Proa Junk Rig Conversion......

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  • 27 Aug 2019 10:49
    Reply # 7851183 on 7833205

    Sure Rael, I am with you on most of what you say.....  getting under way after a shunt happens surely and easily when sail has ample lead over lateral area or there is thrust from a paddle or blade of sorts, like your AD scull. On small proas the sculling overcomes even a lack of sail lead, so we could consider a 30 footer as being a good test case.

    Thinking  about this swing Junk rig, I think that it should be be able to work on my Pahi,   if the motivation, energy and financial outlay is justified enough to shove  things along  to produce the required gear.

    Swinging the sail to the new head should in theory be hassle free with development to take care of surplus sheet ends, which might work with a boom that swings through only 90 deg.

    Having 360 deg rotation of the boom would require a free standing pole mast and I have to agree that cost and weight will go up considerably.

    Also, I like and for practical purposes will retain the traditional shroud, which does relieve the hulls connecting structure of much loading that the unstayed mast bury area of the lee hull would have to bear.

    Headstays are indispensable, so I think the sprits on my Pahi could possibly be used for carrying a ghoster, and inner stays could be runners.

    Last modified: 30 Aug 2019 21:04 | Anonymous member
  • 25 Aug 2019 21:23
    Reply # 7848368 on 7833205

      Jeremy, well, a traditional Pacific Proa rigged with a crab claw and a canting mast will put the CE way ahead of ship centre, vs many modern proas which are rigged with all sorts of rigs that many of them, have CE's way aft.... Bermudas that furl their jibs before shunting, too are poor and slow shunters....

      On both my previous proas with their CE's aft of centre, on the one I would get caught in irons after every shunt, on the bigger one which was schooner rigged, most shunts would end up backwinded!

      Finally, I can say, third time "I got lucky...." this junk rig is a pleasure to shunt. He falls off and sails away in perfect control on a close reach after every shunt, just like a  properly designed Crab Claw with a canting mast would. 

      We still have to prove the advantages of shunters vs tackers, that much I agree, cos we both agree that there are many, still there are a few hurdles to overcome...

      Rudders are something I think a lot about.... For now on a small boat, the steering oar seems pretty good, still far from perfect.

      A boom that  rotates 360 degrees, to me sounds like an unstayed mast.... I doubt you would ever see such a rig on my boat, since I believe the wind should lift the ama through shroud tension, vs hanging the ama off the akas and forcing the builder to build ether very expensive akas or very heavy ones........

      All d best.

    Rael

  • 25 Aug 2019 00:48
    Reply # 7847710 on 7833205

    Rael, what you describe as "white mans problem" re sail area lead when making way after a shunt has always been just so without necessarily being a problem, but when single handing it does become more demanding - certainly in the case of  complexity and very likely in the case of cost.

    My reason for  shunting might only be the same as your's as far as the cost (in $) goes, so we can best continue discussion on this subject once more cruising time on the water has accumulated to prove the effectiveness of our respective lifting rudders.

    Once the rudders have been sorted, I would like to see a sheeting system that controls the free end tidily and effectively......probably along with a boom that rotates through 360deg.

    Last modified: 25 Aug 2019 00:51 | Anonymous member
  • 22 Aug 2019 05:47
    Reply # 7842996 on 7833205

    Jeremy, early testing with "Why Not?" years ago, which was flat bottomed showed a huge advantage to windward with a leeboard vs without. Make O'Break is flat bottomed and much wider then Why Not? therefor drawing less, but sails to windward extremely well, I was making upwind destinations in no time with him. I'm happy with the windward ability of this boat, if I had a GPS I would gladly test him with and without the board.......

    Tacking? as cheating as it was.... Since the bow went through the wind, it's a tack. That's the huge advantage of the scull and having low bows, I will keep on with low bows vs high bows, More like Atlantic proa Cheers VS Russ Browns Jzerro. So if a bigger cruising version had an engine and lifting rudders, it could tack all day long, using the engine to push her through the tack, as long as windage is kept to a minimum.....

    An unstayed rig will carry the CE way aft, requiring what ever to bring the CLR there, I find this to be white man's greatest problem with proa design! Why add weight and drag when all you had to do was move the sail ahead?????? Most modern proas carry their CE's way aft, after shunting they keep floating there caught in irons, waiting for the CLR to fall aft till they get going.... I had this problem in previous proas and will never tolerate it again, in close quarter sailing its a damn pain in the bum.....

