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William R. Watt
 
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Default Fiberglass vs plastic

Brian Nystrom ) writes:

It would cost no more to custom design a plywood kayak built with
computer cut panels than to design a mass produced plywood kayak
built with computer cut panels.


How do you figure that?


companies like Chesapeke(?) Light Craft and Pygmy Boats sell plywood boats
and kits make from computer cut panels. people buy the boats or they
can assemble the kits themselves and save a lot of money.

... The most efficient hulls (least wetted surface
for a given displacement) are rounded in shape, which cannot be built
from flat panels. The cost to produce a mold for a one-off design is
prohibitive. One could have a boat custom designed and strip built, but
how many people are going to pay in excess of $5000 for a kayak?


yes, avoiding moulds for building resin boats one off was my point.
you can custom design and build a plywood or a "stripper" boat cheaper.

as for the preformance of flat panel (hard chine) hulls its actually the
turbulence at the chines which creates more drag at higher speeds compared
to smooth chined hulls. the wetted surface vs wave-making again.

some places you read about wetted surface vs wave-making. other places
its wetted surface vs residual resistance, where residual resistance is
any kind of drag that's not surface friction and includes drag due to
wave-making, poor tracking, hard chines, etc.

Such an approach to designing would answer the
buyer's perrenial question "which kayak is right for me?".


Not if they don't understand the information. Most won't and they're not
going to be willing to learn about hydrodynamics in order to do so.


all part of the education of the paddling public.

I agree with everything you wrote below about the motivation to
buy a kayak but when it comes to the actual purchase people do ask about
which kayak is best for them, likely because they will be spending so much
money on the boat and accessories.

I think people can relate to how much power it should take a person of a
given weight to get the boat to go a certain speed than to how many pounds
of resitance the boat should have at a that speed, especially when you
tell them how much power an average person can sustain paddling. I also
think people could relate better to how tall they should be or how much
they should weigh for a given kayak than just to say "for light people" as
the brochures usually do. The data could be on a website rather than print
a more costly booklet to replace the brochure. All of thse numbers should
be avialable from desingers now, just restate and pass along to buyers.

While you and I and some others here may care about performance data,
it's pretty obvious that most kayak owners don't and never will.


I've actually seen a lot of queries about "what kayak is right for me" and
I suspect its because of the high cost of the boats which makes people stop
and think. Kayaks and canoes cost more than bikes, skis, and skateboards.
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