Flat, hinged or cambered?

  • 26 Aug 2018 21:31
    Reply # 6639623 on 6639557

    Jim,

    frankly, I would only use wood (spruce ?) if I had to, for battens. I have read about too many breakages, and they appear to happen during gybes.

    My hunch about this is that a fairly heavy and compact wooden batten, combined with its stiff and not too strong material (compared to aluminium, grp or bamboo) makes it vulnerable to the jerks at the end of half-long gybes.

    Now, I think I read somewhere that someone had successfully beefed up their wooden battens by adding a layer of glass roving in epoxy. I am not sure if I remember correctly.

    On Marco Polo/Teleport.I used local ash according to the scantlings in the plans. I made each one from two pieces, glued together. I never broke a batten and I don't think Chris and Jess broke any in the Arctic. Ash or similar is recommended for battens in the PJR, pg.157. They report they heard of good resulted from glassing the battens on each side. ((Not top and bottom. )I would use unidirectional glass only. Or carbon fibre tape?



  • 26 Aug 2018 20:39
    Reply # 6639557 on 461931
    Anonymous member (Administrator)

    Jim,

    frankly, I would only use wood (spruce ?) if I had to, for battens. I have read about too many breakages, and they appear to happen during gybes.

    My hunch about this is that a fairly heavy and compact wooden batten, combined with its stiff and not too strong material (compared to aluminium, grp or bamboo) makes it vulnerable to the jerks at the end of half-long gybes.

    Now, I think I read somewhere that someone had successfully beefed up their wooden battens by adding a layer of glass roving in epoxy. I am not sure if I remember correctly.

    These days I aim for big-section, thin-walled aluminium tubes for battens (easy to get at here) with a diameter/wall thickness ratio somewhere between 15 and 35. I once managed to bend a 50 x 1.5mm batten (batten 2 on Johanna, replaced by one of 50 x 3.2mm). I had feared that such a thin-walled tube would collapse, but it just bent.

    Arne


    Last modified: 26 Aug 2018 20:48 | Anonymous member (Administrator)
  • 26 Aug 2018 18:27
    Reply # 6639479 on 461931

    I guess we don't need a new thread. You guys didn't waste any time!

    When Tam Flemming launched Elsie N in 1999, his junk schooner sails had no batten pockets. They were lashed to the battens (PJR style wooden battens) through paired grommets every 12". I had suggested this and Tam boldly went ahead. The leech ends were bolted through the sail. See the album pictures in my profile. Very simple. You can see some water ingress under the epoxy. That just needs better installation detail. I would make a hole drilling jig to ensure standard size and location so battens could be interchanged. Some battens had a slot cut vertically into them at the leech end and a piece of 1/16” aluminum sheet metal glued in the slot. This would ensure the sheetlet strap did not pull out.
    The luff ends were as per Practical Junk Rig.
    Tam reports he had no problems. When he broke a batten in the foresail, gybing, he had easy access to splint and repair it. The boat has made trips from Nova Scotia to Bermuda, Caribbean (twice) Newfoundland and Magdalen Islands. Lots of service. The bolt holes in the sail did not elongate under stress. 

    But David, you have a broader experience to make a comparison. Interesting.

  • 26 Aug 2018 15:53
    Reply # 6639264 on 461931

    Here's something where I can agree with Arne ;-) No, batten pockets are not absolutely necessary, but...

    Over the years, I have seen and/or used:

    • Wooden battens on both sides, bolted through the sail
    • Grommets in the sail, with cable ties or separate lashings or continuous lashings around the batten, with or without a small batten on the reverse side
    • Webbing loops, with or without a cloth cover to match in with the sail
    • Several short lengths of pocket
    • Long pockets from luff to leech with a gap in way of the mast and batten parrel
    Without a doubt, taking into account the whole package of sourcing the materials, making the sail, and assembling and disassembling the rig, the quickest, easiest and most convenient is the last one. But don't underestimate the amount of cloth it takes to make them, it's surprising how much extra, on top of the sail area; make a full calculation before ordering.
  • 26 Aug 2018 15:21
    Reply # 6639254 on 6639202
    Anonymous member (Administrator)
    Jim wrote:
     At the risk of being tarred, feathered and run off the web, I'm going to start another thread: "Are Batten Pockets Really Necessary?"

    Jim,

    Over the years, many have written to me and suggested alternative ways of joining the batten panels and attaching the battens. Most of these involves nuts-and-bolt solutions, metal grommets or even glue. Those who suggest this have had little or no experience with using a sewing machine and struggle with understanding what a wonderful and time-saving tool it is.

    If one is afraid of having a stub of  broken (wooden) batten stuck inside a pocket, then I suggest one makes the pockets in shorter lengths, say of one metre length. I have so far not needed to replace or repair a single sail panel. I have, however, bent a few battens. Since they are of aluminium, they bend instead of break, so they can easily be pulled out, straightened and then stuck back into the pocket. If you know about a faster way of doing that, then let me know.

