Basics of canoe materials
by Steven Gates -- a long time epoxy/composite boatbuilder, who has been repairing OC1s for the past 3 years. Steve will touch upon aspects of OC1 construction, maintenance, and repair. Steve will also welcome specific questions.
Aloha and mahalo for reading this first article about OC1s. We will cover many aspects of these incredible, yet delicate canoes, from what they are made of, how they are made, maintenance, safety, to the actual repair of them. What makes these boats so light, is also what makes them so delicate.
Most of the canoes today are made with epoxy, as opposed to a polyester or "surfboard resin". Epoxy is used in the same way as a polyester resin; it is used to wet out a structural cloth, be it fiberglass, carbon fiber, or Kevlar. Epoxy, however, is a far superior product for many reasons. It is 100% waterproof, polyester is not, it is one of the strongest adhesives available, polyester is not at all, and epoxy is flexible and will not crack easily like polyester. Because of epoxy's flexibility however, boats of all kinds are usually built with a core of foam or wood to add stiffness. This is true even with our OC1s. Most of today's canoes are constructed of a laminate of carbon fiber outside and inside sandwiching a 1/16" foam core. Carbon fiber offers a much better strength to weight ratio than fiberglass, and combined with the foam core and epoxy, results in a strong, stiff, and light laminate. An important note here...although most paddlers are concerned about the weight of their canoe, stiffness is far more important than weight. A canoe flexing in choppy waters will certainly slow you down more than a few pounds of weight. Having repaired all brands of OC1s both old and new, I can say that the manufacturers are making stiffer and lighter boats than just a few years ago.
You may be wondering now, if epoxy is flexible and doesn't crack easily, why does my boat have all these hairline cracks? The finish coat, or color is gel coat, a polyester resin product. The same stuff they use on production big boats. It is the first thing done in the construction; the gel coat is sprayed into the smooth mold, and the epoxy/carbon laminate is applied and vacuum bagged over the color. Gel coat is very brittle, and has been traditionally applied fairly thick. If the canoe flexes a bit, whether from a large seaway or from tightening your tie down straps too tight, the epoxy laminate can handle the flexing, but the gel coat will crack. More about these surface cracks next week!
Posted by SteveGates on Tue, 11/19/2002 - 11:43am