After building an 18' Chesapeake last year I am gearing up to build a 17' Guillemot from scratch this spring. I am interested if anyone has experimented with using materials other than plywood (marine or otherwise) and or strips (e.g. Cedar) to construct a kaytak. Thinking of weight and cost effectiveness I wondered if anyone had attempted to use strips cut from rigid foam insulation such as owens corning FOAMULAR(registered)? It may sound wacky however the material can be cut with a variety of tools and could probably be routed to accept a cove & bead.  Once covered inside and out with glass and expoy it may potentially be strong enough.  Likewise the cockpit could be re-enforced with 4mm plywood for additional strength. It's obvious that the craft would require painting or it could just be left ugly.

Just an idea. Anyone with experience?


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RE: experimentation


Experimentation good....XPS bad. 

Foamular is extruded polystyrene foam, which doesn't have the remotely the shear strength necessary for a sandwich core.

I have considered using PVC foam sheet like Divynicell, but the density is close to the BS1088 and you lose a lot of impact resistance, not to mention the looks.

The techyest choice in core material is honeycomb, which built with carbon fiber faces is as strong, light and stiff (and expensive) as it gets.  But, now we're into molds and I think we're all trying to avoid those.

The long and short of it is that plywood has a lot to offer as a core material. 



RE: experimentation

Thanks - I didn't have high hopes.  I have some scrapes of Foamular, glass and epoxy that I may play around with just to see what it acts like (on a very small scale). I wasn't even certain that the epoxy wouldn't react negatively with the Foamular.

Just goes to show that not all ideas are good ones but where would we be if we didn't try to find out!


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