This is probably was off base Brian, but I was searching around to look for ways to beef up my cabin sides to accept a synthetic chain plate I have an idea for. Considering the same "knees" you are describing, minus the wood and priblems I hope.
I came across this PDF. I will throw it out as you description of the fiberglass with the wood core sounded like this race boats structures. I am serious about going to soft deck fittings. Just matter of time.
http://www.equiplite.com/2009/Frames...plates_WEB.pdf