Having rebuilt my own rudder, I'm very aware the stresses a rudder is under at all times. Rudders are an achilles heel on a boat, and they can age "nicely", if not exposed to severe conditions. A content sleeping dog.

But when you increase those forces dramatically, such as conditions many of those boats were exposed to, my feeling is for every hundred boats on the water today(many are older), a few would suffer rudder problems, inevitably.