If there's no danger of it causing damage to the hull, let it swing... it should simply 'follow the flow' At sea it would be difficult to do anything with it in any event.
Last thing you want, though, is for it to jam hard to one side or the other... could be a tough situation.
I was thinking of installing a bronze eye on both sides of the rudder, near the top, and at the trailing edge. If I had a rudder failure, I might be able to tie a line to these eyes (one line on each side of rudder) and lead them up to the cockpit. then I could secure the rudder in the best case, be able to steer the boat by adjusting these lines.
Does this seem feasible? I would install some large bronze eyes during haul out fot the purpose.