Speed Dream 27 Prototype

Discussion in 'Sailboats' started by Doug Lord, Sep 20, 2011.

  1. Roger Six
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    Roger Six Surge Protector

    If one simply looks at the wind and typical boat speeds in which most races are run, you will understand that a stepped hull is going to work in but a tiny fraction of the conditions in which it will normally sail. That makes the design a poor choice for around the can sailing.

    It's either a small version test bed design for the larger machine, (and that means that it will never be a production, One-Design) or, it's a mid-pack-back marker for everything else where it has to match-up with better boats with more overall design solutions. Can't be both with this form.
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Speed Dream

    Chris, do you think Vlad has any design expertise at all? Is it possible you may have overlooked something?
     
  3. DCockey
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    DCockey Senior Member


    Why not look at it as an interesting concept which has been turned into a boat (unlike most concepts discussed on the internet), and see how it works and what can be learned from it?
     
  4. CutOnce

    CutOnce Previous Member

    David:

    I think your comment is dead on, certainly when said as a third party that has no skin in the game.

    The one concern with the "only cheer them on" attitude is that resources are a very limited quantity, and the number of times you get to try things is a finite number. Money, time, thought, execution, effort, youth, enthusiasm and credibility are expended in completing any development project, and it takes incredible focus to get to the finish line. Some of these qualities are not renewable - no one gets to stop clocks and banks don't finance people with serial business failures.

    Although not as fun to hear as a chorus of cheers, some of the product development proposals we get to comment on Boatdesign.net would actually benefit more from balanced commentary including "less than glowing support."

    Before you start, you have to develop a very focused plan that defines the objectives. In this particular project, it seems like focus and objectives are moving targets - which raises red flags to me. Although just a personal opinion, I really am put off by promoting results publicly before actually building and confirming the results. Underpromise and overdeliver are my personal preferences when it comes to performance - be it functional or marketing we are talking about.

    I think Mr. Murnikov is a way better designer/thinker than perhaps he may be in other business roles. It is hard for the same person to be a marketer, promoter, designer, builder, chief executive, fund raiser and salesman. What makes someone good at some business roles is a negative to others.

    --
    CutOnce
     
  5. Roger Six
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    Roger Six Surge Protector

    I think that we are all looking at this design with that in mind. However, there are also other considerations and I am merely offering but one of them as an argument that is in the mix.
     
  6. Ilan Voyager
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    Ilan Voyager Senior Member

    Parlier's cat (Hydraplaneur) has not been very successful for a all good around boat. This cat had potential downwind in strong breeze and showed it with its records, but the upwind was dramatically bad and painful. In light conditions it stays scotched on the water, the drag is too enormous. The boat has been at Gujan Mestras for sale at 300,000 Euros since 2007, and nobody wants it.
    The stepped hulls have been tried also on one swiss sport cat and at least 2 monohulls (one at Geneva). The results are from bad on the multis to extremely awful on the monos.
    That works only on a small range of conditions and are awful out of their optimal conditions. It's not a problem on a sea plane or a fast motor hull which is used always in the same range of speeds, but on a sail boat used in variable conditions it does not work simply.
    For me it's a false good idea like has been the bulbs on sail monohulls. I'm afraid that some NA "focalizes" on one trick and forget the remaining problems to solve.
    A trimaran with movable foils is fast because; first they are very powerful with lots of "HP" to accelerate and "get out of the hole" keeping a good margin of stability.
    If the tris were brutal or unpredictable, it would be impossible to fly on only an ama. The curve of stability is wide and smooth.
    You have to reduce the sail soon and the wide and rigid platform can support a big, tall mast with lots of sail.
    So in light winds the hulls permit to stay at a decent speed and lose a minimum of time, and when the wind is on light medium you have plenty of power so you can take full advantage of the foils and fly. And the platform is strong enough to keep this advantages when the wind gets harder.
    A monohull can't have such a power with a good stability. Canteen keels, ballast and other complications are unable to give enough stability, plus the platform for rigging the mast is rather narrow and induces very soon compression problems in the mast. Morality with a "fixed" system like a stepped hull you have to bear the penalty of drag in light wind, and you have not enough power and stability to take full advantage of a steeped hull simply because you'll have never enough speed.
    Compare the speeds of 60 feet monohull with a same sized multihull, there is no match.
     
