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Brown-style trailerable/foldable concept

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Joined 2012-02-09

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I like the idea of a trailerable/folding proa and I like the Farrier folding system. How compatible are these?

My best attempt concluded that this is doable up to about 17 foot beam, assuming 1.5 feet of overlap at the connection point. (Reasonable for this system?). The struts ended up 5 feet long. To trailer two parts that are 10 feet wide, and to allow the proa to be stable while pulling up to a trailer, it rests on the pod both on the water and trailer.

17 foot beam, 10 foot ama/aka, 10 foot hull width including mounting beam. 8.5’ width for trailer.

     

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Hi Adam, neat boat! I’m not sure I’m reading your drawing right though. Are the black lines that look like wires under the beam, are they links a la Farrier folding system?

     
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James, you are correct. I should’ve made the links or struts thicker to make that clear. They’re more like placeholders right now in that hinging their ends will result in folding with the two extreme limits shown above.

Farrier’s animation explains the concept it better than my sketch. http://www.f-boat.com/pages/animation.html

      [ Edited: 18 February 2012 11:48 AM by Adam ]
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I like this idea a lot.

There are some opportunities to stray from the Farrier-intended design because a Pacific proa isn’t likely to see the same sort of loading, but I like the way that it works compared to the sliding beam type of scrunching.

Does anyone have drawings or specs of the Farrier kit that we can fool around with?  If it can be made to work I’d be more than happy to buy his stuff off the shelf rather than trying to reinvent the wheel… again!

     
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We are thinking about the same problem. Beam is a general problem for multihulls in narrow marina berth. The additional disadvantage of a cruising proa is the leepod. He generates beam without support on the water. A friend had an idea to stabilize the boat in folded state with inflatable bodies. In this way it may be possible to get enough stability in a marina berth like a foldable trimaran. A two way pump fills and empties the inflatable body, so it could be fixed mounted eg. under the leepod and/or cockpit.

There are other or better ideas for a folding proa around?

     

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Farrier style vertical folding just doesn’t work with proa aka lengths.  Attached is a Sketchup rendering of a workable framework for Proa Aka folding.  The rendering shows the concept fully folded.  The geometry works, and the upper/lower aka arms break down the loads into tension (upper) and compression (lower) for a Pacific Proa.  You could certainly make this less “agricultural” in appearance as long as the geometry and hinge axis are maintained.

Critical elements of the design are making sure there are no single points of failure in the Aka hinge points as well as keeping hinge locking points relevant to multiple axis.

With the folding happening on the longitudinal plane, there is no problem with adequate beam as longer beam means the aka halves just extend further to the front and rear.  Interesting benefit of this concept is that folding could happen on the water. although folded stability would be limited.


Bill in Ottawa

      [ Edited: 01 April 2013 05:13 PM by Bill S. ]

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A few years ago now I redesigned the akas for or Mi6 proa to use the Farrier system. Or boat is 6m long and 2.5m hull spacing (about 3.5m overall beam). I think the farrier system is very good in terms of being relatively simple, high strength and quick and easy to operate. However, it is really designed to apply loading on the ama (the struts underneath are really tension members) and relies on the shrouds to some extent to take the weight of the ama if it is lifted out of the water, so may need to be modified a bit if you have a freestanding mast. The MI6 is mainly an Atlantic proa so it was a good application for this system.

A bit of trivia, at the time I contacted Ian Farrier to see it was ok for us to use the system (we had big ideas of going commercial). As it turned out the patent had run out, but Ian asked us not to use the name ‘Farrier’ if marketing it, as that is his trademark.

     

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