Folding arm materials - Any reason not to use Aluminum?

Discussion in 'Multihulls' started by Jetboy, Feb 7, 2012.

  1. spidennis
    Joined: Feb 2007
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    Location: south padre island, texas

    spidennis Chief Sawdust Sweeper

    AeroRig? I just started a thread on that .... if you get some more pics please add to that thread! and tell me more about it if you can ..... thanks!

    http://www.boatdesign.net/forums/multihulls/biplane-aerorig-cat-42096.html
     
  2. Corley
    Joined: Oct 2009
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    Location: Melbourne, Australia

    Corley epoxy coated

    Ian designed and built the boat himself he has a background in aircraft engineering. I've seen the plans for the boat and they are as detailed as most stock plans. It has an outboard in a pod and a single unstayed carbon, custom designed (by Ian) aerorig style mast. I was surprised how spacious the pod was when on board there isnt much intrusion by the beam hinge where it meets the hull. I'd say the interior has slightly less useable space than say a F22 trimaran well organised though to make the most of the space. The boat has it's rudders in cassettes that can be fully retracted. I assume it has daggerboards in the hulls not a surface piercing foil as theres no case in the pod. He has built the mast but it's not with the boat we are thinking of having him speak about the boat at one of our club meetings I'll take along a video camera if he does.
     
  3. spidennis
    Joined: Feb 2007
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    Location: south padre island, texas

    spidennis Chief Sawdust Sweeper

    "trailerable pod cat 28' " and it folds? I'd sure like to see more of this boat! Especially the folding part! This sounds like the perfect Texas Coastal Cruiser for me! Offshore or in the bay and ICW, pretty mcuh go anywhere, now that would be the cat's meow!
     
  4. basil
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    Location: aUSTRALIA

    basil Senior Member

  5. old dog
    Joined: Dec 2011
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    Location: port stevens

    old dog Junior Member

    Channels tend to twist compared to RHS or tube.
     
  6. warwick
    Joined: Jan 2012
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    Location: papakura south auckland new zealand

    warwick Senior Member

    I agree with old dog as there seams to be little difference between the Ray Kendrick and Ian Farrier folding approach. The approch by TNT 34 trimaran may have improvements in the future, by using a combination of folding and sliding, but may require time for devolopement. The TNT trimaran can be found as thread else where.
     
  7. Jetboy
    Joined: Feb 2012
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    Jetboy Senior Member

    This has been a great learning thread for me. I've seen a lot of ideas I hadn't previously seen before.

    As it turns out, I've found some free access to a water jet to cut whatever I want. I have to pay a small fee per mm of cut, but it's basically free. The big downside is that the table isn't very big. It's only 4' by 4', so that pretty much eliminates the ability to cut the arm beams unless I use two pieces for each one.

    The funny part is that the more I consider the options, the more I end up back at the two most common: the original planned fiberglass or round aluminum tubing. I've still got a bit of time before I need to decide and a lot to learn.


    Has anyone ever seen a tri with adjustable dihedral? I think it would be very nice to have for a cruiser type boat. Especially if, when stopped for fishing or something you could lower the amas so that they are both supporting the boat and give a lot greater stability when not under sail.
     
  8. guzzis3
    Joined: Nov 2009
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    Location: Brisbane

    guzzis3 Senior Member

    Is that a swing wing folding system ? or something else ?
     
  9. Corley
    Joined: Oct 2009
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    Location: Melbourne, Australia

    Corley epoxy coated

    The hulls swing back against the pod a bit like the dragonfly trimaran.
     
  10. oldsailor7
    Joined: May 2008
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    Location: Sydney Australia

    oldsailor7 Senior Member

    Quote:-
    "Has anyone ever seen a tri with adjustable dihedral? I think it would be very nice to have for a cruiser type boat. Especially if, when stopped for fishing or something you could lower the amas so that they are both supporting the boat and give a lot greater stability when not under sail." Quote.

    From my experience with Piver trimarans, which have immersed amas, there is no more special "Stability", or resistance to "Rocking" as the waves pass under the boat. This was especially bad on the Pivers as they had V section amas.
    On a Tri with dihedral, one side of the boat can be "Ballasted" by weighting with a heavy object (such as sailbags etc), or do your fishing from one side by sitting on the ama. The boat then acts rather like a narrow Catamaran. :)
     
  11. warwick
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    warwick Senior Member

    A similer approach was used on the malcom tennent designed catamaran, Streaker. Where the hulls swung back against the pod or the pod swung forward depending on view point.
     
  12. buzzman
    Joined: May 2011
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    Location: Australia

    buzzman Senior Member

    Quick fold system for small tris

    This guy in FL has built a different system, horizontal swing like Draglonly, but low tech and low cost KISS principle.

    OK, so his rig is weird and super-simplified for his specific usage, but his claimed 2-3 mins to launch is mighty impressive, and the hulls can be unfolded on the move, not just on the water.

    Interesting approach, at least.

    http://www.diy-tris.com/2012/5-close-ups.htm
     
  13. warwick
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    Location: papakura south auckland new zealand

    warwick Senior Member

    Jetboy.

    Out of curiosity what did you decide to do as to the cross beam? Have you decided on using the original GRP cross beam design?
     
  14. Jetboy
    Joined: Feb 2012
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    Location: USA

    Jetboy Senior Member

    I haven't built them yet. Just got the second ama off the mold. Due to some unforeseen interruptions the build is going a lot slower than I had hoped. Anyway I did buy all the material to do the GRP version and a vacuum pump so I'm ready to build them, but haven't actually built them yet. Unless I find a good deal on some Aluminum plate I'll probably end up going with GRP.
     

  15. warwick
    Joined: Jan 2012
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    Location: papakura south auckland new zealand

    warwick Senior Member

    It probably the easiest way to go is to follow Ray Kendrick's Plan. As he has already put in the hard work for you. Good luck with your boat you will finish it at some point.
     
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