Multiple headsail, "mainless" sailplan

Discussion in 'Sailboats' started by massandspace, Dec 5, 2017.

  1. fastsailing
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    fastsailing Junior Member

    Using high rake (10...20 degrees) combined with moving the mast step a little forward would reduce structural loads substantially, while allowing same size jibs with same aspect ratio. Position of center of mast would remain the same, upper part moves aft and lower part forward. Also no spreaders would be needed for back shrouds as angle to the mast would be quite reasonable without them.
     
  2. JosephT
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    JosephT Senior Member

  3. sharpii2
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    sharpii2 Senior Member

    An interesting idea, but I think the OP was looking for a rig with no moving spars. And except for its suggestive shape, a Lateen has little in common with a head sail only one.
     
  4. Dolfiman
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    Dolfiman Senior Member

    This photo captured on the net, shot in 2010, it is actually a Baranquilla motor yacht equiped with a mast and two jibs on furls :
    Cata with jib.jpeg
    https://thailand-yachts.com/yachts/catamarans/barranquilla/
     
  5. rwatson
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    rwatson Senior Member

    Another view of the Caravell from my previous post

    Caravel1.jpg
     
  6. Anatol
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    Anatol Senior Member

    This rig is interesting to me for a number of reasons. The question I have is whether the aft sheet position on transom (or is it a canoe stern - worse!) would induce an undesirable curvature in the aft sail, on a reach or more downwind? Or does he shift the tack of the aft sail to windward? And what about downwind? - is the rig set up in a 'tradewinds' arrangement, both jibs poled out?
     
  7. rwatson
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    rwatson Senior Member

    No canoe stern, thank goodness.

    The problem with all loose foot sails, is that you are restricted to the deck geometry.

    I have never spoken to the owner of the local Caravelle, but the original article did suggest poling out options for down wind.
    I have always been curious how the sheeting of the 2nd sail copes with the near vertical shrouds at the stern.

    This design would not be competitive in racing. It makes ease of operation the boss of the design, at the expense of sail optimization abilities.
     
  8. JamesG123
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    JamesG123 Senior Member

    I'd been toying with a very small sailing cat with parallel masts on each hull but the fiddli-ness of twin masts, booms, and associated rigging in any plan put me off on the idea. Mostly in how the booms and traveller(s) encroach upon the center cockpit/deck. Dispensing with them and "simply" going with a pair of headsails fwd' reduces the complication to simply managing the controlling lines.
    Hmmm.... where did I put those drawings.
     
  9. Anatol
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    Anatol Senior Member

    "The problem with all loose foot sails, is that you are restricted to the deck geometry".
    unless you've got two or more hulls :)
    "I have always been curious how the sheeting of the 2nd sail copes with the near vertical shrouds at the stern."
    pulling the tack to windward is an obvious solution, you've got the breadth of the deck there
     
  10. Anatol
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    Anatol Senior Member

    usually called a 'biplane' rig, The idea has a history. It seems obvious for a cat, but in practice I believe there are aerodynamic limitations - like any rig..
     
  11. rwatson
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    rwatson Senior Member

    Well yeah, but Naaah.

    On a beat to windward, the sheet would be under the shroud, and cleated to the stern rail.

    When you go on a reach, and you either pole it out, or try to shape it with the sheet end out past the rail, you would either have to have a second sheet, or unclip and re-clip the sheet to avoid it wrapping around the stay.

    Very inelegant and a safety issue when flogging in heavier winds.
     
  12. Anatol
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    Anatol Senior Member

    I get the shroud problem, blind Freddy could see that :)
    But - in principle - what is the different between pulling the clew to leeward on a track (if there was a track and the shroud wasn't there) and pulling the tack to windward? I mean, what (theoretically) is the drive and balance effect of moving the tack off the centerline? The curve of the foot is just moved to windward. The sail is a little more vertical. The luff now assumes a dihedral line wrt mast. ...
     
  13. JamesG123
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    JamesG123 Senior Member

    I hate that term.
    True.

    Was going to say/speculate more, but I need to ponder on this a bit.
     
  14. CT249
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    CT249 Senior Member

    Because a luff has to be tighter than the leach, and it's extremely hard to achieve that when the luff is being moved around.
     

  15. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    Don't know if the OP is still following this thread, but John Hitch has designed some catamarans that were powered only by head sails. This one is X-IT.

    [​IMG]
     
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