Buying a Boat
Material Matters—Plastic, Fiberglass, or Metal?
By
Tamia Nelson
It used to be simple. If you wanted a kayak or canoe in the 1860s,
you had one choice—wood. (I'm taking about recreational boats, of
course.) Then some clever men started crafting light canoes out of
impregnated paper. Not long after that, builders in Maine got the idea
of covering cedar canoes with painted canvas. Still later, an ingenious
German tailor began making kayaks by stretching waterproof fabric over
jointed wooden frames. And that's more or less the way things stayed
until the 1940s.
Times change. Fabric-and-frame kayaks are still with us, but paper
canoes are mighty hard to find. And only rich folks and hobbyists own
wooden boats, canvas-covered or not. Most of today's canoes and kayaks
are made from three materials: thermoplastic, fiberglass, or aluminum.
Thermoplastic boats are probably most common. They're the easiest to
make, and therefore the cheapest. Build a mold, heat it up, and dump in
pellets of plastic. When the pellets melt, spread the resulting goo
around, then cool the mold and pull out a finished hull. Simple? Not
really. Very complex, in fact. But once the mold's built, the resin
formulated, and the process designed, a manufacturer can pull hulls at a
furious pace. A couple of years ago, the Old Town plant in Maine was
molding 200 hulls a day. Try doing that with a hammer and tacks!
Thermoplastic hulls are usually laminates in which a foam core is
trapped between two plastic skins. The plastic skins can be polyethylene
or vinyl, and the foam core can be acrylonitrile-butadiene-styrene (ABS)
or poly. The ABS-vinyl sandwich is usually known by the shorthand
designation ABS. It's strong. And it's heavy. Poly boats are usually
heavier than comparable ABS boats, but they're also a bit cheaper. You
pays your money and you takes your choice.
Not all thermoplastic boats have laminated hulls. Some kayaks and
inexpensive canoes are made with a single plastic skin. These require an
interior structural framework to keep their shape, and they don't like
spending time in the sun. Unkind writers have coined the phrase "spastic
plastic" to describe the sometimes loopy shape they assume after too
many hours on a roof rack. That's a little too harsh, but
single-thickness thermoplastic hulls do need careful handling.
What about fiberglass? First off, fiberglass is a somewhat misleading
term. The Brits refer to it as glass-reinforced-plastic (GRP), and
that's more accurate. A "fiberglass" hull is made by impregnating glass
fabric with some sort of plastic resin. The cloth is laid in a mold
before being wetted down. When the resin hardens, the resulting hull
takes on whatever shape the parent mold gave it. Fiberglass boats
require hand work, so they're usually more expensive than comparable
thermoplastic canoes and kayaks. Sometimes they're much more
expensive. But they can also be given finer lines, and—with
judicious use of expensive materials like Kevlar and carbon
fiber—they can be made a lot lighter than thermoplastic, with
little or no loss of strength. How does a 19-pound pack canoe sound?
If thermoplastic boats are Hum-Vees, fiberglass boats are Jaguars.
The third choice—for canoes only!—is aluminum. After World
War II, aluminum canoes were state-of-the-art. Now they're barely
hanging on. They're no cheaper than thermoplastic boats, and they're not
appreciably lighter. They're noisy. And the glare from their unpainted
decks can dazzle you. (They also make great reflector ovens on hot
summer days. You're the main dish.) So why have they hung around? They
don't wilt in the sun, for one thing, and they'll hold up better than
either thermoplastic or fiberglass when subject to everyday wear and
tear. Drag a loaded plastic boat up a beach. Turn it over. My, my,
my…. What deep scratches! Do the same thing with a "tin tank,"
though, and you'll be hard pressed to see the damage.
What material should you choose? If price is important, look
at poly first. If you expect to wrap your boat around rocks regularly,
go with ABS (poly's good, too). If you'd like to place first in your
yacht club's annual regatta, you can't beat fiberglass. And if you want
to have the lightest boat on the block, look at Kevlar and carbon-fiber
laminates. (Most of these will have at least one layer of plain-Jim
fiberglass, though. Don't be shocked.)
On the other hand, if you want a boat you can use for thirty years or
more—a boat to go with your 1955 Willys Jeep, say—get a tin
tank. Paint it dull green. It won't be pretty, but you won't have to
move it inside when the sun shines, either. It'll grow on you. 'Nuff
said.
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