Yessssss!!! I wonnnnnn!!!! I got that #!**#*! rusty bolt off my forward crossbar without braking it offff!!!!!
Whew! the thing was so coroded that the top 1/2" of thread is gone. But I did it!!
Now on with the hull repairs
good job, im trying to get the plastic bolt out of my rudders for the cam that is stuck down. Ive been letting some oil soak in there. Anyone got any ideas?
search the H16 forums.. thats been covered a couple times 
I heard that they burn them out with a welding torch or something. I have the same problem with that but for now I'm managing.
if i cant get it out, ill drill it then burn the rest out.
I have the same problem and was told just to leave it in place as even if you get the plastic screw out, you'll never get another one in.
My problem was that the pressure was too much for the cam so the cam couldn't rotate. I ended up pulling the cam out of the top with some pliers, gently fileing the edges of the cam so it could go back in the hole, and cutting the spring slightly to shorten the length, now I have no problems with my rudders.
Turn your rudder upside down and clamp it to something solid. Take a drill with a bit a little smaller than the inside of the threads. When you start drilling the screw out, it will normally break free and start spinning. If it doesn't, after you drill the screw out, peel the remaining plastic away with a screwdriver. When you put the new screw in coat it with anti seize.