What are the advantages of Carbon besides less weight and its beauty? I saw the youtube videos where a carbon and a glass Necky are beaten with a hammer. Both look to be tough. Is one easier to repair? Is one stiffer? All input is welcome!
you will use it more
and love it more and it will turn ugly fast…but never in your eyes.
Ever seen a carbon boat with lots of scratches?
Thats just a starter…
Beyond lighter, stronger, less flexible and better looking, what do you want?
If all that is the case, then
which one is easier to repair.
Without knowing the details of Necky’s
"carbon" layup, I can’t say for sure. Lots of carbon boats, including one I have, have E-glass or S-glass as the outer layer, because carbon doesn’t stand up to abrasion as well. So, if you’re repairing a crack on the outside of the boat, you may be working with glass anyway. But patching carbon is no big deal as long as you know how to wet the patch cloth out properly. (It’s a little easier with glass than with carbon or Kevlar because glass turns clear when wet with resin.)
Now, one detail… When a builder goes for carbon, it’s for customers insisting on lightness first. Some customers don’t pay full attention to stiffness. If you can ascertain that the Necky kayak is just as stiff in carbon layup as it is in glass layup, then if you can afford it, get the lighter boat. You might also ask what cloths they are using on the inside of the boat to prevent propagation of catastrophic breaks. Some Kevlar? Some polyester?
On the hammer beating, note that few
of the blows a composite kayak receives are like sharp hammer blows. When the boat is run into a rock, or tossed against a rock by a wave, the blow is usually less sharp and sudden, but more prolonged, and often accompanied by an inward distortion of the hull beyond that achieved with a hammer. Glass boats, and glass/carbon boats (one of which I have) do pretty well against hammer blows. Real world rock encounters, many of which I have seen and felt against my composite boats, are better resisted with a couple of layers of Kevlar inside the boat. Kevlar can be stretched quite a ways without letting go, and it can often contain small breaks in the outside S-glass or E-glass, so that the small breaks do not become big splits.
Salty may come along and disagree with this, but there it is.
Carbon is stiffer and half the weight of glass at equivalent stiffness than glass but less abrasion resistant. Either one, used, rationally as an outer, compression, layer, needs a high tensile inner layer. Kevlar/Twaron is most common, Spectra is rare and Vectran is rarer yet.
Spectra has serious issues re skin prep degradation over short time and delamination. Great for comp boats, if you break it you survive and the team has another for you.
Vectran we’ll see about. [Trying to get samples of appropriate weight is very difficult, and it cannot be cut with shears.] Maybe tomorrow’s inner, tensile, layer.
for regular use
in a non-racing kayak it’s more of an upprice option, in other words it meets a customers ability to pay more than a functional difference on the water. Material makes a significant difference when you take a design to such an extreme that without that material the boat breaks sooner. Imagine making a 27lb surfski out of carbon instead of a 30lb one out of glass for a racer who has a low body fat ratio. That lighter weight could make a difference for that racer.
Ok,now if you’re talking about a 47lb carbon sea kayak instead of a 52lb one you aren’t going to go faster since it’s not really designed for speed anyway, my gut sense(totally guessing) is that any random impact that will damage the glass boat will damage the carbon boat.
Those boats are STRONG
and G2 they will take blows from the claw side of a framing hammer, striked with sharp objects, and bashing into rocks with barnacles etc, is no big deal… I think if anything they are over-built for the average guy. The seam is incredibly strong as well.
Stiffness is achieved via soric core used extensively.
Lee is correct with his assesment of glass Vs carbon in these boats. Carbon adds “bling” factor and doesn’t save much weight. It is combined with glass.
Vectran: An aerospace company I dealt with tried it and it’s real world properties didn’t match the spec sheet. I have a Vectran glass surf boat prototype that’s doing OK…better than previous Kevlar versions.
As I’ve said many times Kevlar (like spectra but to a lesser extent) does not like to stick to it’s neighbors in tha matrix that well. Impacts can and do cause it to delaminate. As we see in the vid, a plain old glass epoxy boat can endure impact much better than folk think and with no to minimal damage or delam.
I’d use epoxy with a Kevlar lay-up.
Well, as I’ve said, my boats with Kevlar
interiors that have taken punishment (both old) are showing no significant delamination. I just have not seen unusual delamination in Kevlar whitewater boats I have inspected. It is possible to blame the Kevlar for delaminating when it should actually be credited for holding on and not tearing where a pure glass layup would have torn or split. I have seen Kevlar delaminating in the inside of sharp chines where it was subjected to compression forces it does not handle well. In the newest boat I have, the builder used a denser grade of Spheretex to stiffen the chines so that the interior Kevlar layers would not have to handle compression if the chine angle was closed.
There are references in the literature to Kevlar forming a somewhat weaker bond to resin, but the cited difference is not large. So I again suggest that some reports of delamination are actually evidence of Kevlar’s resistance to tearing.
it seems like the soric does a better job than coremat
for distributing stresses beyond the site of impact as well as confining damage to a smaller area with less delamination. That’s just a WAG looking at a friends kevlar CD boat that’s been munched a few times on the chines. I saw a CD boat a few years ago that must of been an experiment in production, had about a 1/4" core to the bottom like the canoes and the bottom had a puncture that broke the skin but didn’t show up on the inside.