Ingeborg, Arne's Marieholm IF

  • 17 Oct 2017 23:43
    Reply # 5319342 on 5318091
    Arne Kverneland wrote:Friction problem with the Fan-up preventer. 

    In the new JRA magazine (#75), Simon Foster describes his experience with a Fan-up preventer to my design. He experienced too much friction from it to make it work properly. I too have experienced this to some degree in my Ingeborg. (See posting 25.July 2017). On the lighter rig of Frøken Sørensen, this was not a problem. I suspect that most of the friction is due to the fact that I passed the FUP line inside the topping lift and sail catchers, so it got squeezed as several panels were dropped. I will now pass the FUP line on the outside of the topping lift and add 2-3 rope hoops under the boom where the line can pass through. This should hopefully help. When I have sorted it out, I shall write a little appendix to the FUP write-up, and let you know.

    Arne



    Hi Arne.  I will be interested to see what your conclusion is.  I also found too much friction on Arion when I rigged an FUP based on your design.  It was attached to the top sheeted batten then came down through small saddles near the back of each batten to a turning block on the boom.  It was ok for the first two panels but once I reefed further, the line started to get trapped in the bundle by the nested battens.  I could drag it through with much difficulty but I feared I might chafe the sail's stitching.  Because of the way the battens stagger slightly when nested, it seems inevitable the line will be trapped, even if it is rigged outside lifts and sail catchers.  It seems to me that the system works well for two nested batten but begins to bind after that. I then made two FUPs, one for the upper sheeted battens and one for the lower ones, which worked better, as the upper FUP was not attached to the battens in the lower part of the sail and could pass outside of the nested bundle.  I currently don't have this rigged and just tie the battens together if I am going to sail downwind deeply reefed, but think a FUP system is very useful for long passages and would definitely rig the two FUP version again if I made a long passage.   Roger Taylor has permanent sail ties attached to the upper two sheeted battens that he uses to tie the bundle together when deeply reefed, but that requires accessing the bundle to tie them.  An adjustable FUP, in my opinion, is preferable.
    Last modified: 17 Oct 2017 23:46 | Anonymous member
  • 17 Oct 2017 10:21
    Reply # 5318091 on 3032430
    Anonymous member (Administrator)
    Friction problem with the Fan-up preventer. 

    In the new JRA magazine (#75), Simon Foster describes his experience with a Fan-up preventer to my design. He experienced too much friction from it to make it work properly. I too have experienced this to some degree in my Ingeborg. (See posting 25.July 2017). On the lighter rig of Frøken Sørensen, this was not a problem. I suspect that most of the friction is due to the fact that I passed the FUP line inside the topping lift and sail catchers, so it got squeezed as several panels were dropped. I will now pass the FUP line on the outside of the topping lift and add 2-3 rope hoops under the boom where the line can pass through. This should hopefully help. When I have sorted it out, I shall write a little appendix to the FUP write-up, and let you know.

    Arne


  • 03 Aug 2017 11:00
    Reply # 5009987 on 3032430
    Anonymous member (Administrator)

    High versus low AR

    So why didn’t Ingeborg walk away from La Barca  upwind, in those conditions, with so much bigger sail area?
    The reason can probably be found on the diagram below. It shows two sails of quite different AR and SA, but with the same height of 10m.

    When sailing on the wind, sails are set with about minimum possible angle of attack. The same amount of wind will pass over both sails, and if both sails have been made with the same camber/chord ratio, the wind will also be deflected the same number of degrees. The two sails should thus produce the same lift and induced drag. The broader sail may have a bit more friction drag, but that is a little factor here. In other words, these two sails should produce about the same performance to windward.

    The rig of the Nordic Folkboat is about as tall as the present JR of Ingeborg, so finer details like camber, planform and parasitic drag factors will decide the outcome of such a test race to windward.

    However, wind tunnel tests have shown that sails with lower AR will accept higher angle of attack before stalling, and will even produce a higher force when stalled. This was clearly demonstrated when Ingeborg with her AR=1.90 sail walked away from La Barca, even on a beam reach.

    This phenomenon has been known for a long time. When the Swedish skerry-cruiser classes were developed about 80-90 years ago, they had a fixed sail area. The designers soon learned to make ultra-tall sails, even by today’s standards. They didn’t have to worry about the downwind leg as they were allowed to set spinnakers (and genoas as well).

    So will I build a taller JR, then? No, I will not. I find it very practical to be able to pass under 10m-bridges. I am more tempted to make a new sail for Ingeborg, with 10% camber in it. That would be interesting  -  and sewing a sail is anyway easy-peasy....

    Arne

    20171017 Edit: Actually, the Bermuda rig of a Folkboat starts at deck level so the total luff length of that rig is quite a bit longer than Ingeborg's rig.

    Last modified: 21 Oct 2017 18:16 | Anonymous member (Administrator)
  • 30 Jul 2017 17:40
    Reply # 5002808 on 3032430
    Deleted user

    About sail trimming. Guilty as charged with a pointy sail!

