Aftmast rigs???

Discussion in 'Sailboats' started by jdardozzi, May 28, 2002.

  1. RHough
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    RHough Retro Dude

    They are Lateen rigs.

    [​IMG]
     
  2. brian eiland
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    brian eiland Senior Member

    You are exactly right in my opinion Philip,....do it, and settle in BEFORE it gets to bad...besides are you in a big hurry. That old adage, 'haste makes waste'

    Here is that sea anchoring subject thread I mentioned. I'm sure you can find many other tales and websites.
    http://www.boatdesign.net/forums/boat-design/parachute-anchors-para-anchor-sea-anchor-10448.html
    Regreatably I've not had time to follow thru with Richard Wood's tale, and there have not been that many other contributors to the thread subject.

    And HERE specifically for some more reference sites
    http://www.boatdesign.net/forums/boat-design/parachute-anchors-para-anchor-sea-anchor-10448-2.html#post270910
     
    Last edited: Oct 25, 2010
  3. brian eiland
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    brian eiland Senior Member

    Well I suspected that...nice looking as well. What do you think they make that forespar out of??
     
  4. RHough
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    RHough Retro Dude

     
  5. brian eiland
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    brian eiland Senior Member

    Static Load Diagram

    Peter I might suggest you just use an even 1000kg for the forestay, then any multiple of that can be factored through to the rest of the rigging a static situation.

    I can give you this diagram that you can enlarge as a starting point. It is not the most up to date one, as I changed the forward jumper strut arrangement quite a bit, but my scanner is not working at the moment so I can't post newer photos or dwgs.
     

    Attached Files:

  6. brian eiland
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    brian eiland Senior Member

    Running with a Sea

    I believe those fellow's work is eclipsed by sailors out there in the soup.
     
  7. brian eiland
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    brian eiland Senior Member

    Lifting Force by the Sails

    You've experienced it, I've experienced it, and a number of other folks....that upwards lift from the sails. Perhaps it more of a phenomena aboard multihuuls that are not heeling over and are unballasted.

    I brought this up long ago back in posting #__. where I also referenced Herresoff's same observations:
    I want to come back to this subject, so I posted this as a reminder.
     
  8. MikeJohns
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    MikeJohns Senior Member

    I don't agree Brian.

    They can run survival situations with a myriad of models headings and wave types and tell you just what is likely to happen and why. Naval architecture has embraced all this factual knowledge. Also its important to understand that such knowledge doesnt get negated by generalisations from limited observation.

    Alarmingly in the commercial world very experienced sailors gut feelings about a vessels safety stability etc are often quite wrong. Which is where myriads of wave tank tests end up driving good design principles and making vessels safer, more controllable and less prone to being lost at sea.

    You really should read the material that comes from those wave tank tests on scale models. It provides invaluable insight to a designer of Blue water boats.
     
  9. Guillermo
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    Guillermo Ingeniero Naval

    Hi Brian!
    Those are the VELA LATINA Class boats in the Canary islands, evolved from traditional boats. Pure racing machines nowadays.

    There is a member of these forums who is a naval architect and crew in one of those teams and has written a very interesting and detailed book about the boats. He offered me one a few years ago. His name is Daniel and is nick here is danielro

    I'm going to bring his attention to this thread as he can explain everything about the boats much better than me.

    All the best.
     
  10. Guillermo
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    Guillermo Ingeniero Naval

    The mast has to be a wooden one weighting at least 70 kg (Rules point 5.4.1)
    But an 60 mm exterior diameter inner tube of whatever material, to reinforce the mast, is allowed. A 2mm additional exterior laminate is also allowed.

    Cheers.
     
  11. brian eiland
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    brian eiland Senior Member

    Thanks Guillermo,
    Is that the mast material, or the spar at the leading edge of the sail?

    That spar is the one I'm interesred in.
     
  12. brian eiland
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    brian eiland Senior Member

    A major problem I would have with wave tank test of actual storm conditions at sea is I doubt they can replicate the orbital motion conditions that exist at the top and trough of big sea waves, particularly those wave energies that have been rolling along for miles. These are a big culprit in the broaching forces excerted on boats in big seas.
     
  13. Guillermo
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    Guillermo Ingeniero Naval

    The spar has to be also a wooden one weighting more than 25 kg (Rules 5.4.2). They call it "palanca".
    Minimum diameter 85 mm, being at the ends no less than 50 mm.
    Can be hollowed and have an up to 60 mm diameter reinforcing interior tube of whatever material, as well as an exterior 2mm GRP sheeting (Annex 1, page 34)

    The only regulation for the size of the sail is that its length along the spar cannot be longer than 13.25 metres.
     
  14. ChiefOren
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    ChiefOren Junior Member

    Alik, yes I have. However, I am not planning such a large overlap. only about half way over the inner jib. Also, I would have a third permanent stay for the storm jib. So any tacking would probably go like this. 1. Turn to the direction you wish to go! 2. inhaul the outer jib and pull it to the other side and deploy. 3. When done with that, THEN do the same for the inner jib.

    You would think that backing the sails would be messy, but by backing the forward sail on the inner sail, you are actually helping the sail to pass over to the other side. Ditto for the inner jib on the storm stay.

    Not very pretty, I must say, and very undignified maybe, but it works, and it's not so hard, esp. if using self-furling rigging.

    Just my humble opinion. I am not a race bug that's for sure.
     

  15. TeddyDiver
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    TeddyDiver Gollywobbler

    You can't change the physics of a wave, tank or open sea, just the scale.
     
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