Daggerboard trunk?

Discussion in 'Multihulls' started by andysailor, Aug 27, 2018.

  1. andysailor
    Joined: May 2017
    Posts: 70
    Likes: 2, Points: 8
    Location: Sweden

    andysailor Junior Member

    I have a daggerboard in the mainhull of my 44ft trimaran. So far I have not been sailing the boat, but been rebuilding it for a year so far. Because I have never sailed a boat with daggerboard before I just don't have any experience on different layout of trunks. Sorry but at the moment I don't have any photos.

    My question is about how these kind of trunks are constructed. Where are the loads? This seem like a big trunk, not a trunk where the daggerboard just bearly fits. There is room inside when the daggerboard is in. (we took the daggerboard out just when we got the boat).

    I have seen on the inside of the trunk there is a lot of unevenness, wondering if this comes from the load from the daggerboard? I would lilke to know more how this kind of trunk works and are constructed (so I also can look for weak points)

  2. peterbike
    Joined: Dec 2017
    Posts: 71
    Likes: 25, Points: 18
    Location: melbourne

    peterbike Junior Member

    Andy, where is the extra room inside the case ?
    Is it on the fore & aft line ? ie; in front & behind ? or all around the c/board ?
    How much is the "unevenness ? 10mm or 100mm ?
    One thought is foam is often put in as crash blocks which are sacrificial - if you run aground - usually in front & behind - but someone may have put it all around ?
    Or it is not the original board ? maybe from another boat ?
    happy travels, Peter
  3. andysailor
    Joined: May 2017
    Posts: 70
    Likes: 2, Points: 8
    Location: Sweden

    andysailor Junior Member

    well, I know a photo would have helped a lot :)
    The trunk itself it rectangular shaped. The daggerboard is oval shaped but has some rectangular shape in upper part.
    In the lower part of the trunk there is a delrin plate (maybe an inch thick) with the shape of the daggerboard cut out.

    The unevenness in the trunk is more or less all over, small like 30-40 mm (If my memory is correct). I think it's built in ply and glassed over.

  4. JamesG123
    Joined: Mar 2015
    Posts: 654
    Likes: 76, Points: 28, Legacy Rep: 10
    Location: Columbus, GA

    JamesG123 Senior Member

    The rectangular part of the daggerboard (the "root" if I remember right) should have a bosses (or just holes) for mounting delrin bearing blocks but maybe not depending on how fastidious the original builder was. The trunk interior itself does not really need to be smooth or even symmetrical as long as it doesn't bind up the board.

    That delrin plate not only supports the daggerboard's weight and keeps it from falling out of the boat, but also transfers its loads against the bottom of the hull and trunk box thru it.
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