Flat, hinged or cambered?

  • 14 Mar 2011 15:08
    Reply # 545453 on 465078
    Graham Cox wrote: OK David, thanks. That gives me two clear options.  My major concern about what choice to make lies not in appearances, but a desire to be able to reef and unreef the sail on a pitch dark night without getting into a tangle or needing to make a lot of adjustments.  Having only limited experience with flat sails and none at all with cambered or hinged, I am trying to read everything I can, ask lots of annoying questions and try to learn from those of you who do have the experience.  The problem with academic knowledge, as opposed to hands-on experience, is that one can get off on a tangent.  My reading seemed to indicate that, in a cambered sail,  the loss of diagonal panel stability gave it a new set of handling characteristics, namely creasing and unpredictable batten stagger.  I can see that the creasing is easy to resolve using either Hong Kong parrels or multiple luff-hauling parrels, but remain unsure about the implications for batten stagger.  My current understanding is that this is not an issue with a fanned sail but may be with the Hasler Mcleod sail.  Obviously it works for Arne so I am sure I can make it work too.  What I am trying to do in this forum is clarify things in my mind.  If there are others out there considering cambered sail upgrades I assume they will also be interested in these matters.


    Hi Graham,

    I have been sailing Edmond Dantes a few seasons now, having reefed and shaken out reefs, dropping and hoisting sails a few times. I can assure you that the battens land just how they please, but I have never had any problems with snagging at the rear end of the sail. Any problems occuring is at the other end, but are easily sorted, but I have to move to the mast to sort snags with parrels/ Hong Kong parrels. Hong Kong parrels sometime gets trapped under the next batten and has to be freed. I have thrown away the luffhauling parrel as it dit not do any significant differece. I have a shock cort tied to the boom to stretch the luff, and ties the battens as I reef to have a taut luff, (good for performace). I find the rig much simpler and easier to use than anticipated after reading all the hot air theory in the various foras discussing this wonderfully simple and efficient rig with the unfortunate name Junk Rig.

    Regards

    Ketil Greve

  • 13 Mar 2011 19:51
    Reply # 544932 on 461931
    Deleted user
    I was finally given a good picture of Easy Go under sail. As a picture is alway worth a thousand words it is better to see it in the Photo Gallery of JRA member's boats. The picture is high res and shows lazy jacks, chafe protection, running parrels, standing parrels and sheeting on flat sails. She is reefed as we are pulling away from a wharf under sail and low powered. Just getting ready to shake out the reefs and bring her up to speed.

