According to the "rigging experts" who have listened to our story, that pumping action is what caused the metal fatigue which broke 2 chain-plates at their tabs, just above the ribs, and just under the decking.
It is rather frustrating that some "experts" will provide a very reasonable explantion that fits with all the history and facts, and then some experts seem to be in denial of that, and point to pitting and corrosion as the culprit.
I feel more like I am in a room full of lawyers than reasonable men. :-)
Doug I feel your frustration. I hate it when experts disagree.
I have a mental picture of what happened, let me know how accurate it is.
The shrouds were a little loose. The wind picks up and the top of the mast is whipping around more than it should. Maybe the top of the mast moving a foot out of column from where it should be. The mast is lets say about 60 feet tall. The top is a foot or two out of column. How much does that affect the angle of the shroud between the deck and the shroud. Maybe one degree.
So the theory that the chain plates were damaged by loading in one storm does not make any sense to me at all.
The place that they broke is exactly where they would be expected to break if they had oxygen depletion corrosion.
Now the mast whipping around certainly didn't help but there was another thread where someone gave his old chain plates to a friend with a machine shop to use for scrap metal because they looked perfect. A few months later the machine shop guy tried to cut one in a shear. It shattered and crumbled.
My son is a rigger in Annapolis and I asked him about this a long time ago. His response was that if you are going to go to the trouble and labor to remove and re-bed then he would never even consider not replacing them.
Of course at rigging shop rates it is a no-brainer but even for do-it yourselfers chain plates are not forever.
I would submit that if there is anyway you can damage a chain-plate by pulling in any direction that is generally up with the wire shroud meant to be attached to it, the chain plate is not properly designed or is damaged.
The chain plate should be able to handle much more than the wire.