easy fix
I have had one of the chain plates pull through the rotting wood mid sail...lucky I did not lose the mass in the bay.I had a machine shop make four stainless stell plates, not very thick. Two for each side.They have three holes to hold the chain plate and are 6' x 6', wide enough to atttach to the wood that has not rotted. The fasten to the wood with small stainless srews.