Brushing your anodes

[steve77]

Our boat Orontes II is an Amazon 49, a steel cutter built in Canada. While speaking with the owner of another steel boat, he asked how often I brushed my zincs. I gave him a blank look.

He said that he regularly dives on his boat to brush the zincs to remove the oxidized layer and ensure he had good protection from his anodes. He said the oxidized layer prevents proper operation of the zinc anodes. I've never heard of this, and thought I would ask if I've been missing something.

Anyone heard of this or regularly do it?

Cheers!

Steve

[tkeithlu]

First, "aluminums" are more appropriate for a steel boat, such as ours.

I don't dive anymore, but I've been using the same 28 aluminum plates for nine years. About every two years I pull the boat and replace the 14 anodes, take the old set, wire brush them, and set them aside for the next haul out. They are pitted beyond reading the cast lettering, but still have lots of surface area - in fact, more than when new given the pitting.

In the meantime, and as a way of knowing that the job needs to be done, I use a silver reference electrode, such as the one cited below. It goes over the side, and my multimeter goes between it and the hull/bonding. As long as I've got more than -1.0 volts, the anodes are fully doing their job. I pulled the boat at -0.9 volts this spring.

Diving them to achieve the same end sounds fine. You can use air tools - just store them in a plastic bag with vegetable oil between uses.

https://www.boatzincs.com/corrosion-...electrode.html