    I trimmed the main on my gaff cutter, slacking off the clew to the give more shape. I also raised the boom using the topping lift to give greater fullness in light winds.

    On my Coromandel I slack the LHP when reaching and Drop the halyard till the bottom parrel is held by the lazy-jacks to get a similar effect.

    This is only my second season under junk rig so I guess all other Junkies know these things!

    By the way, sailing rig stalled gives more heal so a little more length-water-line and increased speed in some hulls with extended bow and or transoms.

    Please keep posting ways of sail adjusting, so we new comers can learn


  • 30 Jul 2017 11:27
    Reply # 5002599 on 3032430
    Deleted user

    Congratulations Arne. 

    A very comprehensive and informative write up of an interesting exercise. 


    I have always liked your belief that a JR boat can safely afford 20/30% more sail area, because it is so easy and safe to reef, and the reefed sail stays just as efficent as the full sail. Something that tends not to happen with reefed Genoas and Pointy main sails. 

    Last modified: 30 Jul 2017 11:29 | Deleted user
  • 30 Jul 2017 11:06
    Reply # 5002595 on 3032430
    Anonymous member (Administrator)

    Last thing first, Annie, the wind direction indicator.

    I did have something like what you describe at the mast top of Johanna. However, I found that the winds around the head of the sail disturbed it when we were running before (and not wanted to gybe). On Frøken Sørensen, and now, on Ingeborg, I use a yard extension stick to make sure the yard will not fall forward of the topping lift, with only three panels set. Then it has been natural to tie the ribbon to that stick. This ribbon lives in quite free wind so it shows the angle between the wind and sail correctly, both when close-hauled and when running before. What I like with the Windex, is the two vanes, which makes it easier to hit the wanted pointing angle each time I tack.

    Pointy rigs.
    To me they come in two main categories; with stiff masts and with bendy masts, as seen on fractional rigs. When the fractional rigs came back in fashion, in the late seventies, their owners soon learned to exploit the ability to flatten the mainsail by tensioning the aft stay. Many new gadgets came on the market; better cleats, winches, “muscle boxes” etc. which made accurate adjustment possible. I doubt if the FB had its mast and mainsail that much adjusted in its first years, but when seeing what could be done to the modern boats, they soon found that the rig of the FB was as made for advanced trimming, and that with simple means.

    One thing I seriously dislike with contemporary Bermudian rigs is all the friction. Unless well maintained or upgraded, the genoa sheet cars get stuck quite soon. In addition, the practice of running halyards inside the mast, plus the fancy one-line reefing mechanism inside the boom, are all real friction traps.

    Less than two weeks ago I crewed on a twenty-one year old Najad 330 around the coast from Kristiansand to Tananger. Despite being a high-quality boat in good conditions, there was a lot of friction everywhere in the rig, even in the roller headsail system. The winches were needed on even ‘light’ jobs. If that Najad were mine, the first job would be to fit a new halyard for the mainsail and run it outside the mast. Same with the reefs; I’d fit ordinary slab reefs.

    Finally
    This little race was against a well-tuned (if not top-notch) FB. Just as when Edward Hooper races against well-tuned Splinters, one should not expect to win. Still, by disregarding sail area limitations with respect to handicap, as I do, it is possible to achieve about the same elapsed time in a race from A to A as those with BR. That is good enough for me.

    Cheers, Arne

     


    Last modified: 30 Jul 2017 11:08 | Anonymous member (Administrator)
  • 30 Jul 2017 01:32
    Reply # 5002298 on 5001482
    Arne Kverneland wrote:I have crewed many times in La Barca on Wednesday races, and I can ensure you that the mainsail’s camber is being adjusted quite frequently. The clew is attached to a runner on the boom, and the clew outhaul is easy to operate  -  just pull a string. Then there is the aft stay tensioner and finally the diamond stay tensioner; a bottle screw on the front of the mast. This last one is generally only set up at rigging the boat, and it limits how much the aft stay can bend the mast. Since there is no time for reefing a sail during a short race, the ability to flatten the mainsail quickly, to depower it, is important.

    In addition to this, the Folkboat has a ‘wall-to-wall’ mainsheet track, and as the photos shows, La Barca has quite a bit twist in its mainsail (I bet the mainsheet car has been pulled up to weather when close-hauled.). That twist does not just happen, but is an important part of the tuning of the sail, since the top section has no foresail in front of it.

    This sounds complicated, but tuning the sails involves very little sweating, as these controls are quite light.

    I wasn't really suggesting that these controls are difficult to manage, just that the majority of sailors can't be bothered with them.  I've sailed on lots of different pointy rig boats with lots of different skippers in my time, and don't remember many of them even glancing at the genoa car, let alone adjusting it.  When I bought my Raven 26, the cars were just about seized - it took a couple of hours to get each one free and the lever moving.  They were in completely different places on the track, one about 250 mm further forward than the other.  This was with a roller reefing jib which, I had thought, should have the lead adjusted each time a couple of rolls are turned into it.  My point really, was that the average junk rigged cruising boat- with a rig as good as yours - will probably be just as efficient for her average skipper as she was with bermudian rig.


