mast

Discussion in 'Multihulls' started by taezow, Sep 16, 2010.

  1. taezow
    Joined: Jul 2009
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    taezow Junior Member

    Do masts for trimarans have to be stronger than the same length mast for a mono?

    In other words, Can I buy a 30 ft mast off a mono hull to replace the 30 ft mast on my tri?

    thanks
     
  2. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    Quick answer is no.

    The righting moment on a trimaran is much higher (basically you can carry full sail for longer and the boat does not heel in gusts)

    You'd be better to look for a mast from a 35fter

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  3. Alik
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    Alik Senior Member

    On an mono, mast is usually designed using RM30 as design load, i.e. righting moment at 30 degrees heel, with safety factors of 2...3.

    On a multi, huge righting moment RM at 10-20 degrees would result much higer loads, but design practice is to reduce safety factors so the mast is not oversized.

    I would suggest to consult mast supplier on the issue.
     
  4. PAR
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    PAR Yacht Designer/Builder

    It all depends on the section you need for your boat. Yes, it's possible that a 30' mono has the same section mast as you need, but again it's the extrusion section that's going to be the key here, not if it's off a mono or not. If you know what the section of you mast is supposed to be, then this is what you'll compare. Since you've asked, it's likely you don't know the section, so calling up Dwyer Masts or some other outfit would be the best advise you could get.
     
  5. alan white
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    alan white Senior Member

    Also, there are few 30 foot monohull sailboats with the same mast scantlings. A 400 sq ft sailplan on one 6000 lb 30 footer uses a smaller mast section than a 20,000 lb 30 footer with 900 sq ft of sail.
    As PAR said, the section is the key variable, which might be the mizzen from a 50 foot ketch or off a 40 ft schooner, etc..
     
  6. ThomD
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    ThomD Senior Member

    The staying base for a trimaran is much wider than on a mono, allowing you to support the mast properly with less tension.
     
  7. taezow
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    taezow Junior Member

    Ok,

    My mast looks stout enough to be on a 35' boat. Looks way too big for my 25' tri. But that is what I need ;]
    I'll get over it looking to big.

    Thanks
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    It would be much easier if you just told us what you have and what you need. Taking a guess at what you need is a fairly sure fire way, of insuring your rig will be inadequate.
     

  9. taezow
    Joined: Jul 2009
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    taezow Junior Member

    What I have is just right. It just looked way to big for my boat, and it is heavy to raise.
    I'm sure it is good, it has been on the boat for 20 years. It looked to me like a over kill, but now I know it is not,

    thank you
     
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