufacturer's boats in Royalex, Royalite, Fiberglass, Kevlar, Spectra etc.
In every case the boats survived the 20' drop just fine with some
scratching. I do not think the results unusual at all but I do think that
boats don't often fall off the factory roof in actual use.

I once watched Darryl Lideigh of Mohawk canoes pound on one of his chopped
fiberglass canoes with a hammer. The boat stood up just fine. Not sure what
that proved. Real life proves more.

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




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Received on Sat Mar 13 1999 - 07:01:46 PST

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