Peter,
Please include a pic of the failed part.
There is the shoe at the bottom of the rudder (embedded in the keel), a collar on the inside of the shaft tube (which serves to prevent water backflow, but also does a fantastic job of preventing re-insertion of the rudder back into the boat, serves no real purpose and often gets removed), and the top-of-the-shaft flange, visible in the cockpit underneath the tiller, which gets through-bolted to the fiberglass cockpit.
Did ES have any estimate on backorder wait time?
Bud Brown