catalina 320 galvanic isolator

[catalina453]

I am a new owner of a 1997 catalina 320. I have experienced rapid zinc deterioration in salt water. I installed two zincs on the prop shaft in October. Today one is gone and the second was reduced to 1/3 of the original size. At the surveyors recommendation I installed a connection between the ac and dc grounds. The electrical diagram shows a galvanic isolator on the ac ground. could the isolator have failed or could there be another cause?

 

[JK_Boston_Catalina310]

Yes, it is absolutely possible that the galvanic isolator failed. I am not sure if that would lead to the rapid zinc loss you are experiencing but it is still something worth checking first.

Maine Sail has a How-to article on Testing a Galvanic Isolator. The one he tests is the exact one that Catalina installed in my boat (or maybe the commissioner, not sure when it was installed).

Anode compatability is something else to consider. There are a number of posts about picking the correct sacrifical anode for your home port. Here is a decent article to start your research.

Good luck and fair winds,

Jesse

 

[Calif. Ted]

Even without a galvanic isolator 2 propshaft zincs reduced to 1/3 of a zinc in a month is "alarming", I can't think of a better way to put it. There's a lot of electrical current traveling a path it shouldn't. Check your isolator first, but I'd expect a stray current either from your boat, a neighboring boat, the dock wiring etc.
Records aren't exact but the hull history of the Cat320 association show that Isolators weren't installed until sometime just prior to hull 492 in 1998. Start looking for that isolator, maybe it's not there.

 

[centerline]

in addition to the galvanic isolator failing, something else is wrong... either with your boat or one not too far from it....
the galvanic isolator can help protect your boat from the symptoms of stray voltage leaks, but it will never cure the problem, so when the isolator fails, the boat suffers even more.