Wooden/Fiberglass Scantlings

Sea Drive:
I admit it; now I am confused. If the mold is built with Airex foam over battens doesn’t the Airex become the core. How is that different then plywood over stringers as a mold? Its may be easier for the backyard builder to slap together the foam rather then build with finely fit joints the wood hull needs. Of course if you don’t have the skill to build the wood mold the rest of the project may perhaps suffer anyway. Six of one and a half dozen of the other.
All the best:
Robert Gainer

 

Robert:

Confused? Seriously? Somehow I doubt it. Anyway, we are probably in the realm of perception here rather than objective reality.

The fact is that an amateur builder can see his way clear to stitch & glue a ply hull over bulkheads and cover it inside and out with 1 or more layers of fiberglass. There may not be any longitudinals at all, or perhaps just at the keel, chine and rail. Just about all the material that he has to buy ends up in the finished boat. The ply is "self-fairing" for the most part. He can join panels with butts, or with taped joints. He has been told that, in the age of epoxy, a close fitting joint is actually undesireable.

The typical amateur builder does not know anything about foam core since none of his buddies have used it, and none was used in building his house. He doesn't want to buy material for, or spend the time to build bulkheads (mold frames) or stringers that don't end up in the finished boat. He distrusts any method that requires stringers close together because that emphasizes that the burden of getting a fair hull is on him. He doesn't know about getting bends in the foam, or how to achieve a fair curve at butts in the foam planks.

Of course, you understand all that. Your point is that with the expenditure of a little time for education, he could build a better boat for similar money using foam core. You might well be right, but are not many amateur builders using foam, and I'll bet the resale value of an amateur foam hull would not be any higher than for a ply core hull.

The final caveat is that there are amateur builders who are as skillful as any professional.