Direct Upwind Sailing

Discussion in 'Hydrodynamics and Aerodynamics' started by Thinkoutbox, Dec 25, 2024.

  1. Thinkoutbox
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    Thinkoutbox Junior Member

  2. jehardiman
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    jehardiman Senior Member

  3. messabout
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    messabout Senior Member

    There ain't no free lunch, especially in boats, Poseidon and those other gods of the sea forbid it.
     
  4. Will Gilmore
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    Will Gilmore Senior Member

    Now, how to convert that system to an all-points-of-sail system. Were you to design a practical 20 meter boat, for example, how do you sail downwind? The DDW vehicle used the wheels to drive the fan, converting the windmill to a propeller drive. However, there needed to be some force pushing the whole vehicle to start the process. Perhapse the wind pushing against the boat can force the propeller in the water to turn such that it drives the fan.

    Allow the wind windmill to swivel for wind power capture, then come about into the wind and the harvest/drive forces reverse?

    -Will
     
  5. Thinkoutbox
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    Thinkoutbox Junior Member

    That is not correct - they work in any size. Jim Bates constructed one in New Zealand see here for an interesting report on his project

     
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  6. Thinkoutbox
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    Thinkoutbox Junior Member

  7. Thinkoutbox
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    Thinkoutbox Junior Member

    This has been done both in model and fullsize see this page; Rotary Sailing Homepage https://www.sailwings.net/rotaryhome.html or https://www.sailwings.net/siteinde.
     
  8. Thinkoutbox
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    Thinkoutbox Junior Member

  9. CT249
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    CT249 Senior Member

    The videos don't seem to show a real boat actually going straight upwind. Worsley's wingsail can do about 2.5 knots downwind in a strong breeze, so it's obviously dramatically slower than a very small and easily-handled conventional sail. So on th available information, one wonders why one would bother. A conventional rig would seem to get upwind faster and often just as easily.
     
  10. Thinkoutbox
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    Thinkoutbox Junior Member

    Why don't you think a boat can go straight upwind? Did you see the videos?
     
  11. gonzo
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    gonzo Senior Member

    Make a free body diagram with the forces involved. There are several videos of toy boat going upwind. They all have some kind of wall or barrier that prevents wind force on the hull. Also, when it gets scaled up, the wind gradient increased the force of the wind significantly.
     
  12. Thinkoutbox
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    Thinkoutbox Junior Member

  13. gonzo
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    gonzo Senior Member

    That video is in a pond below ground surface with a wall around it. I saw it and hence my response.
     
  14. Thinkoutbox
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    Thinkoutbox Junior Member

    So you really think that wall less than a foot high is going to shield the hulls from the wind 300+ feet away?
     

  15. gonzo
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    gonzo Senior Member

    With the terrain around it, yes.
     
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