(Actually it was our back pad eyes that had the issue and not the ones
for storing the running backs...)
It seems those backing plates were added by someone here in California
during commissioning (China Doll was FOB to Long Beach on the back of
a freighter) and used the wrong type of metal.
Both of ours were replaced with an appropriate plate before they got a
chance and failed. They were fairly accessible under the headliner and
didn't match how any of the other backing plates were installed on the
boat.
A friend on a Vancouver 42 did a neat trick with his system by having
them on a retractable T-Track. To deploy, he would simply use his lazy
jib winch and pull the rope (fitted on a t-track fairlead outboard)
and to put them away, a cord would pull the fairlead back all the way
forward where the running backs would store next to the aft lower
shrouds on the mast outboard.
With this system there’s no need to go out of the cockpit to use or
store the running backs and with his deck-stepped mast, he is able to
build a tight strong resultant force triangle with the staysail tack
and keep his rig taught and not fatiguing by wiggling around when
under a load with a staysail.
-Rob.