A proa and aero junk or split rig questions?

  • 12 Jul 2018 22:04
    Reply # 6379172 on 6368944

    @David Thatcher:

    100% with you on Bernd Kholer's cat designs.  If I go cat it would probably be something like the KD122, pelican or even just a bigger Eco 7.5.   I liked Woods designs too, but not so much his nettiquette, which really did come off to me at least as as 'only Woods designs are good' on the various forums.  I do however want my stand up head room in at least some places, and I am not short, thus more like a 40'-43' cat.  :P

    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?


    @David Tyler

    All good points marina wise.  Length will hurt.  After 50' its quite a bit harder to find a marina for long term dockage on the east coast where I would be.    Short term is easier, and of course pricey. ;P   Width wise however?  Being a proa, nothing says I can't build it folding like some other HP designs, so it fits a large mono slip.  Unlike a cat where bridge deck goes between hulls, proa has its 'bridge deck' along one hull.   

    Food and water.  Needed indeed.  Have a few ideas refrigeration wise.  Also some for water that should skip RO and all that goes with it.  Going to play with that a bit to make sure it works first.

    Fuel/power wise?  Thinking electric for now.  So that would be 2-3 kW of solar with about 30kW of used Tesla model S modules to store it.   Have quite a bit to learn about and sort out here tho yet, so that could change.  And is another reason for a light boat.   

    Internet is needed for me for a few years for work as I gear down, which = marina.  BUT 5-8 years down the road?  We will very likely have cell/internet via low earth orbit satellite network up.  Which I am sure saddens some, as there will be no escaping the nets on land or sea unless you go quite far north or south.  

    Maneuvering wise I am aiming electric.  So propulsion (torqueedo or other) mid ship near 'pod' with 360 degrees of thrust vector.  Not perfect, but should be fairly maneuverable if tides are not bad - I hope. But yeah going to have to see here, you are right big is going to be harder than small to get around in.  Question is by how much?  



  • 12 Jul 2018 09:30
    Reply # 6377981 on 6368944

    I think I am right in saying that the only person to make a real success out of live-aboard/ocean crossing proas is Russell Brown, son of veteran multihull designer Jim Brown. So there is some real heritage going on there. Of course there was the Dick Newick proa which did the trans-Atlantic race. I agree with David Tyler that a good bet for a liveaboard, ocean crossing potential multihull would be a catamaran in the 8 to 10 meter size, with a bi-plane junk rig. The designs of Bernd Kohler seem to be very suited to amateur builders, I am building one right now, and this is after having done a lot of research into what is available. For a permanent live-aboard multihull, relatively easy to build, and with ocean crossing potential, his KD860 is one of the best multihull designs currently available. I am not sure what the estimated build time for the design is, but I would guess at least 2 years part time for an experienced builder, but probably 3 to 6 years for someone who is not that experienced and has other things going on in his or her life.

    I think that to do any kind of live-aboard long range cruising in a proa would require a considerable amount of previous multihull experience, which Russell Brown had in depth, having grown up with a multihull designer father, and having done extensive cruising in a multihull as a child. 

    Last modified: 12 Jul 2018 10:01 | Anonymous member
  • 12 Jul 2018 08:33
    Reply # 6377897 on 6368944

    Something else to add into the equation:

    Liveaboards have to find a way to get supplies, water and fuel at regular intervals. In some places, it's possible to anchor/moor off and take a dinghy into harbour, but not everywhere. Marinas charge by length, and then add extra for multis. You would need a deep pocket to berth a 60ft proa, if you could find anywhere where it was physically possible.

    I would say that the hard-headed, practical, achievable choice for a multihull liveaboard would be a bridgedeck cat, biplane rig, 30ft max. The Kohler cats are obvious examples. But by all means have fun with a daysailing proa, to learn the building skills and also to see whether manoeuvring a larger proa into tight corners is something that you'd really want to do on a regular basis. 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.

    Last modified: 12 Jul 2018 08:35 | Anonymous member
  • 12 Jul 2018 02:42
    Reply # 6377558 on 6368944

    Thanks everyone for all the ideas so far.  I am new to sailing/JR in general, so excuse if I have it wrong from what I read.   


