I just sold my Supernova solo canoe and picked up a Bell Merlin II. I needed a lighter boat so that fits the bill. However, I’m wondering how tough kevlar actually is compared to Royalex. I have been paddling primarily small rivers/streams that tend to be a bit rocky. Will this be a problem?

Not if you avoid the rocks…
With me I can always miss the ones I see, however it is the ones I don’t see that cause the problems, like the nice sharp limestone sitting 3" below the calm water in the eddy.

Enjoy the Merlin, but you will need to be a bit more skillful and judicious.

Kevlar does not compress well
ie bouncing off rocks.

I would save the Merlin II for high water where there is no danger of being swept into one in error.

Its a fun boat…but something like a Yellowstone Solo or Argosy would fit your needs better. The Argosy is a good ten lbs lighter than SN.

Or if the water is not too pushy a Mohawk Solo. The 13 is kinda fun…the 14 a little bigger. They are Royalite…and can be used on moving water but not serious rapids (above class 2)

What cloth is used for the outer layers?
Glass? Carbon? I know Bell did not use Kevlar for the outer layers, and Kevlar inside is not a “compression” issue.

Even a pure fiberglass boat will do fine just scraping rocks and mildly bumping rocks. Kevlar increases the ability to withstand impacts. I used a pure FG Mad River on rocky southeastern class 1-2 whitewater for many years, and the only patching I had to do was to repair the bow where I had plowed head on into some rocks; and some wear patches on the axis of the V-bottom. You aren’t going to be stressing your boat the way I do mine. But if you find you’re escalating on the whitewater, pick up a Royalex boat like my Mad River Guide or Synergy.

it could be a single layer of kevlar
if its the UL layup. At this point we don’t know which Kevlar layup it is from the OP

Yes the does compress and rip if the boat gets even in a mild pin. The sides of the hull only have that single layer and the skin coat will crack and spider…beware sharp edges if this happens to you. It did to me and the shards of canoe skin were very painful.

Head on impact is of course much better. No impact is better still.

I have used the UL Merlin II successfully on the Buffalo between Ponca and Pruitt at “just past flood stage” when the river was reopened.

And with less success on a low water shaley sluice with plenty of sharp edges (basalt)

One would hope that Bell would not
use Kevlar for the outside of a canoe. It just is not a satisfactory fabric for an outside layer. Search me why Wenonah and Mad River have persisted in using Kevlar for outside layers. Because it sells better to people who don’t realise what they are getting?