Aye Mapism: The boat is 20 years old and built by Albin Marine in the USA. (As opposed to Albin in Sweden) The reason for doing these thru hull fittings now is that I am having a lot of work done on the boat, an all new sanitary system with holding tank, all plumbing, valves, head, etc, etc redone. With all that stuff out of the way, these fittings were very accessible. Without removing the sanitary system, it would have been much harder, if doable at all. The surveyor who found moisture readings around these thru hull fittings is a guy I have used for 22 years and I thrust him 110%: If he said I should probably re-bed these fittings, I will do it, and did. All good. Yes, solid fiberglass around any openings as should be, but I was not 100% and the plan was to dry out the area with heat lamps and fans if moisture was found, then repair with epoxy and re-instal. Needless to say I was relieved to find solid glass, the comments above about 5200 being used was in response to another poster who mentioned 5200. I would not have started a thread on this, or even mentioned my 6 fittings if Capt. Ken had not said something about not being used on his boats. As for the readings on the Surveyor’s moisture meter, possible wet caulking, some spot leaks from the sanitary system right behind it, whatever. Glad I opened it up and re-bedded, it was a very small part of a big job being done on my boat right now, and I sleep good at night. (We have been shut down for Covid, but back up next week, already have 2 charters Lined up, the vacation is over. )