Gunboat G4 with UptiP Foils

Discussion in 'Multihulls' started by Doug Lord, May 12, 2014.

  1. Gary Baigent
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    Gary Baigent Senior Member

    My 2 cents: I think they're trying to fly too high, foil too deep, boat just has to clear water to be at highest speed, best stability?
     
  2. catsketcher
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    catsketcher Senior Member

    Must be tricky sailing with U tips. As you rise up the CE rises further above the CLR making the boat less stable - which is something normal sailing doesn't do to you. Then the U tips are angled inwards which means that you are sailing on a narrower boat the higher you fly which exacerbates the problem. Could be some very hard bearaways when flying.
     
  3. Doug Lord
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    Doug Lord Flight Ready

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    Phil, I don't think that is right. If you look at the foil it's very much like a "V" with little change in the actual center of lift with varying altitudes.And the higher it flys the more outboard the center of lift moves slightly increasing RM:

    PS- the increase in height of the CE above the CLR is not much if you look at the pictures and when it occurs appears to be more related to the angle of heel of the boat which would be true with any multihull...
     

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  4. Gary Baigent
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    Gary Baigent Senior Member

    Does anyone know the situation and conditions when they flipped?
    My 2 cents worth again; although the foil is raked forward 4-5 degrees the position looks, looks still too far aft, imo, an imbalance waiting to happen. So not knowing the turnover situation, and guessing, the bow probably pivoted in, similar to ETNZ's infamous nose dive crash. No?
     
  5. ch3oh
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    ch3oh Junior Member

    There's a photo in facebook.com/UltimateSailing showing her at 90 deg. heel just before going over. Could it be aftermath of a nosedive? Too bad they flipped, it might not help te racer/cruiser marketing aspect. Still a great boat and seems like there wasn't a lot of damage.
     
  6. CT 249
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    CT 249 Senior Member

    Doug Schickler, who was involved in the design, said on SA she was foiling when she went in;

    "I was wrong about not foiling due to wind speed. Jesus R's Facebook has them foiling under the masthead code without difficulty.

    pieterjan states it was a lack of ease in main as dump is too slow. Seems like virbac all over again.

    The picture seems to show it went over side not bows. Could have been while foiling and there is a geometric reduction in RM with heel for sure."
     
  7. Gary Baigent
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    Gary Baigent Senior Member

    No, ch3oh, that is the boat be hauled back upright by being pulled sideways by a powerboat; you can see the wake - that is if I'm looking at the facebook images you're referring to.
    Well CT, if it was not dropping the main quickly enough (like Vibrac) then maybe they had hydraulic problems (if they have this setup)- which, if the feed lines are small diameter, are too slow. I would have thought they had conventional block/tackle. Just checked, looks hydraulic.
     
  8. ch3oh
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    ch3oh Junior Member

    You missed the pic in q, it was in another album showing 2 other boats and a helicopter flying nearby.
     
  9. Doug Lord
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    Doug Lord Flight Ready

    This is the photo that may show the moment. Still no 100% reliable info about what happened: (photo by Sharon Green)
    click-
     

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  10. groper
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    groper Senior Member

    Well i was wondering how long it would take, i actually thought it might last a bit longer than this but im not surprised... :D

    A boat with such a powerful rig and the like, can simply not be considered a cruising boat... so they added a couple of creature comforts... its still a race boat with extra "stuff" rather than a stripped back cruiser. Hope its back up and sailing before too long...
     
  11. Doug Lord
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    Doug Lord Flight Ready

  12. Doug Lord
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    Doug Lord Flight Ready

    G4 cruiser/racer

    =====================
    CT: Doug S said she WAS foiling-actual quote: "Could have been while foiling..."
     
  13. Doug Lord
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    Doug Lord Flight Ready

    G4 over!

    Looking at this several times,it seems lucky that more than one person wasn't hurt..... Glad it all turned out so well!
    Heres the video: https://vimeo.com/125378004
     
  14. Doug Lord
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    Doug Lord Flight Ready

    G4 over!

    Randy M81 on SA sums it up pretty well:
    From what I can see in the video they were dropping the traveler pretty quickly. I think they just got hit by a puff and didn't bear away with it. Over they went. It was a stupid old-fashioned capsize, just as reported. This doesn't appear to have anything to do with foiling, bow shape, disruptive technology, or any GB conspiracy. It was just a powered-up catamaran being pushed hard and capsizing like catamarans have been capsizing for the last 40 years at least.
     

  15. cavalier mk2
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    cavalier mk2 Senior Member

    Wonder if they will rethink the marketing....a cruiser that needs a chase boat for the crashes is a harder sell...It would seem sensible to work out a righting system to go with the performance package.
     
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