I couldn't find my old post in the archives, maybe it was on sailnet; here is what I did:
1. Remove old handrails.
If the bolts will not turn, just use a crowbar under the hand rail.
2. If the bolts unscrew, then once the hand rails are gone, use the same size drill bit into the hole, and the nuts will come up on it. Drill gently to not damage the bit.
3. Drill right down through the hull into the cabin.
4. At each hole in the headliner, use a 1" hole saw to cut access to the deck.
5. Use a 3/4" hole saw from above to cut right through the deck at each hole.
5A. Some people prefer to use a bent nail, allen key, or some such device in their drill to dig out the balsa core instead of using a hole saw all the way through the deck, I find it very difficult to get all the core out that way.
6. Push some duct tape up through the headliner to cover the hole in the deck, and seal it the best you can. Place some plastic beneath the holes to catch drips from step 7.
7. From above, pour in a little epoxy to the hole. Let it just start to gel, but not go hard. The intention is to wait until it has sealed any drips right through the deck, and then fill the hole while the epoxy is still bonding.
8. Thicken more epoxy with adhesive filler to the point that it will JUST run, almost like peanutbutter. Pour this into the hole until it fills. Be ready to top it up a little if it is still leaking at the bottom. Let it harden fully (overnight).
9. Drill new screw holes for the handrails right through the epoxy fill. Place a 1" circular backing block in the hole in the headliner. Secure the hand rails with appropriate sealant, bolts long enough to go right through the deck and fasten to nuts under the 1" circular backing blocks.
10. You can also mount interior handrails directly under the exterior, which are both useful and nicely cover all the work from inside - teak is expensive of course.
Gareth
Freyja E35 #241 1972