I want to say thanks to this forum who helped me to get my fixer-upper to sail. With your help I was able to do the following repairs:
Modern rudder upgrade
Inspection ports installation
Minor hull patching
I'm happy to say that my wife and...
Since two of the self-drilling ones didn't tighten completely (i think they stripped the fiberglass), I would probably stick with the bolts next time.
For that reason, I put a bead of 4200 around the outside of the port. Not very pretty, but it works.
I did one inspection port with the self drilling screws, the other with nuts & bolts. Two of the self-drilling screws wouldn't completely tighten. Other than that, it worked ok.
The nuts & bolts method was more expensive, but also seems to be more solid.
I caulked with M3 4200, as shown below...
So I finally patched that hole. After some brainstorming, I decided to cut a small piece of aluminum, and glue it into the hole with marine tex. From the underside I made sure that the marine tex squeezed out evenly, and then I leveled it off.
I haven't done a bona fide leak test, but visually...