Definition of Planing

Discussion in 'Hydrodynamics and Aerodynamics' started by Leo Lazauskas, Nov 2, 2012.

  1. gonzo
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    gonzo Senior Member

    If you don't think that an exact definition is of no use, I have no problem. However, since we do and want to discuss it, why not let us alone to do so?
     
  2. Submarine Tom

    Submarine Tom Previous Member

    To whom are you speaking in double negatives Gonzo?

    Since my post precedes yours, I'll assume it was me.

    Read between the lines and you'll see that IS my definition of planing.

    As 42 pages have shown, there is no definition and if there was it would depend entirely on who the audience was.

    Individuals perceive things, including definitions, differently.

    Your last post does nothing to define and is buried in redundant negativity.

    Kind of ironic for what you're advocating don't you think?

    At this point, perhaps the question could be asked:

    "Why define planing?"
     
  3. gonzo
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    gonzo Senior Member

    Please PM if you want to discuss grammar. Even though there is no problem with mine, it would totally derail the discussion on this thread. My comment is for those that say this thread is useless, but keep on posting on it. As to why, it may just be an intellectual exercise, which is a good justification.
     
  4. Submarine Tom

    Submarine Tom Previous Member

    I wouldn't call it grammer I'd call it syntax.

    Yes, your post is confusing at best.

    Just read it again, word for word, slowly and you'll see.

    Why do you keep posting unrelated to planing when that's what you're promoting.

    Confused but humoured.
     
  5. Submarine Tom

    Submarine Tom Previous Member

    Gonzo,

    Please don't ding me Rep points for your over-sights.

    If you make mistakes, own up to them please.

    Stay on topic by answering some of my on topic queries.

    Why such hostility?

    Please Gonzo, lets try to get along without lashing out.

    Enjoy your evening.
     
  6. gonzo
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    gonzo Senior Member

    PM me
     
  7. daiquiri
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    daiquiri Engineering and Design

    Oh come on, guys... Let's carry on with the technical discussion. ;)
     
    1 person likes this.
  8. gonzo
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    gonzo Senior Member

    I think that we commonly say the boat (powerboat) is planing when it lifts and starts accelerating without needing more throttle. Actually, the the engine can be throttled down and the speed maintained. The lift is a relatively easy thing to measure. For example, the average distance of the sheer to the average surface of the water. The speed and power requirements are also relatively easy to measure. However, we are defining planing by reference. It would be really interesting to define it directly.
     
  9. Michael Y
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    Michael Y Junior Member

    Jumping into this discussion very late, but I'll quote this post from page 1. I'm an airplane guy, so to me it is all about lift. What is unique about planing as compared to a hydrofoil shape is that it is all about ram effect and pressure increase on the bottom of the shape, while a foil is (mostly) about pressure decrease and circulation on the top of the shape. Foils cavitate, hull bottoms don't. Except where they do, but you get the idea.

    It just so happens that as the ram effect increases, the hull rises, displacement decreases, wetted surface area decreases, etc. These offset the increase in induced drag due to lift creation.

    That's my two cents worth of thoughts.

    I am tangentially working on the Marine Corps follow-on to the EFV, so the topic is near and dear to me now.

    [​IMG]
     
  10. Submarine Tom

    Submarine Tom Previous Member

    Way to go guys.

    Thanks for alienating me from the thread.

    I think you've confused me with some other members who are intent on derailing things.

    Enjoy your discussion.

    I'm out.

    What a relief 'eh!
     
  11. gonzo
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    gonzo Senior Member

    Welcome Michael Y. The main point of this discussion is to determine the exact point at which a generic hull is planing. We have found specific examples to agree on, but not a definition that can be applied to all vessels. We haven't even found a way to classify vessels to put them into different planing categories :(
     
  12. tom kane
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    tom kane Senior Member

    I still think that quater-beam -buttock angle gives a good indication if a boat hull will plane or not and I think most people know that a flat bottom board is easy to get on plane with a reasonable angle of attack. What else do you need to know.
     
  13. gonzo
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    gonzo Senior Member

    tom kane: if you read this long thread it will answer your question. Your comments are an opinion on how some hulls may plane. However, you have not defined either planing or at what point those hulls start and stop planing. Also, the definition must encompass all possible designs.
     
  14. myark
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    myark Senior Member

    That’s how I have designed the Myark boats, thanks for the common sense from Tom Kane, a innovative boat designer.
     

  15. TANSL
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    TANSL Senior Member

    After more than 630 post, we can say that there are many opinions about what is planing. Not come to a definition of the term. So Tom Kane's opinion is as good as any other, and also provides an objective criterion to locate the boundary between displacement and planing. It seems to me correct your definition, review, tom kane.
    ISO 12215-5, which is well known in Europe, states:
    planning boat: boat in which the maximum speed in flat water and in conditions of maximum displacement is such that V / SQR (LWL)> = 5

    V in knots
    Lwl in meters
     
    Last edited: Mar 21, 2013
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