fiberglass repair - crack in bow

The boat in question is a Bell fiberlar layup. It has a crack at the bow where some gelcoat was chipped off and a little bit of fiberglass is torn leaving a small section of the outside layer of glass/resin detatched from the layer underneath. It is hard to tell just how much of the resin is cracked in the area. There appear to be some thin cracks in the fiberglass, but there aren’t any holes all the way through and nothing except the small loose piece of the outer layer moves when pressed. Directions for fiberglass repair all say to make repairs on the inside, but this is impractical at the very ends. We (this is a friend’s boat) have a few questions about how to proceed:

  1. What is the best way to remove the loose piece without causing any further damage? Would just trying to lift it up and break it off extend the area of delamination? Would you try to cut it off with a knife, or file it down?

  2. After removing the small loose piece would it be appropriate to cover the whole area with a new layer of fiberglass on the outside (sort of a mini skidplate)? There doesn’t appear to be any major structural damage, but being right at the bow, the area is likely to get some additional impact in the future and if there are hairline cracks they could give way.

  3. Would you use polyester resin or epoxy? From what I’ve read it seems that epoxy would be stronger but polyester would be better for adhesion of gelcoat on the outside. My friend would like to apply gelcoat over the repair to blend in with the rest of the boat as much as possible.

    Seems like this sort of thing has been discussed before, but my attempts at searching the archives have yielded very little. Any guidelines for this sort of repair would be much appreciated. Thanks!

Fiberglass repair
More info is needed before a definite course of action can be suggested.

  1. Was the boat constructed with epoxy or polyester resin? If you don’t know, or someone here can’t say for sure, best to contact the manufacturer. Use whatever they did.
  2. If what you are identifying is just a minor penetration of the gel coat and a 1" or so delamination of the outermost layer of glass, an easy fix can be accomplished by:
  3. Using a disposable syringe, inject the appropriate resin under the loose layer of glass. If necessary, drill into the approximate center of the loose area only as deep as the void, and inject the resin there. Wipe away the excess that flows out. Allow this to cure.
  4. Use Marine Tex epoxy to bring the void up to just above the level of the surrounding surface, and, when cured, sand it back flush.
  5. Refinish the surface with a gel coat repair kit.

    Both Marine Tex and gel coat repair kits can be bought at West Marine or Boats US stores, as well as many local marinas.

    Resorting to grinding back large areas of the surface and applying new cloth should only be necessary for a large surface fault, or, more realistically, if the damage is deep enough to be a structural issue.



What I Would Do (Have Done)…
with my epoxy/glass waveski (which you can’t repair from the inside) is to mask around the area and to sand down the outer coat around the edges. Sand it until you see no more separation between the glass and the gelcoat. Feather around the edges. Re-tape around the sanded area and put a new piece of glass that covers over the damaged area onto and over the masking tape. It helps to wet the middle of the damage area with expoxy (but not yet to the edges). Lay the glass on so it sticks flat and smooth. Then tape the outer edges of the glass where it aligns with the masking tape that is already encircling the damaged area. That work the epoxy onto the glass all the way to the the masking tape. Be careful to not move the glass (the taped down edges should help).

I use 2 hour epoxy and have gelcoat coloring that I mix in to match the orginal hull color (of course, you’ll never get a perfect match. Just close). After a bit over an hour, before the epoxy totally hardens, I take a razor blade and trim right along the tape. I then peel of the tape, along with the underlying excess glass, very carefully. What you have left is just the patch and a slight edge formed by the glass and epoxy. When everything is dried, I mask around the edges and then feather the edges to even out with the surrounding area. Lightly sand over the entire patch, mix another batch of colored epoxy and apply another light layer over the entire patch up to the masking tape. Before the epoxy hardens remove the masking tape border.

That’s it. It should hold. The coloring in the epoxy also affords some UV protection.


Fiberglass repair pics
See my related album and the one on gelcoat repair at:

Thanks for the advice and links
My friend filed off the loose piece. Turns out the delamination extended less than an inch away from the break in the outer layer. It is a small enough area that just smoothing it out with a filler would probably be ok, though my friend may try a small fiberglass patch over the damaged area. Either way, the gel coat repair descriptions will be helpful. Thanks. Sounds like the boat should be back on the water before too long.

Always use epoxy for repairs.
It adheres to all resins reliably. Buying vinylester resin is a waste of money, because you will only use a very small amount, and the rest will set up, no matter what you do, before you need it again. West Epoxy will remain usable for at least five years.