: The topic of foam cored kayak building surfaces every once in awhile on this
: Forum. Needless to say, there are still some lingering doubts as to the
: efficacy of the build process, especially in the areas of weight and
: overall boat stiffness.

: Rather than dump a long rant on the gang, I'll let the example of two of the
: best boat designers and builders do the talking for me. There aren't any
: "yeah, but's" to contribute when it comes to who these guys are
: and the level at which they contribute to the sport. It's easy to find
: their respective CV's all over the web, as well as modestly mentioned on
: their own sites.

: Greg Barton's name should be known by every serious kayaker in the world. His
: company, Epic Kayaks, is one of the names you have to include in the top
: three of any real test of touring/racing kayaks and surfskis when it comes
: to delivering performance. Home page: http://www.epickayaks.com/
: Technical elements: http://www.epickayaks.com/tech/kayakanatomy

: Epic has this to say regarding their manufacturing techniques...

: "8.Lightweight, High Tech Materials. Epic kayaks are made with strong,
: durable, lightweight materials including carbon fiber, Kevlar, fiberglass
: and a specially formulated epoxy resin which is stronger and tougher than
: polyester or vinyl ester resin. Epic's sandwich core construction process
: with these materials ensures our kayaks are noticeably lighter than any of
: the competition.
: 9.Vacuum Infusion with Heat Cure. Epoxy resin is infused into our kayaks
: under full vacuum. This eliminates voids and produces Epic's signature
: high strength and lightweight standards. After infusion, our boats are
: post-cured at elevated temperatures to create the strongest and lightest
: kayaks on the market."

: Ted Van Dusen is another name that sits at the table of elite designers and
: builders for not just kayaks, but also rowed racing shells and a whole
: pack of other types of craft, as well as filament wound spars. Home page:
: http://www.vandusenracingboats.com/

: Van Dusen gives this description of their build process...

: "Hull Construction - Van Dusen racing boats are manufactured using
: advanced composite materials and space-age manufacturing technology. All
: our boats start with a pigmented polyurethane gel coat that bonds into the
: laminate during the curing process creating a strong, durable, and UV
: resistant outer layer. Depending on the hull laminate, we use
: pre-impregnated fiberglass and/ or carbon fiber cloth; custom-braided
: graphite and fiberglass parts; Nomex honeycomb, and syntactic cores. We
: were pioneers in the application of gelcoat, pre-impregnated laminates,
: vacuum-bagging and autoclave curing techniques to the manufacture of
: racing boats, and we have maintained a considerable technological lead
: over other manufacturers. Our kayaks, canoes, and racing shells are simply
: the lightest, stiffest, strongest, and most durable boats available
: today."

: Many of the techniques used by both of these two companies are within the
: reach of a decently well-versed home builder, if they take their time to
: do the background, practice some with the materials involved and have an
: open mind as to the potential.

: No, most of you guys do not have access to a supply of pre-preg carbon, but a
: well done infused layup at home is going to be within grams of the exotic
: and virtually unobtainable material.

: Most of you guys do not have a kickin' autoclave, either, but you can make a
: post cure box at home that will do the trick quite nicely.

: You can see for yourself, that there is no weight penalty involved for a
: properly engineered sandwich laminate at these hull sizes. It is true that
: these boats will not have the puncture resistance of a woone cored boat in
: Red Cedar. If you expect to encounter paddling situations where that
: becomes a big time reality, then you build a boat to suit your use regime
: and forget about arguing about the facts of one build style over another.

: If, however, you want the lightest, strongest, stiffest boat that will give
: you the potential that is expresed by the elite athletes on this planet,
: or you just want to say that you build one just like theirs at home, then
: do yourself a favor and take a look at the possibilities and refuse to
: absorb the "conventional wisdom".

: I've built a few boats in this build style over the years, as well as
: maintaining a wooden boat building interest. If there are any questions,
: please feel free to fire away. A few clever Googles on the topic will
: yield enormous resources that show you how it is done, what types of foams
: work best with which kinds of resins, to yield a terrific hull. They may
: not be kayak specific, but they will illustrate the techniques, which are
: the same.

: Chris Ostlind
: Lunada Design

Good post Chris

Btw, everyone should forget they ever heard of honeycombs, it's not a great product for home use, unless you really enjoy punishment and can afford to throw away quite a few hulls until you learn how to bond it correctly.

Bill H.

Bill H.