Radar, gps, bag of potatoes. When your power quits, and you''re in the fog, keep throwing potatoes. When you don''t hear a splash, you''re near a ledge. Otherwise get your tides figured out (20+ foot in the Bay of Fundy with some pretty wild whirlpools), a good set of charts and make sure you know where the CAT (high-speed catamaran that runs Bar Harbor, ME, to Nova Scotia) runs and stay away from its route. They''ve managed to kill one lobsterman in a wooden boat in the fog......