I didn't want to dilute the post "Rudder Loss Solutions" viewtopic.php?f=71&t=47343&start=15
because I think what Tonystott has now come up with is quite ingenious! For new comers who've never experienced a broken rudder line, having a Plan B is a really good idea. Just try sailing your boat without your rudder sometime.
Some of us carry a straight blade paddle like the one shown below, (it's just too difficult to steer with a curved one). I made this from an old canoe paddle and lightweight 1" aluminium pipe. It measures 72" long, has a pvc handle and it's filled with spray foam insulation so it floats. I know I posted some pictures a long time ago when this topic came up, I just can't find them now.
I've used it many times, even if I have to just pull my rudder up to go over shallow areas while still sailing. One day when I caught a crab trap rope and my rudder line went POP, I was able to steer quite well, into a pretty strong headwind, all the way back home.