The square wheel syndrome

Discussion in 'All Things Boats & Boating' started by gonzo, Sep 1, 2020.

  1. gonzo
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    gonzo Senior Member

    And we are already into personal attacks instead of well documented data or proper calculations. Writing in upper case bold letters is not proof.
     
  2. A II
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    A II no senior member → youtu.be/oNjQXmoxiQ8 → I wish

    Crew on ships are often called sailors, and of ships it's often said they sail to their destination, no matter if they're powered by sail or engines, from that I'll think the term also qualifies for wind turbine powered boats and ships.

    Of the shown land vehicle I've said that it drives straight against the wind, but powered by the wind I wouldn't have a problem calling it sailing there either, as it's only the form of the sails that differs from traditional.

    In the Netherlands sails on traditional windmills are common, reefing the sails on a Dutch traditional windmill is called zwichten (Dutch link).

    [​IMG] [​IMG]
     
    Last edited: Sep 2, 2020
  3. gonzo
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    gonzo Senior Member

    Newton's Third law explains it clearly. The windmill, which is not a boat or is freely floating in water, is attached to ground. Therefore, the reaction force is transmitted through the foundations to Earth. A free floating vessel is not anchored to Earth. Further, the maximum theoretical efficiency of a wind turbine is 59%. The realistic value is about 45-47% for turbines with large, slow moving blades. The ones on the examples are much less efficient and probably range on the high 30s at the most.
    Lastly, playing with words about sailors is good for riddles, but not data or proof by any scientific standard.
     
  4. A II
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    A II no senior member → youtu.be/oNjQXmoxiQ8 → I wish

    The principle is the same for land vehicles and boats.
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    I've pointed out where your replies went wrong, and my conclusions from that in three options.
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    What's wrong with the provided proof of principle in a video ?
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    Never said it was, it's just a way of getting attention to the main point which you've managed to miss the first time, like the direction of the wind in the post #8 video.
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    Newton is right, but your conclusions from his laws and the provided video evidence in post #8 are nonsense, as the wind turbine on the as proof of principle shown land vehicle was not attached to ground, like you now talk about.
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    Never presented that as data as you now suggest, it was just clarifying my interpretation of the words sails/sailing in the given context.
     
    Last edited: Sep 4, 2020
  5. Zilver
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    Zilver Junior Member

    Here's a video of a model wind turbine boat going directly against the wind :
     
  6. gonzo
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    gonzo Senior Member

    I don't see a boat going upwind. The waves show the wind coming from the quarter. There is no indication of wind direction. In short, it is not proof.
     
  7. A II
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    A II no senior member → youtu.be/oNjQXmoxiQ8 → I wish

    For anyone who wants to make proof or disproof or just wants to test, Zilver's post #20 video page has a link to very simple updated plans, it pulls itself into the wind with the far forward pull prop and the wind turbine aft of the stern.

    Direct into wind sailing craft (see the text and photos at the linked page)

    [​IMG]

    Tip for lightly pressurising the plastic float bottles for reinforcement, put them in the freezer with the cap off for a while, and put the cap directly on when they come out. In the linked text car tire valves in the caps are used to pressurise the updated plastic float bottles for reinforcement.





    Here's some more model wind turbine boat testing videos of the same poster.
     
    Last edited: Sep 2, 2020
  8. Will Gilmore
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    Will Gilmore Senior Member

    But you do recognize that a sailboat can reach speeds over the water, greater than the wind that drives it, right?

    Ice boats are the extreme, they are capable, regularly, of 40 mph in less than 20 mph winds. The Artemis AC cat claims to be able to sail up steam from a 5 knot wind created only from the current of 5 knots.

    Of course, they are only talking about a thought experiment. The Artemis CAN'T sail directly into the wind, and it can't sail dead down wind faster than the wind. It would have to tack to make a VMG down wind better than wind speed. The polars for most high performance sailboats show the broad reach is the best tack to achieve this in.

    You're a smart guy, Gonzo, I have no doubt you understand this. I agree that sailing directly into the wind is not possible for a sailboat, but almost every sailboat is capable of a positive upwind Velocity Made Good. That means, from a strictly conservation of energy position, there seems to be more energy taken from the wind, than its base "true" wind speed would indicate. Therefore, the energy to move into the wind using only the energy taken from the wind seems possible. Wind resistance is clearly not the only force the wind has to transfer to a machine that would use it.

    I'm also wondering if this is all a distraction from the real issue behind your original post. Are you posting about sailing DUW or about...
    posters who are impossible to convince that their ideas are not viable?

    I know that when I come up with an idea I am pretty attached to it and hate to have someone just say, "That will never work". Appeals to authority like, "If it was a good idea, smarter people than us would have alway thought of it." or "the experts all do it the other way for a reason."

    You get the picture. Yes, there are some ideas picking about that may not be "optimal". Some of them are even my ideas, and it can be maddening to know better and have no way to convince those who will not be convinced.

    "It is useless to attempt to reason a man out of a thing he was never reasoned into." (Jonathan Swift)

    -Will (Dragonfly)
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    ‘A man convinced against his will is of the same opinion still.’
     
  10. Mr Efficiency
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    Mr Efficiency Senior Member

    So all agree you can't sail directly upwind. Next problem please !
     
  11. A II
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    A II no senior member → youtu.be/oNjQXmoxiQ8 → I wish

    This was the last problem on earth, now all is solved.
     
  12. DCockey
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    DCockey Senior Member

    I agree only if the statement is limited to boats without moving aerodynamic elements (moving relative to the boat), and no current.

    It is conceivable that a boats with a suitable wind turbine driving a suitable propeller could move directly upwind.
     
  13. Zilver
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    Zilver Junior Member

    Sorry for the confusing video, this indeed wasn't a good choice. Here's probably a better one .
     
  14. A II
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    A II no senior member → youtu.be/oNjQXmoxiQ8 → I wish

    Great video, thanks for posting !
     

  15. The Q
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    The Q Senior Member

    All this propeller going straight into the wind is much to modern, it's been going on for years.. Scroll down to the Bembridge Redwing, of 1934 vintage https://www.classicboatmuseum.com/boats
     
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