Subject: [harryproa] Re: Materials list, Price!!!!
From: Mike Crawford
Date: 3/3/2006, 6:57 PM

<<You have longitudinal strength in triaxial where needed... Don't really see how a resin filled seam weakens the structure as it is part of the web of the I beam structure.>>

  I'm familiar with sandwich construction, and I don't question that you can make a world-class boat out of polycore. 

  I'm just fond of a boat that has some reasonable structural integrity even before the glass goes on.  A resin seamed tortured polycore hull isn't going to hold much tension (or shape) prior to glassing.

  Thanks for the nidacore reference, by the way.  I need to replace the bunk shelves in my current boat, and this looks like a much better solution than the plywood I inherited.

       - Mike

Robert wrote:
-You have longitudinal strength in triaxial where needed and extra
uni in concentrated areas. A bit of movement in the structure
shouldn't matter provided the material isn't brittle and the stress
and strain parameters coordinate and the bonding is good. Don't
really see haow a resin filled seam weakens the structure as it is
part of the web of the I beam structure.


g-- In, Mike Crawford <jmichael@g...>
> << I actually prefer the resilience of the polycore to the strength
> the Kiri as tests I have read indicate it is better under
>   I think that kiri or cedar would probably test differently than
> but I'm still willing to buy the argument.  For the sake of
> let's say that polycore is stronger in collision.  But what about
as a
> complete structure taking a pounding in a storm?  That's a
> kind of strength.  I'd have more faith in a strip-planked boat with
> longitudinal strength throughout the entire hull, than in a cored
> that's going to have resin-filled seams that won't offer as much
>   That's really the crux of the matter for me.  What's more
> collision or pounding?  I'm personally more concerned about the
> but there's clearly no right answer.
>   Of course, if tortured polycore could save me a few hundred kg,
> a thousand hours, I'd put the intellectual argument aside and jump
on board.
>        - Mike


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