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Zinc / Magnesium / Aluminum - Anodes

Discussion in 'Technical Discussion' started by W. Arthur, Jun 24, 2011.

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  1. Capt J

    Capt J Senior Member

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    Along with zinc anodes, the saltwater package was freshwater cooled, versus the raw water cooled that came standard at the time.
  2. W. Arthur

    W. Arthur New Member

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    Marmot - TY for input on aluminum and zinc. As per info learned so far; I feel currently boating year round in fresh water with inboard through hull shaft that I should change all anodes to magnesium next go round (instead of the zinc I currently use and fastidiously wire brush to keep its surface clean). Do you feel the mag is a better “next choice” anode for my inboard than aluminum... AND... should mag be wire brushed on a regular basis, similar to zinc? Seeing as my pencil anodes in engines and water heater are also zinc, should they too be changed to mag? Any input you may provide re mag and pencil anodes is appreciated. Happy boating!! W.
  3. W. Arthur

    W. Arthur New Member

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    FISH - Corrosionist link you provided has some deep insight via its numerous links. Will take a bit of time for full review/understanding. Again... Thanks for supplying that link! - :D W.
  4. Marmot

    Marmot Senior Member

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    If I were landlocked and only exposed to freshwater (and could obtain them in the sizes needed - and that may be problematic) I would be comfortable using magnesium for all the anodes including the pencils and water heater. More than likely you already have a magnesium in your house water heater.

    As far as brushing them off, if it makes you feel more comfortable it can't really hurt. You will probably cause more damage constantly pulling pencils just to brush them than they will prevent.

    The "secret" to anodes is providing a material that will go away (at an acceptable rate and cost) before the stuff you want to keep in the electrolyte surrounding both. If you need to protect aluminum, sacrifice some magnesium.

    The best insurance you can provide is to make sure you don't have any electrical leakage within the boat and are not exposed to stray electricity at the dock.
  5. Loren Schweizer

    Loren Schweizer YF Associate Writer

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    In other words, install a galvanic isolator with an audio alarm.
  6. W. Arthur

    W. Arthur New Member

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    Loren - Have you recommendations re galvanic isolator manufacturers / models with auto alarm that would best afford protection on a tri cabin twin screw trawler/cruiser... that will likely be kept in fresh water for years to come? We berth, cruise, and anchor out deep into CA SF Bay Delta's 1,100 miles of fairly deep draft, levy lined channels (12’ to 30’ deep) with full-on rivers near and many islands as well as some great towns/cities to visit. Sacramento and other cities on deep draft rivers (40’ to 75’ +) in the delta are cargo-ship supplied via SF Bay GG Bridge. Year round fresh water feed comes from Sierra Nevada Mountains' snow pack run off. We used to dock in SF Bay salt water. Been in SF Delta since April 2009. - Thx, W.
  7. T.K.

    T.K. Senior Member

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    We fit the Victron Energy isolation transformers to our boats.
  8. Fishtigua

    Fishtigua Senior Member

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  9. W. Arthur

    W. Arthur New Member

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    Hello Fish, and, TK-F430 (We fit the Victron Energy isolation transformers to our boats. Life is a game.....)

    I thank you both for galvanic isolator product recommendations. I will review and proceed as determined. I've never left any boat I've owned connected to shore power while it rests at berth; always leaving it connected to dock only by mooring lines with battery banks fully charged and isolated. With a boat held in this condition/position in fresh water, does your experience show that it would be better to keep it connected to shore power and therefore use an isolator? How about a boat held in same condition/position but in salt water rather than fresh... with the salt's approx 10X conductivity ratio compared to fresh? Again, thanks for your input! - W. :)
  10. Loren Schweizer

    Loren Schweizer YF Associate Writer

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    W. Arthur:

    Guest, Newmar, Mercury/Quicksilver and others can supply you with what you need.
    At least one large US yacht manufacturer installed the Merc unit on all their models and it had a buzzer as an alert.
  11. W. Arthur

    W. Arthur New Member

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    Thx, Loren... I'll check em out! - W.