I have a 21 year old Kevlar Bluehole Starburst that has cracked chines. This canoe is a victim of UV damage, and having the gunwales pulled in. It paddles nice, but it is time to let the gunwales back out to relieve the stress on the chines.
To repair the chines, I’ve been tossing up the idea of reinforcing the chines with bias kevlar or carbon fiber tape. Though, I’m concerned this added stiffness will cause the chine to fail at the tape seam instead. So, now, I might use s-glass biased to the crack and over a larger area to reinforce the chine areas.
Any ideas?
Kevlar Bluehole?
I’ve never seen one. Are you the original owner?
Try making a three layer patch (assuming you’re putting the patch on the interior). Do this by cutting one piece 1" wide the length the crack: another one with all four sides 1" wider than the first patch; and then a third that is 1" wider on all four sides than the second. Layup your three layer patch and apply with the smallest one on the hull, largest one is the outside layer. I would use kevlar for the patch, seeing as it is a Kevlar layup
Thank you for the tips.
I’m not the original owner. This boat is actually a Mike McCrea rebuild. It has a Bluehole tag on it. The original owner had it outfitted as a solo and told Mike it was a Starburst.
Are the outer layers Kevlar? Most WW
open boat makers would not use Kevlar for outer layers. I remember inspecting some Kevlar Sunbursts at races, but obviously I would not easily have been able to tell if the outer layers were Kevlar unless I checked for fuzzing.
I would prefer to do that repair with either bias cut S-glass, or possibly with Kevlar/carbon cloth, available from johnrsweet.com
The problem with chines is that, even if the gunwales have not beet pulled in, blows to the bottom of the boat will tend to put tension loads on the chines. This is one place on the outside of the boat where using Kevlar may be helpful. On the INSIDE of the chines, it would be better to use S-glass or carbon, because blows to the bottom of the boat will tend to COMPRESS the inner layers of the chine. But I don’t like to use Kevlar outside where it will fuzz. You decide.
Last year I tried a guy’s Millbrook Defiant, a boat with a flattish bottom and relatively sharp chines. The chines had failed INSIDE because the Kevlar was not up to the compressive loads imposed when the bottom was thumped. But for most of the chine damage, the S-glass outside appeared unsplit. This also illustrates the fact that whether Kevlar should be inside, or S-glass outside, depends on the expected loads. I may have a Defiant made for me, and if so, I may ask the builder (Kaz) to put some S-glass reinforcement over the Kevlar on the inside chine surfaces.
Patches on the outside…
– Last Updated: Jan-24-08 7:50 AM EST –
change the exterior shape of the canoe. All structural patches on composite canoe should be made on the interior in almost all cases. The interior, three layer patch displaces impact and stress over a larger surface area. External work should be cosmetic work (gel coat, painting, etc). Only when you've worn away significant outerlayers of the canoe is an external patch recommended (like adding a skid plate on the bow or stern). If it's a Kevlar canoe to begin with, Kevlar should be used on the inside because it has some flexible characteristics that will absorb impact and stress better than glass or carbon (in most cases).
Just my opinion, I've repaired hundres of canoes.
openboater
Kevlar repair
A couple of suggestion if you decide to repair using Kevlar.
As has been mentioned previously, you can’t sand Kevlar without causing the surface to fuzz. If the repair is on the outside of the hull and you want a smooth finish, put a layer of 4 oz fiberglass over the Kevlar. You can sand and finish the fiberglass. Another trick I have used is to carefully stretch a sheet of Saran Wrap or similar plastic over the patch. You can attach it to the hull, outside of the patch area with masking tape. Stretch it so that there are no wrinkles. With care you can get a nearly flawless finish. This trick works best if the patch is on a highly curved (convex) part of the hull, such as the chine. It also works well if you want a smooth surface on skid plates. It doesn’t work as well on flat surfaces where it is hard to maintain tight contact with the fabric and resin.
Marc Ornstein
Dogpaddle Canoe Works
Ditto…
That trick is good for exterior gel coat work, too. It minimizes wet sanding.
If you do the interior patch in the chine, secure the canoe on it’s side on a pair of saw horses (careful not to the flex the area you’re patching). This way the patch will lay flat and gravity will help it bond better and stay in place. The Saran Wrap (or Peel Ply) trick can also give the patch a clean hand and hold down the stands on the edges of the patch…as the others said, you can’t sand it once you’re done.
openboater
That’s ridiculous. Outside patches
done properly have negligible effect on the progress of the boat, and in addition, no one fixing a whitewater boat is concerned about exterior flow effects. Often the patch MUST go outside to achieve the desired effect. I have never had ANY problem with outside patches.
Not may places you can still buy a
true whitewater boat with gelcoat.
To be slightly less abrasive, aren’t you
strongly influenced by the problem of repairing gelcoat boats? How would a patch on the outside do any less to distribute forces compared to an inside patch? (Of course, if my boat is broken through, I am likely to apply patches outside and in.) Once you have ground the gelcoat away, you should be able to fit at least a couple of layers of S-glass in the depression, maybe three.
I just would not buy a gelcoated canoe or kayak anymore. None of my boats bought in the last 30 years has had gelcoat.
Lincoln Sunburt Lite
I also have a 1990 Lincoln Sunburst from BMO that I paddled for the first time in its life back in January. It is a gel coat boat. No one has been able to tell me what color it is. Mauve, lavender, etc… Anyway, it a great boat!
For the repair on the 87 Starburst, I’m planning to make repairs on the inside and outside. There are many good ideas to choose from. Thank you.
-Jeff