Arion's extreme negative batten stagger - a solution

  • 07 Aug 2012 07:27
    Reply # 1040571 on 1025487
    I have now re-rigged my luff hauling parrels so I can control batten stagger precisely.  I now have two luff parrels, each controlling two battens, 3 & 4 (counting from the top) and 5 & 6.  The parrel goes from the front of the upper batten (of the pair) around the mast, back to a block at the front of the same batten, down through a block at the front of the lower batten then straight down to the deck.  This set up was recommended to my friend and fellow JRA member, Don Halliwell, by Chris Scanes.  When batten 6 is just above the boom (one panel reefed), hauling on the lower luff parrel allows me to induce as much positve stagger as I wish (an inch or so) but when batten number 5 is lowered into the same position (two panels reefed), the parrel works just as effectively.  Ditto the next two battens.  Thus I can induce slight positive stagger in all four parrallel battens.  Batten 2 is the last sheeted batten but it is not a problem as it is both longer than the others and angled up in the fan-shaped head panels.  I also have HK parrels on all sheeted battens.  The sail seems to set nicely and, although I have to observe the sail when reefing / furling, I think perhaps once I have more experience I will be able to sense how much tension I need to put on the parrels.  I'll report more on this set up after my sail to Cairns - I'll be out sailing in a week or so.
  • 01 Aug 2012 23:06
    Reply # 1028073 on 1025487
    I am intrigued by the stick and string idea and am going to try one for my sail, too.  I rather like the idea that perhaps we can all learn so much from such a simple model in and age when, it would seem, that all experimentation and learning has to be done in cyberspace. 

    While it may be difficult to get all the sail you theoretically need on Arion, I think the extra power in the cambered sail will possibly make up for lack of area.  It's great to hear you sounding so excited and positive.  I'm looking forward to hearing about your adventures with your new rig. 

    40 years sailing and still a greenhorn.  But aren't we all?  Surely one of the best things about sailing is that there is always something new to learn.

    Like everyone else here, I'm really looking forward to seeing photos of Arion under sail.
  • 01 Aug 2012 02:37
    Reply # 1027261 on 1025487
    Sticks and string, thanks very much for the invaluable advice.  I would have never thought of that but can see immediately that the different dynamics of cambered sails once again call for a different approach and look forward to doing it.  I am fascinated by Annie's sail so will make one of hers too, though I am not sure if I can get enough sail area on my short, fat, heavy hull with a lower aspect sailplan.  It will probably have to wait for a month or two because all I want to do right now is go sailing but I will report on my observations when I do.  A little experience with my rig will also assist my observations I think.
  • 31 Jul 2012 19:50
    Reply # 1026997 on 1025487

    Hi Graham,

    I will echo Paul’s comments about a stick and string model. You will save yourself a lot of time and effort, and will be able to try many variations simply by pressing a finger at various points on a batten or yard. Every junk sailor should make one of the rig they are using to see how best to set the rig. You’ll get more information per buck than any other way.

    Cheers, Slieve


  • 31 Jul 2012 08:26
    Reply # 1026494 on 1025487
    Graham, while making a cardboard cut out will tell you something, it's also hides a lot. The cardboard cut out is more like a flat sail, lots of diagonal stiffness, so it does not help so much with a cambered sail. What you want to make is a stick and string model. Sticks for the battens and yard string for the sail outline and holding it all together.

    The stick and string model has no diagonal stiffness so behaves very much like a cambered sail. I would encourage you to build one, even one of your existing sail. You will be amazed at just how much you will learn from such a simple model.

