I would appreciate any input available on fiberglass vs. kevlar for kayaks. I understand the weight difference, but has anyone noticed any difference in handling, durability and repairability, etc.? Thanks for your help. Urban
endless battles
there have been quite a few lengthy debates on the relative merits of glass and kevlar. if you use the search function on this site, and select “all messages” you should find many of them.
af
Decide based on weight
That’s what I’ve been told and it seems like the only difference that everyone can agree upon. I was told that you pay about $500 more for kevlar to shed 5 lbs from the weight. If you will be carrying the boat by yourself, it might be worh considering.
Otherwise, do as afolpe suggests and draw your own conclusions.
I dodged the whole issue and bought Carbonlite.
Lou
Depends…
I have a kevlar Shearwater and a fiberglass Revenge, but really can not draw any comparsions because the two boats are so different…
Some composite boats with a really heavy duty layup like the Tsunami boats are about as heavy as plastic.
I noticed one line of boats where the fiberglass version was about$1,000 more than plastic, and only weighed a few pounds less.
Plastic is actually my favorite because it is rugged and durable on the water and off, but I really do not like boats much over 50#. You pretty much have to go to composite to find a SOT over 16’ that is under 50#
Kevlar
I do repairs for a local kayak shop and about 75% of the repairs are on Kevlar boats. It seems to me that as least some ot the logic here with the kayak builders seems to be that because Kevlar is so strong and is unlikely to puncture that they can then go ahead and make the hulls very thin and of course LIGHT which gets everybody happy.
Well, true it is great stuff, but very often the laminate overall is so fragile that it doesn’t take much to fracture it. While the Kevlar itself is strong enough not to fracture, the resin in the laminate DOES! Sure, there isn’t a split open “hole” in the boat, cause that’s Kevlar’s claim to fame (“bullet proof vests”), but there is a bad enough break in the laminate that it can leak and certainly has to be repaired. To top it off Kevlar is pretty fussy to repair for the amateur.
My point of view is that yes, Kevlar is great stuff when used in a kayak, just be sure that the rest of the fiberglass fabric(s) in the hull/deck laminate that accompany the Kevlar are strong enough to keep the boat structurally sound if there is a significant impact to the boat.
Just an opinion
– Last Updated: Apr-29-04 1:02 PM EST –
I admit that I am new to the sport but I had given this issue some thought before we bought out kayaks. The questions I asked myself were as follows;
Would the kevlar kayak be tougher than the fiberglass one? I don't really think so.
Would the weight savings be worth the extra $1000? For someone racing, or someone a little smaller or older perhaps the weight reduction would be worth the effort, but for me and my wife the difference wasn't worth the cost.
Everyone has to do their own evaluation and determine if the difference is worth the cost. In our own case we wanted kayaks that were very tough, but the weight was less important.
if you can afford it
interestingly enough Necky is going straight to carbon/glass for light/strong constructions and not doing kevlar. If one is really looking for a particular level of durability, cost, weight then the boat isn’t going to be 100% glass, kevlar, carbon, or the material du jour. It’ll be a combination of complementary materials for a given load. Marketing has skewed choices to make a person think that a Kevlar boat should be all kevlar,a glass boat should be all glass or a carbon boat should be all carbon.
I don’t think it matters for the parameters you are describing. One buys kevlar kayaks because you have the choice and money for a lighter boat. If you need $500 dollars for something extra then get the glass boat, if you want the lightest boat with practical durability and cost doesn’t matter (rarely does 5-10lbs make or break ones ability to lift a kayak on the roof of a car).
My Decision
When I bought my Revenge the guy had both a kevlar and fiberglass model. The kevlar was a better color for me. The cost difference was not real important to me.
The Revenge is heavier than listed, and a heavier boat than I like, but I went with the fiberglass model because I hope this will be my expedition boat and wanted the more rugged one.
