Veal Heel for Multihull Foilers

Discussion in 'Multihulls' started by Doug Lord, Jul 14, 2009.

  1. Doug Lord
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    Doug Lord Flight Ready

    One of the most recent major contributions to the physics of sailing has come
    from the little Moth monofoiler: it is called "veal heel" after Rohan Veal who developed it. Nothing new about heeling a boat to windward except when that boat is flying on hydrofoils. In that case with the boat heeled to weather the Righting Moment(RM) is increased by the amount the boat and crew CG move to weather of the center of lift of the foils. Not only that but the struts(daggerboard and rudder) supporting the hydrofoils are unloaded and a component of the hydrofoil lift acts to weather improving upwind vmg.
    Multifoilers,to date, have either sailed level or heeled like a "normal" sailboat.( except for an unsuccessful experiment in the C class)
    I think there may be a better way on a high performance trimaran that would use very small "amas" like the Rave but with a major difference: the new boat would use two foils-like a Moth- for boat speeds up to say, 20 knots. After that the boat would deploy(retractable) very small foils from the vicinity of the windward ama that would generate downforce to increase RM.
    I did a rough comparison of two boats each weighing exactly what a Rave does and the wetted surface is less at least up to 30 knots boat speed but whats more drag is less again, at least up to 30 knots. This thing could be designed to be MUCH lighter than a Rave(368lb) and could be substantially faster in 5-20 knots of wind.
    But what is really cool is that the new concept foiler would sail with "veal heel" with the attendant advantages upwind.
    Comments welcome.....
    To see an illustration of the physics of veal heel see Fig 25 of the attached paper(from the International Moth site):
    Rave pix:
    Moth with veal heel:
     

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  2. Paul B

    Paul B Previous Member

    Have you secured the rights to post this technical paper on this BB?

    Have some respect for the intellectual rights of others.
     
  3. Doug Lord
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    Doug Lord Flight Ready

    heres an illustration for an approximately 15' wide "tri"-stb side only:
     

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  4. Cheesy
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    Cheesy Senior Member

    that angle doesnt much look like 20 deg.....
     
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  5. Doug Lord
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    Doug Lord Flight Ready

    ==============
    My apologies. As usual, I got in a hurry and screwed up. The 20 degrees on the drawing made sense at the time because I was thinking of the boat heeling 20 degrees to weather and of the powerfoil strut angled 20 degrees to leeward(of vertical). Not very clear on the drawing,though.
     
  6. Chris Ostlind

    Chris Ostlind Previous Member

    Once again, it's all about the ability to draw and one's ability to express oneself with a simple set of pencils and drafting tools. Logic is explained through a drawing.

    Doug, please get yourself enrolled in a Junior College, 2D drawing, as well as architectural drafting class process and learn how to avoid this in the future.

    Your ability to express yourself in the graphic medium is hurting your cause. Most folks respond a whole lot better to an illustration than they do to along list of numbers.
     
  7. schakel
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    schakel environmental project Msc

  8. Doug Lord
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    Doug Lord Flight Ready

    Veal heel

    Thanks Schakel! And on a foiler it also increases RM. I'm convinced a multihull foiler could be designed to take advantage of these proven benefits.
     
  9. Paul B

    Paul B Previous Member

    And here I thought you would not be able to do worse than your last "sketches".

    So this is your idea of a technical drawing? No scale, dimensions all wrong, produced with a leaky ball point pen? That is something that would not have even been graded by my high school drafting instructor. I would love to see you post a linesplan you have drawn for any of the boats you claim to have designed.

    The fact that you are not ashamed to post something like that on a public forum says quite a bit about your mental state.


    I guess as a designer you are a revolution. By revolution I mean someone who can't actually draw anything, and likes to take other people's calculations and scale them in a linear way in order to post thousands of words of nonsense across the internet.
     
