Chuck Baier wrote:

Rodney, This is a condo marina. They will fix the problem but have no
idea how to track it down. Since it directly affects my boat I will
try and assist them in finding the source. That is why I posed the
question. Chuck

You know that, thru the AC ground lead, all boats plugged into the dock supply are connected together. If you have an aluminum
prop and your neighbour, a brass one, you're making a battery together even without problem in the dock wiring. Check if the
boats without problems are all equiped with a brass prop (or marine stainless) and if those who have corrosion issues don't.
It's just a guess but if so, I don't think the problem is with the dock wiring.

Best way to prevent that, in ANY cases, even if no apparent problems are experienced, is not to leave the shore power cord
plugged while you're not aboard. If your batteries can't keep their charge during the time you're not there, then it may be
time to replace them. Anyway, doing this while the marina checks its wiring should prevent any further problems.

Jean Dufour
Montreal, Qc