    My first takeaway is that to get the sail to flip around is a bit of challenge on a JR proa - partly due to all the bits of string needed.  But, that a double sheeting setup may solve/reduce this issue?  


    Second is that all of this is much, much easier on a tri, and even a cat (if one goes twin mast 'biplane' anyway), because there is only on front and back, and thus no need to flip around.  Note, I would stick to free standing mast as as its one less thing to go wrong/replace/repair and has 'one reef' safety built in.


    So, if I go proa, I need to consider pro(a)s on cons sail wise.  Can it be made to work without too much convolution and still provide advantages?  Hmmm... Will expore some of the blogs posted to see if that helps me sort it out mentally


    For those who asked. The first proa (If I go that route)  would be 25' ish, 300+/- hours build, and essentially a glorified beach cat.  But, it would give me something to sail, learn composites / build techniques, and CNC -as I intend to try some of it on a 3 axis router.  So, if I do decided to go bigger, it will give me a good frame of reference on just how crazy that idea is. :P  


    As to liveaboard?  Yes for a proa 50'-60' (or smaller something else) would be the end goal should I get that far.  Keep in mind that its not a 'harder/longer build' than a smaller cat or tri since its less material for a given X length.  I believe the HP Cruiser 60 is around 2000 hours.  Which is a lot indeed, but not compared to size.  Still, that call is a ways off.


    The madness is a fun looking boat


    That 'keep turning left' tacking proa I have seen images of before, and is pure sex.  Its like Middle Earth and Jules Verne a had a love child who grew up to be a super model.  But looking at all those curves and woodwork?  That is waaay outside my skills zone I think.

     

    Last modified: 12 Jul 2018 03:55 | Anonymous member
  • 11 Jul 2018 18:27
    Reply # 6376557 on 6368944
    Deleted user

    I really don't see anyway to get away from double sheets on a junk rigged proa, but then double sheets have some good points too.

    There's a lot of different opinions on just what constitutes a proa, some quite strongly held, I saw one that was basically a helicopter on pontoons that was apparently a proa. To many, if it can't shunt it's either an asymmetrical cat or a stabilized monohull.

    they don't have to be long and lean either, check out keep turning left, a junk rigged proa that only tacks.  https://www.keepturningleft.co.uk/blogs/junk-rig-proa-lozenge/  it looks pretty roomy.

    I think one of the things that might really make the junk rig shine on a shunter is that it could be fully stayed, not something I'm at all interested in doing, but I've often thought that the only thing that makes the bermuda sail work as well as it does is is that it fits under the backstay so it can be of a much higher aspect ratio and use much bigger head sails.


    That setup in Rael Dobkins video is pretty cool, me, I'm trying to figure out ow to use just one side of the sail.


    bill


    PS: while I could see a junk rig working very well on a tri, I understand that an unstayed mast on a catamaran is problematic to say the least, and a stayed mast on a junk rig is equally problematic.


    Last modified: 11 Jul 2018 22:14 | Deleted user
  • 11 Jul 2018 13:45
    Reply # 6375756 on 6368944

    Dave, you say your long term aim is for a live-aboard.  Whilst a Proa is arguably the most sailing fun for your $, not sure it would make a good live-aboard.  To give sufficient accommodation it would be a big boat, say 40' versus a 25' catamaran.

    Sure, build one for fun, put JR on it, it has been successfully before.  Double sheeting would be the way to go. 

    (tacking proa? !!  they are  asymmetrical catamarans)

    All the best with your journey.

  • 11 Jul 2018 13:44
    Reply # 6375755 on 6368944

    There is an interesting concept from Rael Dobkins on youtube, he intends it for Arne's type of sail but could work for split rig as well. That's if you are into experimenting...

