Books/regulations/articles on large sailboat rig sizing

Discussion in 'Sailboats' started by Claudio Valerio Parboni, Oct 23, 2019.

  1. Claudio Valerio Parboni
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    Claudio Valerio Parboni Junior Member

    EDITED for Clarity

    I am currently studying a Master's Degree in Superyacht Design, and I've been given an assignament to design the hull, interior and produce a weight estimate for a 40m sailing yacht.

    I am trying to establish the weight of the rig as it greatly affects VCG.

    I know I could go through BV or other rig sizing regulations, but given it is outside the scope of my assesment and given that this is only an early stage of the design, I'm looking for a quick estimate of what the mast weight will be.

    I already have established the dimensions for my hull, sails and appendages, but finding data for superyacht rigs is not very easy, hence my struggle

    I understand that my original question might not have been clear, but please don't worry about my knowledge and what I should and shouldn't do about my studies, this is something I believe is not for your interest.

    Otherwise, thanks for your suggestions.
     
    Last edited: Oct 26, 2019
  2. Alik
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    Alik Senior Member

    Don't start from superyacht design, don't jump over Your head. Start from dinghy, then go to yacht, and only then to superyacht ;)

    Sizing of sailing rig - see BV rules for yachts.
     
  3. bajansailor
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    bajansailor Marine Surveyor

    AliK has given you very sound advice Claudio.
    And it does sound like you don't know too much about yacht design - what was the subject of your first degree?
     
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  4. gggGuest
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    gggGuest ...

    AIUI most commercial design courses major on motor craft. This may simply be the first time the OP has had to consider a sailboat. But I suspect few people here are really qualified to offer anything very useful at that sort of scale. However he is simply asking for suggestions on appropriate resources so should any of you know any then post, preferably with enough detail to enable the OP to actually locate the resource in question.
     
  5. TANSL
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    TANSL Senior Member

    This is a statistical study based on more than 100 sailboats and allows a previous sizing of a new project, providing values for the various variables involved in its design, main particulars, surface of sails, position of the pressure center and many other things. I hope it helps.
     

    Attached Files:

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  6. Claudio Valerio Parboni
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    Claudio Valerio Parboni Junior Member

    I have a bachelor's degree in yacht design, I believe I know enough about yachts under 24m.
    I know you can use BV, but it would take too long given that rig sizing is not even in the scope of my current assignment, I'm searching a quick estimate for a preliminary weight and VCG calculation
     
  7. bajansailor
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    bajansailor Marine Surveyor

    My apologies Claudio, I (and no doubt many others ) got the impression that this was your first foray into yacht design.
    Re your bachelor's degree, do you have a copy of Skene's Elements of Yacht Design?
    If not, it is a very useful book, never mind that it is rather old now.
    Here is a link to this book available on the Italian Amazon.
    https://www.amazon.it/Elements-Yacht-Design-Norman-Skene/dp/1574091344/ref=sr_1_1
    Chapter IX is about Spars & Rigging; the book describe's Skene's 'short' and 'long' methods for determining rig loadings, and then you should be able to calculate scantlings?
    I used Skene's 'long' method for a design project many years ago to calculate rig loadings on a small sailing cargo vessel - this was only a pipedream, but the method seemed to work ok.
     
  8. Claudio Valerio Parboni
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    Claudio Valerio Parboni Junior Member

    Thank you, I've seen the book in my uni library, I'll give it a check
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    Other than the advice above from Bajansailor, you really need to establish the 'design'. By that I mean what is the vessel's displacement and what sea states is she designed to sail in.

    Then...all you can do, is look at similar sized boats with similar SORs, see what rigging they have used and make a weight estimate based upon their rig and data at hand. Then add a FoS to it for yours.
    Beyond that, unless you design the whole boat and establish the stability and performance you need to design the rigging itself from first principles, you will not get simple one line answers to what is ostensibly a lengthy and complex iterative procedure.

    Just leg work and gathering data....
     
  10. Claudio Valerio Parboni
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    Claudio Valerio Parboni Junior Member


    I've updated the original question for clarity, please read
     
  11. Claudio Valerio Parboni
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    Claudio Valerio Parboni Junior Member

    I've updated the question for clarity,

    I have 15 years experience sailing and have studied yacht design for my bachelor's mainly interesting in sailing yachts.
    Sizing a rig for a 2-spreader mast is fairly easy using NBS (see Principles of Yacht Design, by Larsson, Eliasson and Orych),
    I've made a spreadsheet that allows me to imput basic data and will easily give me required Ixx and Iyy for mast sections,

    I do agree that superyacht masts are harder to estimate with basic methods.
    It seems to me that I should either go with basic internet research (which is not very strong for a good grade on a university project) or go through the full regulation (which I hope wont take too much time away if I decide to follow).
     
  12. Alik
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    Alik Senior Member

    What You asking is actually insider data. Such data as table of weights makes difference between experienced designer and a beginner. I don't know if anyone designing superyachts who would be willing to share weight specs of his designs to public or possible competitors.

    Say, we have a lot of data for types of boats we do, thus we can start and finish project very fast and with guaranteed result. Others can't, and this is called competition.

    So only way You can get it - make full calcs.
     
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  13. nota
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    nota Junior Member

    J boat size
    basic questions
    racer triangle or distance
    world cruiser
    daysailer
    liveaboard
    ?
    sloop or ketch or schooner ?

    mast made of carbon or alloy ?
    normal or wing or other

    sail type pin head or square top or other
    carbon or dacron

    rigging wire SS or plastic fantastic
    those pole side stays be used ?

    all impact size weight ect

    ruff old school J boat pre-war cup boats used alloy masts and weights are in books carbon 3/5 of alloy weight ?
     
  14. Tad
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    Tad Boat Designer

    For a 38m sloop, carbon mast and furling boom by Southern Spars. I have mast and rigging at 10,149 lbs, boom at 1350 lbs, running rigging 419 and sails at 1680. The bare tube weight was 4169 lbs. For a 41m ketch with carbon spars I have masts and rigging at 9549, booms at 628 and running rigging and sails about 1200 lbs.
     
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  15. rnlock
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    rnlock Junior Member

    Having recently seen pictures and video of an enormous yacht with free standing carbon masts, I wonder what the weight penalty would be. Such a mast would be easier to calculate, and of course it has some advantages. For instance, it may be,more reliable without all those fittings, some of which are critical to the mast's survival.
     
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