Carbon Fibre Masts

Discussion in 'Boat Design' started by Wynand N, Feb 4, 2005.

  1. CTMD
    Joined: Dec 2007
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    CTMD Naval Architect

    There is no reason why you couldn't use a foam core, the trick would be to pre-laminate is with some uni each side before ripping it up for stripping. Alternately you could put some of the external laminate on flat sheets and then kurf cut the inside until it sat happily in the mould.
     
  2. Eric Sponberg
    Joined: Dec 2001
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    Eric Sponberg Senior Member

    Without knowing all the details, I would not comment on the suitability of one mast design over another.

    Righting moment is always the same and does not change. Heeling moment changes with conditions.

    It is OK to reduce safety factor, so long as you understand the implications of what you are doing. In America's Cup competition, safety factors are a little more than 1.0.

    On a multihull, an unstayed rig is not the most efficient form of rig where cost and weight are concerned. A stayed rig is a much better solution.

    On a free-standing rig, a cored carbon laminate will be heavier, harder to make, and more expensive than a solid carbon laminate. This is because a cored laminate achieves it's advantages when the load acts normal (perpendicular) to the skins. In a mast, whether free-standing or stayed, the load acts parallel to (within the plane of) the laminate. So core adds little to no effect in a mast.

    Eric
     
  3. terhohalme
    Joined: Jun 2003
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    terhohalme BEng Boat Technology

    Eric and Alan,

    my catamaran parameters include now righting moment for rig design. It is somehow different from my previous post, but it is done according ISO/DIS 12215-9.

    Terho
     
  4. Archim
    Joined: Apr 2008
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    Location: Barbados, W.I.

    Archim Junior Member

    Draft ISO/WD 12215-9

    From WD_12215-9__E_-2004-03-02.pdf (which is not the latest DIS document), one can read :

    9.2.2 Design heeling moment for sailing multihulls
    For large sailing multihulls, the righting moment is so huge that it would not be realistic to assess the load on rig by equating heeling and righting moment. Therefore for multihulls, the design heeling moment is taken when the fist reef is taken, as calculated in ISO 12217-3, unless the boat is stated by its manufacturer to be designed to "fly a hull". [To be implemented]

    and

    9.4 Distribution of heeling moment between several masts
    For multiple mast rigs the maximum heeling moment of each mast is to be determined on basis of the sail area moment, SAM, of each mast

    Terho, is it the same in the DIS document ?
     

  5. rob denney
    Joined: Feb 2005
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    rob denney Senior Member

     
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