A proa and aero junk or split rig questions?

  • 16 Jul 2018 05:46
    Reply # 6382627 on 6368944
    Deleted user

    as I recall, and it's been a while, Russell Brown uses  a roller reefing jib at each bow to bring the balance forward when close hauled or reaching.

    Since a junk rig could be fully stayed on a pacific proa you could do the same thing, wouldn't even need much of a jib if you used a split junk, or you could use a reddish rig and a huge jib.

    You'd have to use double sheets but that shouldn't be a big deal in a proa, remember, they're not going over your head, or even over the boat, any time a sheet wasn't being used it would be out over the water on the lee side of the boat.


    Bill

  • 16 Jul 2018 00:14
    Reply # 6382344 on 6368944

    The Harryproa concept is certainly more cruising oriented (ie has more accommodations) than Russell Brown's proas, though I think you could also build a Pacific proa with more displacement and still have a fast boat, just not blisteringly fast, like Jzerro, which regularly sails at 17+ knots..  Russell's boat wins hand down for beauty though.  I am not dismissive of junk rig on a proa.  It works for Bill F on his smaller boat, but might need a lot more experimentation for larger, ocean-going designs.  It is a different approach to just building a proven design and going off sailing, assured it will work!  I'd love to see someone have a go though, and our junk rig experience is available through this forum to help the more adventurous members work through these ideas.  New ideas are always fun.  Keep them coming.

    My experience of shunting a proa with Russell's rig is that it is quite relaxed, and once you get your head around the process, you can shunt through moorings or up channels easily.  A friend of mine was tacking laboriously up the narrow channels of the Sandy Straits in his bermudian sloop, inside Australia's Fraser Island, when Jzerro appeared behind him.  Russell rapidly overtook my friend's monohull and disappeared over the northern horizon.  There is a bit of deckwork involved, but there is no rush, it is all quite relaxed, the boat just sits there quietly with the mainsail feathering to leeward.  It would work even better with a junk, if you get the balance and sheeting challenges sorted out.

  • 15 Jul 2018 04:29
    Reply # 6381706 on 6368944

    Well part of the point is to see what the experts like you are saying?  Why would it work? Why wouldn’t it work?  Did you think of X?  And so on.  Should I just do the ‘standard’ and build a cat or tri?    That is what has been happening, and I thank everyone who has (or will) contribute.

    Why consider a HP?

    Intelligent infusion promises to be fast build and light for the strength and fairly mess/fairing free.  It is not as cheap as epoxy/glass and ply however.  As always trade offs. . .   But build speed is certainly a thing, as ‘even if my time is free, it is not without value.’

    HP proas can be built lighter than a cat or tri because all the real loads are on the LW hull between the beams where the masts and sails are.  And light means easy to power electrically, or otherwise.   Easier to sail in light breezes means less motoring and also favors electric power, or just not using fuel.   As an aside, batteries for 30kW should come in at around 450 ish lbs with a container and BMS if I go the Tesla route.   Not great, but not horrible either, considering many diesel pieces/parts and fuel are not exactly light either.

    Should sail fastish.  Even the HP cruisers can do wind speed on certain points of sail, at least up to 20 knots or so from those that have 'em.  After that I do believe the bows will start to dive per what I have read.  

    Set up for single handing.  Not a lot of moving about or things to do.  And what is ‘to do’ can be done from the helm including anchoring.  And the helm is dead center fore/aft so about the safest place one can be.  Proof will be in the pudding here if it works as advertised for a small one if I this route.

    Why not a HP?

    Maneuvering really is the big one I hear from just about everyone, and it seems quite a valid point.  So I am going to see on the HP forum how those with the actual big HPs deal / think about this.  I can talk about 360 drive and so on but that is just theory, and the realities of sailing probably trump theory.   Please do keep finding darts to throw here. 

