Seam Sealer Advice Needed

[Marcia]

I have finally hauled my PY23 for repainting. While poking around on the underside I found that the caulk that (at one time) sealed the iron keel to the fiberglass hull has badly in need of replacing. I dug out all the old caulk and cleaned out what looked like gobs of grey plumbers putty (it went up several inches) and now want to refill the space properly, once everything dries out. What would be the best caulk or other material to use?

 

[Don S/V ILLusion]

probably not caulk

Marcia
It's pretty unlikely this is simple caulk (unless some idiot tried that as a repair).
Keels are attached first by keel bolts and then with a proper adhesive bonding caulk sealer, often 3M 5200. From your description, it doesn't sound that 5200 or something equivalent was used as it would be very hard and come out in chunks, if at all.

You have two choices -
you can try replacing all loose material with a good sealant like 5200, or
you can remove the keel and do it right.

If you choose the former, which is obviously much easier, get used to doing it frequently. I would STRONGLY recommend against taking the easy route as an iron keel and SS keel bolts in a constantly wet environment will create serious corrosion of the bolts which may have already occurred. Dropping the keel will allow close inspection.