I recently flipped (and Partially turtled) my 16 when i was by myself. Kind of a scarey thing, but I did not panic.
I have a righting back, but I could not adjust the line correctly so it did not work. I even had the masthead about 4-5 feet underwater.
I'm still not sure how I did this, but I was able to walk with the righting line as far back on the cat as I could, and as I sunk the transom, and jumped onto the rear crossbar, the cat went completely turtle but with the bows up, kind of like one of those dolphin tricks at Sea World hi hi. Anyways with the momentum I completely brought the boat capsized on the other side. With the mast up out of the water, I was able to sail the boat on it's side with the tramp on to the lee shore of the bay.
Then I just walked the mast up using the shrouds, and once the boat was back up, I hopped on and went out for some more fun
That day was fairly windy too, everyone else had 2 or three people on their cats. My friend was there to get pictures (Though he got none of the capsize
), so I felt very proud..