    Longer for given accommodations.  Yup.  And longer is more expensive to dock even if I I do go folding ama.  Further marina’s will likely be in my future for a least a few years after it it is built.  That said if it less hours to build?  Then, that also counters quite a fair number of years of additional marina fees as well, depending.  One reason I need to try build a little one.  Quite a few NAs seem to think their way is fast(est) and they cannot all be right. :P  That said, it is possible to have decent accommodations – HP is not the same as a JZero.  

    Sailing on edge?  So here I would say not with a cruising HP. And since that is what I am eventually considering I should be good.  I mean Blind Date is a 50’ HP and charters sight impaired first time sailors for example.  It can’t be an always on the edge sort of boat, and the (admittedly few) videos back that up.

    Probably not junk riggable without some major experimenting.  So Annie and Graham I think are calling it here in that the convolutions of making the JR work, especially in bad conditions, with shunting are probably not worth it on a proa.   Incidentally, my thoughts for JR were that I could get a bit more SA/D for light winds, use (and fix with) low cost materials, have easy reefing, and if a panel was damaged = not fatal, which is a pretty nice feature if you are cruising I would think.       



    Edit:

    Just to add here, assume 2-3 people living aboard and wanting to not be on top of each other 24/7.  Hence  the 40'+. 

    Hull choice for batteries?  I am back and forth on this.  I am leaning toward not the LW hull with masts on it due to lightning.  That side might have cheapish 'disposable' (and separate) power (cheap e-bike batteries, cheap inverter, cheap mppt and 2-3 solar panels) since no major loads would be there anyway.  LED lighting, usb chargers and done.  Maybe an outlet or two for notebooks or whatever. 

    Last modified: 15 Jul 2018 04:46 | Anonymous member
  • 15 Jul 2018 04:04
    Reply # 6381680 on 6368944
    Deleted user

    The whole point of a proa is that you get a longer, more stable boat for the least cost in weight and money and longer boats are faster, so they usually end up being speed machines, but they don't have to be.

    The pacific style shunting proa that keeps it's ama to windward has the added advantage of even more weight savings because there's very little stress on the cross beams so they don't need to be anywhere near as heavy as an atlantic or tacking proa, catamaran, or tri where the cross beams need to be able to carry the entire weight of the boat plus crew, cargo, and heeling forces. also the ama itself doesn't need to be all that big either as it just has to carry the weight of the cross beams.

    Most proas can be beached.

    They're certainly not ideal for liveaboards, but I don't see why they couldn't be made to work, might cost a bit of speed, but then every boat is essentially a collection of tradeoffs.

    If I ever build a cruising proa I'll probably keep the batteries in the ama.

    The junk rig is wanted to avoid all that extra deck work, just have to figure out how to make it work, might take a while, after all, the chinese worked on the junk rig for over 3 milenia and it still isn't quite perfect :) 

    Rael Dobkins is working on what I call a dipping junk that'll let him move a hasler/macleod rig fore and aft from the cockpit, looks a bit cumbersome at the moment, but he'll get it figured out.

    I think a 60' proa would be excessive for a single person living aboard, Gaia's dream is 71' and has berths for 12 people and room for a car or an ultralight aircraft on deck. 

    40' would likely be more than enough, Russell Brown lived aboard his first proa Jezero for a summer, she was 30' and his newer proas have been between 36-39 feet. I still wouldn't want to have to maneuver a 40' boat through a harbor or marina singlehanded.

    Bill



  • 15 Jul 2018 01:03
    Reply # 6381628 on 6368944
    I confess that I just don't get this idea at all.  Surely, the whole point of a proa, as Graham pointed out, is that it's a high performance sailing machine, which, I would have thought, is the antithesis of a liveaboard home. The weight of the batteries alone, in a boat with electric power, would be considerable.

