A proa and aero junk or split rig questions?

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  • 26 Nov 2018 05:00
    Reply # 6932235 on 6928257
    Anonymous wrote:

    Jeremy, thanks for the clarification that the boat you are building is a traditional Tahitian Pahi and not the Wharram cat.  I have cruised with Wharram Pahis, though, and they are capable little boats.  I look forward to seeing more of your project as it progresses, both the general design and how you develop the rig.

    Maybe I have been greatly influenced by Russell Brown, but for me, the Pacific proa, with its ama always to windward, is the only proa I am interested in.  That means it shunts, of course, and the bow becomes the stern.  So the challenge is to evolve a rig and rudders/steering oars that can be easily reversed without running around all over the boat like a demented chook.  I'm also focused on liveaboard cruising, usually singlehanded. 

    The rudders are merely a matter of choice.  I like the simplicity of steering oars, but pivoting on the beams, a few feet out from the main hull, rather than at the "now" stern, as in traditional craft.  The steering oar is held down by a "kicking strap" that passes through a turning block in the cockpit floor.  This is released when you want to lift the oar and a downhaul at the inboard end holds it clear of the water.

    The other option I like is Russell Brown's daggerboard lifting rudders, in cases, but these seem vulnerable to damage.  Russell had downhauls on his, and could raise and lower them from the cockpit. 

    Because Russell's jibs were hanked on, he still had a bit of running around to do.  Mind you, he mostly strolled.  With roller-reefing jibs, you could theoretically stay in the cockpit with his rig, but I am keen to see a workable reversing junk rig that both retains its balance in both directions and does not require shifting too much stuff.  basically a rig that can be entirely worked from the cockpit. 

    I think the 'start small and work your way up' approach has a lot of merit, either with models or dinghy-sized proas, allowing one to experiment with different ideas at reasonable cost.  I am busy cruising at the moment (and researching articles for the JRA) but I am watching this space with keen interest.

    Graham, the shunting Polynesian Pahi is the Tuamotu archipelago canoe, whereas the Tahitian one is a tacker, and probably why Wharram uses that name, and also because it has a v bottom, while the Tahitian Va'a is a flattish bottomed dugout.


    My pahi (named Pahi Iti) has a chordate hull section, though, like the original.

    Like most people, Wharram apparently does not think the Polynesians built or sailed shunters, until Fijians showed them how.

    Anyway, there is enough evidence to reveal that they did in fact shunt their double ended Pahi, using Oceanic sprit sails on two masts and steered with long steering sweeps.

    Effectively, the bigger lee hull is the vaca, and the smaller w/ward one the Ama....pretty much the Pacific Proa configuration, in that there is a dedicated windward side, as is there a lee side......not too different to the way a Russel Brown proa sails.

    Rudders on my Pahi are not too very different to the steering oars you mention, except that they have much more blade and very short looms, with  tiller control. They do have the the kicking strap, beside other simple rigging components.

    Main difference, is that they are raked to prevent ventilation, whereas the trailing oars pull air down the blade.But they do kick-up, much like the oars.

    Sail rig on my Pahi is a near copy of the historic thing, but I am using re-purposed conventional sails (like mainsails turned upside down and modified), along with staysails as well.

    Sure, handling of the rig is likely be comparable to a Bermudan rig in some respect. but being  a split rig, should be easier to manage.

    Cost saving is a big factor in my case ( why I continue with the split sprit rig), But the rotating una rig that I am onto, could be the thing to have for easy reefing/shunting, if and when it is sorted, along with the financial viability aspect.

    Since I need to have a tender for Pahi iti, building one with the balanced wishbone junk type sail would be the best way to go from here, I think.


     


    Last modified: 26 Nov 2018 05:31 | Anonymous member
  • 26 Nov 2018 01:05
    Reply # 6932002 on 6368944

    There has been some discussion here before about hull shapes, or sections, in particular, the rounded vee section of Russell Brown's Jzerro compared to chines or flat bottomed boats.  I thought I'd post here some pictures of a 23ft fishing proa being built in Hawaii by Tim Mann, who is a veteran multihull builder and voyager, having first set sail from California in his teens, 30 odd years ago.  His wife and 4 young-adult children are now part of the project.  The 23 footer is a prototype for a 37 footer he hopes may eventually become a fleet of Pacific fishing craft, and a 75 footer he wants to eventually build.  Of major interest is that the 23 footer has a narrow flat bottom, and a couple of chines above.  Tim is a friend of Russell Brown.  I am not sure if Russell is a consultant on Tim's project, but he is certainly an influence.  And I wonder if Tim might have influenced Russell too, since Russell's Jester Class Proa (see my thread, Interesting proas) also has the same sections, and razor-sharp lines, though these are also reminiscent of Russell's firs proa, the 30ft Jzero.  Click on the images to see full size.


    Last modified: 26 Nov 2018 01:10 | Anonymous member
  • 24 Nov 2018 23:16
    Reply # 6930964 on 6368944
    David Thatcher wrote:

    I have been in love with multihulls from my early twenties. I used to drool over the Jim Brown Searunner designs, and then was lucky enough to own and cruise a Searunner 37 for 5 years throughout the Pacific. So anything that has that Jim Brown, Russel Brown look gets my heart thumping, and there is something very Russel Brown about the proa Madness.

