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Tystie's rig - the 2015 model

  • 29 May 2015 02:08
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    Reply # 3361409 on 3302473
    Deleted user

    Hi Ash, 

    If you look closely at the pictures you can see a cord that is woven through the battens and the hinge in a figure-8.  This keeps the battens tight against the hinge.  The figure-eight is a nice arrangement as it allows the hinge to articulate vertically.  For the prototype I used polyester cord I had handy, I suspect dyneema might be a better choice for the final production.
  • 28 May 2015 22:09
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    Reply # 3361084 on 3302473
    Deleted user

    Darren,

    This is very interesting, keep going!

    How will you keep the alloy battens from pulling apart , ie the sheets pull aft , in a real setup?

    Ash
  • 28 May 2015 18:02
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    Reply # 3360574 on 3302473
    Deleted user

    Hi Dennis,

    I've done just what your proposing and built a prototype.  I've uploaded a couple of pics to the Illustrations section of the technical forum.  

    http://www.junkrigassociation.org/page-1401723/41430382

    http://www.junkrigassociation.org/page-1401723/41430385

    http://www.junkrigassociation.org/page-1401723/41430468

    The pics show the prototype made from PVC.  It was used to make a mould and the hinge inside the aluminum tube is made from polyurethane cast from the mould.  I'd like to experiment with a few different hardnesses and cure times of polyurethane, but overall it is a very easy method to generate identical batten hinges.  You do have to make another mould if you want to decrease articulation for the upper battens, but since I'm refitting a schooner I get bit more from each mould.  The aluminum batten-ends can be cut easily with a router and a simple jig.  The batten-ends are cut to an ellipsoid shape which allows them to rotate with the hinge (no sliding of batten relative to hinge)(imagine a tire rolling on the road rather than skidding), rather than the surfaces sliding against each other as you would have in a plain bearing (whether or not this will reduce wear remains to be seen).  

    This hinge meets the design criteria David has laid out and is largely derived from his ideas.  It is strong enough that I can fix one end of the batten horizontally and hang my weight (180lb, 82kg, 13 stone) at a distance of 14" from the hinge).  I can send dxf drawing file to anyone interested.

    Last modified: 21 Jun 2015 18:28 | Deleted user
  • 28 May 2015 00:31
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    Reply # 3359608 on 3302473
    Deleted user

    Thank you.

    If I understand you right, the vertical articulation is to give the non-horizontal force vector a little "wiggle room" to sort itself out and bend the batten horizontally.

    I agree that a tubular batten makes the most sense.  I am trying to sketch out a hinge mechanism similar to your that articulates in two directions  and spreads out the load as well as yours.


    Dennis
  • 27 May 2015 17:37
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    Reply # 3359067 on 3302473
    Anonymous member
    It's because the batten can misbehave if it isn't there. You can see the same kind of thing if you make a one-piece batten or yard that is deep, vertically, but thin, horizontally. If you ask it to take a vertical load, it will simply turn through 90 degrees on its axis, so that it can bend vertically. To reiterate: for stable performance, a round tube is best, for a yard, one-piece batten or hinged batten.


  • 25 May 2015 14:02
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    Reply # 3354888 on 3302473
    Deleted user

    David,

    I understand the need for horizontal articulation of the batten (actually, that is the whole purpose of the hinge). What is the purpose of vertical articulation?


    Dennis
  • 20 May 2015 19:04
    Quote
    Reply # 3350048 on 3346372
    Anonymous member
    dennis gibbons wrote:

    David,

    1.Is the manner of fabrication of your square section battens somewhere I can find?

    2. How do you achieve and limit the vertical articulation of the battens?

    3.  Are you concerned about wear on the wooden hinges by the motion over the bolt?

    4. Have you experimented with hinge placement?  (i.e. 1/3 back from the luff verses 1/4 vs 1/2)

    Dennis (lurking in the shadows)


    1. The batten section is only rectangular because that's what I had, as leftovers from the wingsail. I don't advise using square or rectangular. Round is better, to give equal articulation in all directions.

    2. The hinge limits the articulation. My oak hinges are parallel sided, looked at from the side. I should relieve the undersides to give as much articulstionas possible, without, of course, exceeding the horizontal articulation.

    3. Time will tell.

    4. No, I've put the hinge where I believe it ought to be, in the are 35% - 40% aft.
  • 20 May 2015 18:58
    Quote
    Reply # 3350042 on 3346162
    Anonymous member
    Jerry Stebbing wrote:

    David, when you say 'just the right spot' for the aft attachment of your short batten parrels, is this as shown in PJR, ie in line with the aft face of the mast, and a common parrel length based on the maximum mast girth?

    The photos seem to show this as the sail's balance increases as the mast gets narrower, but did you just use the same parrel length on all battens and just let the sail find its own natural position, or are they different lengths for each batten?

    The batten downhauls look from the photos to be attached at the same point as the aft parrel attachment, but the photo resolution isn't quite enough to be certain. Is this correct?

    Yes, the right spot is in line with where you want the aft face of the mast to lie, and I had to experiment with the slackness, so that the sail would drop readily, and the mast would lie as planned with the halyard pulling it forward. I glued and screwed some 6mm HDPE strips to the battens to act as the bearing and also to position the aft ends of batten parrels. The distance from the luff increases towards the top of the sail, to bring the yard further forward so as to decrease the angle between halyard and mast. However, this distance is going to vary from rig to rig, according to the flexibility of the mast particularly, and also the sail shape, so I can't give any detailed guidance.

    Yes, the downhauls are attached at the aft parrel attachment points.
  • 20 May 2015 18:48
    Quote
    Reply # 3350037 on 3346062
    Anonymous member
    Bertrand Fercot wrote:

    Bonjour David

    In which area you plan to be in NZ?

    We'll land the NE of the NZ at the end of next November and we'll be verry happy to meet you again and to talk about wingsails.

    Have a good Pacific crossing.

    Bertrand

    I'll be in Northland, mostly around Whangerei.
  • 17 May 2015 18:20
    Quote
    Reply # 3346372 on 3302473
    Deleted user

    David,

    1.Is the manner of fabrication of your square section battens somewhere I can find?

    2. How do you achieve and limit the vertical articulation of the battens?

    3.  Are you concerned about wear on the wooden hinges by the motion over the bolt?

    4. Have you experimented with hinge placement?  (i.e. 1/3 back from the luff verses 1/4 vs 1/2)

    Dennis (lurking in the shadows)
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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