isolated backstay construction

Discussion in 'Sailboats' started by wndsnd, May 9, 2006.

  1. wndsnd
    Joined: May 2006
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    Location: Massachusetts

    wndsnd New Member

    My 1969 D&M Classic Tartan 37 has an isolated backstay. I do not know it's age. There seems to be a top and bottom nut that is screwed into the isolator. Each nut seems to be secured with a stainless ferrule to keep them from backing out. Each ferrule is cracked.

    Can some one explain how the backstay is constructed. Does the stay continue through the isolator or is it swaged top and bottom. Are these ferrules as I suspect part of a system to keep the swages from backing out? Or, are they part of the construction of the stay itself.

    My big question is the stay subject to failure because of these cracks.

    Thanks
    Windsound
     
  2. MikeJohns
    Joined: Aug 2004
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    Location: Australia

    MikeJohns Senior Member

    Some insulators came out with norseman type fittings. These rely on a cone shape spreading and squeezing the strands to make the attachment.

    Unless you know the brand of insulator you are going to have to remove the stay and pull things apart to check it. Loss of the backstay would likely mean loss of the rig under sail.

    To remove, slacken the forestay a few turns, lead a halyard aft and tighten it up or use the topping lift (as a temporary backstay). The backstay should now be slack
    Attach a line to lower the stay on ( you don't want it falling to the deck)
    You can knock the pins out or remove the shackles and down she comes, it's actually a very easy job, but be careful up there !

    Hope this helps
     
  3. wndsnd
    Joined: May 2006
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    wndsnd New Member

    Thanks Mike,

    Is the insulator designed to separate the back stay mechanically? I am unsure of it's function. I believe it is to use the back stay as an antenna for a radio ssb. However I don't understand how it works.
     
  4. MikeJohns
    Joined: Aug 2004
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    MikeJohns Senior Member

    Yes there is an interlocking mechanical arrangement filled with ceramic such that the ceramic is only in compression from the wire stress, the internal metal parts do not touch . There should be two of these normaly and the section between is connected to the SSB radio output.

    Cheers
     
  5. Buc
    Joined: Aug 2005
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    Location: Olympia

    Buc Junior Member

    Navtec, one of the makers of backstay insulators, indicates their units will not last as long as the wire and should be replaced after a maximum of ten years. If you see cracks anywhere, it's probably time.

    If you don't plan to install a ham or marine SSB radio, you're probably better off replacing the backstay with straight 1x19 wire.
     

  6. wndsnd
    Joined: May 2006
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    Location: Massachusetts

    wndsnd New Member

    That is the plan. It is better safe than sorry.

    Thanks for all the input
    Windsound
     
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