Have you every heard your diver say" Hey boss, your zincs need to be replaced again" after you had him replace them a month or so ago. There are many reasons why this could be happening, but let's start with the most common problem, the marinas grounding grid. When you connect that all so wonderful shore power to your boat you are also connecting into the marina's grounding grid which all the other boats are tied into as well. Let's say that you have your neighbor that tells you his zincs are working fine and hasn't replaced them in 6 months, but your pulling your hair out replacing these suckers every month. Well as fate may have it your boat being tied into the same grounding grid as his boat your anode loss may be protecting his boat up to 40% or more. Being tied into shore power makes all of your submerged metallic structures electrically continuous with the grounding grid and every boat on you dock that is tied into that common electrical ground. This allows for your anodes protective current, (which is to be protecting your boat) to be lost to the common ground and your neighbor's boats insufficient anode protection or any ground faults associated with your neighbors boat. This anode current loss can be 40% or more which cause pre-mature anode deterioration and replacement on your boat. Not only can neighbors boats cause this, but any other submerge metallic structures that are tied into the grounding grid i.e. (Electrical conduits, Water piping, steel pipe piles, steel sheet pile, etc.)

Benefits of having a Galvanic Isolator installed on your boat:

-Extended Anode life

-Isolates your boat from any shorts to the grounding grid 

-Eliminates AC/DC stray current issues

-Protects you boat any where you plug into shore power.

-Low cost 

Happy Boating!