Not that I would endorse this, BUT...

Flying a flag upside down is generally accepted as a distress signal. I think that could apply in this case. Here's a good one to use:

http://store.ussailing.org/viewItem.asp?ItemID=72900&UnitCde=1&Desc=Small Rectangular Burgee&Search=N

Hey, if you join, you can even save $5! More benefits of joining!

Mike