    A boat that will require more room to tack? Added to its considerable beam, this could make it awkward sailing up rivers and through areas with coral.  The beam (marinas apart - and who can either afford or wants to spend much time in a marina?) probably won't be much of an issue in the Pacific, but the idea of taking a 60ft proa into some of the old, European harbours and then trying to secure it alongside a stone wall with a 6m tidal range would be daunting.  But if you intend to stay in open anchorages 'far from the madding crowd', then the footprint of the boat won't be that much of an issue.

    But surely the whole point of junk rig is to be able to avoid deck work, which a shunting proa appears to provide in spades!  Or maybe the ease of reefing is the major appeal here.  But I feel I am missing something.
    Last modified: 15 Jul 2018 01:13 | Anonymous member
  • 14 Jul 2018 00:18
    Reply # 6380678 on 6368944

    I don't think Gaia's Dream has circumnavigated, or gone anywhere much, apart from a short coastal passage down the NSW coast after launching.  It has a very complex rig and I believe Ini never quite resolved some of its technical issues.  In recent years he has been busy with other matters but might get back to the boat one day.  He is an experienced proa sailor, having previously sailed a 38ft proa from Holland to Australia, and I give him full credit for having the courage to try radical ideas on a large scale.

    I remember Russell Brown telling me about a 60 knot gale he encountered off the Cook Islands on Jzerro, his 37ft proa.  He hove to with a backed storm jib and rode it out without drama.  Occasionally a wave would lift the ama (to windward), and the pod (on the leeward side) would slam into the sea, but this stopped the boat from heeling any further.  It would just slide sideways.  He said he felt quite relaxed and confident in the boat's seaworthiness.  I think you could cross an ocean in Madness, if you were brave enough, and Russell told me that if he designed another proa it would only be about 30ft.  He even gave me a sketch of what it would look like, and it looks very much like Madness.  But Russell is the ultimate minimalist, and on Madness you'd have to add another notch to your belt! If you aren't as skinny as Russell at the beginning of the passage you will be by the end!  But Madness really is a jewel of a boat.

    If I built it though, with the intention of cruising offshore, I would be tempted to put Russell's signature rig on it, which is brilliant, or maybe use two unstayed masts, like the rig drawn for Mbuli.  I'd like to see one with junk rig, but it needs to be capable of reefing, furling, shunting, etc, on a dark and windy night, in a squall at 0300hrs, without getting into a tangle, if you sail offshore.  I cannot see how to achieve that with a proa. Now there is a challenge for you.

    Last modified: 14 Jul 2018 00:20 | Anonymous member
  • 13 Jul 2018 15:51
    Reply # 6380125 on 6368944
    Deleted user

    If you mean Richard Woods form sailingcatamarans.com I've built one of his Duo Dinghys, he does come off as a bit uptight, but of the 3 sets of plans I've bought his were by far the best written and easiest to follow and he was interested and great about getting back to me quickly with info and help. 

    I can relate to not wanting to buy from someone you don't care for, when I was researching proas almost all the information I could find was in forum posts and about every third post was Troy Denning bad mouthing someone else's boat, now I really have to work at taking the man seriously.

     You asked about double sheets, thats having a seperate sheet and sheeting point for each side of the sail, usually because the sheetlets can't be passed around the leach of the sail, pretty much the only option on a shunter.

    There are a lot of bits and bobs on a junk sail, enough that I would never have made sense of it without a lot of reading and some hands on practice, still figuring out what some lines do, just discovered yesterday that pulling the lower luff hauling parrel as tight as it'll go gives about a 50% boost in efficiency in very light air, I'm starting to think Blondie Hasler should have called his book The Infinitely Adjustable Junk Rig :)

    when shunting, the cross beams on a proa take only a tiny fraction of the stresses that the cross beams on a catamaran have to endure, so the Pacific proa form does lend itself to folding or telescoping crossbeams as long as you don't plan on tacking, I think I'd want the option, just in case.

