Well it's been a while, but then it's winter outside.
I took advantage of the record setting warm weather just before Xmas and pulled the port side upper and aft lower chain plates. Despite having a large volume of water tucked away in the air gaps and hollows there was not a single spec of corrosion or de-lamination of the glass.
In short, other than having water under and around the embedded plates there was no safety reason to pull them, the plates were fine and the glass was fine.
I put a 50 grit sanding disk on my grinder and sanded the entire newly exposed bulkhelds down to mostly flat and smooth in just under two hours total time for both sides. 13, 500 rpm does wonders that a conventional oscillating sander just can not do. Half inch thick ridges of fiberglass just powder away in seconds.
That's the bad part, the powder doesn't just float out over the side of the boat. I have a 1/4 of dust everywhere that now needs cleaning up despite the vaccuum and walls of plastic meant to contain it.
I took a couple cell phone pics after a rough clean up but they are blurry as heck (so was I, it had been a full 8 hours of grinding, contorting and pulling/bashing. I crunched two finger tips when a previously stubborn plate gave way to a mighty pull.
Here's the only blurry one worth looking at - followed by what it looked like before sanding it down.