Hull anode on GRP sailboat?

Discussion in 'Boat Design' started by skippeer, May 5, 2019.

  1. skippeer
    Joined: Feb 2019
    Posts: 10
    Likes: 0, Points: 1
    Location: Sweden

    skippeer Junior Member

    I have read that a zinc anode only protect metall components up to 50-60 cm.
    I have a GRP sailboat build in Sweden (The Recreational Craft Directive, Directive 94/25/EC), no bonding, lead keel and isolation transformation for 230 Volts shore power.
    On the middle of the hull do I have a hull zinc anode which I can't figure out the function of, it is 4-5 meter to rudder, propeller and thruster.

    I am considering to remove the hull anode next winter but before that I need a second opinion.
    Is it useless on my sailboat or what is it protecting?
     
  2. Blueknarr
    Joined: Aug 2017
    Posts: 626
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    Location: Colorado

    Blueknarr Senior Member

    Any metallic thru hulls?
     
  3. skippeer
    Joined: Feb 2019
    Posts: 10
    Likes: 0, Points: 1
    Location: Sweden

    skippeer Junior Member

    No cable from hull anode to any thrugh hull fitting (made of marine bronze), all thrugh hull fittings are isolated in line with European standards (they are different compared with American standards).
    To be honest I have not yet been able to follow the inside cable from the hull anode due to it's hidden path behind warm water heater, air heater + misc. yacht components.
     
  4. JamesG123
    Joined: Mar 2015
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    Location: Columbus, GA

    JamesG123 Senior Member

    If there is a cable going from the anode to something then it probably had a practical purpose at one time. Might still be, or whatever it was protecting might have been removed. Yes an anode in isolation on a GPR hull is pretty much useless.
     
  5. Dejay
    Joined: Mar 2018
    Posts: 315
    Likes: 42, Points: 28
    Location: Europe

    Dejay Senior Newbie

    You could check with a multimeter / continuity tester if there is an electrical connection to the anode.
     

  6. skippeer
    Joined: Feb 2019
    Posts: 10
    Likes: 0, Points: 1
    Location: Sweden

    skippeer Junior Member

    okay, you support my thought to remove the hull anode now when there is no metal fitting within 2 feet.

    I will investigate the cabling from both HF ground plate and the hull anode this summer.


    Thx for the help
     
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