'No heeling' sailboat

Discussion in 'Sailboats' started by Guillermo, Mar 21, 2007.

  1. Guillermo
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    Guillermo Ingeniero Naval

    The naval architects Jean-Marc Tabuteau and François Rougier designed a special hull construction to meet Guy Broquaire concept of a no-heeling sailing boat.
    COGITO performs Guy Broquaire's patented 'canting rig' that allows the hull to stay flat on the water (a maximum of 10º heel).

    See: http://www.voiliers-cogito.fr/topic/index.html

    The original COGITO sailboat demonstrator was launched in Cherbourg in August 2005. Anyone has heard something else on this system?

    Cheers
     

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  2. DanishBagger
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    DanishBagger Never Again

    From the looks of it, isn't it basically just depowering the rig? Introducing complexity where one might as well just reef, or am I missing something?

    Heh! I would be very worried about that mast in a crowded marina, if those blokes came around my parts.
     
  3. alan white
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    alan white Senior Member

    Possible if keel cants through direct linkage with mast. The result is similar to a round midsection canoe hull with fixed rig and keel.
    Form stability has a benefit though, which is that its resistence curve through all angles of heel can be shaped to favor greater initial resistence. This could also be done with linkage between keel and rig, though it would be a bit more complicated.
    Further complication would be required to prevent dramatic roll from beam seas passing under a wide after-section, meaning shock absorber-like dampers which would have to be designed to allow for sudden puffs.
    another means to counter rig forces would be a pendulum within the hull, which would allow a fixed (partially-ballasted or non-ballasted keel). The hole through the hull is thus eliminated, but a section of the cabin is unusable due to the arm and pendulum-weight, which are not going to be located close to the mast, but at the boat's center of bouyancy.
    Trade-offs of active ballast systems with the rig involved would be cost or comprimised reliability (your choice), limitation to unshrouded rigs, extreme alignment requirements for fore and aft stays (if backstay is present), headsail luff tensioning problems (if backstay is not present), designing good roll control, capsize recovery (this may not apply on the con side of pro/con, but lacks the history to calculate with any real confidence), and lastly a lock-up device of sufficient strength that it cannot fail under any circumstances, as it will be used when the boat's mass is moving relative to the rig/ballast mass.
    In favor of the design, it will sometimes go faster for the same reason boats with canting keels do, in that the broad stern and flat sections give bouyancy without submersion, the helm is no longer affected by heeling a pointed box shape, and comfort is enhanced by cruising in an upright hull.
    The potential disaster might well be the result of simple economics. How do you engineer such a boat to sell enough copies to those who see more pro than con (like MacGregor owners) and do it without extreme cost (like MacGregor does), while still building a boat that a good sailor would take to sea (unlike MacGregor does)?
    Of course, I saw no drawings of the workings of the boat. Sometimes someone comes up with a new design and it is exceedingly clever; both marketable and functional.

    Alan
     
  4. harhhnt
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    harhhnt Junior Member

    Hey, Why Not A Gyroscope In The Vessel Itself? The Occupants Could Pedal Power It!
     
  5. Vega
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    Vega Senior Member

  6. Mikey
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    Mikey Senior Member

    Another innovative design idea that will make boats even more expensive. Yes, it's great but... do people want even more expensive boats? Don't they rather want sailing boats that they can afford to buy? And maintain... High tech does not only cost more to manufacture, it also costs more to maintain.

    Mikey
     
  7. longliner45
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    longliner45 Senior Member

    im sorry ,only an idiot would buy a sailboat like that,,,,the designer forgot why I sail,,,,,,I sail to feel the breese in my face ,,,I sail to feel the ocean spray on my brow,and to hear the screams of thrill,if I want a sailboat that doesnt have this ,,,,,,,whats the point?,,might as well use gasoline,,,,,,longliner
     
  8. Mikey
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    Mikey Senior Member

    Well, maybe we should not call the buyer an idiot. We should realize that everything in our lives are controlled by our core values and that they are different for different people. So people buy different things, good, how boring life would be if everybody bought the same things.

    Our values seem to be the same in this case longliner, I certainly would never buy the boat too :)
     
  9. longliner45
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    longliner45 Senior Member

    you design a boat for profit ,,to attract a market,,or to improve speed and handleing,or ,preformance,,I know everyone has a different cup of tea,,, but I dont think this boat will make it,,,its kinda like lee Ioococa for chystler auto and the K car ,,,,,,he desided everyone will drive a K car,,so he retooled a plant and made nothing but Kcars,,,,,no one bought them,,,I think the same applies here,if you forget who is buying ,,,,you have lost your market,,,this boat is going nowhere,,longliner
     
  10. alan white
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    alan white Senior Member

    Purists are not well understood by innovators who are not purists. They don't need to understand purists. They need only understand markets.
    I don't think the effort behind this new boat design understands markets or purists. There is another kind of person who is neither purist or marketing genius. He is an idealist, and probably a charismatic one, unless he's very wealthy. Sometimes idealists succeed in doing things nobody else was nuts enough to try, but mostly they fail, like Tucker or DeLorean or Buckminster Fuller did with cars.
    Still, I'm glad people do such things. I wouldn't buy a hinged sailboat either, but I can understand why people invent and believe in things like that.
    And if I'd invented it, I would definately rather sail it than any other boat.
    I wouldn't kid myself into thinking everyone else would feel the same thrill though. An idealist might not make the same distinction.