    http://www.junkrigassociation.org/resources/SiteAlbums/781899/easygosailing.jpg
    Last modified: 13 Mar 2011 19:51 | Deleted user
    Merged topic from TECHNICAL FORUM: 15 Aug 2018 20:49
  • 18 Nov 2010 02:25
    Reply # 465099 on 461931
    Some of this is a copy of what I put on the R & D forum but I wanted to include it here too.  My major concern about what choice to make lies not in appearances (I am an untidy person at the best of times and my favourite word in the English dictionary is ramshackle!) but a desire to be able to reef and unreef the sail on a pitch dark night without getting into a tangle or needing to make a lot of adjustments.  Having only limited experience with flat sails and none at all with cambered or hinged, I am trying to read everything I can, ask lots of annoying questions and try to learn from those of you who do have the experience.  The problem with academic knowledge, as opposed to hands-on experience, is that one can get off on a tangent.  My reading seemed to indicate that, in a cambered sail,  the loss of diagonal panel stability gave it a new set of handling characteristics, namely creasing and unpredictable batten stagger.  I can see that the creasing is easy to resolve using either Hong Kong parrels or multiple luff-hauling parrels, but remain unsure about the implications for batten stagger.  My current understanding is that this is not an issue with a fanned sail but may be with the Hasler Mcleod sail.  Obviously it works for Arne so I am sure I can make it work too but I'd appreciate some more feedback on this point.  What I am trying to do in this forum is clarify things in my mind.  If there are others out there considering cambered sail upgrades I assume they will also be interested in these matters.
    My experience sailing Arion with Bermudian rig concurs with Annie and Arne's conclusion -  weatherhelm is always a sign of carrying too much sail and I can cure it by reefing, in particular the main, (with a lot more effort than on a junk!) but once again, I am uncertain if this is the whole story in junk-rigged yachts.  Some  comments suggest that part of the problem lies in the centre of effort being so far outboard and I note that Annie sailed Badger under the main downwind, with the foresail sheeted in flat, having discovered that the boat wanted to round up when Badger was sailed under foresail alone.  Can you clarify this for me?   On Arion, moving the sail area forward is also beneficial when pressing the boat hard to windward.  I end up with a double-reefed main before I start reefing much of the headsail on its furler.  My sistership eases the sail forward by about 600mm, until the luff is parrallel with the mast, when the wind freshens, whatever the point of sail.  This seems to be a function of the beamy, cat-boat-style  hull developing weatherhelm when heeled.  Sailing to windward with the junk rig I will at least be able to adjust the sail area to achieve optimal heel without a lot of effort.  The boat's balance would benefit from a two-masted junk rig but I feel it is too small for that.  I note also that a number of single-masted junks, including Tystie, set their rigs up with variable balance.  However, I also know how easily driven Arion is off the wind.  Pushing hard, I can sit on 5.5 knots all day but am on edge all the time.  If I reef, the speed drops to 4 knots and I can go back to my book, so hopefully, given the ease of reefing the junk rig, this will be the easiest option.  However, I am still curious about this balance issue.  Mostly, I look forward to getting the rig in the boat and developing my practical knowledge so that I can stop annoying you all.
  • 18 Nov 2010 01:30
    Reply # 465078 on 461931
    OK David, thanks. That gives me two clear options.  My major concern about what choice to make lies not in appearances, but a desire to be able to reef and unreef the sail on a pitch dark night without getting into a tangle or needing to make a lot of adjustments.  Having only limited experience with flat sails and none at all with cambered or hinged, I am trying to read everything I can, ask lots of annoying questions and try to learn from those of you who do have the experience.  The problem with academic knowledge, as opposed to hands-on experience, is that one can get off on a tangent.  My reading seemed to indicate that, in a cambered sail,  the loss of diagonal panel stability gave it a new set of handling characteristics, namely creasing and unpredictable batten stagger.  I can see that the creasing is easy to resolve using either Hong Kong parrels or multiple luff-hauling parrels, but remain unsure about the implications for batten stagger.  My current understanding is that this is not an issue with a fanned sail but may be with the Hasler Mcleod sail.  Obviously it works for Arne so I am sure I can make it work too.  What I am trying to do in this forum is clarify things in my mind.  If there are others out there considering cambered sail upgrades I assume they will also be interested in these matters.
    Merged topic from TECHNICAL FORUM: 15 Aug 2018 20:49
  • 17 Nov 2010 20:16
    Reply # 464852 on 461931
    I, too, am surprised that people should think a cambered sail will be more difficult to set up.  After all, it's essentially a flat sail with baggy bits.  Now I can see that the more obsessive/compulsive personalities (such, I regret to say, as myself) may end up getting grey hairs in an effort to eliminate every crease and wrinkle, but even I can see that they don't matter.  Certainly on Badger, we would put the sail on and then twitch standing lines over the next week or so until we were pleased with the overall appearance.  But sailing with Badger taught me that junk rig isn't tidy, especially once the sail is reefed.  You may not like it, but you just have to live with it.

    And Arne is so right about reefing.  The debate about 'excessive weather helm' on single-masted junks has been going on for as long as I've been a member of the JRA - and I was one of the first.  For all that time, plaintive voices have been saying: if you have too much weather helm, reef the sail.  And still people come back and say they have too much weather helm when reaching fast.  They forget how efficient the rig is compared with those silly triangles - it's powering you along while the triangles are backing and filling.  Drop a couple of reefs and relax, otherwise you might spill your beer.

    Meanwhile, back to pondering how to pull in the lower taper on my mast.

    Annie
  • 17 Nov 2010 09:24
    Reply # 464541 on 463865
    Graham Cox wrote:

      So, to sum up, my idea involves using my existing Hasler Mcleod sailplan, and building a standard cambered sail from Odyssey 111 material, with 6% camber, barrel or horizontal cut, but with one hinge as well to give me more effective camber.  If this is a good idea, where is the best place to put the hinge?

    This is just about what I did on Ivory Gull, Graham, with a hinge at 40%, but with less than 6% camber built in . That was in the early days of cambered junk sails, when we were gently seeing how far we could go. I have no way of knowing what will happen with 6% camber plus a hinge, but my instinct  tells me that you've lost the advantage of putting in a hinge, if the after part of the sail is no longer flat, and you'd be better off with  fully cambered sail and no hinge.
  • 16 Nov 2010 19:07
    Reply # 464189 on 461931
    Anonymous member (Administrator)

    Stavanger, Tuesday

    Hi Graham and all

    The complexity of "setting up" the cambered panel sail.

