Proa cruising sailboat design, help get this idea out of my head...

Discussion in 'Boat Design' started by 360weatherbound, Mar 2, 2010.

  1. 360weatherbound
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    360weatherbound Junior Member

    Could one take a canoe type hull, narrow hull, make it 35' long or so (enclosed. Put an outriggor sized large enough to support a decent deck and two sails, (so the sails would be on the outriggor).

    I imagine this boat would be quick, have less room than a monohull but more than the hulls of the 35' cats I see. Faster and cheaper to build than either. There is just two of us, we dont need all the space of a 35' cat but I like the deck space. And wouldn't putting the sails on the outrigger keep the proa related problems at bay (wind blowing you over).

    It could sail like a proa ,atlantic or pacific. It would be shallow draft, beachable anywhere, backed out of the surf.

    As a home build one would just halve to make just half the mold, being as the ends would be symetrical.

    Why not???
     
  2. Guest625101138

    Guest625101138 Previous Member

    You have it back to front. You want the long hull as the lee hull and the mast mounted on this. The sails need to swing free through 180 degrees because a proa sails in either direction.

    You load the windward hull with gear and body weight to counteract the moment from the sails. As the sails load up the windward hull lifts and the load is transferred to the long slender hull so you get good speed with little loads.

    Some pictures here:
    http://www.harryproa.com/designs.htm#other

    Rob Denney is currently building a 50ft long origami proa suitable for fast ocean crossings. They work out to be very low cost for the speed potential.
     
  3. marshmat
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    marshmat Senior Member

    It's doable, and if you don't have an overall length constraint, it could make a lot of sense.

    The pacific variety (rig on the long hull to leeward) seem to be preferred for cruising over the atlantic variety (rig to windward) for a number of reasons, much lower structural loads being among them.

    Successful proas always seem to end up as very long boats for their volume and weight. At 35' LOA, a cruising proa of Pacific type might have the accommodations we're used to seeing in 25' cabin cruisers; one of Rob Denney's "Harryproa" types would have slightly more room than this (they carry their rig to leeward and their cabin to windward).

    Wind-induced capsize is common among small, experimental proas, but should be easy to prevent at the design stage for larger craft- it's basically a matter of balancing the available righting moment (from the outrigger's weight and its distance from the main hull) with the overturning moment from the sails, allowing for a suitable safety factor.

    Proa enthusiasts have an online subculture of their own ( http://www.proafile.com/ , http://wikiproa.pbworks.com/ , etc.)

    Also check out Inigo Wijnen's boats ( http://www.pacificproa.nl/ ) for inspiration. At 21.6 m LOA and displacing nine tonnes in cruising mode, Gaia's Dream is roughly comparable to the average 38-40' (12 m) cruising cat in terms of usable interior space and rig size (although GD's interior is set up for a different purpose), and- with a 17 tonne maximum displacement- substantially superior to the 40' cat in cargo carrying ability.
     
  4. 360weatherbound
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    360weatherbound Junior Member

    The Harry Proas look to expensive and time consuming to build.
    Thanks for the links Matt. I came accross a bimaran "jasmine" I was thinking more in the lines of something like that. I haven't heard how it sails or any other designs similar.
     
  5. peterAustralia
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    peterAustralia Senior Member

    hi

    Here is a list of proas
    http://www.wingo.com/proa/links.html (the best list of all)

    The best discussion group by far is this
    http://groups.yahoo.com/group/proa_file/

    Yes you can design a proa if you wish. The trouble is that they tend to be long in regard to the amount of accommodation you get. A 2 person pacific proa (maybe more for shorter trips) like Jzerro comes out at 37ft. There are 3 broadly similar craft by Russ Brown, Cimba..Jzerro and Kauri,, one may be for sale

    I am not a fan of HarryProa boats, but in fairness they do appear to do what they claim, one has crossed the Tasman sea recently. Additionally are reputed to be quite ecomomical to build in terms of price, if you ask Rob Denney you may be pleasantly suprised. Several have been built so there is a track record there.

    The big downside of a proa is that you need 2 rudders and a reversable rig, this adds complication.

    There is another craft that is called a tacking proa or tacking outrigger. It is like a catamaran but one hull is bigger than the other. Peter Mirow is currently building a 30ft tacking outrigger for his family in Brazil. Based on his blog he should be on the water very soon.

    You may be best to see if you can find a 30ft tri going second hand. With the ecomomy in the US still quite bad, I assume prices are low.


    For the sort of craft I am talking about see here,
    www.tacking-outrigger.com

    For Peter Mirow's 30ft craft please see here. He has some articles besides his boat, but there is plenty of detail on his boatbuilding progress
    http://arpex.blogspot.com/

    There is a proa called Ping Pong, was 7m from memory. It has a very simple hull shape that ought be simple to build. Tehro Halme is the builder/designer from memory.

    Peter E.
     
  6. Alik
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    Alik Senior Member

    Every boat is an investment, and it should be re-sellable. Is proa (or any other weird boat) re-sellable?
     
