Rudder post repair

[Seaman gagging]

Need advice on rudder post fix 1997 Catalina 36. The problem is the post seems to have worn a larger hole were it comes through the fiberglass box that the rudder is hung from. As you can see I don't have all the terminology right. So my first question is should I hire a professional? My plan is to 5200 or epoxy marine plywood on the inside of the box and cut a starboard piece that would act as a new collar. Screw the starboard collar to the marine plywood. On top of that I replace the old that the post is held up by. There is a bolt that goes throw the fiberglass collar and rudder post. The fiberglass collar would ride on the new starboard collar. Next step is to tackle the delaminated fiberglass on the bottom side. There is another collar that was glasses into the bottom side of the box. This broke away and my plan is to epoxy it back in place. At the same time the fiberglass has also delaminated and needs to be epoxied back. At this point the rudder has dropped about a 1/2 inch and the quadrant has been resting on thebfiberglass inspection shelf. I can pull the quadrant up fairly easily and keep it place till I rehang to on the collar Question. I can remove the deck plate. The screws come out easily, however it won't budge. Could it be glassed in or glued in place? I am doing the job in the water. Would you advise to pull the boat and drop the rudder and began at the beginning? Did the repair once and all held until I started surfing some waves and everything released. I epoxied the starboard collar in place and it didn't hold. That's why I'm going with marine plywood and screwing the starboard into that. Thanks for all and any advice.