Two meter troll wrote:
....
do folks actually have the rudder it self fail or is it normally some
system connected to it?
Ive had the cables or chains or hydro fail. but never had a rudder
actually fail. most times I had a mechanical back up system or a
tiller so it might have been a little inconvenient but not earth
shaking.

My first keel boat was a Paceship Eastwind, similar to a Cape Dory 25.
The rudder was cored, and the coring had rotted a bit, allowing the
paddles that were welded to the post to wiggle. We opened it up and
filled it with epoxy. It wasn't close to failure, but I could imagine
the paddles breaking through the side of the rudder. I could also
imagine the weld failing if there was a hidden weakness.

My hunch has always been that the most common failure was a bent or
broken post, because they are often undersized on cheaply built boats.