normally you do...in a cold molded boat, the wood planking gives a lot of the strength and the glass is more for waterproofing.....when using a foam core...it gives the spacing required for hull stiffness....but the strength comes from the glass skins, inside and out
Great thread!,, Core cel is an SAN foam, in short and from what you linked it is much tougher, for example. in an impact the foam is more forgiving than other types of Marine grade foam!, true as Paul stated it will not rot nor will it absorb water as its closed cell, as compared to open cel like that of a sponge. If you are from South florida and a fishing junky you have seen it many times before,, its used as a hull core in the Garlington 61, along with them its made its way up to the outer banks too,, I think Paul Spencer has been using it for awhile to, and us shore billys here in Southern Maryland as well!
With boats as shapley as we build it purchased in bead and cove strips held on the jig with temporary fasteners , glasses, faired and flipped over!
Your hull will have more glass on it then that of a wood compsiye cold molded boat will have,, but she will still be a light, very strong, very fuel efficance boat, with two hull skins
If you check out Envi 17 inshore build under Pulling the triger the boat is being built from Core Cell. So i don't think anyone here will give you a hard time. I am also looking at starting my boats using Core Cell. It is easier than wood but there are a few things that are done diffrent form the wood version.
Advantages are: When damaged and water enters the foam it does not rot.
You can use polyester resin or epoxy.
it is lighter than timber boats.
Disadvantages are: You use a bit more glass in the boat and that is about it.