I’m looking at a used kevlar canoe (Nova Craft Prospector 17). It’s weathered and bleached out at the ends. how does this affect the strength of the kevlar? Plus it was made in 95, how does age affect the kevlar?
OK
I’m not sure I fully understand what you mean by “bleached out” at the ends.
However, as far as I know, all Novacraft canoes have gel-coat. This stuff isn’t the best for strength-to-weight, but it is great at blocking UV light. The UV light will not damage the kevlar, but it will break down the resin.
Long story short - if the canoe is coloured with gel coat or paint, and there isn’t structural damage you can see, or major soft spots you can feel, it is almost certainly going to be good.
Novacraft made a few varieties of kevlar, one of the more popular being CAP, which was kevlar and polyester. It is a decent lay-up, though I am not a fan of foam cores.
Age won’t affect Kevlar and won’t
affect the resin. When the laminate gets beaten repeatedly against rocks, racks, etc., there is microscopic resin cracking and maybe delamination that, eventually, weakens the laminate. But hulls made the way NovaCraft makes them tend to last a very long time.
Not sure what you mean about the ends looking bleached, but I would be more concerned about damage at the borders of the foam core, or crossways splits in the inner surface of the foam core. If such are absent, that’s good.
One has to expect composite boats to show evidence that the laminate has been bruised over time. If Royalex boats weren’t covered with vinyl skin inside and out, you’d probably see bruising of the ABS structural layers.
Bleached out
On the ends of the canoe, About the last 2-3 feet the color (maroon or dark red) is bleached out or discolored. It looks like it got this way from the sun or from weathering. The rest of the canoe the color is good. I’m thinking the canoe was partially covered with a tarp and got weathered from exposrue to the weather ( it was under an open sided shed) or it got bleached out from the sun. Otherwise there are just a lot of small scratches to it like from sand and small rocks. Although on the sides there are a couple of large cracks where the outer gel coat is cracked off. Leaving an area of about an 1/8 to a 1/4 inch wide area with no gel coat to it.
I’m leary of buying this canoe due to the discoloration and the cracks possibly affecting the strength of the kevlar.
Is it a deal?
I’d need a good deal to buy a boat bleached out from the sun. But that said, I did buy one bleached out on the ends from being stored under a deck with an end sticking out. That was 8 years ago and I’ve had no issues with the laminate.
That’s what gel-coat is for
Gel coat adds weight, and no strength. If you want a good laminate and are storing it inside, skin-coat is much better for strength/weight.
However, gel coat is perfect as a sacrificial layer. The fact that it is faded shows how it took the sun in place of the laminate. I’m betting it is functionally just fine, and if you want to, simply sand the gel-coat and either polish it, or add a coat of paint to make it look better.