No, no rudder
backup. The answer is to make absolutely certain that the rudder
is strongly attached. I am very confident in that, but at this point of being in the water
for 40 years I think it might be possible that the plywood
deep inside the fiberglass
is wet. If so that would be a concern. I'm not losing sleep about it but I would probably want to drill a few test holes before an ocean crossing
I agree with Jim about the slight delay with a trim tab, which can result in a late response and an over-correction. You really want the response to an overtaking wave to be fast so as to minimize the yaw. Pendulums should be a bit faster.