Just a note of clarification.
Those building boats for their own use are not required to use any particular
reinforcement material as long as the lay-up is declared at the time of
measurement and noted on the certificate. Those building for commercial sale
must
use the required composite lay-up. That having been said, you would be
foolish to build the boat with e-glass on the outside because the cost savings
is
small compared to the time investment. This is one area where I take issue
with
Nick Schades book. I'll never use e-glass on any strip built project again
because of the significant increase in weight required to achieve the same
strength. Remember, I built 001 this way and it weighs 35lbs more than 002 and
both boats have nearly identical same stiffness and strength.
I realize that I've created some confusion regarding the outside lay-up of
the hull and deck. You can use either 6 oz or 9 oz s-glass. The test results
(on the website) have shown only a relatively small difference in deflection
and I expect the hydromat results will be similar. When you compare these
results with the 49er sample, you get a good overall picture. Typically, both
weights of s-glass are most readily available in 8-plaite satin finish. This
material is a bit hard to use when using multiple layers, however, we are not.
Generally, I would recommend the 6 oz for those who are not vacuum bagging (the
majority) and 9 oz (actually 8.7 oz.) for those who are (mostly professional
builders). Both lay-ups should easily meet the minimum weight requirements
with reasonable care during construction. Remember, if you are too light you
will be required to add the weight close enough to the ends to pass the swing
test. There is no advantage to building a boat that is underweight by more
than
a couple of pounds.
The hybrid material that we use on the inside is really easy to work with
(except cutting across the Kevlar requires special scissors). It will lay flat
on any contour-a fact that you'll appreciate on the inside of the bow.
Everyone must keep one of the inspection port cutouts on file to surrender to
the measurer at the time of measurement.
Best regards,
Bram
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