    In case it turns out I have under-dimensioned a batten or two in a sail, and need a new one which doesn’t go into the original pocket, I know I can rip open the single seam holding my old pocket and install a new, wider one. With a sail assembled with Amateur Method B this can be done without having to put any of the sail under the arm of the sewing machine.

    Conclusion: One certainly doesn’t need to use batten pockets, but please let me know about any quicker and easier alternative :-) .

    Arne


    Last modified: 26 Aug 2018 20:15 | Anonymous member (Administrator)
  • 26 Aug 2018 14:35
    Reply # 6639244 on 6639200
    Jim wrote:
    I have used hinges + cambered panels, changed to cambered panels, changed back again to flat sail with hinges, and now I'm going to stick with my current approach as giving the best all-round solution - some of each. I want to see all of these in a sail: good performance, easy to look at, easy to set well, easy to live with under cruising conditions. I get all of these with Weaverbird's current sail.
     How things have developed and matured over the years. Do you have a consolidated drawing of Weverbird's sail.? I ask this before looking. Forgive me if you have.

    Jim, you can find some drawings here.
  • 26 Aug 2018 13:34
    Reply # 6639202 on 6638174
    One will of course also need rather roomy batten pockets for this sort of hinges. Malena’s 40mm hinges just made it into the pockets.
     At the risk of being tarred, feathered and run off the web, I'm going to start another thread: "Are Batten Pockets Really Necessary?"
  • 26 Aug 2018 13:28
    Reply # 6639200 on 6639079
    I have used hinges + cambered panels, changed to cambered panels, changed back again to flat sail with hinges, and now I'm going to stick with my current approach as giving the best all-round solution - some of each. I want to see all of these in a sail: good performance, easy to look at, easy to set well, easy to live with under cruising conditions. I get all of these with Weaverbird's current sail.
     How things have developed and matured over the years. Do you have a consolidated drawing of Weverbird's sail.? I ask this before looking. Forgive me if you have.

    I really enjoyed sharing ideas with Arne back in the 90's. Great fun. My second picture was as far as I got on my side. it was intended that the double-spindle be made of strong plastic. A friend who worked for a plastics company offered to have a free set made as a research project. I almost started but I think Arne was shifting his interest to the cambered sail and I backed off to see what would happen there.


  • 26 Aug 2018 09:56
    Reply # 6639079 on 6639077
    Arne wrote:
    Gary Pearce wrote:OK,

    I need to ask a really dumb question here, please excuse my ignorance but .....

    why are hinges needed at all ?


    Gary, 

    I can only speculate why some stick with hinges and some have changed to baggy or cambered panels instead. 

    I have used hinges + cambered panels, changed to cambered panels, changed back again to flat sail with hinges, and now I'm going to stick with my current approach as giving the best all-round solution - some of each. I want to see all of these in a sail: good performance, easy to look at, easy to set well, easy to live with under cruising conditions. I get all of these with Weaverbird's current sail.
  • 26 Aug 2018 09:06
    Reply # 6639077 on 6638897
    Anonymous member (Administrator)
    Gary Pearce wrote:OK,


    I need to ask a really dumb question here, please excuse my ignorance but .....

    why are hinges needed at all ?


    Gary,

    your question isn’t dumb at all. The reason why I built hinges in the battens of my Malena (1991, Newsletter 24), was that I was not satisfied with the performance of her new, flat junksail. The hinges were a quick and dirty method of adding camber to the sail, and thus ‘supercharging’ it. I then built my first sail with baggy panels and straight battens (1992-1994, NL28 and 30). This was partly out of curiosity because photos of some Chinese Junks showed baggy panels. I also looked at my hinges as a sort of stopgap solution. Performance-wise the sails with baggy panels are in the same league as the ones with hinged battens.

    I can only speculate why some stick with hinges and some have changed to baggy or cambered panels instead. The most rational reason for the hinges is that one already has a flat sail in good conditions, so will make use of it, but still improve its performance to windward.

    Aesthetics is another reason.
    My armchair hunch is that our eyes have been adjusted to like sleek, wrinkle-free and spotless surfaces, as seen on cars and grp-boats. In general, sails built with hinges have fewer winkles, and may look sleeker and tidier than baggy sails, like those I make. I remember visitors who came to attend JR rallies in Stavanger. There they got a strong dose of Stavanger junks with baggy panels. More than one said that they had looked as these sail as very untidy, and even ugly, before the rally, but after sailing with them, they changes their mind. However, there are those who still get eye-sore at watching my baggy sails. I guess it’s a question of acquired taste  -  as with most things.

    One fellow, who for sure has not converted to the sleek, spotless aesthetics, is Nick Skeates, the creator of the popular Wylo II design. His boat has a gaff rig while others have rigged their boats as JR ketches. Here is a video clip from Nick’s boat.

    Cheers,
    Arne

     

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

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software