I continue to advocate UHMW for all the reasons sited in this
thread. With UHMW your boat acts like it has a Teflon shell and will
slid up and over submerged obstacles like rocks and logs. I'm
positive if you follow a good building practice with normal bracing
and bulkheads then plate you boat with this incredible substance you
will have a three part protection system.
1. Plywood is stronger than most plain wood when comparing equal
2. Fiberglass with epoxy provides another excellent layer that will
allow an impact to be spread over a larger area to absorb the impact
instead of a puncture.
3. Finally UHMW is and has been in use on wooden boats for years and
is becoming a favorite coating for craft exposed to white water or
rocky beaches where no other bottom protection works like UHMW.
I implore all boat builders to become acquainted with UHMW, it could
save your life or hours of cutting and scraping out wood rot. Maybe
you're afraid of the weight cost but I have used a .22 rifle(in a
safe area) and if you shoot at UHMW(3/8") directly on it will flatten
the bullet if the UHMW is backed by plywood. By itself it allows
penetration but no further travel. Not as effective as kevlar but
UHMW is supposed to provide a super slick surface that will provide
something that slides past and over rocks, eliminating punctures.
I have used UHMW on drift boats that survived my poor navigation
down some of the most treacherous white water the pacific northwest
has to offer. The outcome, Rivers 7 oars. Boats, well over 100
anadromous fish including steelhead, Salmon and Char. Some rapids
caused impacts that would have literally torn the bottom out of a
plain plywood with fiberglass covered bottom.
I cannot make anyone use UHMW but I will use it myself when I know
the safety of myself, family and other passengers depend on my good
judgment. UHMW is the greatest innovation for wooden boats since
bronze screws. The views expressed here are mine alone and do not
represent Yahoo or others who post on this forum(LOL).
--- In bolger@y..., "Ned Asplundh" <nasplundh@y...> wrote:
> Lookee here:
> ...for one builder's take on the "good, bad and ugly" of differing
> reinforcement fabrics.
> --- In bolger@y..., David Ryan <david@c...> wrote:
> > FBBB --
> > As you all know, I am a big advocate of glassing over plywood
> > anywhere the sun beat down on it. Theres's simply no comparison
> > between how long a prime&paint finish lasts vs. glass/epoxy/paint.
> > However, I've had no good experience "glassing for impact
> > on my small boats.
> > The inevitable result is the glass fails at the point of impact,
> > allowing water to creep under the glass job. Over time, the
> > of this are even worse than using no glass at all! Glass
> > trapped water does nasty things to the wood, etc.
> > Now that doesn't mean I don't double up around chines, and other
> > pointy parts of the boat. But I don't expect my "impact
> > either." Perhaps on a larger craft you could build up the glass
> > enough to provide some meaningful protection, but I think on a
> > cheap boat it's both cost and weight prohibitive.
> > YIBB,
> > David
> > --
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