A tied hybrid system for junk rigs -- can it work?

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  • 18 Nov 2019 00:51
    Reply # 8126449 on 3399298

    I've submitted the write-up of WAYWARD's prototype rig to the JRA. 

    It's currently readable here.

    Dave Z

  • 18 Nov 2019 00:44
    Reply # 8126433 on 8087657
    One thing I noticed when I hoisted my first cambered panel sail in 1994, was that the luff and leech no longer would flutter, the way they sometimes did on the flat sail. If that is a problem in your flat mizzen, I suggest you stitch on a low-stretch boltrope. If you stitch it on a bit taut, you will introduce a very light camber, and the weights will mostly move out to luff and leech, and keep these quiet.

    Arne


    Hi Arne,

    We haven't had a fluttering problem as such, except when we're pinching (rather a too common occurance, I'm afraid!). It always appears as a warning in the lowest panel (which is also slightly more scalloped).

    I like your use of bolt ropes, and used the webbing version in our prototype.

    Dave Z

  • 12 Nov 2019 17:44
    Reply # 8103512 on 8102635
    Anonymous wrote:Our preferred method would have been narrow webbing with one side sewn hook and the other loop (good quality), long enough for a couple rounds of self-adhering overlap. This would have been very easy to adjust!
    Hook and loop strap can be purchased as one piece premade. It is much thinner than sewing two bits together and does not bunch up when wrapped around things. I use it as a musician for "tying" cables together. (I put a hole in and poke the free end through that so they don't get lost) The stuff I get is only 1 inch wide (from Fanny Fabrics) and I do not know if it is available in wider sizes.
  • 12 Nov 2019 17:37
    Reply # 8103489 on 8088939
    Anonymous wrote:

    Here are a few shots of our prototype main, Thai style lashings sized to induce 8% camber. Unfortunately, we didn't seem to take any after final adjustments. Sigh.

    It may make sense to include some barrel shape in the panels for minimum camber. The one thing I would question is how accurate can one make the camber with this method? Do you make a table of lash lengths for each camber tried? Do you just measure the longest lash and make the rest hold the sail fair? The "jiblets" are not lashed but I would think they would benefit more from adjustment than the main as they are in clean air. Being able to change the chord angle for the jiblets would also be interesting.

    I'll write all this up, sometime this winter. Hopefully, next summer, we'll be able to compare solid sails to Thai lashed, cambered sails (which may apply to a lesser degree with 'hinged' sails).

    Dave Z

    I too would be interested in this write up.
  • 12 Nov 2019 03:41
    Reply # 8102635 on 3399298

    One thing I should mention... we were building remote so had to make do with lashings (using a tarred nylon seine twine).

    Our preferred method would have been narrow webbing with one side sewn hook and the other loop (good quality), long enough for a couple rounds of self-adhering overlap. This would have been very easy to adjust!

    The lashings weren't too bad and cheap, but tedious to adjust.

    Dave Z



  • 03 Nov 2019 18:32
    Reply # 8089476 on 8088939
    Dave Z wrote:

    Here are a few shots of our prototype main, Thai style lashings sized to induce 8% camber.

    What's this? Tied panels, a split rig, and leeboards as a bonus. I think I can safely say that someone has tried out the thing I was thinking of. I very much look forward to your write-up Dave, and later on to the comparison with sewn sails.

  • 03 Nov 2019 05:25
    Reply # 8088939 on 3399298

    Here are a few shots of our prototype main, Thai style lashings sized to induce 8% camber. Unfortunately, we didn't seem to take any after final adjustments. Sigh.

    So imagine nice, smooth setting panels.

    The upper, 'crab claw' panels are flat cut (idea was to act more like headboards, reducing any need to top up the lug). The deep hollows help move the CE inboard, reducing weather helm, especially when deep reefed in heavy winds.

    Continuous, aft sheeting on main and mizzen at 6 and 5 parts, respectively. Each pair of battens is connected by a simple span (sheetlet), and the lowest part of the mizzen sheet is run forward along the boom to its tabernacle. Will eventually rework main sheeting to reduce twist.

    Sail position is controlled by standing batten and yard parrels.

    Downhauls are temporary, only being clipped to batten parrels in heavy weather.

    The SJR main points higher than the mizzen, so can be eased to a close reach when the mizzen is closed hauled (angle diff can be seen in first pic).

    I'll write all this up, sometime this winter. Hopefully, next summer, we'll be able to compare solid sails to Thai lashed, cambered sails (which may apply to a lesser degree with 'hinged' sails).

    Dave Z



  • 03 Nov 2019 03:55
    Reply # 8088906 on 3399298

    RE Telltales: Right ya both are.

    RE Pockets ("how about using a mesh material for one side of the batten pocket, hopefully reduce mildew."):

    That could work, I suppose, if the mesh material could be low stretch.

    But marline hitches with paracord have been cheap, quick and easy for us. Plus I kinda like doing it and the way it looks.

    A lot of what we (Anke and I) do is for such small (and quirky) vanities as these!  8)

    Dave Z

  • 02 Nov 2019 15:57
    Reply # 8088237 on 8087964
    Anonymous wrote:

    Dave,

    With a flat sail it is difficult to see and feel the lift, I found the leach telltales very useful.


    Bonjour

    In experimentation leach telltales are not sufficent as they don't show the airflow around the sail or wing profile/camber.

    It is more efficient, in particular to compare different cambers to incorporate telltales all along the sail profiles. When the airflow is laminar the telltales are parallel to the airflow. When the airflow is turbulent the telltales are falling.

    Eric

    Last modified: 02 Nov 2019 16:02 | Anonymous member
  • 02 Nov 2019 09:11
    Reply # 8087964 on 3399298

    Dave,

    how about using a mesh material for one side of the batten pocket, hopefully reduce mildew.

    With a flat sail it is difficult to see and feel the lift, I found the leach telltales very useful.

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