M_Boats: caulk for centerboard pins

Question: What exactly is the black non hardening caulk that I dug out of both side of the centerboard pivot pin hole on my 1982 M-23? I seem to remember a post (possibly by Jerry) that mentioned filling the remainder of the stop and pivot pin holes with a non hardening caulk. This stuff was fairly easy to remove and held up extremely well since I suspect the board hasn't been removed since 1982. I'd like to use it again, or something similar. I thought I remembered a post about this but have not been able to find it. Jeff