I sail on a fresh water lake too, but last summer I had to swim home when my boat threw me off and kept going downwind on it's side faster than I could swim for it. Of course I was in the middle of the lake when it happened, not near one side or the other. I counted 4 power boats that passed by me in the 90 minutes it took me to swim to shore.

I waved my white hat and yelled but not one of them saw me. There were whitecaps and it's very hard to see someone (or hear them) from a powerboat if you aren't looking for them. I wish I'd had a flare (or a teather) that day!

You would think at least one of them might have seen a cat on it's side going downwind with nobody on it and maybe started looking but no. This happened about an hour before sunset, it was dark when I got to the beach, my biggest fear became getting run over by a powerboat or a close encounter with a gator. <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />

Now I clip myself to the mainsheet when I'm out alone, you can't depend on powerboats to see you.