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New junk rig leeboarder

  • 04 Oct 2012 20:14
    Quote
    Reply # 1094017 on 1089431
    Anonymous member
    Thanks Ketil,
    Glad to hear the mast is doing well.
    You have got a nice busy racing agenda over there!
  • 04 Oct 2012 20:09
    Quote
    Reply # 1094013 on 1089431
    Anonymous member

    Hi David,

    Never tried googling 'Schouw' before and it surprises me there's nothing to be found.

    The one you found, 'zeeschouw' , is a development that arose after they started building

    iron and later steel boats. These were used for fishing on the former Zuiderzee now

    IJsselmeer.

    The basic type was smaller and used on lakes and canals for all kinds of purposes.

    I designed my boat myself using the 5 panels and bow transom that are typical.

     I like the simplicity of the flatpanel construction. Now I would have built an even simpler

    shape probably.


    The wingsail drew me to the JRA originally as I see it as a potential high(er) speed

    rig. I built two easy rigs for proas from carbon. These are fast boats that need rigs

    that keep their shape. The aero rig has a jib that wil suffer from forestay sag as

    the apparent wind increases. We added backstays on the boom which works but

    things get too complex that way.

    Using carbon could be a good way of building strong and lightweight wishbones for a

    wingsail.

    Do you consider the wingsail suitable for high speed David?

    After all is a high speed sail not just a sail capable of producing adequate lift at 

    high apparent wind speed ?
  • 03 Oct 2012 17:41
    Quote
    Reply # 1092496 on 1089431
    Anonymous member
    Hi Rudolph,
    Thanks for the background information. I tried Googling 'schouw', and got nowhere. Then I tried 'zeeschouw', and got some good images here. The defining characteristics seem to be that there is a bow transom, and the hull is hard chine with five panels, is that right? The shape lends itself very well to modern plywood construction.

    Are you a professional worker with carbon fibre? Since making the wishbones for my wingsails, by assembling from aluminium sections, it has occurred to me that what is really needed is someone who can make a carbon fibre wishbone, all bonded together into one piece, with no weak mechanical fastenings. And what Ketil really needs to go even faster is a wingsail on his carbon fibre mast ... :-)
  • 03 Oct 2012 09:19
    Quote
    Reply # 1092118 on 1089431
    Anonymous member
    I did this the wrong way around, I should have introduced myself first.
    So here goes.
    I am a member of JRA since 2010. Before that I have been watching JR sites fo some
    time. 
    The reason I got interested in the JR  is that I very much like unstayed masts on sailing boats. And an unstayed mast needs a sail to suit. The JR and soft wing sail seem very
    good possiblities.
    I have some experience with aero rigs and initially I was very enthousiastic about the concentration of loads in that rig. Later on I got the feeling it was too complex and
    also in bigger rigs I would like to loose the high strung leeches and things like that.

    So it seems a bit like going back into time but sailing traditional fishing boats from this
    region (Northern Netherlands) tought me these old boats work great if you use them 
    what they are made for.

    I decided to build a new rig for my own boat and choose Arne's preferred sail with
    camber by means of shelf foot.
    Hopefully this be a bit of a basis to have meaningfull discussions on all boating (..)
    subjects.
    Regards,
    Rudolf 


     
  • 02 Oct 2012 15:42
    Quote
    Reply # 1091382 on 1089431
    Anonymous member

    Welcome on board the Junkie brigade. I hope you will have as much fun as I have had using the very versatile junk rig.

    PS. The mast really got a good beating on the return trip. I did not reef until 20 knots of wind when poor Marie G was heeled too much over for comfort.
  • 01 Oct 2012 20:49
    Quote
    Message # 1089431
    Anonymous member
    Finally I sailed the new JR I built for my 10m leeboarder.
    It is very well behaved and easy to sail.
    My boat is a traditional Dutch type called 'schouw' ( scow).
    It has a flat bottom and leeboards, and it is open , no cabin of any kind.
    I built her myself from ply and epoxy in 2000.
    She was rigged traditional with a gaff rig and a relatively short unstayed mast.
    In the end I was not happy with the performance of the rig especially upwind as a 
    jib is not a great idea on an unstayed mast Also sail area was small at 32 m2.

    I considered a new larger gaff rig with a taller mast and stays. But I really like unstayed masts and doing away with lots of deck gear.
    Some years ago I stumbled over Bertrand Fercots "Pha" with its parallel soft wingsails.
    I was looking far an alternative for a high performance rig that would not be 
    high strung as is usual today. Soft wings I still find very interesting but I decided to start with a more 'classic looking' rig a learn to handle that first.

    The rig is a 'Johanna type',designed by Victor Wintertun, with camber by using 
    the shelf foot method.
    It has about 43m2 of projected area. 
    I used tanbark dacron sailcloth. The battens are alu tube 50mm dia.
    The yard is made of PVC foam covered with glass and carbon.
    Also I built a  new carbon mast for this rig.
    To be able to alter mast location if needed and to speed things up (well...),
    I built a temporary mast tabernacle that is a very tight fit between some existing 
    side deck supports and is braced to the existing tabernacle.
    In the design the mast heels forward a couple of degrees. But up to now I have 
    only sailed it (twice) with the mast vertical. As it is balance is good, very light steering 
    loads but maybe the sail will set easier with the mast heeling forward.
    It needs a good pull on the THP to get rid of the creases and the margin seems small.

    Sailing is very different and funny enough it is very unexiting even when off the wind it
    seems very fast. I'm not sure what upwind performance of the rig is but I must add that 
    I sailed it very conservatively to keep the tabernacle in place.
    There are no photos yet of the new junk sailing but I hope to be able post some soon.
    Regards,

    Rudolf vd Brug





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