Tayana 42 rudder post assembly

[Deepseabee]

Hi everyone,

I'm trying to find information about a '89 Tayana 42 aft cockpit rudder assembly.

Ours has what looks to be a piece of ply wood shimming under the brass shaft-seal base (see pictures for context).

This wood has gotten wet over the years, apparently from an overhead fresh water leak from the deck (rain and washing) and is now rotten in a few places. I'm trying to understand the role this wooden piece played, and obviously nervous about sea water intrusion, it the whole rudder shifting under strain.

Does anyone know how these go together? What's underneath these posts, and just generally what I should expect in replacing this with some sort of plastic/composite board?

Does this require a haul out? The base of this component sits approximately 2-3 inches below water line.



Thanks for any ideas, help, links, or drawings