I purchased a new rudder a year and a half ago. I was "shaving" down my old rudder in preparation for fairing and noticed moisture coming from within. Further investigation revealed a fair amount of water had saturated parts of the core. I removed more of the laminate to allow for drying. My plan is (was) to rebuild the rudder, fair it then offer it for sale. The rudder has been drying for over a year and is ready to be "refurbished." I would be willing to sell it as-is for considerably less than the normal used price. Sounds like with the modifications you are planning, this may be what you're looking for. I sail Lake Michigan out of Manitowoc, WI but live in Iowa. If interested send me an Email.
Steve Sullivan
Temptation, #311