  7. Guest625101138

    Guest625101138 Previous Member

    Alik
    I agree that resale may be a buying factor but I strongly disagree that any recreational boat is an investment in the financial sense. They are most often a significant liability. No one buying or building a boat for their recreational use should be deluded into thinking they have an investment in the making. The old saying that they are a hole in the water you pour money into is not far off the mark.

    Rob's latest proa should end up setting him back about AUD20k. With a bit of sorting it will be a safe ocean boat capable of averaging well over 10kts with a small crew. If you can get over the quirkiness of a proa they make a lot of sense.

    By the opening post I doubt that anyone contemplating extending a canoe is thinking about resale. I also expect that the budget is quite small and the boat mostly experimental. The investment is in the learning experience - maybe get the proa bug.
     
  8. peterAustralia
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    peterAustralia Senior Member

    alik

    I look at Rob Denney's boats and I look at Peter Mirow's boat, and they look resellable to me. Sure they are different from the mainstream.

    Russ Brown and his proas, well resale value is not much, but then again resale for any 30 year old 2 tonne mulithull will not be high. Russ Brown has sailed tens of thousands of Ocean miles. For the money invested he seemed to get a lot of value in terms of boat performance and ability.

    Some of these cruising mulithulls seem to cost just a bit more than some of these hotted up beach cats. Some of these hot cats have reduced greatly in value as there is now a newer hotter faster version. Who made the good decision and who made the bad decision?

    Peter E.
     
  9. Alik
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    Alik Senior Member

    Resellable? What is potential market of proas?

    OK, seems I don't need to convince anyone do not build a proa. You have Your own proa plans already :D
     
  10. marshmat
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    marshmat Senior Member

    There obviously isn't as big a market for proas and other "weird" craft as there is for, say, 38' charter cats.

    But I concur with Rick- few of us looking at recreational boats are expecting them to be an "investment" in the financial sense. Boats may not depreciate as quickly as cars, but by and large, they don't hold or gain value in the way a house does. There are exceptions, of course, but these exceptions tend to be rare and finely crafted vessels beyond the financial realities of most folks.

    Given a choice between spending 30 years to save $300,000 for a fancy boat, or spending $100,000 and 10 years part-time work to get out on the water two decades sooner, I think I could live with a lower resale value after getting two decades of extra cruising time out of the deal. You could say the same about any unusual or home-built boat; I don't think being a proa is much of a liability if it gets you out there sooner or on a cheaper budget than you'd otherwise have to deal with.
     
  11. 360weatherbound
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    360weatherbound Junior Member

    Regarding a market

    Thanks Peter great help.

    Rick, I get it. The small hull can be big enough to support two sails, unstayed.

    Regarding a market, Whats that 38 ft cat going for? 300K I would be nervous taking it anywhere. I have never sailed a proa, but keeping your back to the wind sounds great.

    How about a resonably priced, fast sailing RV for a couple, it can be beached just about anywhere, has a bathroom, kitchen, comfortable bed and a flat ride. The smallest RV has it so can a boat. If it were twice as fast as a monohull and a third the cost of those cats, of course there would be a market. No bridge deck to build, One hull to finish.

    What would make it great for a home builder would be bulding half a mold, I dont know why it wouldn't work. Build one end then build the other, then attach.

    I am going to find one around 20 ft or so that I can build. Whats the worst that can happen, you have a great canoe with a outriggor and a deck between them. Even if I have to put a motor on it:)
     
  12. Guest625101138

    Guest625101138 Previous Member

    Take the time to look through the photos that Rob Denny has of his Solitarry build on the Yahoo site for harryproa. He has AUD13k in the boat so far and he will end up with about AUD20k for a 50ft boat. You will need to log into Yayoo to see them. There is also his costs to date for Solitarry in a spreadsheet down the bottom of the files page.

    The attached photo shows a little proa on a trailer. It gives an idea of proportions. I suggest you go to about 30 to 35ft on the lee hull. The windward probably half that length. You will likely need to have some way to spread the hulls as you can see with the beams in the photo to reduce trailer width. If you only want to experiment then at least go to 24ft with the lee hull. This can be car-topped.

    The hulls can be made from 4 flat panels. You do not need to worry about rounded bottom. A little rocker in the bows will give some lift and reduce the tendency to nose dive. From what I see of them there is a lot of ideas on rudders but I do not know if there is an ideal solution. Rob was having some thought about the dipping type rudders I have used on my pedal boats.

    There are also many videos on Youtube of the harryproas.
     

    Attached Files:

    Last edited: Mar 7, 2010
  13. keith66
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    keith66 Senior Member

    Every boatbuilder who has an ounce of quirkiness has probably entertained the idea of building a proa & many will have done so.
    I have built two, one dreadful & one much better, i can recomend the experience, they are the best fun with your clothes on, but i doubt they will catch on with the yachting market, you do tend to get funny looks sailing one!
     
  14. terhohalme
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    terhohalme BEng Boat Technology

    Yes, this was mine:

    http://wikiproa.pbworks.com/Terho+Halme's+%22Ping-Pong%22
     

  15. gonzo
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    gonzo Senior Member

    Proas shunt instead of tacking or jibing. They usually have a mast that pivots to acommodate that style of sailing.
     
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