  10. TeddyDiver
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    TeddyDiver Gollywobbler

    A bit obsessed about your own opinion of your ultimate superiority compared to lower lifeforms trying to make some sense every now and then? :D
     
  11. Doug Lord
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    Doug Lord Flight Ready

    Power Foil Equiped Multihull Foiler

    As mentioned earlier,I did a rough comparison of two boats each weighing exactly what a Rave does and the wetted surface is less at least up to 30 knots boat speed but whats more drag is less again, at least up to 30 knots. This thing could be designed to be MUCH lighter than a Rave(368lb) and could be substantially faster in 5-20 knots of wind.
    But what is really cool is that the new concept foiler would sail with "veal heel" with the attendant advantages upwind and with RM. The Power Foil system allows a lighter boat, faster boat across the wind spectrum .

    Veal Heel-see fig 25 here:
     

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  12. BWD
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    BWD Senior Member

    Dude, with all due respect, you ought to stop saying, "veal heel"
    I have never heard Rohan Veal say it (probably because he is not a ******), so why should you say it?

    There is another term for "veal heel."
    It's equilibrium.
    If no one found it before Veal, it is likely because they suck.
    Or were mentally constipated from too much conventional sailing. The right heeling angle for the moth is a discovery to make in the first outing, unless you want to be swimming the whole time, and/or flailing downwind.

    Anyway sorry for the digression ;)

    Back to the topic,

    What all those dam numbahs don't do,
    is dance with the water like a real boat.

    See you probably haven't realized it, but with the power foils, you have also approached your former grail, the jumpin boat.

    Small foils may be DESIGNED to only provide X percent of of Y or blah blah proportion ratio RM, deployed at v velocity with SA blah blah,
    but what they do is load up as hard as you load them, faster than bigger ones,
    and they blow out faster too.

    The idea that the adjustable sailor *** can compensate for a sudden change in RM of 30% or so is very optimistic, especially considering that the RM change from the foil blowing out or stalling is (1) nearly instantaneous and (2) not the first event in the chain leading to a crash, but the 2nd or 3rd, following an awkward weight shift, falling off a wave, a big gust, etc.
    Case in point, (although in this case the foil venting likely was the first problem, see the video) see below the most famous boat yet to depend on anything like a power foil, the hi speed hydrofoil jumpin boat extraordinaire:
     

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  13. Doug Lord
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    Doug Lord Flight Ready

    Multifoiler Power Foils

    Ah, "Dude", 'veal heel' is a term that is part of the lexicon of bi-foiler design. It's major advantages are relevant ONLY to bi-foilers and do not apply to any other boats except ,of course, to bi-foil multihulls designed to use Power Foils.
    The advantages of veal heel on a bi-foiler:
    1) produces side force from the lifting foils that can unload the vertical fin reducing the chance of ventilation. (major)
    2) increases RM regardless of altitude(as long as hull structure is clear of the water).(major-very significant-approx. 20% increase in RM)
    3) produces lift component from the sail that reduces foil loading.(minor)
    4) shifts helmsman closer to the water decreasing the impact of his wind shadow on the sail and putting him in a slower moving portion of the wind boundary layer.(minor)
    Equilibrium is NOT another term for "veal heel" though a boat being sailed with "veal heel" may be temporarily in equilibrium, particularly if it is using Power Foils....
    There has NEVER been a multifoiler designed to use veal heel- it is a brand new application of the technology with tremendous benefits.
    There is plenty of information around about foils being used with "negative lift"-to hold the windward side down(Rave,Hobie Trifoiler,F3). Should the windward foil "let go" on a boat like the Rave you can lose 30% or more of the total RM and still recover without any movable ballast at all.
    A Power Foil equipped foiler(with wand based altitude control on each power foil set to control negative lift) would have an even better chance of recovery.
    In some respects the Power Foil equipped multifoiler is similar to the Rave when the power foils are deployed but the big difference is that in light to moderate air it would be sailed like a Moth or Mirabaud using only two foils and "veal heel" upwind. The drag reduction in light and moderate air is substantial compared to the Rave in those conditions. And when the Power Foils are deployed in heavy air the resulting system has most of the advantages of the Rave system up to a designed wind strength(which might be less than or equal to a Raves designed wind strength)-with less drag.
    -----
    Here's what Greg Ketterman said about the windward foil adding to RM on the Hobie Trifoiler:
    "Hydrofoil boats can be categorized into two categories; 1) Incidence controlled hydrofoils and 2) surface piercing hydrofoils. The difference lies in the way the boat maintains the proper altitude above the water surface. A surface piercing hydrofoil boat maintains proper height by varying the amount of foil submerged. The boat raises up as the speed increases and reduces the amount of foil submerged and therefore the lift. The boat finds equilibrium at the proper altitude. An incidence controlled hydrofoil sailboat has a mechanism that controls the angle of attack of the foil to maintain the proper altitude. It is generally believed that surface piercing is simpler, but incidence control is more efficient. In reality, it is the method that works with fewer problems that is simpler.
    From the beginning it was felt that incidence control was better suited for a sailboat even though most of the existing hydrofoil sailboats were of the surface piercing type. There are many advantages of the incidence controlled foils; however, the most important is what I call the DLA (dynamic leveling affect). This is the increase in righting moment or stability due to the ability of the windward foil to pull down. The DLA has little affect on the low wind performance, but it essentially makes the top speed of the boat limited to the strength of the boat. Conventional boats with a finite amount of righting moment can only extract so much power from the wind, but with the DLA, the righting moment is virtually unlimited."
     
