Strength of Kevlar

I recently posted regarding the best racing sea kayaks. Although I did buy an ICF boat (SRS Delphine) and raced in the Masters Sprint Nationals, I still like the idea of racing sea kayaks. Here in GA, we have several races on N. GA rivers. These rivers are mainly flat, but have some small class I rapids and just about all of our rivers have rocks. Most of the folks entering in these races use plastic sea kayaks or rec boats.

I have a plastic Necky Elaho and it is very, very heavy (60+ lbs), and I find I don’t want to even bother with it because it is soooo hard to load and unload. I’m thinking of buying a kevlar or fiberglass sea kayak for these races. Someone is selling a kevlar CD Extreme (only 47 lbs) for a very reasonable price, but I’m wondering can the kevlar handle the inevitable rock bashing or should I stick with plastic?

Thanks for any advice.

Looking for the same/similar info
Ironically, was trying to do a similar search just prior to seeing this post.

I have a friend who is looking to get a kevlar boat and I’m pretty sure I recall some difficulties in repairing them should they get damaged but was unable to find any info here.

She is under the impression that they are indestructable because that’s what they use for bullet-proof vests and combat helmets.

I think I recall hearing that they can break on rocks (or if dropped) fairly easily.

I’ve owned…
a Kev version of C.D.'s Caribu and currently own a C.D. Andromeda in kev. I’ve hit, on occasion, rock hard enough to stop the old Caribu with no more than scratched gel. That boat was also employed many a time as an ‘ice breaker’ with no other effect than scuffed gel again. Both my Wenonah Advantage and Odyessy ( 2,000+ miles)were used extensively in Ontario for years and even loaded full with two paddlers the Odyssey came away with no more than superficial scratches and a one time ‘gouge’ in the core area after hittiong rock. Ya… it might look a bit ‘peach fuzzy’ on the ends but there are still many, many servicable trips left in that old boy. The stuff IS bomber, but some light weight race version boats may not be as heavy of a kev lay-up and may be somewhat more prone to damage. You can always request a keel strip or extra reinforcing if you are in doubt, or for piece 'o mind. Have no fear of the stuff!

dropping it
If kevlar boats could be dropped and broken easily, I would be screwed by now.

Kevlar and rocks
Kevlar and kevlar-carbon are frequently the materials of choice for kayaks designed to race on Class 1 - III rivers. However, an important difference between a kevlar river runner and a kevlar sea kayak is that the composite bulkheads a sea kayak make the hull more rigid and less able to slide over rocks without sustaining damage.

Maybe someone here can advise you about the practicality of modifying or removing the bulkheads to allow more flex in the hull.

sure, get it
it probably weighs closer to 50lbs but get it anyway.

Stiffer areas in a Kevlar hull may
cause more wear from dragging, and may increase the risk of local tearing under a severe blow. However, my experience using S-glass/Kevlar and S-glass/carbon decked boats in whitewater is that they do not break easily or wear seriously, even under the pedestal seat where flex is limited.

There should be a couple of layers of S-glass or E-glass on the outside, and at least two layers of Kevlar inside to ensure adequate resistance to breaking.

I would not remove bulkheads. If (as one hopes) the “Kevlar” sea kayak comes without gelcoat, I would consider adding one or two layers of S-glass over the bulkhead areas if wear seemed excessive. If one did remove bulkheads, it might be a good idea to put in longitudinal minicell walls. These can flex a little to keep wear down, and the keep the hull stiff enough to perform well.

It depends on how much work you want
to do on the boat after each race, and the river flow.

On a class I river you are going to be scraping over a bunch of gravel bars.

If the flow is not fast, you will probably just scrape some of the gel coat off, which will keep you touching the boat up after each race.

If the flow is fast, and the rocks are sharp you are liable to punch a hole hole into the kevlar cloth.

I race both canoes and kayaks in down river races which are similar to what you describe.

I sometimes take my ultra light kevlar canoe which has no gel coat and several times have had to use epoxy to touch up bad scrapes where the original epoxy has scraped off.

But I would not take my QCC kayak with a gelcoat finish since I wouldn’t want to be touching up the gelcoat after the race.

I use my plastic kayak whick can take a beating.

The other option is if you can scout the river prior to the race, and there is high water where you won’t be scraping, go ahead and use the composite boat, but if it is low and shallow stick with plastic.

If you enjoy racing as much as I do, you need several different boats for the conditions.