    PS. As Slieve points out (below) you can learn a lot by just poking the model with a finger. However take a bit more time, rig a mast (suitable stick/dowel) on a stable base then you can add control lines and see exactly what happens when you adjust them.
    Last modified: 01 Aug 2012 01:41 | Anonymous member
  • 31 Jul 2012 06:02
    Reply # 1026421 on 1025487
    When I build my next sail I think I will revert to a full length yard as this seems best with the Hasler Mcleod sailplan.  When I get some time I am going to make cardboard cutouts of Arion's sail as it is, as it would be with a full length yard and of Annie's sail plan and suspend them with a pin from the midpoint of their yards.  Arion's current sailplan will swing forward the most but I will be interested to compare them.  When David Tyler designed my cambered sail he shortened the yard from 4.6m to 4.3m.  I later recut the sail to suit the 3.3m yard I had used on my Reddish style flat sail, not understanding the implications of doing so.  Swinging the sail forward before furling or reefing works nicely for the time being and I will get some miles under my belt now and have some fun.  When I do build another sail I will have enough experience to make better decisions.  I may have been sailing the oceans for 40 years but when it comes to junks, particularly cambered junk sails, I am a greenhorn.
  • 30 Jul 2012 10:09
    Reply # 1025628 on 1025487
    Anonymous member (Administrator)

                                                                             Stavanger, Monday

    Graham, I am glad to read what you write here and that you are back on board in Arion.

    Your friend Jay Reynolds seems to have come up with the obvious solution to avoid negative batten stagger when reefing. The reason why I get away with a fixed tack parrel and only have negative batten stagger after the first reef, in my boats, is probably that my rigs are not set up with shifting them fore and aft in mind. Therefore the batten parrels are moderately short and will thus prevent the sails from falling forward more than a bit as the first reef is taken. This could have given problems with increased friction if the batten parrels had been made even shorter to take away the entire negative batten stagger. The key is to find the right balance, but if this is difficult to find, then Jay’s method is a winner. BTW, I too let the sheet fly while reefing if conditions (space) permit. This lets me set up the throat and yard parrels for best set of the sail.

    Happy sailing!


    PS: After having seen how well Broremann’s sail set when reefed after I started to clip the tack-line to the lowest batten parrel, I will now also try downhauls on Johanna’s sail. More strings!

    Last modified: 30 Jul 2012 18:08 | Anonymous member (Administrator)
  • 30 Jul 2012 09:18
    Reply # 1025599 on 1025487
    Glad that you found a solution, though obviously fixing the head would be best. How did you come to have a yard that is so much shorter than the battens?

    Hope you'll post some pics soon, am keen to see what you have :-)
    Last modified: 30 Jul 2012 09:20 | Anonymous member
  • 30 Jul 2012 06:12
    Message # 1025487
    At the time I sold Arion last year, I had not been able to solve or understand why I had such extreme nergative batten stagger.  Each batten came down about 200mm forward of the one below it and the sheets got into a hopeless tangle.  I could control it by hauling on the multiple luff hauling parrels just before the batten nested but that required observation of the process and I did not fancy my chances on a dark and windy night.  Arne recently mentioned to me that he had been experimenting with the position of the halyard on the yard with some success in controlling negative batten stagger and this set me thinking.  I remembered the sketch in PJR of the sail hanging unrestrained from the halyard - the tack was way forward.  In practice, the sail is held in the sailing position by the tack parrell which pulls the boom aft. With a flat sail, lowering the sail with the boom in the sailing position (assuming it has the correct geometry) is not a problem because the diagonal tension in the flat panels stops the battens moving forward and gives some positive stagger.  However there is nothing to stop the battens of a cambered sail from moving forward once you ease the halyard.  In Arion's case it is exacerbated by having a short yard, 3.3m, against the batten length of 4.6m.  This effectively moves the halyard attachment a long way forward which significantly increases the sail's desire to swing forward when gravity takes command.  One solution would be to recut the sail and revert to a full length yard, perhaps with the attachment point a bit aft of the middle of the yard.  When I discussed this with Jay Reynolds (who owned Arion for the last 8 months before selling it back to me today), he agreed it was probably the best design profile for a Hasler Mcleod sail profile (fanned sails like Annie's and David's do not seem to have this problem) but he has a simpler solution, one that he has always used even with flat sails.  He has a running tack parrell and always lets it off before reefing or furling the sail (as well as always feathering the sail).  This allows the sail to do what it wants, ie swing forward until it is restrained by the long standing parrels on boom and battens.  When the halyard is eased then, the battens are no longer trying to dive forwards and come down straight or even with slight positive stagger.  Arion's sail now works just fine.  Wish I had thought of that!
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