Hydroptere-61 knots(70.15mph) Peak

Discussion in 'Multihulls' started by Doug Lord, Apr 1, 2011.

  1. P Flados
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    P Flados Senior Member

    First couple of hours were single digits for both wind speed and boat speed. They are out in better wind now (low single digits), but the boat is still staying what looks pretty close to wind speed.

    Definitely not doing anything like the speeds that we remember seeing in all of the videos.

    Does anyone know if they made much if any adjustments in order to improve light wind performance.
     
  2. Corley
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    Corley epoxy coated

    The Hydroptere teams press releases contain very little in the way of substantive information. Having said that I'm glad they are finally going, better they make the attempt and fall short than keep deferring indefinitely. Stan Honey once said something along the lines that it took so long for BP5 to claim the Jules Verne because they didn't start often enough which seems a reasonable evaluation.
     
  3. Doug Lord
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    Doug Lord Flight Ready

  4. Doug Lord
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    Doug Lord Flight Ready

    Hydroptere

    21.3 knots right now! Go Hydroptere!
     
  5. P Flados
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    P Flados Senior Member

    6/22/15 @ 18:00 PST they got into the teens and pretty much stayed in the teens until

    6/23/15 @ 07:00 PST when they pushed into the low 20s. Slowly increased until

    6/23/15 @ 10:00 PST they got up to 27 kts. The peak I saw was 28.4 at 11:00 PST.

    The speed slowly dropped going back into the teens at 14:00 and then at 16:00 they made it back into the low 20s.

    The winds for the period above were probably mostly in the high teens. The have probably seen a little bit in the low to mid 20s. The wind was pretty close to 90° from boat course at the start of the above and swinging around to say 110° to boat course.
     
  6. P Flados
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    P Flados Senior Member

    They have been in the low 20s for 3 hours now.
     
  7. mcm
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    mcm Senior Member

    Hydroptere's success always makes me question the majority opinion here that the increased ventilation and cavitation of surface piercing foils makes them less beneficial over-all compared to the usual in hull foils.

    Are there any contrary opinions in support of surface piercing foils out there ?
     
  8. Doug Halsey
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    Doug Halsey Senior Member

    I'm a big fan of surface-piercing foils. The inherent pitch stability & the natural reduction of unnecessary foil area at high speeds are big advantages. I'm sure that Hydroptere's success is due to the use of surface-piercing foils (not in spite of them).

    However, if you want to fly in very light wind, you need lots of foil area (& span), so fully-submerged foils may be better, in that case.

    I don't see any reason why cavitation should be worse on a surface-piercing foil & ventilation is usually manageable if the foils have large enough dihedral.
     
  9. rcnesneg
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    rcnesneg Senior Member

    More importantly, why do you guys think they tacked south? Their old course looked a bit high so they might be trying to reach the lay-line for Hawaii. I hope that's why anyways...
     
  10. Doug Halsey
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    Doug Halsey Senior Member

    No need to be rude about it, rcnesneg.

    Some people are more interested in boat design & others are more interested in strategy & tactics.

    However, this is a Boat Design forum.
     
  11. Doug Lord
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    Doug Lord Flight Ready

    Hydroptere

    ----------------------------
    I agree, Doug....
     
  12. P Flados
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    P Flados Senior Member

    My guess is that they can only make good VMG so low. The wind direction was shifting around. If they had shifted more to the North to keep VMG, their course would have pushed up to an area of lower overall wind speeds. Although they seem to be going at close to 90° to the direction they wanted to go, I really do think that the jibe was needed. The time spent going south seemed to be a little long, but we shall see.

    The angles on the jibes were not very impressive (or very not impressive).

    So far, a rental on a used non-winning AC 72 (or even the the cat that got left behind after loosing to BOR 90 aka Dogzilla) would have looked like better boats for the winds so far. I think either of these choices with just a little bit of open water tweaking would have be doing at least 10 - 15 kts better average speeds and much better jibing angles (if needed at all) than what we have seen.
     
  13. mcm
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    mcm Senior Member

    Is that the same dihedral as the height of the floats relative to the main hull ?
     
  14. champ0815
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    champ0815 Senior Member

    (from the tracker)
    This explains the detour, but I think they (or the wind conditions) are overall a bit slow for breaking the current record.
     

  15. Doug Halsey
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    Doug Halsey Senior Member

    Of course, not! I'm talking about the angle at which the foils pierce the surface of the water.
     
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