new split junk Oceaan 22

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  • 30 Sep 2020 21:43
    Reply # 9275339 on 9029100

    Thanks for pitching in Slieve.

    I saw on Richard's website (Amina's sail) and here on Rudfolf's design that the current line of thinking is now for 4 panels and 1 top panel.  Emmelene's sail (Amina's old sail) has 5 panels and 1 top panel. Is that more or less correct?

    I 4 * 4,5m2 + 1 * 2m2 should do the trick leading to the following measurements:

    4 big panels: 2,5m * 1,5m (behind the mast)

    4 jiblets: 0,5m * 1,5m

    Battens of about 3,45m

    Current sail is the standard H&M flat sail of about 18m2.

    The Corromandel design really needs a lot a wind to get going, so I think that adding about 2 m2 is not a bad thing. Maybe I am over ambitious. Please set me straight.

    Undoutedly I am missing a host of measurements and I 'l have to work these out from the documentes on the website.

    BUT if you see anything going badly wrong here, I would like to hear it. I'll ask my local sailmaker to eventually build the sail for me.



  • 30 Sep 2020 08:24
    Reply # 9273664 on 9029100

    I'm not sure there was a drawing from me as I can't find one either.

    S

  • 29 Sep 2020 16:07
    Reply # 9272071 on 9029100

    Somehow the email containing the drawing from Slieve seems to be missing. I do have a printed version but that is covered with measurements lines and text added by me.

    Rudolf

  • 26 Sep 2020 12:42
    Reply # 9266227 on 9029100

    He Rudolph,

    Bit odd to do this in english as we are both dutch but it is al for à Good Cause.

    Any drawings you could share?

    Beste groet,

    Antoine



    Last modified: 26 Sep 2020 15:32 | Anonymous member
  • 26 Sep 2020 10:13
    Reply # 9266048 on 9029100

    Hoi Antoine.

    The sail is 23m2 and I built it myself.

    groet

    Rudolf

  • 25 Sep 2020 22:04
    Reply # 9265293 on 9029100

    Hoi Rudolph,

    Who build your Sail?

    Is it about 20m2?

    beste groet,

    Antoine


  • 25 Sep 2020 20:47
    Reply # 9265120 on 9029100

    Yes Arne, the light cloth is a benefit to light wind sailing. The sail sets in the lightest breeze, the cloth is 80gsm ripstop nylon. The sail catcher is from the same cloth which was a bad idea. It is torn in several places. This is caused mostly I suppose by the fact that the rig and mast have to be lowered and erected each time we take the boat out as its berth can only be reached  by passing under a bridge 1.40m high (less with stronger easterlies). Handling it with the sail bundle inside easily causes damage when it snags somewhere.

    Tacking is roughly trough 90 degrees, I didn’t exactly measure but it is as good as you would want it to be. Also there very little leeway, exceptionally little to my mind. The boat really goes where she’s looking. Even on a rough trip upwind on the Ijsselmeer with steep short waves we kept up very well with boats much larger as ours.

    I have given the jibs a lot of thought before I started building the sail. Made a test panel, jib and main scale 1:2 . The only (unworkable) solution I could think of until now was to have batten in the leech of the jib  a bit shorter than the middle panel that is thinner at its ends so it gradually arcs into the shelfs while keeping the leech straighter in the middle. It would not take long for the leech to be shredded I suppose. As they are now the jibs seem to do a good job, different solutions I can think of all seem to be very complicated.  Also performance being as it is there is no great need for changing anything.

    Graeme, the skou has been in the shed for some time. I have had a couple of bad years and didn’t have the energy.  But she really is a fast boat, we have had her planing on a broad reach and passing every boat in sight, amazing. That was with the first (gaff) rig though. With her JR I haven’t met the right conditions yet to try that again.


         


  • 25 Sep 2020 09:43
    Reply # 9264032 on 9029100
    Anonymous member (Administrator)

    Congratulations, Rudolf

    with another successful JR conversion. Apart from your fine work and Slieve’s good design, I think that your choice of light cloth (80gsm nylon) is a factor to the rig’s success. On my 7-panel, ordinary JR for my last boat, Frøken Sørensen, I used the Odyssey 3 of around 220gsm. This was on the heavy side for such a small 20sqm sail (only 2.86 sqm per panel). It could therefore be  reluctant to inflate and set properly in the very lightest winds.

    The load in the cloth of a junkrig panel is so low that it is hard to believe. The general advice should therefore be to aim for no more than half the weight of an ordinary sail of the same area.

    Cheers, Arne


    Last modified: 25 Sep 2020 14:07 | Anonymous member (Administrator)
  • 25 Sep 2020 01:13
    Reply # 9263446 on 9029100
    Anonymous member (Administrator)

    Thanks for the write-up Rudolph. The split junk rig is looking more and more promising, and thanks for outlining the developments you have made.

    I saw a 90 degree shelf (on Zane's Pango, sail by Paul Thompson) and those panels, a little slow to inflate in light wind - once they filled, they looked powerful and the sail pulled very well. What weight of sail cloth did you use on your Oceaan 22?

    Also, I had another look at the photos of your boat (on your opening post to this thread). It is interesting to see the 90 degree shelf forming perfectly on the mains - and compare with the jibs which, supported in an entirely different way, inflate in an entirely different way, giving quite a different final shape compared with the theoretical drawing. I think maybe the design of these bulging SJR jibs with their un-tensioned leech, calls for a different design paradigm than the mains, or the panels of a contiguous sail. It seems to be a bit of an art form to design jibs, and must have been a big leap of faith for Slieve when that first sail was built. And you have now moved a long way from the parameters of the original Poppy.

    Well done. Whatever the theory - "the proof of the pudding is in the eating."

    (While all this is going on, what's happening to your lovely De Skou with its lofty and powerful Johanna sail - superbly adapted to shallow water and canal sailing, she must be a real flyer too?)

    Last modified: 25 Sep 2020 02:38 | Anonymous member (Administrator)
  • 24 Sep 2020 23:33
    Reply # 9263295 on 9029100

    Great to hear Rudolph you’re really pleased, you’ve got me itching to meet other boats on the water now.

    What angle do you feel you are tacking through?

    cheers

    paul

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