Thanks for the replies. Sorry, I was unclear. My boat is on a hook,
miles from any marina, with only one boat on another hook a hundred
yards away. To the best of my knowledge, he has no issues with his
zincs. My battery switch is off, with the bilge switch being the only
thing powered on the entire boat. This bilge switch in the bilge is new
within the last year. The connection to it is out of the bilge water.

A salvage guy who does work for me said it could be the bilge switch
eating away my zincs. Does this seem feasible? Larry and Brian, should I
still follow your recommended tests considering the above?

Stephen