    I wonder what has happened. How has this myth been developed that the cambered panel sails are difficult to set up or operate? Is it because of the problems with the Sunbird sails which seem to be set up without Hong Kong (HK) parrels and even batten parrels? Or is it just "being felt" that cambered panel sails are difficult to handle, just because?

    The procedure of initial setting up a cambered panel sail is mainly to get the HK parrels right. I adjust them one by one as the sail goes up the first time. Then I maybe readjust one or two of them once or twice the next trip. Job done. From then on the sail is "flat" with respect to handling. The job of setting up the HK parrels will be the same whether the camber has been made to be 4, 8 or 12%. Don't let any one tell you that it is complicated.It is not. As for looks, most tastes are acquired -- I have always meant that a fullrigger's rig is a real mess...

    Rudder

    You write that my Johanna must have exceptional balance. Yes, she has a well balanced hull, but even Johanna will run out of rudder if pressed hard on a beam-to-broad reach. On that leg she will be heeling and the whole sail will be well outside the boat (more than when running). The speed will be touching 7.0kts, the "sound barrier" of that hull type. Dropping a panel or two will restore easy steering and the speed will have dropped with less than 0.5kts. If you look at Johanna’s rudder in my photo section, you will see a really good rudder: The position is well aft, the size is ok and a generous balance horn ensures light tiller forces (Tom Metcalfe’s article in the NL55 shows how much problems you get if an inferior rudder has been fitted). It is my opinion that the matter of rudder authority has almost been disregarded by the western JR world. This is in big contrast to the Chinese who fitted their boats and ships with huge, balanced and retractable rudders. They didn’t seem to rely on shifting the mainsail over to lighten steering. And of course, they didn’t have the downwind-friendly square sails.

    We have still much to learn...

    Arne

    Last modified: 16 Nov 2010 19:07 | Anonymous member (Administrator)
  • 16 Nov 2010 04:29
    Reply # 463865 on 461931

    As I have just written in the General Discussion forum, under "Flat, hinged or cambered sails", I am working towards building a standard cambered sail, with barrel-cut or horizontal panels, as Arne does, but with a maximum of 6% camber as David suggests, hoping to minimise any setting up issues. A few wrinkles don't worry me.  However, I agree with Arne that I could benefit from more camber, so am thinking of combining the standard 6% cambered sail with one hinge in the middle of the batten as David suggests.  I understand and like the benefits of David's suggestion to make the back half of the sail flat, but to get more than 6%, say 10 - 12% camber, I would need to have a lot more draft in the forward section of the sail and I don't know if I want to do that, as I immediately think of things flapping again.  Really, I don't want to see another flapping sail in my life once I make this conversion.  I want to let the sheets go and know the sail with weathercock quietly.  It occurs to me that if I put the hinge right in the middle, without making the back of the sail flat, that the camber may end up a bit too far aft.  Perhaps, with a fully-cambered sail, if I put the hinge at 40% it would be better?  40% of 4.6m gives me 1.84m forward of the hinge, so I assume I should be able to move the sail across the mast off the wind to some extent without reverse hinging?   So, to sum up, my idea involves using my existing Hasler Mcleod sailplan, and building a standard cambered sail from Odyssey 111 material, with 6% camber, barrel or horizontal cut, but with one hinge as well to give me more effective camber.  If this is a good idea, where is the best place to put the hinge?

