On Thu, 2 Jul 2009 08:50:46 -0700 (PDT), Frogwatch
wrote:

Assume a storm is 10 km X 10 km which is 10^8 m2. If you sail under
said storm and stay, your (my) sailboat is then 10^-5 of the storm
area. We have to guess the number of cloud to ground strikes for a
storm and multiply by it to get our probability for getting struck if
you insist on sailing into a thunderstorm. I think this number will
come out to anywhere from .001 to .01.

Somewhere back in the late '80s/early 90s, a group of about 200
sailboats went into a severe thunderstorm during a race on Long Island
Sound. Three boats were hit, one twice, empirically sounds like .02