    If you haven't seen her yet check out Inigo Wijnen's Gaia's Dream  a 70' proa that's circumnavigated and can haul 12 tons of cargo, that's right, a 70' ship that can haul a whole 12 tons of freight :) 


    Edit, oops, my bad, a whole 7 tons of freight :D


    Bill


    Last modified: 13 Jul 2018 16:02 | Deleted user
  • 13 Jul 2018 06:17
    Reply # 6379639 on 6368944

    This forum thread has made me pull out my study plans for the proa 'Madness'., which I purchased a couple of years ago. I see that it has the same displacement as the 6 meter catamaran I am building, uses almost the same number of sheets of plywood, yet has just about double the sail area. That boat would fly. Maybe that is why the design has the name 'Madness'!! It would be interesting to see how it performed with some type of junk rig.

    Last modified: 13 Jul 2018 06:18 | Anonymous member
  • 13 Jul 2018 01:26
    Reply # 6379349 on 6377897
     I've seen a big proa, moored on the Pittwater, Australia, and the thought of bringing it into harbour is enough to put me right off proas.

    Oh, I can see that boat on its mooring from where I am sitting, and I can tell you it does not move very often. No idea about the reason for that though.

    On the proa front I need to say that I know Rob Denny (of Harryproa) pretty well and have a lot of respect for his designs. He thinks well outside the box and is not afraid to fail. Or succeed of course. 

    Right now he is working on a triscaph (as one does) amongst other things.

    His "intelligent infusion" is also pretty clever and can allow rapid construction, if you dont mind using resins.

    Most of his designs can have different windward hulls which can allow you to do a day boat and later add accomodation BUT

    The strength of the proa is its long easily driven hull and light weight / low stress however as David points out long vessels are expensive to berth, and there are fewer moorings for longer boats.

    I have seen a video of Rob happily shunting through moored boats on the Brisbane river without stress ..... but he IS used to sailing proas.

    Anyway I would urge a look at the Harryproa website or the harryproa yahoo group for no other reason than that its extremely interesting.

    And remember that to get the multihull advantage it really really really has to be light. Really light, with the vast empty spaces kept empty. Otherwise you might as well have a monohull. 

    And for cruising while astronomical speeds are possible, its generally too noisy to sleep below much above 14 knots. 

    Cheers




  • 12 Jul 2018 23:25
    Reply # 6379238 on 6379172
    Anonymous wrote:

    @David Thatcher:

    I am however curious however on why live aboard/cruising would be harder on a proa then a cat or tri?   Tack/gybe vs shunt - okay, yes a difference.  Honestly that seems really more like a push tho.   Shunt is (in theory) easier, but it needs more room.  So then what else would make it a bad call?  Keeping in mind this is a cruising HP, not a Pac or Atlantic proa, so flying hulls or dipping a pod and such is not going to be a thing?


    You would need to go to quite a large proa to achieve the live-aboard space of a catamaran such as the KD860. Even a large proa which might seem a simple boat to build is going to consume a lot of time and money. Then the more length you have the more difficult it is to find marina berths and anchorage space, and the costs involved with a large vessel really mount up.

    Russell Brown has never made his designs available to the general public. He probably could have made a reasonable amount of money selling his designs, but I suspect the reason for this, and I think I have read it somewhere, is that he realised the risks associated with ocean sailing in proas. It would be 'sailing on the edge' most of the time, and not for the inexperienced.

    Anyway, try building a smaller vessel first. If you want something with usable accomodation try a small catamaran such as one of Bernd Kohler's designs, or a Wharram. You could also look for a small trimaran design of which there are some available, maybe a Marple Sea Clipper design if plans are still available. If you want some real proa experience in a boat which you could do some coastal cruising you could build the proa 'Madness' from Chesapeake Light Craft. I think for a 9 meter boat this would be one of the quickest and least expensive to build. This would give you some real boat building, and proa sailing experience. Then you could see where you want to go for a more long tern cruiser. 

     
    Last modified: 12 Jul 2018 23:26 | Anonymous member
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