I am in NORCAL and the coast is very rocky, and the Sierra Lakes are full of granite boulders. If I lived in Florida, I would have bought the Kevlar model…
Another issue
If you go to the Paddleshop site – home of Onno Paddles – there’s a good treatise on materials and chemistry. It’s at http://www.eteamz.com/paddleshop/ and I can’t recall how much he discusses f-glas vs. kevlar.
One thing that hasn’t come up is that kevlar retains some integrity even when the material it’s bedded in has been destroyed. The advantage cited there is that Kevlar boats will hold together when damaged, and can be cobbled back together with duct tape when on an expedition far from civilization.
I’m with Cuda, however. Plastic is my material of choice, and I’ll just suffer through the extra pounds. That said, if anyone has a kevlar boat ready to donate to a worthy cause…
While I have some composites,
I also give the thumbs up to plastic. The difference in cost can be an additional boat, a superlight paddle (which can really make a difference) or some other quantum leap in enjoyment. It has also been my verified and documented experience that the liklihood of the boat being dropped onto a hard surface, and the degree of resulting damage, are directly proportional to the cost of the boat.
I had
kevlar, fiberglass, carbon kevlar, and plastic.
of the composites I like the carbon kevlar the most it stiff and light. I don’t like the kevlar layup as much as fiberglass. The glass is stiffer the kevlar has to much flex for me and not worth the extra money. Even at the same price I would take the glass over the kevlar if wieght was not a issue.
Fiberglass vs. Kevlar
If a similar message appears I apologize, my first posting seems to have vanished. As I understand it, Kevlar is much more durable than fiberglass pound for pound. This implies that if two otherwise identical boats were built to the same weight the Kevlar one would be the more durable one. Most builders build for light weight, however, so a typical Kevlar boat would be lighter, but not more durable than the same design executed in fiberglass. It doesn’t have to be that way but it often is.
Kevlar is reportedly more difficult to work with and to repair and this factor probably adds part of the cost difference.
Kevlar is the better material, but it costs more. You pays your money and takes your choice. Both materials are excellent.
Regards,
Bill
kevlar vs fiberglass
Some kevlar boats have more flex and are more fragile than fiberglass boats. Some fiberglass boats have more flex and are more fragile than kevlar boats. A lot depends on the builder and the particular layup.
In my mind, a good kevlar layup should have less flex than a fiberglass layup of the same model – and should be several pounds lighter. If the builder uses a kevlar layup and aims to acheive more than an 10% reduction in weight from the fiberglass model, it starts to be a tender layup.
In whitewater slalom boats, where
light weight (20 lb), ability to take hard impacts, and stiffness are all important, a common layup is a couple of layers of S-glass outside for stiffness, compression strength, and smooth wearing; and a couple of layers of Kevlar inside to keep the hull from breaking or tearing inward when struck hard. A pure Kevlar boat would not work. There are a few S-glass outside/Carbon inside boats; I have one, but I would not have ordered it that way. (I bought it from Adam Clawson, who designed it to race in ‘96 Olympics.)
Millbrook Boats kind of dominates the open canoe slalom market, and designer/builder “Kaz” uses S-glass outside, Kevlar inside, and inside Kevlar reinforcement at impact spots. His 13’ open slalom boats run about 26 pounds and are reasonably stiff.
If you can make a boat stiff enough, the boat will not bend enough under impact for S-glass and Carbon cloth to break or tear. It is hard to make a boat THAT stiff, but for some conditions it can be done. (My S-glass/Carbon slalom c-1 has never broken, but I am careful.) To meet a reasonable weight target and end up with a boat that will stay in one piece until the trip is over, putting one or two layers of Kevlar on the inside of the layup is an effective thing to do. But it will work (in my view) only if S-glass on the outside makes the boat stiff enough so that the (high) tension and tear limits of the Kevlar are not exceeded.
need to know more about the type
of canoe/kayak you have or are interested in and why.
My experience with a P&H Quest in Kevlar was pretty good overall. The layup was good, it’s just that the overall approach to making boats lighter is using less material in the hull.
