Anodes

Discussion in 'Boat Design' started by rfleet1066, Dec 7, 2015.

  1. rfleet1066
    Joined: Feb 2012
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    Location: New Kent, VA USA

    rfleet1066 rfleet1066

    My river boat is about ready to launch. I need to affix anodes and need guidance as to amount and placement. Please advise.

    Ryland
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    You need to post more information. For example, size of the boat, material of the hull, shaft, propeller, drive, etc. materials.
     
  3. rfleet1066
    Joined: Feb 2012
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    Location: New Kent, VA USA

    rfleet1066 rfleet1066

    Specs

    She's a tri-hull pontoon, 60 feet long hulls, 60" diameter each, 3/8" thick steel, one Cat diesel long tail drive, calculated 9 knot top speed, 6 knot cruise at 2.5 gph, 85000 lbs empty, deck capacity 35000 lbs, 26" waterline loaded. Protected waters.

    Ryland
     
  4. Barry
    Joined: Mar 2002
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    Barry Senior Member

    http://www.performancemetals.com/anodes/AnodeFAQs.shtml
    Some good info here. The missing information is the amount and size of the anodes.
    A factor in your boat will be of course if it is painted to limit the area of exposed steel to the water.
    Might be worth a call to these guys to get some sizing
     
  5. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    360 ft of hull surface is quite a stretch. I would use aluminum strips, approx 20 sq.in. every 10 ft, mounted with stainless bolts.
    Shaft and prop need extra protection, like a 2-part cylindrical electrode clamped on the shaft.
     
  6. rfleet1066
    Joined: Feb 2012
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    Location: New Kent, VA USA

    rfleet1066 rfleet1066

    Anode Alloy

    Is there a particular aluminum alloy that is best?

    Ryland
     
  7. Barry
    Joined: Mar 2002
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    Barry Senior Member

    If you looked at the Performance Metals link that I posted, they mention/suggest Navalloy, which has some other elements in it.
    It would be worth the read.
    An interesting point is that an anode can oxide over and limit the effectiveness of the anode. The Navalloy (which might be their proprietary alloy but other anode manufacturers might have their own equivalent) is supposed to be better than ordinary alloyed aluminum
    On the other hand it might be just hype
     

  8. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Any alloy can be used, even the very cheap ones like "Zamac" that contain a large percentage of zinc, although the lifetime is shorter.
    I would prefer a construction alloy, containing mainly Al, Mg and Cu. The surface must of course not be anodized or coated.
     
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