This little Catalina 22 is my first boat, and for my first project I replaced the 40-year-old garden hose valve they glassed directly to the hull with a proper seacock, following Maine Sail's instructions.
It is probably overkill to upsize from 3/4" to 1" and go all bronze on a little boat that's being sailed on a little lake, but I want to learn how to do things The Right Way.
So yes, my first boat project involved drilling a new hole in the boat and plugging an old one. Both sink-the-boat propositions.
Other that the slight kink in the one hose because the bend radius is a bit tight, I'm quite happy with the results.
Things I have learned:
A) Apparently I have a wimpy drill press, because I burned out the motor using a 6" hole saw to cut the backing plate from G10. Ohmygod that G10 stuff is crazy hard. I had to finish the cut with my hand drill. I think if I were to do it again I would cut an octagon with my table saw.
B) Working with epoxy is fun! That stuff is great. And so simple. I was intimidated, especially since these are both below-the-waterline, but I feel very good about the results. Oh, except it's not fun when you're on your back working where you can barely reach because the swing keel is blocking you and also the epoxy is rapidly hardening because 8 pumps was probably too big a batch. Yes, I have epoxy in my hair.
C) Sikaflex 291 is amazingly resistant to removal. It's everywhere and it won't go away. It's the herpes of boat products.
Anyway, boat goes in Friday, I'll report back if my repairs are actually watertight.