Adding an extra layer of kevlar

I’m thinking of adding an extra layer of kevlar to my canoe. Any idea how much weight it would add to a 17’x32"x14" canoe? How much could I expect to pay to have it done?

Thanks in advance,


Why? Where?

all over
the outside of the hull. UV has laid a beating on it over the years.

I’m not all that knowledgable about …
… about all the different ways kevlar has been used in canoes , but I just don’t ever remember seeing a layup that had the kevlar as the outside layer ??

You must have some type of gel coat as a finish surface on the outside of the hull , don’t you ??

skin coat clear coat gel coat
all are different and there are different resins used.

You might try this excerpt from a Cliff Jacobsen book,M1

Skin coat
Thanks for the info folks. it’s a Wenonah ultralight with a skin coat. Does anyone know how much weight another layer of kevlar will add and what it may costto have it done?

Kevlar is very sub-optimal as an
outside cloth. It excels as an inside cloth.

Adding any cloth layer to the outside will add a lot of weight and contribute little to hull integrity. If you wanted to add anything, I would recommend a layer of 6 oz E-glass, added only to the bottom and up over the chines. But I honestly think its a waste of time and money, and just a way to add weight.

Again, you almost never want Kevlar on the outside of a boat, except in a crude skid plate.

I sure would like an answer
to my original question.

want truly expert advice?
re read Eric’s post and contact him directly. he’s a master and freely offers his prodigious expertise. you will be thankful in the end.

5 to 20 pounds
Depends on how much of an expert you have do it, but because boats are not built by building them inside out, it will look ugly and probably be over-saturated with resin; thus heavy. The Kevlar is going to run you $150 and labor at least $200-$300 on the low end. If you are determined to do this, I too suggest E-glass over Kevlar. If you are going to add weight, might as well make your boat stronger as long as you are making it heavier.

That’s what I needed to know to weigh all the options.

When people don’t answer your main
question, it may be because they are trying to help you make a big mistake. If you asked what first aid kit you should choose before running Niagra Falls, what kinds of answers might you expect?

Say goodbye to "ultra-light"
However you approach this “fix-it,” it’s a good bet your Kevlar Ultra-Light will no longer be ultra light.

I can empathize. I have two W. ultra-lights that I keep on a rack outdoors all year. I try to keep them clean and to wax them occasionally. But the smart thing for me would be to take a car out of the garage and put the boats in instead.

At some point, my 34 lb Prism will probably need to be replaced with something more…robust, and heavy. I know that’s no help for you. It falls in the category of “live and learn.”

Well, it needn’t be a LOT heavier to
be quite a bit more durable. Check out the offerings from Millbrook Boats and from Bluewater. Both builders have also built slalom racing and whitewater boats for many years.

I can’t answer your initial question as far as weight or cost.

The weight will depend on which fabric you choose. Heavier fabrics are not only heavier but will require additional coats of resin to fill the weave in order to give you a smooth surface. More resin means more weight.

The cost will depend on who does the work, which resin you use, and again, which fabric weight you choose. Epoxy resin would probably be the best choice; it’s also the most expensive.

Another thing to think about is whether or not you’d want to use Kevlar for a repair. Kevlar is very difficult (impossible??) to sand. When you try to sand it, it turns into a fuzzy mess. I’m not sure you’d get a smooth surface where the cloth was cut at the stems. Kevlar is much better suited for laying-up in a female mold and/or vacuum-bagging.

Good luck,

Pedro Almeida

Of course, if one uses Kevlar only for
repairs INSIDE the boat, where it is truly useful, then the issue of sanding may not arise. I added a two layer stiffening patch under the seat of an old kayak, and with normal self-discipline, I ended up with a fully wet out job, but one devoid of any visible puddles or extra resin. The edges of each added Kevlar layer were easy to sand to acceptable smoothness. If I had been bothered by the tiny amount of fuzz left by sanding, I would have burned it off with a propane torch.

The problem with Kevlar is not with sanding, but with the awful fuzzies that result when a boat with Kevlar outside is dragged.

Another option
Refinish via varnish.


He does a very good demo of
varnishing, and his “brand x” boat hole patching approach is admirable also.

I wish I could understand why he repeatedly shoots himself in the foot with his exaggerated and contemptous criticisms of other boat builders. I hate gelcoat as much as he does, but I have NEVER had chunks of gelcoat break off my gelcoated boats, both of which were hammered hard in Georgia whitewater. And get his crack about how nobody drives Corvettes in winter. Right.

He could move into composite whitewater boat building at any time if he wanted to, and his products would be OK. But when I compare the modesty of whitewater boat builders like Gary Barton, Andy Bridge, and Kaz of Millbrook with this guy’s narcissistic exaggerations, I can only be grateful that he is the exception amongst the “knowledgeable,” not the rule.

it’s like he’s got an axe to grind
in researching Souris River canoes, i read his whole site, it took me a few days… i get the impression he has had to spend a lot of time explaining to people the merits of epoxy, and perhaps taking flak from other retailers over the years, due to competition. it does seem a bit excessive.

Rough answer to original question.
Calculate the surface area you want to cover with the weight of the cloth you want to use … then double it if you have not worked with resins before … or add half the weight of the cloth if you have.