There are several ways to repair fastener holes in a transom, and they each have their advantages and disadvantages. They all share a [two initial steps]:
- use a drill to remove any rotted wood, and
- chamfer the gel coat with a chamfering bit
A large drill bit for to chamber the holse, perhaps if you ran it in reverse, but I always use an inexpensive chamfering bit. After that, you have some choices--and I’ve done all of these:
Option 1Put some masking tape around the hole and squirt some epoxy (whatever you have on hand) into the hole. Use a matchstick or something similar to get the epoxy down into the hole itself. Wipe off the excess with a rag, and remove the masking tape after the epoxy dries. This is easy and cheap, but it’s the least cosmetically appealing. Expect the epoxy to yellow over time. If the hole is larger than one made by a mounting screw, you could add some thickener to keep the epoxy from sagging, or you can cover the hole with clear packing tape, or do both.
Option 2Squirt Loctite Marine Epoxy into the hole to overfill slightly, cover with clear masking tape to prevent sagging, and remove the tape the next day. This leaves a shiny spot whose color is close to that of my 1990 17-foot hull. I’ve added thickener before, but for small screw holes it didn’t seem to matter. For larger and deeper holes, I’ve loaded the epoxy into a plastic syringe and injected it into the hole, which limits the mess a bit. This option is easy, and I’ve got a few holes repaired like this on my transom currently. This option is my first choice if I’m going to cover the hole repair with another transducer bracket.
Option 3Perform wither option 1 or 2, then the next day (or the next year--it doesn’t matter), sand down the epoxy down until there is a very slight depression, then apply a coat of gel coat repair paste, allow to set, and sand it down until it’s flush with the hull. I’ve done this repair several times on my transom, and the repair is almost invisible. It’s also by far the most tedious and expensive option.
If you are considering this, I recommend watching this YouTube video: “How to Repair Screw Holes in a Fiberglass Boat” (
https://www.youtube.com/watch?v=b3ea4Lr ... ormanGooch)
The presentation includes the source for the Spectrum repair paste. This gel coat repair paste can also be used (without the epoxy) to repair superficial dings in your hull. It’s pricey stuff and the color match may not be 100%, but I think it’s the best method for fastener hole repair if you are looking for the best cosmetic appearance.