Hi
I had to redo my port deck along the cabin too- leaks from the stanchion base and from the jib block tracl pretty much turned to core to mush. I cut away the delaminated deck and cleaned out the debris until I got to sound wood that was still adhered to the glass, then dried it out as best I could (not an easy undertaking in Seattle in winter) then cut endgrain fir blocks to fill the core, embedded them in epoxy and glassed over it all again then painted it.Turned out surprisingly well, considering. I also glassed in a much more substantial backing plate for the stanchion base so the load is much better supported. There are any number of sources for info on how to fiberglass and it's really pretty easy. It also has the benefit of being easily removed with just some grinding if you don't like the result and want to try again. It's been three years since I did mine and I haven't had any problems- no leaks, no flex, no cracks so I'm pretty happy.
Tom