Regarding removal of the centerboard, I would ill advise against tapping because if that metal rod should ever get into the threads of the centerboard housing and damage those threads that the retaining bolt holds the centerboard bracket in place, you will end up having to relpace the centerboard housing. If you will check earlier posts, I would recommend that the board be dropped. The easiest way to loosed up that bracket so it will come out is to simply work the centerboard back and forth and it will come out. There is no need to tap and take that chance of screwing the threads up in the centerboard housing. Hunter no longer makes that bracket and you would have to have one special made and that is a costly mistake. I was involved from day one of the conception of the 23.5, introducing it for Hunter and probably sold about 25% of the production. When removing the centerboards, this was the way I use to remove all my centerboards.
In the bracket is a stainless steel rod . There is a hole in the centerboard which that ss rod goes thru. The later boats I believe had a hard plastic sleeve that went over that rod to make it easier for the centerboard to swing on. Over the years, I saw those centerboards in pretty good shape but the hole the retaining bracket went thru and/or the plastic sleeve wore out. Replacing the plastic sleeve usually solved that issue. In some cases there were plastic bushings between the centerboard and the housing it was in and if that broke or wore out, simply replacing those would solve that issue.
Because of the confinement of the retaining pin in the area of the hull trunk housing, any nuts outside of that housing could possibly damage the hull. When putting that retaining ss rod pin back in place, to keep it in place, put some duck tape on the outside to keep it from falling out when reinserting the assembly into the hull.
Any questions, feel free to email me.
crazy dave condon