For the record, I can't think of any application in a boat where you would use plywood without
glassing over it, even if it's just a single unit of 6oz to protect the epoxy barrier from abrasion like you see in plywood boats. In this application, the plywood provides an inexpensive core material to space the two laminates apart without any significant compressibility within the core material.
I haven't worked much with carbon, so I have a couple questions myself.
Would the weight savings be worth the cost of the material for this application ? I can see it if that's how the rest of the boat is built, but as a retro on an admittedly-inexpensive boat it seems like money better spent elsewhere.
What would be the advantage of carbon in this application ?
Dieselboy, if by 'Styrofoam' you mean blue- and pink-board, I gotta disagree with you. Yes it's used for body panels in many custom vehicles, but only where an inexpensive material is needed to hold shape. Using it as coring in a structural panel cause it to fail in long cracks that subject the glass to wicked shearing forces along a sharp line in the same place on the inner and outer laminates. If you can point me to a true unibody (structural) application that uses it for coring I'll happily stand corrected because it'll give me a lot more options in my own work once I figure out how they get the resin to saturate it...
Originally Posted by mitiempo
Yes plywood could be used - the original builder did.
According to the OP, it was the fact that balsa core and NOT plywood was used for core that got him here. There are many (most?) production boats out there with plywood that never gives a worry as long as it's encapsulated. Plywood coring just doesn't fail without help - either through water ingress or mechanical damage.