Internal or external chainplates?

Discussion in 'Fiberglass and Composite Boat Building' started by San Juan Sailor, Mar 23, 2009.

  1. San Juan Sailor
    Joined: Mar 2009
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    Location: San Juan Island, WA.

    San Juan Sailor Junior Member

    I'm restoring a 32' Mariner ketch. A previous owner had replaced the mizzen chainplates with external ones. I'm not sure of the reason yet. So I'm wondering if anyone has any opinions or preferences about internal or external chainplates. I could go either way at this point.

    I have a boat restoration blog going;
  2. dreamer
    Joined: Nov 2004
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    Location: Minnesota, USA

    dreamer Soñadora

    I think the current issue of Sail magazine has a brief discussion on this. In the article, the old chainplate corroded in half. That would be my guess with your boat. That or they were pretty close to corroding.

    If it doesn't matter to you, I would think external chainplates would be the most worry free. At least they'd be easy to inspect. Just make sure you've got the 'knees' for them (backing).

    I would guess you don't see external chainplates much just because they are not the preferred 'look'. Technically they'll give you more support than internal chainplates.
  3. Landlubber
    Joined: Jun 2007
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    Location: Brisbane

    Landlubber Senior Member

    Old Chinese boats were prone to glass in stainless steel chain plates, a bad idea at anytime.

    Stick with the external plates mate, they are honest, and visible. Corrosion from locking out the oxygen is an undesirable consequence of burying ss.

  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    From a performance stand point check to see if you inboard chain plate locations, interfere with the boom's travel when the sheets are well eased out. If you need more boom travel, then an outboard mount will offer a little.

    Other considerations are leak potential (as previously noted by others) chaffing other boats in a "rafting" situation or at a dock, where the exposed chain plate fasteners can carve right through a boat parked next to you in short order.

    Headsail sheeting angles aren't an issue. Mizzen mule sheeting angles shouldn't be an issue either.

    External chain plates are easy to inspect and easy to bed. They aren't as "modern" as internal and may not be in keeping with the rest of the style of modern yachts, but yours should have no difficulty with this aspect.
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