I’m one of those that can’t resist adding to the fleet when a bargain comes along. So, I just got a 2004 Wilderness Systems Tempest 170 Pro in Kevlar. The kayak is in nice shape but one thing I’ll have to do is patch the inside of the hull where the previous owners heels appear to have worn through the Kevlar. That won’t be a problem, but I was surprised to see that the hull appears to have at least four layers of cloth in that area. You can see the separate rings of cloth in the photo, plus an intact forth layer in the middle.
I didn’t know that kayak hulls are built up with this many layers. Is this typical? Did Wilderness Systems just reinforce the hull in this area knowing it might wear?
I’m not concerned about anything, just curious how composite hulls are usually configured.
That is typical. Composite materials are usually built up from many layers of thinner cloth, rather than fewer layers of thick cloth. Depends a bit on what is being built, but that’s generally the rule.
And given that he wore through that many layers, I’d maybe think that isn’t Kevlar, even though the color looks right. Most likely just plain 'ol fiberglass, or maybe the outer layers are Kevlar and the inner ones are glass. Kevlar is really resistant to abrasion. But in any case that’s a pretty easy fix.
Based on the weights given in reviews I’ve read, it appears to be the Kevlar version of the kayak, but of course that doesn’t mean it’s all Kevlar. I weighed the kayak at 51 lbs. Maybe a bit heavy for Kevlar but light for fiberglass. So perhaps it’s a hybrid build.
Here’s a close up. The center unworn spot looks a bit more yellow, so perhaps that layer is glass.
There was a time when most whitewater kayakers built their own composite kayaks because there were few or no rotomolded options. Charlie Walbridge’s classic book “The Boatbuilder’s Manual” has advice on how many layers of what type of fabric were best.
A four layer hull and four layer deck were recommended for most uses and the strongest combination seemed to be two outer layers of S fiberglass and two inner layers of aramid. For a lighter weight boat a three layer deck might be considered. Two layer boats were suitable only for slalom racing where light weight was a priority.
Instead of full blankets of fabric most composite builders these days use “partials” in high stress or high weight-bearing areas with fewer layers for example on the hull sides in the quarters above the water line. So the total number of layers is often not uniform over the entire hull and often the deck is lighter in weight than the hull.
If that was Kevlar, it would be seriously frayed, so I agree that it’s fiberglass. That said, the gold color indicates that one or more of the outer layer is Kevlar. To fix this, you need to remove the bulk of the white-ish loose glass and feather the edges. I prefer a curved carbide scraper for this, but you can do it by sanding. Just be very careful not to sand the Kevlar or you will end up with a horrendous, fuzzy mess. Once all the loose material is gone, you can repair the area with 4 - 6 ounce fiberglass layers, overlapping by at least an inch all around. Unless you’re on a really tight budget, use marine epoxy rather than the typical polyester resin that comes with fiberglassing kits. If your heels will rest in the same place, add an extra 2-3 sacrificial layers to prevent this type of damage from recurring.
I’d say kevlar most if not all of it. I’d bet it’s all Kevlar. Fuzzy like Kevlar. You can get some 220 wetordry paper to sand it. Weight says kevlar to me also.
No clue how anyone could let it get that bad.
Sometimes they use core mat to stiffen hulls between the layers.
I’m really comfy using scrapers but have never used a curved one. I’ve always flexed a straight scraper to produce the curve. Too old for that now. Is there a particular curved scraper that you prefer or recommend?
My wife and I have Kevlar boats and that wear is a bit worse but typical after several thousand miles. We had wear going into the second layer before we noticed it. Just used progressively larger pieces of fiberglass over the holes and then a top rectangular layer covering the whole area. I’m not of the “fine piece of furniture school” and just wanted to reduce further wear. We keep an eye on that area now and will brush on a thin layer of epoxy if I see any new wear before it gets to the fabric. Hard rubber heels and sand will do that to a boat.
It’s interesting that the kayak in general is in really nice shape. Bright gelcoat, no gouges, no impact dings. So, it looks like it was well cared for. It is odd that the previous owner(s) never noticed the wear inside.
Thanks for the advice, bnystrom. I have some fiberglass cloth and epoxy resin so I’m set there. I also have a straight carbide scraper but agree that a curved one would be really nice for this. Time to start shopping.
Fiberglass and epoxy will work fine for the repair. I would plan on at least a 3 layer patch with the largest patch overlapping onto undamaged hull by 2 inches. You could use 4 oz/sq. yd. material but the weight savings over 6 oz. cloth would be insignificant and cosmetics is not an issue so I would use the heavier weight material.
