> ... if you achieve the same resin volume fraction with both the CF and the
> glass, the CF lay-up will weigh significantly more than the glass lay-up.

It's because of idiosyncracies such as this that carbon really shines when it's composited in a vacuum bag layup. All the fibers are compressed to their flattest state and the resulting resin requirements are reduced along with the compression of the fabric. This yields the lightest possible skin at the strongest possible potential.

The backside? Carbon typically costs as much as EIGHT TIMES as much as E-glass. If absolute weight savings are important and you have the budget to absorb it, (such as the needs of pure race boats) then carbon is a wonderful solution.

I have said before, ususally about the use of Kevlar for small boats, that S-glass is a much better alternative. With a negligible weight difference from carbon and a much easier handling, repair and overall application potential, S-glass really does beat carbon as well as Kevlar. Throw in the price advantage and it becomes very clear that if you want to build an everyday, higher performance or expedition level boat, use the S-glass build layup. My take.

Carbon has one very powerful intangible factor and that's the sexy look and techy panache that is derived when anything cool made from carbon fiber comes into view. In some corner of our psyche we all hope to drive a Formula One car someday with their carbon tubs and eyeball flinging acceleration and braking. Mental imagery such as that is difficult to overcome with working class S-glass as your hull sandwich.

I have nothing against carbon. (though I do steer clear of Kevlar whenever possible) In fact, I'm using a decent amount of it in a new, performance sailing canoe/trimaran I'm building right now in hybrid construction. The 6 oz., twill lays-up easily and when bias cut, takes to organic curves readily.

It's amazingly tough on tools and sand paper when saturated with cured epoxy so you'll have to allow for additional expense for those materials and sharpening time when using it for your project.

I don't know that it's been done, but I'd like to see one of Nick's boats built from stripped, Airex foam with carbon skins inside and out and finished with a crystal clear, two part PU. Put that boat out on the beach, next to the same model in wood, at any wooden boat show and stand back to listen to the ensuing discussion.

Chris