Chris wanted to see some pictures of a failing centerboard, so I
thought an open discussion might be in order, (since I am going to
make another).
This centerboard was made as per the instructions from Bram and or
Greg, to the best of my ability. I started using it in the 06 regatta
in FL, so it has seen 3 seasons. Before going to FL in 08, I removed
some surface scratches by filling and sanding back to a smooth and
fair finish. The first blister appeared 2 days before the 08 regatta,
and every time I sail, it gets larger, and now is on both sides. It
still works, but has become increasingly difficult to lower and raise.
You can see 1 large bulge on the starboard side, and 2 on the port
side. The origional rudder broke under heavy air just after the 07
regatta. The pictures of the foam core are the new rudder made just
before the 08 regatta, with wood strips inserted to help handle the
loads it incurs, (which I believe are enormous)
I'm not an engineer, but it seems hybrid and carbon cannot handle
compression very well, or maybe it's just a limited number of cycles
it can handle. I don't know if altitude has anything to do with it,
but these boards were made at 4500' msl. The fact that they are black
probably has a lot to do with failure, although I tried my best to
keep them out of direct sunlight. If you add heat to epoxy resin it
will soften.
I will build another centerboard with a foam core, but it will have
stringers (4 or 5) to help with the loads the skins incure. Hopefuly
it will last indefinitly, or at least longer than the first.
If anyone has any ideas on making foam cored boards last longer,
please chime in.
Mark
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These pictures were sent with Picasa, from Google.
Try it out here: http://picasa.google.com/
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