beach catamaran hull plans

Discussion in 'Multihulls' started by spidennis, Feb 8, 2012.

  1. spidennis
    Joined: Feb 2007
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    spidennis Chief Sawdust Sweeper

    so I'm presently doing a bunch of house re modeling and went into the nearest town for tile, Brownsville, and on the way back I slam on the brakes to go see this place called Esco, a ship breaking yard. Always wanted to go in but I'd know what would happen ...... anyway this was the day ...... lot's of cool stuff but I was on a mission, to find some aluminum box beam. They had angle, channel, I beam, but not what I was looking for, but some of that angle and channel was looking good! I'll have to think about just how I can use it. There was also aluminum bed frames and hospital litters that I could use as the platform and wings, or whatever! 2.50/lb aluminum or stainless . I walked out empty handed but I'll be back, after the house re mod is finished.
     

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  2. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    Its not really a party barge, look here

    http://wam-v.com/

    They did a big one (Spyder?) that was moored in Pt Richmond, San Francisco a few years ago. The video is quite interesting as it shows a relatively stable deck on very flexible hulls going through waves

    But the photo does show what happens with lots of hinges, probably the heaviest part of the boat

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  3. spidennis
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    spidennis Chief Sawdust Sweeper

    It's a remarkable vessel (on that link) to say the least, but I'm not quite sure what it's mission is. Something could be learned from looking at all that suspension, hinging and so on. Wish I could have seen it up close! I'm trying to keep my folding system as basic as possible, the less there is the less to go wrong, KISS.

    The sea clipper is pretty basic, but from what I see it has flexing problems. The attachment points are "single" with no kind of backup support.

    The prindle16 has two bolts on each hull attachment, I'll use the same kind of thing. the outside bolt will be the pivoting point. the inside "connection" (which I'm still working out) will securely fasten the beam to the hull.

    the same thing goes for the center platform but I'll have some kind of backup bar to join the two "halves" from either side.

    There are a few different ways of doing all of this, the hinge points could be on the outside, the inside, or the middle, I'm trying them all.

    pics and video coming ....
     
  4. spidennis
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    spidennis Chief Sawdust Sweeper

    I got this flush mount thru hull bolt system that I worked out.

    There will be threads on the top of the bolt, then the plate fits overtop and gets tighten down with a knobnut (for lack of a better term). I can use square stock instead of the round bar (from the prindle), drill it , slide the bolt shaft in then weld it, all easy enough to do. The hulls of course will be strong at these connections.

    I've also considered a backing block on the hull for the beam to mate against.



    In this first pic I show a single bolt (it's a #2 for the model)
    but there's no way of really making this work.
    [​IMG]

    [​IMG]

    Now imagine one on each side of the beam once the hulls are extended,
    the bolts get dropped into the slot, quarter turn to fit in the holder below deck,
    plate placed on top and it gets nutted down.
    [​IMG]

    [​IMG]
     
  5. waynemarlow
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    waynemarlow Senior Member

    Not sure you are following my idea through here, attach very small volume long AMA's ( training wheels ) like a trimaran and you have a very stable craft that the rig can lie along, bits can fit inside the boat and it won't be much more than 70 kilos. Do as I plan and only have 1 AMA and it would be less than 60kgs

    Having built a F16 from scratch, getting less than 23 kgs hulls is difficult, add in rig and beams and ancillaries and I'm betting your design will be over 140kgs when its ready to go. Would I push 140kgs or 60 kgs for 40 miles, thats a no brainer.
     
  6. spidennis
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    spidennis Chief Sawdust Sweeper

    Ok, proa style then? Similar to what Randy Smyth has going on with Sizzor? but only one outrigger?

    A trimaran I can sail, but a proa? I got no idea about changing direction .... :?:

    [​IMG]

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  7. waynemarlow
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    waynemarlow Senior Member

    You definately do need to think a little more out of the box if you think you will be sailing an IC backwards, think single AMA on the predominate lee or windward side ( not sure on that bit where the best benefit, leverage without dragging the AMA or safety by immersing the AMA ) and a Hobie style wing net on the other. By my calculations on the design I had in mind, about 2.35m on one side and 1.35m outboard of the hull centre line on the net side. Do away with the sliding seat ( about 8kgs in total ) and simply fit a trapeze ( about 0.2 kgs ), far more comfortable.