  14. BWD
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    BWD Senior Member

    Nope. A few kooks on the net does not a lexicon make.
    It is windward heel, pure and simple.
    Even if some mothies themselves say otherwise.
    The new technology may deserve a new name but the application of age old technique (hiking and balance) to it does not.
    People have been excercising the cerebellum for millions of years.
    This moth stuff is not exactly news, btw, so no need to keep re-explaining it.

    Equilibrium?
    Wudja mean not in equilibrium?
    If not in equilibrium it would be levitating, sinking, capsizing, etc.
    Trust you understand the reference frame and type of equilibrium meant.
    It's all about equilibrium, in sailing as in life.

    because the damn thing is so wide and heavy nobody wanted one even though it is fast.

    The problem with little foils is despite designers' efforts, in reality they both load up and ventilate at inopportune times. Works for boards because the sailor or surfer is so big and mobile relative to everything else, he can rapidly unweight and reset the flow. Not so simple on a boat, have to ride it out, come off plane, off foil, etc. Sailrocket example illustrates the pitfall of relying on hydrofoil for RM.

    The brilliance of the moths etc is that they don't rely on the foils for RM, but allow the sailor to literally and figuratively leverage the foils to control RM, via your favorite concept, windward heel, without adding more rococco crap to the design. On that I think we agree and it is fairly well understood. I just maintain the fewer foils and wands, the better.

    But anyway, why don't you prove your power foil concept with a sailing example, good luck.
    But first why not just get the bifoiler up and running if you can.
    While I am no fan of your web rants, I'll definitely congratulate you if you can get that foiler to foil, on any number of foils. Get it on youtube. ;)
     

  15. Doug Lord
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    Doug Lord Flight Ready

    You're wrong about veal heel-but so what. Veal Heel is the key to adapting Power Foils to a multifoiler.
    You're understanding of what Power Foils do is suspect when you make a statement like you did about Sailrocket: it does not use foils for Righting Moment-not even a little one.
    http://www.sailrocket.com/boat.htm

    =========================
    The reason "veal heel" is part of the lexicon of bi-foiler design is multifaceted. If you just say "windward heel" that could apply to any boat heeling to windward from a windsurfer on up. There are very specific things(see my last post) that veal heel refers to that windward heel does not cover. The specificity of the term "veel heel" sets it apart from just using "windward heel".
     
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