On paper I have sketched out a few ideas for a "backup rudder" - something to get me out of trouble if, for any reason, the usual rudder is out of action and repairing it is not an easy option.
Today I knocked something together as a trial:
The general idea is that the wooden bit (presently being varnished) is strapped behind the back seat - using a roofrack strap around the hull (or preferably tied down to the fittings on the deck just behind the seat). The hole will stick out the side of the boat about 6". The straps in the pic are to hold the "end" of the wood in place (it detaches).
The following paddle/rudder will live in front hatch. The brown stuff (not quite finished) is plumber's putty epoxy mix (will spray the brown stuff black). Looks mad but is very strong and adheres to anything.
I made this rudder from a carbon Dragonboat paddle (Ebay) and a section of paddleshaft from a split paddle.
Hope to test it in a few days...