Canoes have been built in a surprisingly wide range of materials, including, bark, skin, cloth and even paper. The most common modern materials include composites, such as, fiberglass or kevlar cloth bonded with polyester, vinylester or epoxy resins. These materials are light, strong yet easily repairable. Glass or kevlar are the first choice of designers who want fine lines or complex designs because they can be made into any shape imaginable. Kevlar is expensive yet very strong and light. If you are rich, you can get graphite or other hi-tech materials in the mix.
Another common synthetic is ABS, a laminate of vinyl around a foam core of acrylonitrile butadiene styrene. ABS is common in whitewater canoes because it is tough and has a "memory." That is, if it's dented, the dent will push out to the original boat shape.
Polyethylene is another common material that is less expensive than the other synthetics but is heavier. It can come "linear" or "cross linked." The cross linked polymer chain is stronger but heavier that the linear polymer.
Let's not forget GOA. Good Old Aluminum can make a fine boat. It was the Grumman company that made canoeing affordable after World War II when they used their aircraft expertise to build boats. Many a whitewater river was run with Grumman boats with "shoe" keels and many mountain lakes were crossed with the Grumman standard. Aluminum boats are still a good buy and perform well under a wide range of conditions. However, with a few notable exceptions, the design choices are very limited. They are noisy and cold and they stick to river rocks better that other materials.
Wood is back! Once considered old fashioned, wood or wood and canvas boats have become a refuge for people who recognize that canoeing is not just a sport but an art. For sheer beauty, wood is unrivaled. There are two common types. The wood and canvas canoe is the older design and has ribs and a cover much like its birch bark predecessor. The more common technique is the wood strip canoe where thin wood strips are glued up and covered with a single waterproof layer of fiberglass, making a very light, strong and thin shell of a boat. Choice of woods and the addition of inlayed pieces make for a work of art. Less common are boats built with marine plywood or with lapstrake construction. Almost all boat designs, no matter what the final material, began life as a wood prototype.
Boaters who want ruggedness and low maintenance get ABS or Polyethylene boats. The highest performance boats are usually kevlar. When told that a polyethylene boat would stand up to river rocks better than his kevlar boat, a top paddler responded, "The goal is to paddle around the rocks, not into them!"
All synthetic canoes would sink if they capsized and filled with
water unless they had additional floatation. Canoes often have air
chambers built into the ends of the boat to provide that floatation.
ABS canoes float because of the foam ABS core. In either case, the
built-in floatation is just enough to keep the boat on the surface of
the water. Whitewater boaters usually add floatation, such as foam or
air bags, to keep their boats higher in the water. Some times they add
enough floation to keep the boat afloat and upright with them in it
while they bail the water out.