    Merged topic from TECHNICAL FORUM: 15 Aug 2018 20:49
  • 16 Nov 2010 03:20
    Reply # 463814 on 461931
    I had a chuckle over Annie's suggestion that I could snip off the camber easily enough if I find I don't like it - the same idea had occured to me but it seemed almost sacreligious to say so!  My questions about negative batten stagger relate to my reading Arne's comments in his article titled "Batten stagger in cambered sails", (see Arne's page) which appears to say that his cambered sail developed negative batten stagger when reefing the first panel, leading him to shorten his boom, and neutral batten stagger above that, where he used rubber hose extensions, as well as doubling the rise in boom and battens from the standard Hasler Mcleod sailplan.  The Hong Kong Parrels help of course but they go slack as you lower each panel.  That is why I was wondering about multiple luff-hauling parrels (but I wouldn't leave off the standing parrels as some do).  And, unlike Arne, I want to use long standing parrels, to allow me to adjust the balance of the sail when off the wind, as this has proved beneficial on my sistership - Arne's boat seems to have exceptional balance on all points of sailing, which may account for his not needing to do this.  Otherwise, I like Arne's sails, both the way they look and their construction method.  The wrinkles don't worry me at all.  (But then I never was much of a fancy yachtsman, just a scruffy South Seas vagabond.)  I love the wonderful photo in the frontpiece of Practical Junk Rig, showing a junk sailing wing and wing up the harbour.  Now there are some baggy sails!  A friend who has sailed extensively in the East mused to me once that Eastern junk sails were all baggy, unlike the then-contemporary flat Western sails, and he wondered if there wasn't a reason for them being so, besides their material construction.  I have until January to make my final decision on the sail but at this stage am favouring a little bit of Arne, a little bit of David, that is building the sail with Arne's barrel cut, or horizontal panel method, but building the sail much flatter that he does, sticking to the 6% camber David suggests, which I feel will reduce the amount of 'setting up" required.  However, I also agree with Arne that a slow, heavy, short, fat boat like mine would benefit from 10 - 12 % camber - I am just not willing to build it into the sail, so I am very interested in the idea of combining camber with one hinge and will be going now to the R & D page to ask more about that.
  • 15 Nov 2010 22:37
    Reply # 463632 on 461931

    In the Article 'Some Thoughts' published in Newsletter 40, I mentioned the idea of using camber combined with hinges to get the camber right forward in the sail, so I find it interesting that the idea is now being discussed. I must admit that I am not a fan of hinges, believing that a 'solid pole' has less to go wrong, but it would be interesting to see how the combined camber/ hinge would work in practice.

    For some reason some people seem to have the idea that cambered panels are complicated and difficult to live with. I have been told that even the commercially built shelf foot sails are causing a lot of fiddling to set them up. Making enquiries about this I find that the 'professionals' do not seem to clearly understand Arne's simple cambered rig. For some reason they are rigging the sails with neither batten parrels nor Hong Kong parrels, and are trying to remove creases with multiple luff hauling parrels which need to be adjusted on a regular basis.

    The simple Hasler/ Mcleod sail with cambered panels only really needs standing Hong Kong parrels to replace the diagonal stability and rigidity of the flat sail to make it behave like a simple flat sail, but with the added performance. Why make life difficult when it is really quite simple?

    Incidentally, I am not 100% convinced that the shelf-foot method of building the commercial version of the cambered sail is the best way. Looking at the 3 pictures of Jonathan Snodgrass’s ‘Lexia’ in the newsletter 55 I feel there is more material hanging around than is necessary. When I told Chris Scanes that I had used a variation of a shelf-foot to make the ‘jibs’ of my split rig he rushed off and started building the sails with the simple shelf-foot as he could understand them. He didn’t listen when I explained that I had modified the shelf-foot idea and ended up with the same camber but with less material across the panel.

     

    Chris claims that the shelf-foot is easier (do we understand ‘Cheaper’) to build than round and broadseam method I talked him through for his first successful cambered sail, but I feel that he used it because he was not happy the calculations I had done for the latter sail, and could not guarantee to reproduce them for a different sized sail. The real question when you look at Lexia’s sails is, if using the shelf foot method, should it be modified to improve the set?

     

    Personally, I still think that if you are worried about the little wrinkles in Arne’s sail then the vertical cloths with Round and Broadseam is probably easier and quicker to build than the shelf foot when the calculations are run off on the computer.

     

    Cheers

    Slieve

     

    PS.

    Reading the above after posting it I realise I may have given a wrong impression. The point of the posting was to encourage the readers to question and discuss if there may be a better method of making the shelf-foot sails. The reference to the photos of ‘Lexia’ were an attempt to illustrate the point and not to criticise the boat or its sails. Speaking to Jonathan before I wrote the above he told me that the photos were all taken in a flat calm, and in such conditions all cambered sails will show some excess cloth to a greater or lesser extent over a flat sail as on the Barbican 33 ‘Janvier Aquila’ in the third photo. Jonathan did confirm that when a light breeze did arrive ‘Lexia’, with her cambered sail did show the expected better performance over the flat sailed boat. There is no question in my mind that a cambered sail will outperform a flat sail, and in particular when sailing to windward. I am convinced that Jonathan was right in fitting cambered sails to 'Lexia', and will enjoy the better performance they will bring. My question is ‘can the shelf-foot sail be built with less material to do the same job?’

    PS This is a straight copy of my post in the R & D forum.

    Last modified: 15 Nov 2010 22:37 | Anonymous member
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