    A.
     
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  11. Guillermo
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    Guillermo Ingeniero Naval

    I find it makes little sense not to take advantage of the righting moments due to forms and counteract heeling forces only with weight from the keel. That limits seriously the ability of the boat to carry sails up at the angles they are more efficient (upright). To get enough 'righting moment' for that should obligue to have a very heavy bulb well down.

    Also I would like to know how they handle to keep the stay with the proper tension. It seems to me it should slack or overtension when the mast is tilted, unless the attachement of the stay on deck is exactly on the zenith of the center of gyration of mast.

    The only advantage I can see is to use it as a 'releasing valve' for when in gusts. Something like keeping the mast fixed till you reach, let's say 10º heel, and then, instead of easying sheets you let the mast to tilt. But it sounds like a very expensive solution, very far away from the KISS principle.

    I think the the idea is going to have difficulties to pass through in the market, in my opinion, not only because of price or the KISS principle, but also because if you like to sail flat you'd better go multihulls.

    Anyhow I'm interested in knowing how are they succeeding (if they are at all!)

    Cheers.
    .
     
  12. DanishBagger
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    DanishBagger Never Again

    I'm really not into multihulls, but Guillermo, you're so right. If I wanted to sail flat, i'd certainly go for a multihull. In comparison, I would get a simpler, faster, cheaper boat, with more livable space (perhaps outside) for the same price. A dragonfly swing wing (dock fees are dear in Denmark) sounds about right.

    If I had a mooring, I'd go for a non-folding version, perhaps a catamaran, if I had the choice between the tilting mast and a multihull.

    I can see why one would want to tilt the mast _into_ the wind, but not as the above one does it.
     
  13. alan white
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    alan white Senior Member

    "Also I would like to know how they handle to keep the stay with the proper tension. It seems to me it should slack or overtension when the mast is tilted, unless the attachement of the stay on deck is exactly on the zenith of the center of gyration of mast."

    Guillermo

    Right. The axial alignment of the stays is absolutely necessary. Good sized bearings would also be required at the attachments below the turnbuckles. And to lock up the mast, a massive pin would have to engage while the boat might well be in violent motion. The shock would have to be absorbed without failure of mast or hull, a shock of instant deceleration of several massive components.
    A sail in a puff normally is afforded a slight but crucial "soft start" allowing force to be transmitted without the unequal accelleration between mast top and base exceeding the elasticity of the material used. Not only would a sudden lock-up be a frightening maneuver when the boat is rolling, but it's assumed there's a limit to the angle to which the mast can "heel".
    Imagine the boat has been rolled by the face of a wave or swell, so that it has heeled to windward, while the mast is swinging to leeward due to a sudden gust. It reaches its limit before it normally would due to the boat's heel the other way. The shock would possibly snap the mast off like a toothpick, probably at the base.
    All of these problems are engineering glitches, easily solved by shock-absorbing materials and complication. This is no problem if cost is no object, and the boat never goes offshore. The whole boat could be made of titanium and graphite I suppose. I would question the wisdom of building it to sell to the public. Comprimises in the area of materials and workmanship would make for a potentially dangerous boat.

    A.
     
  14. Mychael
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    Mychael Mychael

    Maybe it would have a market for people that want to "sail" but are not really "sailors" if you get my meaning. Like people that only ever bother to learn how to drive a car with automatic transmission. Maybe that ype of boat would suit the weekenders who want to be out on the water in a "sailboat" but would only go out in a sheltered bay on a sunny day.

    Mychael
     

  15. alan white
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    alan white Senior Member

    Deep keel, necessary to limit hull form stability contribution to 10 degrees, is perhaps 6 ft on a 28 ft boat. There will also be a window on the underbody as wide as the distance up to the axis of the structure requires, and it is closer to the deck than the underbody. This window, more wide than long, would be as deep as required to allow structural integrity of the hull----- maybe three or more inches. I assume this is covered by a thin outer cover attached to the keel stem.
    In Maine at least, such a keel would first grap lobster pot warps with the keel bulb, which would then slide up the keel stem and get caught between the outer "window cover" and the hull. This is inshore sailing in protected waters on a sunny day. The rope would jam the rig/keel at some angle like perhaps 25% and keep it there, whereapon the boat will heel to a dramatic angle and be stuck in place too.
    Without the outer "window cover", the hydrodynamics would be horrible. The boat could never plane. It would be sluggish even in light air.
    The problem could be solved, one might think, with a soft cover, but now there's a better chance for things to get in than before.
    The keel is deep, so this boat must seek deeper water. Inshore means, generally, increasing shoal conditions. Maine waters are out because of pot warps, but so are half the other inshore cruising areas and places like the Bahamas or Cape Cod because of shoal water.
    Forget the Thames estuary, or a thousand other potential locations.
    It's amazing how these limitations stack up as soon as the boat has been limited to inshore areas.


    A.
     
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