Flat bottom/vertical sides/flat deck/ flat everything

Discussion in 'Sailboats' started by Ron Cook, Apr 3, 2009.

  1. Ron Cook
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    Ron Cook Junior Member

    Might as well let it all hang out. Here is simplification to the extreme. This boats disp. is 20,000# loa 60'. The first image with the aft rig I drew, the second in color is the hull shape that Tanton submitted to me after seeing my.

    This boat would be very fast, to build and to sail if you can put up with some pounding

    Hope you guys enjoy these images
     

    Attached Files:

  2. yacht371
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    yacht371 Yacht Designer

    Ray Hunt 110 and 210

    I think Ray Hunt did it better a LONG time ago with the 110 and 210 classes.

    http://www.210class.com
     
  3. Ron Cook
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    Ron Cook Junior Member

    Apples And Oranges

    The 210 and the 110 are great designs although they have nothing to do with the concept presented above.
     
  4. sharpii2
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    sharpii2 Senior Member

    I have two questions.

    One. How are these keels supposed to work? Is one supposed to be canted out with the other down? The drawings are a bit ambiguous.

    Two. How are you supposed to control this boat when reefed down in a gale?
    As the big jib is rolled up or replaced with a smaller one, The Horizontal Center of Area (HCA) is bound to move forward causing a lee helm. But maybe the draggy aft mast and rigging will counter act that, acting like a defacto mizzen sail.

    Other than that, I think it is a cool design. It reminds me of the earlier Open classes.
     
  5. PAR
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    PAR Yacht Designer/Builder

    I think with all those flat panels you'll have huge structural issues, not to mention a teeth jarring ride. From a structural point of view, it makes no sense to employ inherently weaker design concepts on a vessel of this size. A conically developed surface is so much stronger for the same weight that it just can't be discounted, plus the advantages of better sailing lines and hull form. I find it had to imagine Yves-Marie would sign off on something like this.
     
  6. ancient kayaker
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    ancient kayaker aka Terry Haines

    "Build a simple dinghy" by Nicolson and Reynolds had several boats of similar shape but they were much smaller. They seemed to be rather heavily built, probably for the reasons given by PAR.
     
  7. Ron Cook
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    Ron Cook Junior Member

    Two questions

    The reason for the two keels is so the boat can take to the bottom at rest. In light air the lee keel is raised to reduce drag. In heaver stuff it can be left down to increase righting moment. The boat also has lifting rudders to also reduce drag and to help the boat take the bottom at rest.

    The boat will balance to a point because of the drag of the aft mast. Then an inter head stay will need to be deployed with heavy air sail to maintain balance. The boat should lay a hull well without a sail up because of the aft mast.

    The aft mast concept in the 23' prototype shown below.
     
  8. Ron Cook
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    Ron Cook Junior Member

    Photo

    The halftone print photo won't upload. I'll try again in the morning.
     
  9. PAR
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    PAR Yacht Designer/Builder

    Why the God awful hull form? On a project as substantial as a 60' yacht, it would serve well to optimize the hull form for the intended use and build method.
     
  10. CT 249
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    CT 249 Senior Member

    I get the minimalist idea, but remain totally unconvinced about the rig. There is a reason that so many of the world's fastest sailboats, absolutely or for their size, have big mains and small (or no) jibs.

    While big boats are different, the whole idea that mains are slow is shown to be incorrect by Moths, A Class cats, C Class cats, windsurfers, Macquarie Innovator (the world's fastest boat as of a couple of days ago), etc etc etc.

    Sure, jibs are great and have their place, but considering the vast amount of real-world experience that demonstrates that the supposed problems* of a mast in front of the sail are way outweighed by the actual benefits.

    If this is a faster and better rig, then all of the world's top sailors are stupid. That's not true.

    * interesting to see that the WB Sails work indicates that masts actually improve a sail's efficiency.
     
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  11. Tanton
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    Tanton Senior Member

    Pretty much what I wrote about the concept at the time. To flat, to much pounding, basically a bad proposition.
    In the 60's, I sailed on Attila, a Star where all the proportions were multiply by 3. A fantastic boat but weak on structure. On the other end the Hunt's 110, 210 and my 44' 610 are valid. The InsTanton approach, see another thread, is my solution for simple, fast hull with many good qualities.
     
  12. Ron Cook
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    Ron Cook Junior Member

    God awful

    The reason for the god awful hull form that it is the simplest and the easiest to build. As far as the pounding goes this hull will not pound anymore than the slab sided flat U shaped hulls that are common now. When the boat heels 10 degrees it presents a V to the water. As far as pounding down wind you are going with the wave train so pounding should not be too bad. The driving force behind this concept is ease and speed of building it. I believe this hull form will be much faster than many may think. Structure is simply not a problem the hull shape is a big box beam. The flat panels just take a few more stringers to produce a light strong panel. High speed 160 miles an hour unlimited power bats have proved that.

    The rig is a tried concept a 24’ Bolger with this rig and hull from was built it sailed beautifully and did not pound. The main idea behind this rig on a big boat is the ease handling by one person in all conditions. Roll out the sail and go sailing, roll up the sail and go home!

    For me the interest in a hull and rig like this is one person can build it and one person can sail it. The rest of the world is not stupid or wrong is is just a different take on the subjest.

    Tear it up guys.
     
  13. ancient kayaker
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    ancient kayaker aka Terry Haines

    You can't build the planks flat and raise them into position to form the box beam as is often done for a small boat as they'll break and are in any case too heavy, so you will have to add ply planks over a frame. The ply skin will add rigidity to the frame but the frame must be fair and stay so during the skinning work. The ply sheets will have to be cut to fit, square corners or not. I can see how the square corners might simplify frame construction a bit, but the effort saved is not likely to be great.

    Because the panels are so flat pounding forces will pass directly through the skin into the frame itself, which must therefore be heavily reinforced. A barge is a good example of how massive a slab-sided box structure must be. Modern lightweight designs strive for a monocoque approach in which the skin deflects and distributes these forces over a wider area.

    Bolger is a magician. His designs are far more sophisticated than they seem.
     
  14. timothy22
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    timothy22 Junior Member

    As I recall, Phil Bolger's justification for the rectangular sections in the AS29 and others was to maximize form stability by carrying the max beam all the way down to the chines. Yves-Marie designed a similar boat, he would be the expert on that. They would be easy to set up, but I don't recall having any trouble with the few conic-sectioned v-bottom boats I helped build. In fact, the yard foreman had us leave the stringers loose in the frames until after the planking went on, so that the ply would be free to assume the natural curves imposed on it by the keel, chines and sheer.
     

  15. PAR
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    PAR Yacht Designer/Builder

    I think you need a much stronger grasp on the fundamentals of engineering (and hydrodynamics), just to get a handle on why all those flat panels are a bad idea. You'll be required to make a heavier structure just to support them.

    As far as shape, considering the obvious simplicity of this, you'd think that someone much brighter then us would have thought of it years ago. In reality it was, has been tried and guess why it's not currently used.

    In smaller sizes, where live ballast is a huge percentage of the righting effort, it offers some merit, though the shapes you've employed are all wrong in this regard, well planned and shaped box sectioned hulls perform nicely.

    This particular design seems to be biting off more conflicting and speculative concepts and elements then it the designer can chew. As a rule it's usually best to gnaw on one element at a time so you know where to look for improvement. Once each is reasonably refined, then a combination is worth while.
     
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