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  1. #91
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    Howdy Bruce,

    I only like rigs that control twist in some way.

    That's why I very much like Balance lugs and sprit boomed sails.

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  3. #92
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    Quote Originally Posted by Boatmik View Post
    Howdy Bruce,

    I only like rigs that control twist in some way.

    That's why I very much like Balance lugs and sprit boomed sails.
    So the square topped sprit sail could work?

  4. #93
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    Quote Originally Posted by woodeneye View Post
    So the square topped sprit sail could work?
    Do you know this Danish class?

    Velkommen til Megin



    Her spritsail is really perfect!
    Aloha!
    Robert Hoffman
    http://robhosailor.blogspot.com/


  5. #94
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    Tilburg, the Netherlands
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    Quote Originally Posted by woodeneye View Post
    So the square topped sprit sail could work?
    I don't think that you can control twist as easily and automatically as with a balanced lug or sprit rig. I also think that the rig should match the looks of the boat which I think this won't.

    I have been (re)checking the OZ racer site and I can imagine that the hull maybe a sort of GIS meets OZ racer. Just wondering of course since I believe that MIK has the concept and ideas for this boat more or less thougt out.

    Joost
    Last edited by Joost; 30th April 2012 at 08:52 AM. Reason: Spelling error

  6. #95
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    Sep 2008
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    Default square top sprit boomed sail

    Square top sprit boomed sail works. Here is the squaretop spritboomed mizzen sail on my Apple 16. Has one jiffy reef. Leech cut slightly hollow to avoid more battens. Has a plastic track glued onto the back of the mast to take slugs sewn onto the luff. Flattens nicely in a breeze with the snotter, downhaul and bendy fibreglass mast (Zoom 8 dinghy). Solid tapered wood would do.
    Peter

  7. #96
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    I'm thinking more along the lines of a square top sprit sail, but with a conventional boom. Like the Optimist sail, just with a square top, taller and narrower...

  8. #97
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    Quote Originally Posted by Glug View Post
    Square top sprit boomed sail works. Here is the squaretop spritboomed mizzen sail on my Apple 16. Has one jiffy reef. Leech cut slightly hollow to avoid more battens. Has a plastic track glued onto the back of the mast to take slugs sewn onto the luff. Flattens nicely in a breeze with the snotter, downhaul and bendy fibreglass mast (Zoom 8 dinghy). Solid tapered wood would do.
    Peter
    Yes, this should work very nicely. This is essentially the same sail as used by millions of windsurfers where the wishbone boom works the same way as the sprit boom here. The sprit boom tensions the leach quite nicely through the foot avoiding too much twist in the top of the sail.

    I believe that Bruce is more questioning whether a modern version of the traditional sprit rig (i.e. using both a sprit and a conventional boom) may work. Similarties can be seen with certain sails employed by Hobby mirage sails which use a batten instead of a spit in the same place to support a square head.

    Best regards, Joost

  9. #98
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    Peter,

    By the way, interesting approach modernising an old concept (your mizzen).

    Did you make this choice aimed at additional drive where often the choice (and size) of the mizzen indicates that it is more rigged to improve handling?

    Joost

  10. #99
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    Uppsala Sweden
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    Default sprit sail

    Did you make this choice aimed at additional drive where often the choice (and size) of the mizzen indicates that it is more rigged to improve handling?
    Joost

    The area is between the designer's small and large mizzens, at 5.4 sM (main is is 8.3 sM). The flat top is to allow excess wind to spill off the top by twist of the top of the sail, and give a decent area with a relatively short mast.

    Bruce, is this what you are after (see picture of Norwegian boats) or the Melonseed type (red sail)? and attached is a excerpt from Wooden Boat forum a few years ago by Todd Bradshaw who wrote the great book on canoe rigs.

    Peter

  11. #100
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    Quote Originally Posted by Glug View Post
    [I]

    Bruce, is this what you are after (see picture of Norwegian boats) or the Melonseed type (red sail)? and attached is a excerpt from Wooden Boat forum a few years ago by Todd Bradshaw who wrote the great book on canoe rigs.
    Very close. Just more square at the top and taller to give a more modern look to it. I like the bi-radial cut sail on the Norwegian boat which should give good performance and sail control in all wind strengths.

    The downside is the expense of such a one-off sail. Because of this, I still support the use of the 4 rig Laser concept.

  12. #101
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    I'm beginning to wonder if the sprit is defunct because it is unnecessary? All the modern square top rigs are supported by a batten at an angle. Even the foiling Moth which has a pocket luff supports the square top sail. Construction of such a sail could be very simple indeed.

    Attachment 206942

  13. #102
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    A square head sail with a batten supporting the head would be far simpler, cleaner looking and without having to construct a sprit which would add weight aloft and which spoils the sail shape on one tack.

    Just my thoughts.

    Best regards,

    Joost

  14. #103
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    Sep 2008
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    Uppsala Sweden
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    Default sprit-like batten on 18 footer

    This batten makes the top back (clew?) higher than the masthead (throat?). It's not perspective. Next newest thing on Aussie 18 fotters, if they don't have a curved Dutch gaff-like top.

  15. #104
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  16. #105
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    Howdy,

    Details like a square top raised at the back are really difficult to judge in terms of their true efficacy. I would suspect the effect would be really tiny if anything at all.

    More fundamental is what the rest of the rig is doing. The mast bend, the luff round, the batten stiffness, how much downhaul and vang.

    Separating all the different effects out is very difficult.

    Generally when something appears one season it is interesting only if the boat performs very well. If it does .. then everyone tends to think that it was the most obvious feature.


    This is a sailboard sail from the previous year. Looking carefully it does look like the square bit is just twisting off where the eliptical outline of the sail is standing up quite nicely.

    Going bck to development ...

    But usually it is a much more subtle balance. But the other more subtle effects are so difficult to quantify that we tend to get recurring trends

    stiff masts with small luff round
    flexible masts with bigger luff round
    stiff masts with small luff round.

    Generally in one or two seasons there are no clear and obvious developments. But over a decade there is a substantial improvement.

    Quite interesting!

    Michael

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