: The original question asked if a boat could be built from foam. The answer
: was and is "yes".
Of course they can and are every day. They can be built of concrete. The question is: Is this a good technique for a home builder to build a safe, efficient and asthetically pleasing craft?
: Glass-foam-glass is same as scrim-foam-scrim.
The scrim is not structural, it merely hold the blocks of foam in place until the resin is applied. The resin disolves the adhesive holding the scrim to the foam.
: If you use bead and cove router bit, the edges of foam will not have open
: gaps needing filling and fairing as your described foam system.
I think you will find trying to machine blue foam a somewhat amusing process. Just don't let the router pull you fingers into the bit along with your foam strips. I'd leave the voids and fill them with epoxy to create little stringers.
: A simple "female" mould is all that is required.
I was attempting to describe the two building processes used. Certainly, for home building you would not build production tooling, you would use a one-off method. The article you attach informs that for using foam 3/8" thick a station mold is needed every 6 to 8". For the hull described that's 41 molds to set up and align. Assuming you're planning on using 1/4" strips you'll probably have to go to 4" spacing to adequately support the foam. That's 55 molds or templates for an 18' kayak. Compare that to 9 for a wood strip design and I think you'd have to concede my point on tooling.
: Mechanical fasteners are NOT required - you use a little dab of hot glue to
: hold the foam strip in place on each female template.
Might work, but as you remove the partially competed hull from the female tooling some foam will be torn away from what will be the outside of your hull at each of those 55 molds. This damage will have to be filled and faired. This why I prefer the male mold method for one-off foam core. This damage or the necessary fasterners are on the inside of the hull.
: In case you missed the first posting - please read the following article -
: and discuss the merits or shortcomings with the guy who built the boat -
: all I was doing is passing on his method in response to the original
: question. Each person is going to make their own decision if this is a
: viable alternative method for their needs.

: "Quick Hull-building
: From: Dave Culp "
I've read the article, but I don't feel there is enough information to evaulate the product. For instance there is no description of the lay up schedule. Generally, boats under 30' are not built with a core because the thickness of the fiberglass required to provide minimal protection from penetration (no spike heels, please) provides sufficent strength for the hull without the need from further strengthing from a foam core. So the boat resulting from the method described may indeed be seaworthy, or viable as you say, it's just heavier than it needs to be. With a power boat that's no problem, just up the horsepower. In a wood strip boat the wood provides the penetration protection while the glass provides the abrasion and water resistance, as well as, complementing the wood's strength.