Bummer. I feel your pain. Most of the accessories, like pumps, lights, most gages, and odd motors should not be damaged by a short reverse voltage. The electronics, like the perfect pass, radio, trim tab module and engine control module may be permanently damaged, though. Breakers and fuses are no help, as they only sense the amount of current, but cannot tell which direction it is flowing. A simple diode will prevent damage...but most electronics don't provide one in their circuits.