I'll bet that there was a little more play in the rudder around the casting, which tipped them off to bigger issues.

Before any race of that magnitude, I'd probably do the same thing. I mean, who wants to break down in the middle of a 500 mile race because of something really stupid (like a rudder arm breaking) that could have been prevented?

Team Fully Involved had a pretty good idea, too. They put a clevis pin(?) instead of rivets on the rudder arms. This allowed the rudders to be interchangeable in case the one they needed was damaged. They'd just switch with the other one, flip the rudder arm upside down (so the elbow curved the correct direction), and reattach the crossbar & tiller extension (so the damaged rudder was on the windward side).

And those beams weren't seated in epoxy before? Your boat will be a bit faster now that its dry and stiff....