With respect to the grounding thing, it had been said that you could survive a lightning strike in a pool by not touching the sides or bottom (and therefore grounding yourself).
While not having the "bravado" to test this theory (see aforementioned freezer comment <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> ), I guess lessons from underwater welding could be loosely translated to this larger scale. The arc welders they use can do some damage if you're not careful.
So, by not being grounded in the first place (on the water), you stand a slightly better chance of not being a conduit for the lightning?
I'm still of the belief that when your number's up, there isn't much you can do about it...