Someone asked this question over at SotP so I thought I’d answer it in both places.

Currently trying to get my head around the different materials canoes are made from (ignoring wood for the moment).

I paddle a 17′ Novacraft Prospector. I’d say it was made from “bog standard ever-so-slightly-rubbery plastic; y’know, normal canoe stuff.”
It’s tough as hell. Someone told me it’s a single layer construction
called “SP” (as opposed to “SP3″ which is apparently the same plastic
but with a foam sandwich type of affair going on).

I’ve paddled something in “Blue Steel,” which I understand to be
kevlarish? It was lighter but gave the impression that pointy rocks
would affect it more profoundly than plastic offerings.

I’ve also seen and fondled a few other Blue Steel esque boats (mainly
Novacrafts) but was told they were not Blue Steel. Couple of nice big
punched dents in the side from rocks and again felt more brittle and
fibrous (maybe… hazy memory) than plastic.
Is this where Royalex and Royalite come in. Are Royalex and Royalite plasticy or more of the kevlarish persuasion?

What else is out there?

The SP3 and both Royalex iterations are a sandwich of plastic with a
foam core. A typical kayak is solid plastic and the blue steel is just
a fancy kevlar blend.

SP3 and Royalex come as a flat sheet that get heated and smashed into a
mold to make a boat. Kayaks are poured into a mold as liquid and
sloshed around (roto molded) to stick to the inside of the mold.
Kevlar, fiberglass or blue steel are fabric that is laid onto a mold
with epoxy or other resin and allowed to dry.

Kevlar or laminate is the stiffest followed by royalex then
polyethylene. Both Royalex and polyethylene have the ability to bounce
back after hitting something with royalex being a bit better at this.
Polyethylene typically has a thicker skin over the foam and is
considered tougher and thus heavier. Laminate boats don’t really pop
back into shape and the epoxy or gel coat layers are somewhat fragile
compared to the others.

It’s better to talk about them for specific uses.

For whitewater or rough use such as a rental the SP3 (Polyethylene) is best unless weight is a concern.

Royalex is lightweight and handles abrasion and impacts relatively
well. It is stiffer than poly but not as stiff as a laminate. So its a
good all rounder for WW, down river trips and lakes.

Laminates are excellent if all you do are lakes and deep easy water
where bouncing off of rocks doesn’t happen. These boats are typically
60% lighter and stiffer (more responsive to strokes) than the other
lay-ups. If you’re crossing huge expanses of open water then carrying
the canoe on long portages then kevlar is the way to go.

Another important consideration is cost. Laminate is the most expensive, poly is the cheapest.

I have a Nova Craft Prospector 17 in Royalex Lite and my wife and I do canoe trips like this.

Here’s a clip from Wenonah making a kevlar canoe.