    AMA to WINDWARD! at ALL TIMES!! Still, if under emergency, a Pacific could become an Atlantic I see nothing wrong with that.

    A bigger version for cruising will have a small outboard and lifting rudders, After my Greece cruise with "Why Not?", I mentioned in the video, that lifting rudders are coming up....... The Oar is too clumsy.

    Jeremy this is the simplest way I could come up with having a proper shunting and reefable sail that truly works on a proa. Cruising versions of around 30 feet don't seem to be a problem, the way I see it anyway..... Time will tell.

    Gonna go cruising autumn with him and if I like most of the design..... Next year this type of rig goes onto My 23 foot proa that was designed for cruising, from there, if the force is strong with us we will get bigger...............   

    Keep Shunting man!

    Rael.

  • 22 Aug 2019 04:45
    Reply # 7842965 on 7833205

    Rael, if you are dead set on using a daggerboard, for whatever reason then at least one if not a pair of other steerer foils are needed.

    Looking more carefully at the footage it shows you rowing with that AD scull to get the craft veered through the wind when tacking, so a rudder probably would not achieve that yaw moment and  the cat idea would fail.Also, it was more like a 1/2 jibe to get the ama up to w/ward...is cheating as far as tacking goes.

    You do use stays as well I see and the only way to get rid of them would be to step the mast free-standing, which calls for use of boards to effect balance, so it's back to two steerers anyway and being able to shunt keeps the ama to w/ward, where we want it hey?.

    Scaling up and carrying the scull over at each shunt looks to be problematic, though, so I am all for having two bi-directional rudders, which is a way. to get around need for the daggerboard.

    I hear what others are saying about the need for shift of CE when shunting and notice how this is working in for you, well done.

    The movie and design certainly shows how successful it gets in flat water when kept to smallish scale.

    Not to challenge you, but hoping you find reward..... waiting to see the cruising version.  

    Last modified: 22 Aug 2019 04:52 | Anonymous member
  • 21 Aug 2019 06:02
    Reply # 7839067 on 7833205

    Jeremy, Always good 2 hear from you. Yes, works better then expected.....

    So putting this on a cat as long as it has shrouds and a head stay no problem, but that would just be an ordinary stayed junk rig on a cat. Still I didn't really get your point about bi directional rudders on a cat? or did you mean on a proa?? Please explain that idea in detail, it's interesting.

    As for this concept Bum steering could be made to work, and dagger must be raised, true, but that daggerboard is amazing! don't forget these are two flat bottomed hulls...

    Going to the shipyard....

    All d best

    Rael. 

  • 21 Aug 2019 04:10
    Reply # 7838994 on 7833205

    Noticing that tacking was a solution when backwinded and that sailing off the lee shore  seemed to work out with the ama to lee, it figures that an asset of the rig is it's ability to be stepped above deck on a multi.... should thus suit a catamaran as well as a proa and then the cat configuration wont require bi-directional rudders.

    When sailing witht ama to w/ward in PAC proa mode, the balance is neat and the old 'bum steering' ( weight shift steering method) might even be a goer, if getting rid of underwater appendages is considered. 

  • 20 Aug 2019 21:23
    Reply # 7838421 on 7833205

    Thanks Scott,

    It FEELS amazing, It's been a long road, almost to hell and back, One sentence kept me going..... "You didn't fail till you quit" so I went on and it worked! 

    All d best.

    Rael.

  • 20 Aug 2019 21:19
    Reply # 7838419 on 7833205

    Graham, I do  intend to finally go cruising, Greek Islands, it's high time!

    Been a long 7 years and 3 proas that kept getting smaller and smaller, The first one a 23 foot bomb shell that almost killed me is waiting for such a rig which will happen spring next year. Next, I hope to build a 33 footer, a 10 meter, Still I feel I will be able to work it the same way, a bit of muscle, not more..... The wind does half the work for you anyway....

    Just for fun, here's Crystal Clears maiden voyage, This girl flattens seas......

    https://youtu.be/4yAm2QgKc1c 

    And Thanx for sharing your opinion about the potential, cos I really hope this thing changes what many people think about Pacific Proas. Cos I have a dream.... A day will come, and in every marina the will be  a junk rigged proa.........

    Last modified: 20 Aug 2019 22:32 | Anonymous member
  • 20 Aug 2019 21:08
    Reply # 7838381 on 7833205

    Phil, thanks, yea this rig has been under development for 2 years, it did burn out most of my brain cells..........

    Finally recovetrng!!!!

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