I have a 24’ Baja Islander and I noticed the previous owner used a tapcon (concrete style screw) to secure the bracket for the hatch cylinder to the hull. Except these screws have backed out and wollered out the holes for the original bolts (not even sure what kind they would be). However this doesn’t seem right. I am looking at replacing the bolts/screws but what should I use? I have no access underneath the fiberglass “shelf” it mounts to otherwise I would use large fender washers and stainless steel bolts.

I considered a lag bolt of some kind but I am not sure how the fiberglass will react with a coarse bolt like that gnawing it’s way in.

Thoughts?

Fill the hole with epoxy. After it cures drill and tap the hole for the appropriate size machine bolt such as a 1/4-20 stainless. Put permanent Loctite on the bolts as you install them.

Not to sound ignorant, but filling the holes with epoxy will be strong enough for the torque/leverage?

What type of epoxy do I use if that’s the case? Is there a specific type for this application or will just any epoxy work?

Look up West System epoxy, they have a ton of technical information on how to use their product. And yes with the right additives the epoxy will be plenty strong
I would use fumed silica (cabosil) and micro fibers in this application.
Do some test pieces before the first time you use it in the real thing

As he said. You can't go wrong with West System. They have a high strength additive for bedding hardware. Their website will tell you.

Awesome. Thanks a ton.