  7. Doug Lord
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    Doug Lord Flight Ready

    Ilan, I disagree about whats possible with a monohull. The last page of this thread has an updated set of specs for a 60' monofoiler. Another poster here did a comparison and found that it was likely to be faster that a 60' ORMA tri. http://www.boatdesign.net/forums/sa...ng-monofoiler-design-discussion-15143-12.html
    The key for a monohull to beat a multihull, in my opinion, is that it must use:
    1)-2 lifting foils,
    2)-sliding on deck ballast and
    3)-Veal Heel.
    These elements all combine to reduce drag and increase power to carry sail. The sketch below shows a preliminary drawing of a 30' self-righting keelboat foiler, a version of which is being built now. Numbers: http://www.boatdesign.net/forums/sailboats/foiling-keelboat-30-a-38395.html
    What Vlad wants to do is most definitely possible but I'm convinced that lifting hydrofoils will eventually play a central role.
     

    Attached Files:

    Last edited: Oct 29, 2012
  8. Stephen Ditmore
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    Stephen Ditmore Senior Member

    That's just it, I'm struggling to understand what he's thinking. It has the SA/displacement ratio of a light air boat and the bottom shape of a high speed planing boat. But most high speed planing boats maintain more bottom area forward (circumscribed by the chine). What result do you get if you put this boat through the Donald Blount Assoc. dynamic instability calculator? Even if they're able to bring CG aft, will they be able to keep it far enough aft to keep the wind acting on the high center-of-effort from pushing the part of the boat aft of the step out of the water? As soon as that happens the forward planing surface loses angle of incidence. Perhaps in a heavy wind they just blow the rig off using exploding bolts, and pop a kite-sail!

    But let's say he is right. What has he shown, exactly?
     
  9. Doug Lord
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    Doug Lord Flight Ready

    ====================
    Thats all well and good except it's not viable in the real world when you're trying to put together a project to raise money to build the fastest sailboat in the world. Thats the key to this project. Vlad has a team behind him which includes the Russian search engine Yandex and Brian Hancock. They must talk up the potential of the project and the prototype.
     
  10. Stephen Ditmore
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    Stephen Ditmore Senior Member

    But I don't think this forum is the place for that. I'm not in favor of meanness, but I am in favor of critical evaluation yielding insight.
     
  11. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    SpeedDream

    =========================
    I think it is important to present new thinking like the 27 and Vlads ultimate goal on a design forum like this. People are free to say anything that pops in their heads regarding Vlads plans, prototype, new dinghy etc. and they do that as can readily be seen.
     
  12. sean9c
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    sean9c Senior Member

    By printing untrue and misleading information?
     
  13. Doug Lord
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    Doug Lord Flight Ready

    ==========
    No.
     
  14. Corley
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    Corley epoxy coated


  15. Ilan Voyager
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    Ilan Voyager Senior Member

    Doug, the future will tell us but until now none monohull has been able to win against a multihull, and the examples are so numerous.

    It's a problem of basic geometry on sail boats. The big problem to solve on sail boats is that, instead of motor boats where the center of power is about aligned with the hull, the center of the sails and thus the power is several meters above the hull, and almost never aligned with the hull. So you have instability torques and big ones to fight.

    The simplest solution is to enlarge the platform, and create enough stability to counteract the torques induced by the sails. Furthermore the rigid wide platform permits to have more sails with a simpler rigging and less compression on the mast. Nowadays, it is unusual to break a mast on a multi.

    The monohull is not wide enough and thus has not enough stability and can't carry enough sail. It's a brutal fact. Worst it has to carry the penalty dead weight of the ballasts and keel. Whatever the NA can imagine (hull shape, foils, canting keels, etc...) the fact remains. If it has so efficient foils that it won't heel, the mast will cause problems, and there will be not enough diagonal stability even with a canting keel which has a big hydrodynamic cost. Make a diagram and you will understand.

    About the monofoiler; it's very nice on the 14 feet as the heavy computer with fast sensors and 1/10 second reactions (the skipper...) weights at least 3 times the weight of the boat. How do you get in real world the same effect on a 60 feet sail monofoiler? Again diagrams, and you'll see the issue. Monofoilers are not new and none has gone further than the step of small boats for protected waters, and they had not the problems of carrying sails with the inherent instability. I can insure you that several teams of engineers have worked on the problem on patrol foilers, with several configurations including monofoilers.

    Oceanic trimarans have become so efficient that to beat them on the Atlantic crossing you need ferry catamarans (multi again!) 300 feet long with 36000 HP...For an around the world race there is no boat, nor ship to beat them. Even a fast war ship is unable to keep its machines at full speed for 30000 miles or during 45 days, they will be destroyed well before.
     
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