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

    What do you mean by limited range of use? In a sense, the Hobie trifoiler and Rave had a limited range of use because they were so heavy they couldn't foil in under 10-12 knots of wind. But they were exceedingly fast in strong winds. Their limitations weren't due to the dual independent altitude control systems(that allow the windward foil to pull down), the limitations were strictly due to weight. Both Greg Ketterman and Dr. Sam Bradfield(Trifoiler and Rave) are working on new foilers-should be very interesting to see the final versions sailing!
    --
    Blue Arrow, in your picture above was not designed as a full flying foiler according to what I've read-might have been much faster if she had been?
     
  2. Chris Ostlind

    Chris Ostlind Previous Member

    Clearly, Stefan, you haven't taken the proper pharmaceutical cocktail necessary to clear your vision. ;-)
     
  3. Stefan H
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    Stefan H Junior Member

    By limited range of use I mean that they are unpractical because they can only be used in specific conditions. For speedsailing with offshore wind (windsurfing term for wind that blows from the beach). Once the waves get too high the foil on the windward side goes too high and the boat could capsize. (you can read it on the Hobie website, although keep in mind that they are bias since they are the ones that use to sell it) In my opinion, the point of having a boat is the ability to go from point A to point B, not just as another toy to compete with my windsurfboards. But I also sail in a bit tougher conditions in Sweden so seaworthiness becomes a bigger factor. Sometimes a forgotten factor in these theory boat design threads.

    If Blue Arrow would have been designed like Hydroptere it would be faster too...although Hydroptere also has a limited range of use...Why? That is life, you cannot both eat the cookie and have it left. You figure it out.

    Chris:?: , If you have nothing to say, say nothing :p ...but maybe you are right... maybe after a few pharmaceutical cocktails (mainly polyester,epoxy and maybe some urethane) I will get a vision about a trifoiler that can sail in any conditions both specificly and unspecificly, faster than all other boats...and then it will be able to land on the moon. Why not? Because I say so!!!

    Just joking :p :)
     
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  4. Chris Ostlind

    Chris Ostlind Previous Member

    What are you doing up this late?

    Yeah, one can only iterate the response you have given about limited capability so many times and then one just easily banks left and turns on the humor light.

    For the record, I concur about the bandwidth of wind speeds in which these boats can operate. Yes, they are cool... to a point and then they are all about excess stuff that just makes it more difficult to be a regular sailor on a budget. I'm not dissing foiling, just making the point that they are very specific machines, for select conditions and they cost a ton for that privelege.

    Waiting to see what fabulous things might come forth from Ketterman and the good Doctor Sam, is kinda anti-climactic. They simply are not going to overcome the high expense to build and operate a foiling boat and the subsequent cost to the consumer... in a terrible economic climate. If I were these two guys, I'd take my time developing the next iteration and see if the economy will shake-out to the point where this kind of boat "might" be able to make sense.

    So, Stefan, what kinds of boat projects are you working on now, that you are drawn to comment on the "Veal Heel" thread?
     
  5. Stefan H
    Joined: Dec 2009
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    Stefan H Junior Member

    I´m working on the design of hydrofoils and at this point I´m on the research stage so brainstorming all sorts of ideas both good and bad helps me alot. Hopefully other people will find some value in my comments too.
     
  6. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    --------------------------
    I don't know what specific boat or boats you might be referencing but to use the RAVE as an example, there are/were only two limiting conditions:
    1) light air because the boat was so heavy,
    2) certain big, short period wave conditions where the boat will "bottom out"-the bottom hits the waves even with the boat flying at max height.
    ---------
    Both these are subject to design solutions-in other words these limitations are characteristic of the RAVE not of the type of hydrofoil system.
    Dr. Bradfield has designed a new boat -the Osprey- that address both the limitations of the Rave-for instance it will take off as early as or earlier than a Moth!
    The concept boat in this thread goes further and allows a multihull foiler to sail on just two foils in a wide range of conditions while being able to deploy small foils to aid in RM in heavy weather.My bet is that this may be the fastest type of multifoiler around a course in every condition...It utilizes proven technology and applies a proven technique in a manner consistent with the current uses of both in the real world.

    ======================
    Stefan, that is a gorgeus tri in your profile-is that your boat?
     
  7. Chris Ostlind

    Chris Ostlind Previous Member

    Doug,

    That's an M23, or Multi 23, whatever you'd like to call it. Says so right on the sail. If you want to buy one in the US, contact Mike Leneman in Marina del Rey, California. I think that there are two of them in Florida that you can go see and maybe get a demo ride.

    As to the rest of that post above.

    Yes, the site is called boatdesign.net; A place where boat designs can be bandied-about and shared with other members for commentary, be it critical, or otherwise.

    Doug, your so-called Heeling Foiler with the put-up, take-down foils in the outer pods idea, is just that... an idea. There isn't a working model of the suggested foiler and certainly not a working example at full size from which one could extrapolate performance and sailing characteristics in any way that would be called dependable data. Further, there isn't another boat of this type upon which this concept has been based. This business of previous good works would allow you to extend, if you will, the meaningful attributes of the existing craft and apply them, carefully, to that which you propose.

