Chain Plate Replacement
I replaced the chain plates several years ago. There is no secret technique other than to disassemble the cabinetry as little as possible and to be as non-destructive as you can. As I recall, one tool that was instrumental was a Japenese style pull saw. It has a thin flexible blade that can be slid into a gap and then cuts with a pull. I think they're available at the home improvement type stores.
After consultation with Doug Stephenson, I proceeded. Doug's most helpful hint, other than to cause as little damage as possible, was that when the triangular boxes surrounding the aft lowers / aft intermediate stays have had every accessible screw removed, to gently "rip" the box free. I approached that point with trepidation, but gently pulling the boxe(s) free did the trick. It turns out that there are screws that cannot be reached at the very top. I can't remember for sure if it is the P or S, but I think it's the P side.
Looking around, all the other chain plates are accessible with simple, albeit time consuming, disassembly. This is a good winter project. Take your time and take plenty of pictures to help putting it all back together and to post an article on http://www.WhitbyBrewerSailboats.com
What I found was that the original chain plates had a fiber material tightly packed in the lower gap where the chain plate exited the deck. I removed all of that packing as it prevented leaks from flowing off the chain plates, preventing their easy detection and potentially created a perfect environment for oxygen starvation.
I had new chain plates fabricated and replaced all of the bolts, washers and nuts. The knees appeared in perfect condition which pleased me greatly.
It was a big job but in the end, resulted in no visual effect inside the cabin. I can now get to the chain plates for inspection with little hassle as all of the hidden cabinet hardware is gone.
I hope this helps. Feel free to ask any follow up questions. Let's hope the search function is fixed soon.
Greg Temple, My Destiny, W42 #313