Most kayak manufacturers still use glass or diolene for the deck in any “kevlar” boat they sell. The stiffness seemed the same between any other glass P&H Quest out there. The durability though was a bit suspect. I think glass with the heavier layup is better overall. It resists damage better, not because of the glass or diolene, but because there is simply more material and it is less flimsy.
The weight savings is negligible. I’m glad I owned at least one Kevlar kayak, if I found another used one I wouldn’t shy away from buying it, but I wouldn’t pay more for it new personally.
Carbonlite is a new material that eddyline uses. Don’t know how that is to repair, but their kayaks are noticeably lighter. The boat shop at lee’s always talks about the P&H prototype of a 100% carbon layup of a Quest that was 28 lbs. Hopefully this is the future. Don’t know what they durability of 100% carbon is, but the weight savings is pretty good. Just imagine what amateur boat builders could do with marine plywood, carbon, and epoxy! The boat would probably blow away in the wind it would be a teak glider…
Perhaps
I like to think that kevlar made a difference when my dearly beloved dropped the stern of my kayak onto the asphalt from shoulder height. Landed right on a focused spot on the keel tip and just chipped the gel coat. Not that I’m going to try it with a fiberglass one to compare…
BTW Necky kevlar boats have been kevlar-carbon for years. And mine incorporates a stiffener of the ultimate composite – a wood dowel along the keel line. But the new ones look sweet. Whatever floats…
I got my boat because I liked the way it fit and paddled. Kevlar was a bonus. Yeah, after a day of loading and unloading boats to demo the kevlar was nice.
Geez! Another dyslexic screen name Padalin, Padalin 
assateague
First off, thanks everyone for your input!
I have my heart set on an Impex Assateague and am deciding between f/g and probably the c/k - with weight vs strength vs cash issues. With all of today’s modern technology, getting the kayak on/off my vehicle is not an issue, it’s the effort of getting the boat from beside my car to the water at launch sites etc. (generally a couple of hundred yards)where I would appreciate the lighter weight. I paddle around the barrier islands off of Virginia, and strength and repairability are considerations as I often have to make hard landings onto shell beaches so I’m not washed out to sea. If strength and repairability are equal between f/g and c/k, weight will be the deciding factor, if fiberglass is the best for my paddling conditions, I’ll use the saved money to buy more Wheaties.
Thanks again for your help -----Urban
generalizations
it’s really not possible to generalize from a material type to a particular model. “will the Impex X in kevlar be more/less durable than the glass one?”. The ONLY way to know is to talk to someone who KNOWS the boat. You can get folks at shops or the manufacturer who are only relaying what they’ve heard and what they’ve heard may not be from someone who’s had a stretch of time with both boats in the conditions that determine durability. The only generalizations I’d say is that if the kevlar or carbon boats is SUBSTANTIALLY (someone mentioned 10%,maybe 15%)lighter then it’s not going to be more durable than the glass one.
If you are light then your boat will be more durable!
Repairability
was something that you mentioned. Near here
(eastern MA coast) there is an establishment that
has for many years sold and serviced “portable,
affordable boats” The proprieter does the repairs personally. When I was making a decision on which material to consider, I put the question to the number one employee of said establishment. She replied that although Kevlar can be repaired using (mostly) traditional methods, there would be a great deal of cussing heard while these repairs were being made. Not so with fibreglass.
I am told also that wetting out Kevlar as well as cutting the material is difficult due to it’s stiffness.
If you anticipate needing to make repairs more than very occasionally, the fiberglass seems to be a better choice. As someone previously stated, perhaps a better use for the extra money would be an upgraded paddle, etc.
Regardless, paddle before you buy. Maybe try to rent/borrow for a day, or better yet, a week.
Happy paddling.
Mike.
Call or E Mail Danny @ Impex
If you haven’t already spoken with him. He’s more than helpful, and will tell you in no uncertain terms which layup will be best suited to your needs. He’s proud of his company’s product; this is readily apparent in the enthusiam that comes across in conversation. There may be a thread to this effect on their website message board also; a search will let you know. Good Luck.