Haloing ?

[Viking76]

I was advised that I have haloing around my hull zinc plate. It looks like an irregular circular pattern loss of bottom paint around my hull zinc plate. This zinc hull plate was added approx 5 years ago and connected into the bonding system. I was told that I may have too many zincs. Can you have to many zincs? It was added because the shaft, rudder, and trim tab zincs barely last thru the season. Haloing? Cause? Fix?

 

[Billylll]

I have never heard the term Haloing. However you may have stray current from a miswired dock pedestal to another boat near your boat. If you have the ability to measure stray current I would start there. The problem could also be on your boat with a DC wire laying in bilge water to bad connections on the bonding circuit. Also does your barrier coat contain copper or some other metal oxide in it?
I am thinking out loud.
Bill

 

[Billylll]

I assume your boat is a Viking? Are you on a mooring ball, stand alone dock or a marina?
Are you always hooked up to AC power?
Bill

 

[pdecat]

usually stray current. You will find alot of info online about proper zincing and measuring and looking for stray current sources. Haloing is a common term for bottom paint erroding near zincs.