    Have a look at the Ninja Pro http://www.sail-the-difference.com/home/english/the_features_of_the_easy_to_use_smg_catamaran/ninja/ if you staill haven't quite grasped the concept.
    [​IMG]

    The nice thing about the IC unlimited it will give you good sail area upwind with the original sails, fit a furler screacher as well ( trapeze + ama gives you increased righting moment ) + the original 20 + metres spinny and you have all the sail you would ever need in avery light weight package.
     
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  8. spidennis
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    spidennis Chief Sawdust Sweeper

    ok, I think I'm getting a grasp on this ........

    concerns:
    low bridges, got to demount the mast quick enough and set back up.
    Rivers, this has to be paddled or rowed somehow.
    Portage. How well does this come apart? and pack onto a cart. (no bike)
     
  9. waynemarlow
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    waynemarlow Senior Member

    Now that is the conundrum only you can sort out, its been done often enough before so I certainly would not be trying to reinvent the wheel.

    Just a thought, fold in the wing net and you basically have a wide dinghy which could be rowed using oars ( one could be the boom ) rather than a single canoe paddle, you gotta think outside the box
     
  10. Doug Lord
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    Doug Lord Flight Ready

    -------
    Scissors(?) is the way I'd want to go: very low wetted surface, high L/B ratio, high SA/WS ratio. I don't think you can even approach that with an IC conversion. And it folds and is paddleable---and it's a proven winner.
    But you're looking to use it on a different type of course than Smythe's boat, right?
    The more you can stretch out any weight bearing hull to get a higher L/B ratio the better off you'll be in my opinion.... Good Luck!
     
  11. spidennis
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    spidennis Chief Sawdust Sweeper

    Randy's plan (I believe) was to use the Boat Switch Rule all along. I also believe he's part of the reason for the rule. He's not portaging this boat where I plan on using the original rules and doing the portage, one boat, one man, no help (just like I do all my adventures).

    So in a way we are in different classes even though both class 5. Sure, who wouldn't want Sizzor to race in? But I'm not about to copy Randy's efforts, not when there's other designs to try out "per the original rulz".

    [​IMG]

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    [​IMG]
     
  12. spidennis
    Joined: Feb 2007
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    spidennis Chief Sawdust Sweeper

    Here's the latest update:

    Hi Dennis,
    once ready the Razor plans will include every detail needed to build it, table of offsets and all. Availability TBA.

    Best,
    Blade Catamarans
     
  13. BobBill
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    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Beach Cats


    FWIW,

    I would think the Ninja lends itself well to varied water, but looks not to be home project. Ninja only avail in South Africa, I believe.

    On that line, perhaps, an updated Malibu Outrigger design is in order, with folding akas and with glass/foam ama. Plans are not expensive, and updating with above and carbon boom and yard might just put this design back in the picture, as I am slowly planning to do.

    No stays, solid ply design...easy to alter, trail, beach, surf use.

    Eminently simple built design and way sturdy. Orig class min weight was 350...lots to work with here.

    Included pic of a aka hinge I located on WWW, but not scissors style, but simpler.
     

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  14. spidennis
    Joined: Feb 2007
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    spidennis Chief Sawdust Sweeper

    The Everglades Challenge is now underway, and conditions are tough!
    The Ultimate Florida Challenge started at the same time as the EC but they just keep going! Get a feel for what the requirement are by following the race. I'm not getting any work done with this is in progress!

    http://watertribe.org/forums/
     

  15. upchurchmr
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    upchurchmr Senior Member

    Chris White designed a tacking Proa in the 70's I believe. Everything I've seen later looks like a copy, including the Ninja (much more complicated). Sorry I don't remember the name and it is no longer shown on his website (he's doing big expensive boats now and making a living). If you have any interest send him an email, I really liked the boat - seems like several others did also.

     
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