KSH,

When I lived in the D.C. area, I used to do a lot of windsurfing in Chesapeake Bay. I did get stung a few times, but it was not nearly as bad as a bee sting, IMHO. Still, though, if you have a sensitivity to such things, I would be concerned. And, of course, I was above the water far more than I was IN it!

Good luck!

Alex