You can cut out a template from brown packing paper that corresponds to the shape of the defect but is 2" larger concentrically. Trace the outline of this onto your fabric then trim off an inch or two all around for the second patch, and repeat the process for the third. Your repair will be stronger if you orient the lines of the weft and weave for each of the layers to that they run at a bias to those of the hull fabric and to each other. You can feather the edge of each layer as you go or do so for all of them at the end.
For a final layer of fiberglass coving the whole area near the pedals I use painter’s tape about 1-2" beyond the fiberglass. I then brush the epoxy up to the tape. Immediately afterwards when I have smoothed out the epoxy I remove the tape. Not really necessary, but it makes a neater repair. Use newspaper in front of the repaired area to catch any drips or spills.
It’s fairly easy to miss this type of wear as how often do you get a light and look inside the front of your kayak? Although this is an extreme case.
I look and clean the fronts of my kayaks after every use. Cables can fray and snap after time. Hardware can loosen on a rudder, skeg, or just a foot brace.
Can’t fix much out on the water. I’d never want to be out in rough water handicapped. I check my float bags on every trip. Check bungee’s and deck lines. Sixty seconds I can see and feel everything on a kayak. Like a pilot walking around his plane no matter how many trained people work on it.
Recently I had to repair a hole in the hull of my Scamp sailboat. The boat was on the trailer, and I had to work lying on my back looking up. I breakout in a rash if uncured epoxy touches me. I carefully applied a coat of epoxy to the repaired area. Then to keep the fiberglass work from dripping I used a sheet of waxed paper (freezer paper) laid the cutout fiberglass patch on the wax paper and saturated it with epoxy. I then lifted it the wax paper and fiberglass up sticking it like a piece of tape over the repair. When done right you can eliminate the bubbles by rolling it on slowly. The next day I just peeled the wax paper off and had a smooth hard patch.
Looking at the inside of the hull with light cardboard taped to the outside for drawing a pattern. I cut back to good wood when removing the rot.
I laid the fiberglass on the wax paper wrong. Note the orientation of the cardboard pattern and the patched hull. So, I had to pull the wetted fiberglass off the wax paper and flip it over before applying. Otherwise, I would not have had a few air pockets.
For fiberglass work, a flexible steel scraper doesn’t work well, as it dulls really quickly. I use Sandvik/Bahco carbide scrapers, that have 50mm or 65mm reversible blades that are straight on one side and curved on the other. The curve isn’t very pronounced, but it’s enough to keep the ends from digging into the surface. Looking at their website, It appears that they may not make this style blade any longer, but Allway Tools makes this scraper with a double sided curved blade:
Allway blades also fit Sanvik/Bahco handles and they have a more pronounced curve. Prices on these seem to vary widely, so shop around.
I managed to wear heel holes in my '70’s fiberglass kayak after thousands of miles. Noticed it for decades but it didn’t become a problem until I got a slow leak. My inexpert repair didn’t work.
All it takes to do that is beach launches - the sand that sticks to your footwear does the rest. I added gorilla tape inside my new boat to avoid the problem. If yours doesn’t leak yet you might do the same instead of repairing it.
Wolf,
You have a really nice boat. I am impressed that anyone could paddle enough to show that kind of wear. Kevlar normally tends to show fuzzy fibers when it is abraded. In the photo it appears that has started to happen around the edges of each layer. Quality marine epoxy and some fiberglass cloth will easily make the repair. It won’t even show.
Just wash the area with soap and water to remove any amide blush that forms on the epoxy. Lightly sand with 220 and wipe down with alcohol before adding the fiberglass and epoxy.
I’ve determined that kayak does appear to be Kevlar. I happen to be keeping an eye out for a lightweight boat for a friend in Maine. I inquired about another Tempest 170 Pro that I saw on Facebook in Maine (friend doesn’t do Facebook), and asked for a picture of the cockpit to try to determine if it’s glass or Kevlar. The picture is shown below. You can see that it’s a much whiter material, typical of fiberglass. The cockpit on my Tempest is the second photo and definitely has the browner Kevlar look.
Yes, your hull is the Kevlar model, but that doesn’t mean that every layer in the layup is Kevlar. The worn layers are obviously fiberglass because they’re clear and transparent where they aren’t worn, and white at the worn edge. Kevlar is translucent and amber colored. Regardless, fiberglass is the best material to repair it with, unless you can find some Dynel cloth, which is extremely wear resistant. Kevlar is expensive and somewhat of a pain to work with. Do a little research online and you’ll see.
