I had a friend of mine that got stuck for a couple of hours turtled on a Viper 21 (21' sport monohull) off Hilton Head. He had to wait until a powerboat would help them pull the boat back on it's side. By then the keel-stepped mast had warbled a big hole in the top of the deck. A little later while cranking up the keel in preparation for putting it on the trailer, the eye pulled out of the top of the keel and it went straight to the bottom.

We later talked about how he might have had some luck by hoisting a couple of life vests or the throwables he had on board up the spinnaker halyard...hindsight is 20/20.