: Charlie... here's the quote from my post:"For really small craft with
: simple load path solutions such as kayaks, the advantages are pretty much
: nullified when compared to a wood cored boat. When it comes to a more
: substantial boat, though, foam has very distinct advantages over wood, be
: it structural, lighter weight, or in its impervious nature towards water
: invasion and subsequent rot."

The way I've heard it expressed was that foam-core hulls alway need a lot of fabric/epoxy laminates because foam offers little resistance to penetration. It does offer weight benefits in hulls ove 25' where there is usually a lot of internal structures that can be built lightweight with foam/glass.

: Perhaps you could tell me where I do the dancing when it says, very clearly,
: that weight advantages are nullified for small craft?

: Charlie... again, you've restated issues that have already been covered in
: previous posts.

: The single objective reason to NOT use foam cores in small craft would be
: puncture resistance, as all other issues tend to become moot in light of
: build techniques and materials available. Puncture resistance, Charlie,
: and that is pretty much it. That compared to the rot potential of any
: wooden boat once water enters the core. While I tend to agree that wooden
: cored kayaks and canoes do not, typically, have a rotting issue associated
: as they spend so little time in the water when compared to their stored
: state, it is an issue with the material, nevertheless.

: For racing kayaks, this means that foam and honeycomb cores are the way to go
: if one wants stiffness, as well as an extremely light boat structure. Get
: on the phone with Ted Van Dusen, ask him why he uses Nomex cores and/or
: foam when building light, fast boats for the world's best paddlers and see
: what he says. Ask him about wooden cored craft of the same type and,
: again, witness the answers given.

You are making comparisons that don't connect with what Wolfson is doing. His posting suggests that he has a strip hull and wants to build a lightweight deck. His choice was foam core. Besides being light the deck must be stiff enough to support the weight of the paddler and it must have engineering characteristics like sufficient strength in tension and compression to support the the sides of the hull. If the deck starts flexing so will the hull. I think the strength depends on sufficient glass/epoxy laminates that may eliminate the possibilty of any saving of weight.
If Wolfson is experimenting (he didn't say he was) there's no harm done. If he wants a usable lightweight deck ASAP fiddling with foam-core isn't a guaranteed choice.

: As to larger boats that are using foam cores as opposed to wood... right now,
: Charlie, there's a 97 foot trimaran blasting around the world at a record
: pace never before seen for a solo crewed vessel. This boat, IDEC, is built
: in carbon/foam/carbon laminates taken from bagged, female molds.

: With all the money, resources and design expertise, along with skipper
: demands, sponsor expectations and the unbelievavble crucible of sailing at
: 25+ knots for days and weeks on end, non-stop, in the worst conditions on
: the planet, what would possibly keep these collected experts from choosing
: wood cores for the boat when it is so totally available for the project?

I am a sailer but, not much of one. I do know that ocean racing has gotten to the point where competative boats are being built to the very edge of engineering capabilities and numerous examples have blown apart on the water because the parameters of design were unexpectedly exceeded by a small percentage.
Why what the big boys do is of concern to anyone building a kayak in his basement is beyond me. In this case we are only talking about a kayak deck.

: Wood is a great material for certain applications and not so great for
: others. A designer/builder has to weigh the value of each type of material
: for each type of application.

: Since this (the original question from Mike Wolfson about how to edge glue
: the foam panels) was about the building of a one-off, hybrid materials
: (foam core and wood core) racing boat for his own use, I don't see any
: problem at all in giving him the best answer possible and wishing him well
: in his efforts.

: With a working example shown, via the production of a Nomex (honeycomb) cored
: craft with pre-preg laminates, vacuum bagged female mold and autoclaved
: cured construction, where could the argument you present, possibly come
: from?

: Mike could have a bigger target in mind, he could be simply curious about the
: build techniques, he could be looking at a finished boat that meets his
: design objectives differently than would yours...

: I get that you find the business of a foam cored build technique to be
: unnecessary in light of building in wood. OK, but isn't that your
: preference and not necessarily one that applies across the board for
: another guy's project?

: And lastly, Charlie... have you ever built a foam cored boat before? I've
: done two, performance sailing trimarans of my own design now in foam core
: construction and am planning the build of a third as we speak. I've also
: built, extensively, in wooden core (strips and ply) There's a place for
: both build types depending on end use, target builder, design goals,
: design style and a long list of objective and subjective reasons after
: that.

You are correct. I can't duel with you on the basis of resumes. But the practical physics of a kayak deck doesn't require an architects license. All you have to do is place an undecked kayak on horses and push down on the middle. The distortion you see is part of what has to begotten control of.
A truely strong, lightweight deck for this hull could be quickly made from 3mm okuome and some deck beams to establish camber. Not very sexy and probably a little homely but readily done in basements, backyards and garages.

: Perhaps you could open the door to the potential of other build styles,
: rather than close it?