Re: [Paddlewise] British Heavies "crumple"

From: Brian Curtiss <bc_at_asdi.com>
Date: Tue, 15 Apr 2003 08:42:17 -0600
>...the color has little to do with the failure.  The issue is
>probably a combination of a bad batch of resin, air tight hatches, and moving
>from 7500 ft. elevation to sea level plus the color and sun.

Actually, the dark color (at least in part) helped.

If moving the boats from 7500' to sea level really caused the 
problem, the color may have both helped and hurt.  If you assume a 50 
deg F (10 deg C, 283 deg K) temperature at altitude, the pressure 
difference relative to ambient (at sea level) varies between -7.3 psi 
(with no internal temperature change) to -4.1 psi (with an internal 
temperature of 120F = 49C = 322K).   If heated up enough (to about 
213F in this example) the pressure difference would be zero.

Where the color may have hurt is in the strength of the hull.  Does a 
fiberglass (or carbon fiber or kevlar) layup get weaker when heated 
to 100-120 degrees or so?

I converted these pressures into feet of water to put it into a 
context to which most of us can relate: 7.3 psi == 16.5 feet of 
water, 4.1 == 9.4 feet of water.

Brian Curtiss
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Received on Tue Apr 15 2003 - 07:42:22 PDT

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