    Cheers,

    Eerik

  • 11 Jul 2018 01:04
    Reply # 6375024 on 6374983
    Anonymous wrote:

    It seems to me that a single mast aero-junk rig would be ideally suited to a proa. That way when you shunt both mainsail and jib swing around to the other end of the boat so all you need to do is change the mainsheet around. A split junk would work as well, but I suspect the aero-junk might have better windward performance (?).

    Chesapeake Light Craft have a couple of proa designs for amateur builders.  


    Bear in mind, though that a single mast on a proa will be amidships.  The Harryproa has quite a lot of its sail area forward of the mast.  I wonder if you can get enough sail area forward of the mast and still weathercock?  Possibly radical positioning of ther daggerboards might solve this issue? Sheeting might also be a challenge,  I am not sure how you would get the multiple-part junk sheet from one end of the boat to the other.  It is long enough on boats that do not alternate bow and stern!  I love proas (Madness, a 30ft design that Russell Brown had much input into is my favourite) and would like to see someone solve these issues.  At this stage of idea development, I'd choose a little trimaran for junk rig.  Second choice a cat.  I met a Marples 28ft tri that was built in 100 hours by one man (he said his only power tool was a 4 inch angle grinder - I'd add a jigsaw), and which has sailed thousands of ocean miles.  It is a very basic, cheap boat.  Watching developments with interest.
  • 11 Jul 2018 00:54
    Reply # 6374999 on 6368944
    Deleted user

    Hi Dave

    There are a few Proa enthusiasts here, I'm working on a 16' pacific (ama to windward) shunter at the moment and I'm planning on a split junk for it.

    Proas have a lot of advantages which means there are a lot of tradeoffs,  just for example, for the same cost in weight and money you get a much longer, faster boat, which costs much more to keep in a slip, every silver lining has a cloud :)

    when you say small, how small do you mean? I think harry proa has designs right down to about 16'

    Gary Dierking has a great book "Building Outrigger Canoes" with 3 sets of plans, 2 different hawaiian style proas, one in plywood and the other in cedar strip plank as well as an asymmetrical Proa in cedar strip. Just don't read the strip plank sections unless you really want to go there because he makes it sound like such a fantastic way to build you'll want to go there :)

     I think all three designs can be stretched or shrunk, the plywood hawaiian style can be built in one piece or sections that bolts together, one guy made his in 7' sections so he could keep it in the closet of his dorm room, I'm building mine in 8' sections, just the ends at the moment, but I may build a middle section for it someday, or two, or three :)

    The plans in the book are ok, but if you're not fairly handy you might want to pay for a plan set, the book is ~ $25 and the plan sets are about $140 us each and much more complete. 

    I'm also fairly frugal and went with the book, haven't had any problems yet, Gary is really good about helping out with information.

    Gary has played around with junk rigs too, here's his blog with a tacking JR Proa 

    I don't think Mr Denning has tried any other rigs, he seems to be fairly focused on racing and triangles.

    Chesapeake Light Craft  have a couple of proa designs, Mbuli, a whalebacked proa is about 20' I think and he has a longer one, Madness that is 31' if I recall and bluewater capable is designed along the lines of Russell Browns proas, think they may have actually worked together on that design.

    you can find a lot of info here in the junk rig information section, split junk information is in the "Public Domain Files" under Slieve McGalliard's files, I strongly recommend reading Arne Kverneland files as well, his are mostly on the Hassler/McCloud rig but a lot of the information and ideas he covers will apply in some way to almost any junk rig design, with all the writing he does I don't know when he finds time to sail :)

    If you don't mind the rather hefty price tag, "The Practical Junk Rig" is probably the most complete text on the junk rig but doesn't have anything specific to the aero rig or split junk as both were developed since it was written.

    Good luck with your build, I hope some of that helps.


    Bill







  • 11 Jul 2018 00:16
    Reply # 6374983 on 6368944

    It seems to me that a single mast aero-junk rig would be ideally suited to a proa. That way when you shunt both mainsail and jib swing around to the other end of the boat so all you need to do is change the mainsheet around. A split junk would work as well, but I suspect the aero-junk might have better windward performance (?).

    Chesapeake Light Craft have a couple of proa designs for amateur builders.  

       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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