    The reason Madness has that Russel Brown look is, of course, because he was a consultant to John Harris of CLC, though his name does not appear in the promotional material.  It might on the actual plans, I don't know.  It looks very similar to a sketch he made for me when he was in Australia 20 years ago.  We were sitting around on Jzerro, shooting the breeze, and he commented that if he ever built another proa it would be about 30ft, similar to Jzerro but with less sheer.  Seeing my excitement, he made a freehand pencil drawing for me.  It looked remarkably like Madness.

    I keep returning to look at Madness myself, dreaming of skipping across the Whitsunday Passage at 15 knots.  I'd have to have a nest ashore for when I wasn't out on the boat, or at least a storage container!  You can buy a CNC routed kit of the ply panels for US $4000, not sure if the shipping costs would make that practical.  The plans have full-size patterns, so some patience and a jigsaw might be the best way.

    Russell also designed another boat called the Jester Class Proa for Bieker Boats, and plans were supposedly going to be available from Bieker Boats but I am not sure if they are.  This boat has a bit more volume than Madness, and interestingly, it has chines in both hulls.  This is something I discussed with Russell.  I was thinking of a chine in the ama, with a narrow flat bottom for the main hull and a single chine, but Russell was unenthusiastic about the flat bottom.  He conceded that chines would make a good cruising design.  The ama on the Jester proa has one chine, above the at rest waterline, and the main hull has three, with the upper chine just above the waterline.  The bottom has a tiny flat on it.

    If I was going to live permanently aboard a proa I'd go for more volume in the hulls at the expense of speed and thrills.  It would still be a very exciting boat, but even the Jester Class Proa is starting to become biggish.  Russell's rig, especially with roller-reefing jibs, is clever, but I think I'd look at a cat ketch rig with rotating unstayed masts.  Russell concedes that these are great for cruising but the speed loss is unacceptable if you want to race, since you cannot set headsails, particularly lightweight genoas.   In one 350 mile windward race, the tine original Jzero beat a 42ft Newick proa with cat ketch rig by 18 hours.  But I am not interested in racing.  That's why I called this thread Minimalistic cruising multihulls.

    I think a junk rig with minimal lead, or even a junkette rig, would work fine, with double sheets on each sail.  I think the halyard and other control lines (apart from the sheets) would need to be on the masts, so you go to the mast to reef or furl.  You'd ease the sheet until the sail is feathering (altering course if necessary), then step up to the mast.  That is not so onerous, as you are well inboard at all times.  If the boat is no more than 30ft, the engineering for the rotating masts will not be too complex.

  • 22 Nov 2018 03:23
    Reply # 6928257 on 6368944

    Jeremy, thanks for the clarification that the boat you are building is a traditional Tahitian Pahi and not the Wharram cat.  I have cruised with Wharram Pahis, though, and they are capable little boats.  I look forward to seeing more of your project as it progresses, both the general design and how you develop the rig.

    Maybe I have been greatly influenced by Russell Brown, but for me, the Pacific proa, with its ama always to windward, is the only proa I am interested in.  That means it shunts, of course, and the bow becomes the stern.  So the challenge is to evolve a rig and rudders/steering oars that can be easily reversed without running around all over the boat like a demented chook.  I'm also focused on liveaboard cruising, usually singlehanded. 

    The rudders are merely a matter of choice.  I like the simplicity of steering oars, but pivoting on the beams, a few feet out from the main hull, rather than at the "now" stern, as in traditional craft.  The steering oar is held down by a "kicking strap" that passes through a turning block in the cockpit floor.  This is released when you want to lift the oar and a downhaul at the inboard end holds it clear of the water.

    The other option I like is Russell Brown's daggerboard lifting rudders, in cases, but these seem vulnerable to damage.  Russell had downhauls on his, and could raise and lower them from the cockpit. 

    Because Russell's jibs were hanked on, he still had a bit of running around to do.  Mind you, he mostly strolled.  With roller-reefing jibs, you could theoretically stay in the cockpit with his rig, but I am keen to see a workable reversing junk rig that both retains its balance in both directions and does not require shifting too much stuff.  basically a rig that can be entirely worked from the cockpit. 

    I think the 'start small and work your way up' approach has a lot of merit, either with models or dinghy-sized proas, allowing one to experiment with different ideas at reasonable cost.  I am busy cruising at the moment (and researching articles for the JRA) but I am watching this space with keen interest.

  • 21 Nov 2018 19:11
    Reply # 6925585 on 6368944

    Most of the usual suspects from the internet proa world are opining here, I see....except for Rob Denney and Russel Brown, that is.

    NOT wishing to be argumentative, but to tell it like it is for myself - so it is,that going to the roots has been worthwhile a thing - there is the Micronesian proa( an outrigger vaca ama configuration with ah Oceanic lateen sail on one mast), then there is  another Pacific proa, the Tuamotuan Pahi ( a double canoe shunter, with a longer leeward hull, having two masts, schooner style, carrying Oceanic sprit sails, as well as a quadrilateral sail).

