I am a beginner of sorts, have a80% roll and have done the tuck a number of times with no problems so when some friends asked if i wanted to do the natty i thought id give it a try.
   It was rainy and VERY foggy.  I started below pattons run and we were going to take out at surfing rapid.  The problem was that while the others in the group were very experienced I needed more time for course corrections and didnt have it due to the fog.  I got to the rapid just up from going under the bridge (just above the park with restrooms etc).  Went thru the big wave and then got sort of sideways.
   Thats when the shit hit the fan.  Upside down in a flash.  No big deal I thought, Ive done this before.  Except that as I flipped i ended up on the back deck with my head being dragged and bouncing on the bottom.  I have read that if you just keep your cool since you have allready hit the rock you can recover.  Ok I thought.  It was at about that time that a rock ripped my paddle from my hands.  
   Now i thought that might be a bad sign and decided to bail.  The only thing was I was still pushed against the back deck and couldnt get to my grab loop.  It was at that instant that I hit a rather big rock underwater and the force of that rock actually pulled me out of my cockpit.  Id like to find the rock and thank it as I think my only option at that point was to fill my cockpit with fecal material (due to the fright lol) and use it to push myself out.
   The swim while cold wasnt bad but I must say that the thirty or forty seconds that all the mahem took place in will stick in my mind.