On any cat, if you have time to sit down, sit down and hold on. Unhook when the boat comes to rest, climb down quickly to avoid turtle.
If the capsize happens quick, try to dive behind the main sail, you may break the shock cord, but you will be clear of the sail. My old 20 sail has a head dent from a crew that landedon the sail, but if it was a Tiger main, he would have gone right through.
Sometimes there is nothing you can do so ripping a sail is far better than injuring yourself on any hard piece of equipment. Avoid the boom.