A junk rig for Weaverbird

  • 06 Jun 2017 21:41
    Reply # 4883899 on 4876481
    David Tyler wrote:

    As with Arne and Ingeborg, I also enjoyed sailing with a good junk rig on a good boat, yesterday. I was at the top of Loch Etive, and had to beat the ten miles down to Taynuilt in a wind that varied from nothing to more than 15 knots, and from all directions as it found its way around and over the mountains. An uncountable number of tacks, as I worked the windshifts as well as I could. A bermudan boat would have motored ;-) Five hours for ten miles, an average VMG of 2 knots, which wasn't bad in the conditions. 

    There was a noticeable "good tack/bad tack". 4.8 - 5 knots with mast to leeward of the sail, 4.3 - 4.5 knots with mast to windward, when the wind was strong enough to give me maximum speed.

    Ideal territory for a good junk rig! And not unlike some of Arne's home waters. I can't wait to experience that relative "ease" - continuing sailing when I know I wouldn't have bothered with the gaff cutter rig. Thanks for the boost to the mid-conversion morale!!

    Pol.

  • 02 Jun 2017 22:05
    Reply # 4877477 on 3858224
    Deleted user

    David - thanks for the photo and the description.  Also to the contribution of observations of good/bad tack.  On our Freedom, the rigging is set up for battens on the starboard side of the mast - sounds good for racing and getting off the line :)

    Erik

  • 02 Jun 2017 10:47
    Reply # 4876481 on 3858224

    As with Arne and Ingeborg, I also enjoyed sailing with a good junk rig on a good boat, yesterday. I was at the top of Loch Etive, and had to beat the ten miles down to Taynuilt in a wind that varied from nothing to more than 15 knots, and from all directions as it found its way around and over the mountains. An uncountable number of tacks, as I worked the windshifts as well as I could. A bermudan boat would have motored ;-) Five hours for ten miles, an average VMG of 2 knots, which wasn't bad in the conditions. 

    There was a noticeable "good tack/bad tack". 4.8 - 5 knots with mast to leeward of the sail, 4.3 - 4.5 knots with mast to windward, when the wind was strong enough to give me maximum speed.

  • 26 May 2017 08:55
    Reply # 4853725 on 3858224

    I don't think I've mentioned this before, by over the winter, I made some changes to the battens.

    The lower battens were 30mm diameter, and the higher, more highly stressed battens were 38mm diameter - all GRP tube. The 30mm diameter battens were a little more flexible than I liked. 

    Now they are all 38mm diameter, and for the sake of getting the most stiffness and strength with the least weight, I invested in CFRP for the new tubes that I bought. I used the existing GRP tubes for the forward battens, where the extra weight would be helpful in dropping the sail, and used the new CFRP tubes for the after battens, where the reduced weight and increased stiffness was most beneficial.

    At the same time, I moved the second hinge further aft, so that the sail camber line is now a smoother curve. The hinges are now at 30% and 56% of the batten length. Also at the same time, I re-machined the hinges to increase their half angle from 4° to 5°. The camber is now about 10%. These changes may have moved the CP a little further aft, but in my case this is a good thing, as I needed just a little more weather helm. The helm balance is now excellent, with very little rudder angle being needed on all points of sail.

    Last modified: 26 May 2017 08:59 | Anonymous member
  • 25 May 2017 11:47
    Reply # 4852132 on 3858224

    At last, a calm sunny day, and I could take a photo of the LHP.

    Following this in the album are some photos of how I use stainless steel rings to prevent the halyard, YHP and LHP from getting around to the wrong side of the luff.

  • 21 May 2017 01:52
    Reply # 4843987 on 3858224
    Deleted user

    David - as always thanks for the info.  If you have a chance, can you provide some pictures.  

    Cheers,


    Erik

  • 20 May 2017 14:08
    Reply # 4843417 on 4023786
    Erik and Evi Menzel Ivey wrote:

    David:  I think you will be very happy using the low friction rings for the sheeting system.  I've used then in the wishbone boom on our Freedom, and on a vang on a smaller boat.  The anodizing is super hard and thick and the friction when using spectra line is surprisingly low.  There is a good series of articles on this website, http://l-36.com/articles.php?menu=2, regarding the use of the rings and also some rappel rings, which are less expensive.  I've also noticed that arborists are using these rings, though the coating looks different and may not be as durable.  

    Cheers, 

      Erik

    I am indeed very happy. I' m using Antal 10x7 low friction rings with 4mm Dyneema in sheet spans, a Barton 38mm as a sheet block with 10mm braid on braid sheet and 4mm Dyneema sheet span, and a Barton 16mm in place of a block in the 8mm braid on braid LHP; in all cases, very successfully.
    Last modified: 25 May 2017 13:59 | Anonymous member
  • 19 May 2017 14:46
    Reply # 4841951 on 3858224

    Yes, last year I used short batten parcels and no LHP, and thought it to be workable for a small rig like mine. I achieved an adequate set without the LHP, but still needed a running line in the form of a downhaul. The point is that the LHP can do more than a downhaul - it pulls the sail in, down and back at the same time.

    This year, I have made the batten parrels a little longer, so that the LHP becomes necessary to haul the sail back; further, it enables me to adjust the amount that the sail is hauled back, whereas the short batten parrels just fix the sail in one position. This doesn't matter where the mast is totally stiff, but does matter where there is some mast bend. 

    You're right, I did change my mind. I aimed for simplicity in a small boat's rig, and found it to be not such a good option as I thought it would be.

    But all this is by the way, when considering your rig. With a much larger sail, the use of short batten parrels would be insupportable, there would be an intolerably large amount of friction.

  • 17 May 2017 06:03
    Reply # 4837471 on 4821908
    Deleted user
    David Tyler wrote:

    I've been playing with various configurations of THP, LHP and downhauls , and surprise,  surprise, the best option for the top of the sail seems to be a good old-fashioned LHP, working on the top three battens. Sometimes the old ways are the best. I still have a spanned downhaul for the first two reefs. 


    David - If I recall correctly, previously you seemed quite satisfied with only using batten parallels.  Since I am planing on using the same plan form, what is making you add LHP?


    Erik 

  • 09 May 2017 13:03
    Reply # 4821908 on 3858224

    I've been playing with various configurations of THP, LHP and downhauls , and surprise,  surprise, the best option for the top of the sail seems to be a good old-fashioned LHP, working on the top three battens. Sometimes the old ways are the best. I still have a spanned downhaul for the first two reefs. 

       " ...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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