This has to be galvanic corrosion, correct?

[shimari]

Originally Posted by boatpoker

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You can go to ABYCinc.org to find a Certified Marine Corrosion tech or buy one of these to plug into your multi-tester and track down the issue. There are others on the market but this one comes with a pretty straight forward booklet that tells you how to do it. https://www.boatzincs.com/corrosion-...electrode.html

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Thanks for that link. I'm glad to see they've lowered the price considerably since I last looked at getting one.

[Icarus]

Originally Posted by EmeraldCoastSailor

Seems like all of a sudden a few months ago I started suffering serious damage to my iron keel. My yard guy thinks it is from an electrical problem on neighbor boats. I am fixing the boat but not sure I can do much more than hang a zinc fish. 2009 Beneteau 343

Your cast iron keel is corroding... Not electrolysis
However, check your earth leakage transformer

[GordMay]

Originally Posted by jamhass

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We were in a marina and found our zincs were eroding rather too fast. Boat for sale next slip over looked a bit dodgey, with a questionable electrical cable etc. Moved to a different slip, problem went away...

That bears a disturbing resemblance to the argument, used by a sailor, who, when asked why he called a purple powder, that he sprinkled around his dock ''elephant repellent,'' replied, ''Well, you don't see any elephants around here, do you?''

[EmeraldCoastSailor]

Update on my situation:
I am in the process of getting testing gear and some professional help. I failed to mention earlier that the boat on my port side developed a leak that switches on bilge pump every 20-30 minutes. The leak developed about 3-4 weeks before I noticed something wrong.

I confirmed the neighbor's boat has an old float switch and that there are hot wires in a wet bilge. Lots of research and I hope I can professional assistance soon. I hate that my suspicion is centered on my neighbor's boat but if you saw it you would understand. Of course it might be something else.

My iron keel has a nice thick get coat of course with primer and paint. The stray current blew off the protective coating and it looks like someone took a pickaxe to my keel. Pieces are just gone. No issues on shaft or prop.

Crazy!