Carbon Boat Repair

I got a damaged boat super cheap on ebay, the guy thought it was fiberglass, when I picked it up I found it was carbon. It’s a racing SOT so very little is accessible from the inside. I seem to remember that carbon is difficult or impossible to repair but a search here didn’t reveal anything. I figured I’d ask here while I’m searching other venues. In the meantime I’ve got to duct tape it and see how fast it is before I start possibly fatal repairs, it’s 22’x 18" so it should fly.



how about
i WOULD check dealers like wenonah , bell ect, and see what repair kits they offer for their carbon boats

The following was posted on another
forum. To adapt, skip the dishing-out step, as your carbon layup may be very thin. Get some carbon cloth from John Sweet, or maybe some of his carbon/Kevlar weave. Or you can even use three layers of S-glass. The nice thing about using S-glass is it wets out clear, and you can see through it.

  1. (Patch mostly from inside, if you can.)
  2. If patch is to be inside, you can use Kevlar. It will withstand inward stretching better than fiberglass.
  3. If patching outside, go to, contact John Sweet, and obtain either pure S-glass, or perhaps one of his mixes of Kevlar/carbon.
  4. pencil an oval around the crack, maybe two or three inches away from the crack.
  5. Using sweat equity or a rotary sanding disk, dish out the pencilled oval. Deepest right on the crack, and tapering out to the edges. It’s a matter of judgement and taste how much you dish out right at the crack, and also a matter of how thin the original layup is. If the original layup is quite thin, you may not want to dish out much at all. If it is a thick layup, then it is necessary to thin the layup, or the crack line will still “work” after the patch is done.
  6. Your patch should consist of at least three concentric layers of cloth. Cutting on the bias, so that the fibers cross the crack diagonally, is desirable, and will help the patches conform to convex or complex hullforms.
  7. Use a reliable epoxy like West. You can also use vinylester, which Sweet can sell you, but epoxy keeps in the can, while vinylester will gel and then harden after some months. Epoxy sticks well to vinylester boats. Vinylester does not always stick as well to epoxy.
  8. Clean the dished-out laminate. Back the other side of the crack with tape, if possible. Mask around the dished out area to stop messy runs. Have some plastic wrap and electrical tape on hand if you are doing an external patch.
  9. Mix the epoxy. I use cut pieces of plastic milk carton to work resin through the cloth, so get whatever you want to use in order. Wear gloves, vinyl rather than latex if possible.
  10. Here’s the counter-intuitive part. THE LARGEST PATCH GOES ONTO THE BOAT FIRST, then the next largest, and so on down to the smallest patch. Wet out the largest patch on the boat, then place the next on, and wet it out as much as possible from the resin in the first patch. Add more resin only when you are sure you have to.
  11. Once you have all the concentric patches on and wet out so they look clear, if it is an EXTERIOR patch, then cut some clear plastic food wrap, press gently down over all the patches, and use slips of stretchy electrical tape to pull the food wrap down on the patches. This results in a smooth surface, squeezes out some extra resin, and suppresses the seam lines of the successive patch layers.
  12. If it is an inside patch, sometimes you can put food wrap over it and apply pressure with a sack of sand or similar method.

Thanks all!!!
It’s looking a lot less intimidating than it was.

I duct taped the boat and took it out today and it is fast but it’ll take a lot of getting used to.