    In order to make predictions as to how a boat will behave, suggested on these pages with passages such as, "The concept boat in this thread goes further and allows a multihull foiler to sail on just two foils in a wide range of conditions while being able to deploy small foils to aid in RM in heavy weather. My bet is that this may be the fastest type of multifoiler around a course in every condition..." one should minimally draw upon existing technology that has been demonstrated to be workable, as well as effective. As in, specifically related to and having been thoroughly researched, as well as demonstrated.

    You have done none of this.

    If you want us to believe that this boat "might" be able to work as proposed, then get out there and do a sailing, well-behaving model, OR build a full-size boat (we're all waiting for that potential) with Youtube video to support all the claims.

    I'm not coming down on you as a singled out individual. This is the same sort of proof of concept that would be asked of anyone in the design field who wishes to make distinct claims as to the performance of a specific creation, which has no existing relevant design for reference.

    I am also not insisting that you produce something at some build schedule that I might find appropriate, as this is your project and you can work on it at your pace. It's the out there claims that have no resonance, no connective tissue, to the functional reality of the existing physical product.

    I wish it were otherwise, Doug, but this concept is now and shall remain, an ethereal amalgamation of vapor until you prove otherwise. It might be good to modify your claiming language about the design until such time as the beast is up and running for all to see.

    Best of luck in your pursuit of the above.
     
  8. DaveJ
    Joined: Jun 2009
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    DaveJ Senior Member

    As the sketch stands Doug, i can see a problem with the design, the outrigger foil is cantered inward, so the veel heel of the outrigger will impose on any veel heel gain you get from the main foil. Which ever foil gives the most lift will will effect the over direction the boat will "make good", in other words if most of the lift is from the outrigger foils, the boat will crab more away from the wind, which is not what you want.
     
  9. Doug Lord
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    Doug Lord Flight Ready

    Dave, the outboard foil pulls down, not up like the main foil. Therefore, the horizontal component of its (negative) lift is in exactly the same direction as the horizontal component of the main foil lift-both foils act together to unload their vertical struts and to improve windward ability. The arrows in the sketch show the direction of the lift components of both foils:
    ( Note-just noticed that the arrow depicting the horizontal(windward) lift component of the small Power Foil is a little hard to see but it is there-parrallel to and in the same direction as the same component of the main foil.)
     

    Attached Files:

  10. Chris Ostlind

    Chris Ostlind Previous Member

    And if the wind shuts off, such as one might encounter in heavy, gusting conditions, that groovey outboard foil just might pull your fanny right on over on your backside where you get to swim while trying to physically avoid the pointy ends and edges of the outboard foil in the turbulent water.

    It's simple, add more stuff that has an input on overall control of the boat and you will suffer from the same stuff should things not go as planned in this oh-so-consistent sailing environment we all know and love.

    "Simplicate and add lightness"
    - Colin Chapman
     
  11. DaveJ
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    DaveJ Senior Member

    Sorry missed that little detail of the arrows
     
  12. Doug Lord
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    Doug Lord Flight Ready

    --------
    Thats ok,Dave. What is your opinion of the concept now?
     
  13. Gary Baigent
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    Gary Baigent Senior Member

    Doug, you know my opinion on negative attack on the windward foil - what is that angle? At least 8-10 degrees negative to make it work? Equals **** loads of drag.
    Went sailing on the Flasher yesterday, wind against tide, gusting 20 knots, **** sea condition and Harry went really well to windward. A foiler that beats, climbing out to weather from other boats .... is a good foiler. Reaching in waves was a continuous surf. Absolutely no crashing - whereas before it would be tripping and burying, then leaping up like a deranged nutter to sprint, then bury again.
    Here's a shot in light airs of the windward foil - and the minimal drag from that pisses me off. Plus a shot of the new foil setup.
     

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  14. Doug Lord
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    Doug Lord Flight Ready

    --------------------------------
    1.5-2 degrees maximum, 63412 section .4-.6 Lift coeficient
    ================
    Sounds like the foils are working like you wanted them to...mostly. Can you adjust the angle of incidence of the foil relative to the ama? No altitude control, right?
    Just out of curiosity,why do you have the foils angled down? Boat looks good!
     

  15. DaveJ
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    DaveJ Senior Member

    I was never against your concept, mostly reading the thread mildly in the back ground, marking the differenace in solutions you choose compaired to a conecpt i've been toying with.
    I want to foil a Cat, but to achieve a better "made good" course have the cambers change on vertical sections of the invert T shape foils. I also want to keep the boat flat, as more perpendicular the sails are to the wind, the more power you get from them, as you start to tilt the sail either into or away from the wind, your decreasing your sail area. But this is all in my head and haven't done any numbers to work out if it is posible. I have too much on my plate at the moment so i doubt this idea will get anywhere.
     
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