    It's great that another FB is getting junk rig.  I'm looking forward to hearing about her.

    BTW I don't know how you can sail without a wind direction indicator!  I can't cope when sailing a boat without one.  Now I understand even more why you love your telltales.  I find the best and cheapest, is a metre of bamboo with a screw in the top.  Two washers on the screw and between them, 600 mm of something like ribbon (mesh, like you find lining pockets of togs or sports pants is best), with a hole at one end either melted in or sealed with glue and held between the washers.  You put up the cane like a burgee stick (two clove hitches, one in the middle, on at the bottom) on a spare (light) halyard, hauled to the masthead, with most of the cane well above the tricolour light.  This sort of telltale doesn't foul and is very sensitive to any wind. 


  • 29 Jul 2017 18:11
    Reply # 5001819 on 3032430
    Anonymous member (Administrator)

    Ketil

    The whole idea with this test was to compare the rigs, and as much as possible eliminate tactics and changes in wind-strength and -direction. As for Ingeborg’s bigger SA; to my defence; Allan could, and probably did adjust the camber in his big mainsail, something I cannot do. Moreover, the FB didn’t have to sail a straight run, so was saved from falling badly behind us there. I can easily live with up to 5% speed difference to windward. We were fully close-hauled most of the last leg, and Ingeborg only spent 3,6% more time on it than La Barca, so I cannot complain. Whether the beat is two or five miles long, should not make any difference, percent-wise  -  the stern of the faster boat only gets smaller at the end of a longer leg.

    None of us have electronics on board to monitor speed through water, or wind data. La Barca has a Windex in the mast top. I consider fitting one as well, as I am not very good at landing on the right pointing angle after each tacking. However, I am quick enough to tack if the wind shifts.

    Arne

    PS:
    Allan went cruising after our test. In the evening I got a text-message, simply saying “
    40m2!“: He has now got a 23sqm gennaker, which added to his 17sqm mainsail should be...
    Let’s hope he doesn’t break another mast.

     


  • 29 Jul 2017 16:35
    Reply # 5001705 on 3032430

    Hei Arne,

    Your Writeup sums up the performanceof the junkrig pretty good. Running and reaching agaist a boat without spinnaker is a piece of cake. You even cheated With a bigger sail aerea. If you had a long beat,you would see the difference, and he would probably massacrete you by beating in the windshifts. As you sailed together, tacticts did not interfered With the results. Very Nice done, and results as I have experienced it. Put the Write up in the section of measuring junkrig performance. 

  • 29 Jul 2017 11:11
    Reply # 5001482 on 3032430
    Anonymous member (Administrator)

    Thanks Annie.
    It was quite a relief to find that my Ingeborg performs at least in the same league as the FB to windward. It both did, and did not surprise me that La Barca did so well on the reach legs. That big, easily tuned mainsail is good, and Allan knows how to use it. (..neither the mainsail nor jib is ever stuffed in bags  -  Allan take the racing sails off and roll them up after each outing...)

    I have crewed many times in La Barca on Wednesday races, and I can ensure you that the mainsail’s camber is being adjusted quite frequently. The clew is attached to a runner on the boom, and the clew outhaul is easy to operate  -  just pull a string. Then there is the aft stay tensioner and finally the diamond stay tensioner; a bottle screw on the front of the mast. This last one is generally only set up at rigging the boat, and it limits how much the aft stay can bend the mast. Since there is no time for reefing a sail during a short race, the ability to flatten the mainsail quickly, to depower it, is important.

    In addition to this, the Folkboat has a ‘wall-to-wall’ mainsheet track, and as the photos shows, La Barca has quite a bit twist in its mainsail (I bet the mainsheet car has been pulled up to weather when close-hauled.). That twist does not just happen, but is an important part of the tuning of the sail, since the top section has no foresail in front of it.

    This sounds complicated, but tuning the sails involves very little sweating, as these controls are quite light.

    I still think that the Bermuda rig of the Folkboat is just about the best that has been designed for a little boat. Just look at the simple staying on the second photo of that write-up. The only, small penalty is that the mast section must be about 10% bigger than on similar rigs with lower and upper shrouds.

    As for Ingeborg’s performance. I don’t think her extra sail area is of much help to windward. It is the length of the luff and amount (and shape) of the camber which decides the all-important drag angle. However, as the sailing angle to the wind is widened, the extra area pays back, more and more. During this match race, I learned to sheet in the sail harder on the reach, and just let the leech telltales collapse most of the time. On the wind, however, it is still best to have the telltales flying, or just flying, in light winds.

    Before I make a new sail, I will hear from a JRA member in Denmark who is rigging his IF to a slightly revised  JR sailplan, with shorter battens and with AR=2.00 (Ingeborg; 1.90). If that turns out to be good, I might make a copy of it, but with 10% camber.

    Arne


    Last modified: 19 Aug 2017 21:52 | Anonymous member (Administrator)
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