Posted by Jim Pippit on 3/1/2013
Aluminum has long been a staple of the summer camp canoeing experience. Most middle-aged canoeists got their start in Aluminum boats. Aluminum offers good corrosion resistance and is least affected by prolonged exposure to sunlight. It is pretty strong and rigid. For all of its benefits, however, aluminum isn’t a common (read: popular) material nowadays. It is heavy, conducts heat (cold feet for early morning paddles), sticks to rocks rather than bouncing off (don’t ask me how I know), and noisy (drop a tacklebox and fish for miles know you’re there). Most aluminum canoes are symmetrical, to keep manufacturing costs down. This doesn’t always translate into the best canoeing experience. Luckily, technology has provided a lot of exciting alternatives to aluminum.
We call them poly, or sometimes just plastic. Polyethylene is a very popular material for recreational canoes. Most polyethylene canoes are made with a rotomolded multi-layer construction.
The multi-layer method (common to all of Old Town’s Discovery series and Mad River’s TT boats) adds a foam core to the outer layer. Most multi-layer versions cap the foam core with an inner layer. The extra depth adds to the stiffness of the hull and allows the designer to reduce weight (think corrugated cardboard).
Not all poly-based boats are the same. The type of plastic used can vary from manufacturer to manufacturer and from model year to model year. Typically, long linear poly chains are better. They are stiffer and stronger, and can be recycled. Crosslink poly (strong yes, but not recyclable) is less common than it used to be, but is still seen.
Royalex is the trade name of an ABS sandwich. It layers a vinyl skin, ABS sheets, a foam core, more ABS sheets, and a vinyl skin again. It is manufactured by the Uniroyal company. Royalex shares a lot of the same characteristics as multi-layer poly canoes, but offers some nice improvements as well. It is stiffer and lighter than poly, while remaining incredibly tough; lots of whitewater canoes are made of Royalex. It is more expensive, too. Weight typically has an inverse relationship with cost.
Composite construction canoes use a fiber and a resin to provide a stiff, sleek hull. Composite canoes can be molded into very complex shapes, and they typically have very low friction coefficients. This translates into sleek, efficient hulls. Differing materials and/or methods of construction will yield different weights and/or strengths.
Fiberglass is the granddaddy of the composite line. It is typically the heaviest and most inexpensive composite material. Its big advantage for today’s paddler is that it’s not hard to maintain. Scratches and heavy dings can be repaired easily.
Kevlar is an Aramid fiber from DuPont. Most folks know it as the primary material in bulletproof vests. A warning: do not shoot your Kevlar canoe. Kevlar canoes are built to be either very tough or lightweight, but stopping speeding lead is not in their design parameters. Kevlar is tricky and expensive stuff to work with in manufacturing. It is also difficult (though not impossible) to repair. Some manufacturers put one layer of fiberglass on the outside of the hull to aid in fixing dings. This adds weight, so others leave it off.
Carbon or Kevlar/carbon lay-ups promise yet more weight savings. They are typically used in racing boats, or for people with very tender backs. Carbon fiber is extremely rigid and strong for its weight, but the stiffness comes at a cost. Rather than deforming and deflecting on impact, it can break or shatter. It is an impressive material, but should be matched with an appropriate use.
Prepreg (pre-impregnated) fabrics are a new innovation, courtesy of the aircraft industry. Normal composites have the resin added late in the game. Prepregs come with the resin already in place. There are different schemes to cure the resin, but the result is always a very lightweight (and surprisingly strong) hull. Prepreg materials are very difficult to work with, and that translates to a formidable price tag.
Lots of people have discovered the joys of wood boats. Wood is very strong, very malleable, quite light, and easy to work with. Some wood boats are built to be skin on frame; others are solid and covered with fiberglass or canvas. Properly maintained, they can last forever. I really like the “feel” of a wood/canvas canoe. There is something magical about its combination of stiffness and suppleness while gliding through the water. Wood comes at a price, too, but is often a worthwhile investment in craftsmanship and a lifetime of memories on the water.