    Of course there are the historic shunters from Fiji and Tonga, both purported to be derivative of the Micronesian model, after which, come the gaggle of modern types, from Atlantic through 'Harryproa' and 'Indian proa', to  whatever have you have on offer.

    As I observe, most  modern proponents have all but 'given up the ghost', with barely a brave soul soldiering on.

    Any future for the proa surely has to be one of personal indulgence, involving a sucker for punishment - hullo me.

    When I finish my Pahi ( which is based on the Tuamotu Polynesian proa, and has nothing do with the Wharram catamaran he calls a Pahi), I will have to prove his practicality under sail, although, accomodation space as a motor boat or floating batch make things just fine, with a good number of berths, a galley, a settee area and even a spot for a little woodburner stove.

    Other than that, the chips have just fallen into place on how I might build a micro version of such a Pahi, Junk rigged to boot, if I have to resort to building another project in the tiny garage that is from now on my workshop.

    Writing stuff on this forum has only happened, because a front passing over has chased me from the tent that is the 'workspace' for the Pahi, down at the waterside.

    As has been the case for at least the last 40 years, drawing or sketching a boat design has been the best I can do when not making progress on an actual build project.

    This process has resulted in my eventually seeing a way to Junk rig a proa, with a view to making it a reality..... this being a possibility as long as things can be kept really small.

    earlier on this thread, Rael mentions James Brett, who goes to show that Junk rig does wwork on a shunter..... plain to see, for anyone interested, by looking at youtube clips of him sailing on the Hauraki and lake Pupuki. 

    He shows how the rig is configured and works, and this much I understand from my own experience, although I have been too busy with other things to have given the time to have a look at Free Radical.

    Lack of sufficient interest stems from the observation that the mast is stepped harryproa style - in the lee hull, well away from direct support from the connecting beams, and also the rudders tacked to the hull topsides only.

    These deficiencies could be corrected by some design changes, and then the lee hull could be used as a heads compartment, without resorting to a free standing schooner rig.


    Last modified: 21 Nov 2018 20:03 | Anonymous member
  • 28 Aug 2018 00:19
    Reply # 6641707 on 6368944

    things are going much more slowly than I would have liked, but Larry Daryl and Daryl is coming along nicely, just need to get the daggerboard rigged so I can move it back and forth and flip it if I decide shunting is doable and I can throw her in the water. Oar steering and I'll be using the sail from my dinghy to start, but once I get it working I'll start on a new junk sail.

    I put the mast step at the CLR, she probably won't go backwards all that great but I thought I'd try :)


    Billl F

  • 19 Aug 2018 08:10
    Reply # 6582216 on 6581024
    Bill F wrote:

    ran across this paper on wind tunnel tests on 10 different micronesian sails, though someone might find it interesting, wonder if anyone has ever done anything similar with junk sails. 


    Bill


    This could be interesting, and I see it originated just down the road from where I live. I am building a little 6 meter cruising catamaran. I would love to have a junk rig on the boat but I don't think it is going to work out for a variety of reasons. My next best option is the designed gunter rig, which is an 'alternative rig' these days. But perhaps some type of Micronesian/Polynesian rig warrants at least a certain amount of investigation.
    Last modified: 19 Aug 2018 08:11 | Anonymous member
  • 18 Aug 2018 13:31
    Reply # 6581024 on 6368944

    I think part of the problem is needing a military escort for part of the way to protect against pirates.


    ran across this paper on wind tunnel tests on 10 different micronesian sails, though someone might find it interesting, wonder if anyone has ever done anything similar with junk sails. 


    Bill


  • 17 Aug 2018 20:55
    Reply # 6580155 on 6578702
    Anonymous wrote:

    Man it just sucks that he can't get a decent price for Nixie, that's a nice boat and from the build thread it looks like he did everything right, I mentioned it to Mark T. he liked the price but he wasn't too thrilled with the location, and he was thinking pounds sterling not USD, so it's about 22% less than he thought.

    Shipping or paying a delivery skipper to sail the boat might be a tad expensive.  Then again, even new boats are commissioned from yards in Asia.  

    I wonder whether there are sailing vloggers who could make a living by sailing an unusual boat without being paid anything extra, and who are competent enough to be trusted with the boat.  Dylan Winter, of Keep Turning Left?

    This here might be a useful resource for building small proas: http://expandacraft.com/shop/



    Last modified: 17 Aug 2018 20:57 | Anonymous member
  • 17 Aug 2018 12:54
    Reply # 6579386 on 6368944

    Now that is a beautiful boat!

    Garry Dierking calls that type of mainsail a the tacking crabclaw, although he hangs his on a stub mast. It basically trades off most of the versatility of the crabclaw for control.


    The Wharrams with crabclaws don't shunt, that's where the crabclaw is a handful, moving what is essentially a giant kite from one end of the boat to the other can be pretty hazardous in heavy weather.


    I don't think the super tanker shunts either, wouldn't that be something to see? :)


    Bill

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