Re: [Paddlewise] Life of plastic boats

Ken,

Thomas Hobbs got the description of plastic boat life essentially
correct in 1641.  When compared to their fiberglass cousins, "The
life of [plastic boats] is nasty, brutish and short."  

I don't know about all plastics but my AquaTerra Chinook age 7
years was definitely showing cracks in rounded areas and had
always been stored indoors.  Dave Kruger can give you the
chemistry but one dramatic demo of the fragility of poly
containers came years ago on a mountaineering expedition I'd
organized on the Monarch Icecap in BC.  We arranged for a bush
plane to resupply us with an air drop after reaching the icecap
plateau.  The drop arrived more or less on time and in place but
the results were an eye opener.  We figured poly bottles and
containers would be the most secure, flexible and impact
resistant so we gathered our spare climbing bottles etc. and
loaded them with rum, butter, honey, and and other gooey
goodies.  All the messy stuff was in 4-7 year old Nalgene
bottles, Tupperware and other high-grade but somewhat aged poly
containers.  We also had some last minute additions -- 2/3 gallon
of Coleman fuel in the can, canned fruit in a mailing tube, and
canned meats.  Everything was packed together in a multilayered
semi-hard drop container, very tightly packed).  We figured the
tin would not make it but counted on the plastic.  Wrong, wrong,
wrong.  *Every* poly container shattered upon impact.  The butter
and the run and the honey mixed nicely with my spare clothes and
etc.  You can imagine the mess.   Upon examination, the poly
containers looked like shards of glass -- splintered and
cracked.  The tin?  Everything was fine!  The Coleman fuel can
distorted and stretched in shape, as did many of the other tin
containers, but all remained intact.  On subsequent climbing
trips we used tin containers with much success and avoided any
more poly unless it held nothing more vital than oats or toilet
paper.  

So I don't know about boats, but poly bottles and boxes of a
certain age, subjected to sudden shock, are not the best.    

RGM

Ken Cooperstein wrote:
> 
> One of the folding boat enthusiasts (who shall remain nameless, except
> to say that he is Ralph Diaz) wrote in his book that plastic boats have
> a life of about eight years and then become brittle.
> 
> Is this because of UV damage?  Or other chemical breakdown?  Does it
> afflict both straght chain and cross-linked polyethylene?
> 
> I have my doubts about this assertion because I own a number of
> polyethylene objects that are over 20 years old and they are still
> flexible and like new.  OTOH, polyethylene left in the sun does indeed
> fall apart pretty quick -- a problem that can be solved for kayaks by
> proper storage.
> 
> Ken Cooperstein
> 
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-- 
Richard G. Mitchell, Jr.
Department of Sociology
Oregon State University
Corvallis, OR 97331
U.S.A.
(541) 752-1323 phone/fax
mitchelr_at_ucs.orst.edu
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