Scarab 16

Discussion in 'Multihulls' started by Brorsan, Feb 6, 2011.

  1. captainsideburn
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    captainsideburn Junior Member

    The cat is an Attunga, a late 1950s design. It was built in 1962. I had a rather catastrophic capsize 18 months ago, so I'm slowly rebuilding :(

    I fully agree, a nice dry spot is good, I just feel its not worth the sacrifices on a multihull smaller than maybe the above mentioned buccaneer. Unless you really are going to use a cabin everytime you go sailing, the resultant cramped cockpit is just not to my liking :p
     
  2. dstgean
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    dstgean Senior Member

    I'm in agreement there as well. I'm a bigger guy with a really long torso, so most of the seats in boats don't work for me with headroom--cars too for that matter. Longer boats accomodate cabins without looking too bulky. Interestingly some of the microcruisers have gone away from having a cockpit at all. For cruising in the long term--say longer than a week, I think a cabin is a REALLY nice feature. Some folks can deal with the exposure better than others I guess, but for beachcruising I like the open boat. For cruising, I'd prefer a cabin even if it means a longer boat to care for, pay for moorage, etc. One *could* add length only rather than volume, but that seems to be a temptation no one can resist.

    Dan
     
  3. rayaldridge
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    rayaldridge Senior Member

    I think it's true that in really small boats, you just have to choose between a cockpit and a cabin-- if you try to have both, neither will be very good.

    On another forum, someone posted a link to a page about the folks who have crossed the Atlantic on beach cats. It makes for fairly horrifying reading-- skin rotting off the feet of the first to do it, lengthy hospital stays after only a couple of weeks of voyaging, and so forth. I think it's the nature of the voyage rather than its duration, since people backpack for months at a time. If you can occasionally get warm and dry, then you can cruise in a camp cruiser like Slider. Ida Little and Mike Walsh camped for months in the Bahamas, with a Hobie 14 and a canoe. But they made camps ashore-- they didn't live aboard.

    [​IMG]
     
  4. Brorsan
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    Brorsan Junior Member

    Oh, another question, why is not the building method of tortured ply used nowdays in small multis? I kow it is harder to make drawings for it, but is that the only reason?
     
  5. captainsideburn
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    captainsideburn Junior Member

    +1 i've often wodered this
     
  6. jamez
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    jamez Senior Member


    If you are talking fold-up It might be that difficulties with shape control, limitations in available hull shapes and difficulties in torturing ply thicker than 5-6mm count against it. Also once you have a boat shape ( in any other than the very smallest hulls) you have to spend time putting in frames, stringers or other internal reinforcement, bulkheads etc.

    That said Kurt Hughes CM boats are a variant of tortured ply and hull shape was pretty consistent in 100s of Tornados built that way.

    Assuming we're talking bigger than 20' There are designs out there but you would be hard pressed to find a full set of plans for some of them.

    Examples with plans ( and I have no idea how comprehensive these are)

    http://www.tcdesign.co.nz/bt_790racing.htm

    http://www.tennantdesign.co.nz/index.php?page=red-shift

    The JT 8.5s (pic below), built from 4mm ply, have turned out competitive race boats in the 8.5 class here (2 sailing) and good solid boats too. There are no plans as such but information might be available to loft the panels and fold up the hulls. Probably not a good choice for a first project ;). It really is seat of the pants stuff. IMO Anyone contemplating building a sizeable boat this way should at least read Gougeons chapter on the subject, watch Kurt Hughes CM DVD and probably talk to someone whose built one.
     

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  7. luckystrike
    Joined: Feb 2010
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    luckystrike Power Kraut

    Tortured Ply (TP) is a real magical building method and suitable for the amas if they have a v-shaped bottom. The amas of my 30 footer tri are done this way. But I designed them in the "Nigel Irens Style" of the 1990ths, having a boat designed for good overall speed and seaworthiness, but not for absolute top speeds.

    The Mainhulls of today are to much U-shaped or trapezoid in the bottoms to be compatible with TP. For TP the hull has to be long and slim (10:1 or better)

    The problem with TP today is, that you can design them with the help of computers, but you can not be 100% sure that the ply is managing the bend or breaks during the foldup. In the yellow "West Systems" book the design process is supported by scaled modelling, and so did I. Nevertheless I had a real nervous time building my amas but it worked out for me.

    Kurt Hughes has a further develloped TP building method called Cylinder Molding and the most radical TP design of today is the "Blade" F16 race cat.

    For most people it is not tolerable to have a building method that maybe will fail during the built or to have tolerances in the measures of the boat compared to the drawings.

    Best Regards, Michel
     
  8. captainsideburn
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    captainsideburn Junior Member

    Thats what I'm talking about, if you can do it with a small cat like a blade, far tighter curves etc, why not something bigger, the curves would of course be slacker and easier. I'm convinced its not that it can't be done, but that its more difficult to have consistency.
    Both the blade and Gary's http://www.boatdesign.net/forums/multihulls/alternative-marvelous-buccaneer-24-a-32382-11.html show that it can be done. And as Jamez's example shows it can be thin ply, so keeping it nice and light. I guess its the consistency and that composite has so much more control over all aspects of the shape, that drives designers to use that more.
     
  9. jamez
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    jamez Senior Member

  10. Brorsan
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    Brorsan Junior Member

    Jamez, what a nightmare! having your boat smashed and partly sunk one month after launch, uurg.
     
  11. jamez
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    jamez Senior Member

    Yes, to be honest I'm surprised it wasn't completely demolished. That barge was huge.
     
  12. jamez
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    jamez Senior Member

    Apologies for continuing the thread drift :D Some vid of the other JT8.5; you can get a good idea of the hull shape that was achieved.

    http://www.youtube.com/watch?v=hKzoYju7H3k&feature=related
     
  13. captainsideburn
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    captainsideburn Junior Member

    jamez, thats sweet, who designed it?
     
  14. jamez
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    jamez Senior Member

    Its designed by John Tetzlaff, who also recently launched his new 8.5 tri (designed with input from Tim Clissold) that Samnz's new boat and Lucifer have evolved from (hope I haven't left anybodyout :D). Pics are of Johns boat with cedar strip and ply main hull, tortured ply floats, ply/carbon beams. Also Sams boat currently being built, uses more foam, less ply.
     

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  15. Brorsan
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    Brorsan Junior Member

    Very "clean" look on that tri Jamez, is it allowed to call a multihul beautiful? Nah, that is to strong word, good looking is better suited. :)
     
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