AC 36 Foiling Monohulls

Discussion in 'Sailboats' started by OzFred, Sep 13, 2017.

  1. OzFred
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    OzFred Senior Member

    It seems that the next America's Cup in 2020 will be sailed in foiling monohulls. What will the boats look like? Will it be good or bad for sailing? Will there be any trickle down? All this and more will be revealed… eventually.
     
  2. michaeljc
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    michaeljc Senior Member

    Thanks for the new topic. I am sure that there will be many technical subjects to discuss. Will a monohull be able to foil the whole track?
     
  3. fastsailing
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    fastsailing Junior Member

    I don't think there is much to discuss before knowing the rules for the new class of Ac-boats or at very least some educated guess about them, based on something defender and CofR has stated. Now it seems all we have is speculation by those not knowing.
    We don't even know if the boat has any ballast weight or not. Or if it has, is it used in the bulb&keel, or in some other form, like water ballast laterally as far away from the centerline as possible.
     
  4. schakel
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    schakel environmental project Msc

    I agree with the waterballast solution Fastsailing. Congrats for your remark.
    Anyone agrees with the new AC teams?
    My two cent thoughts:
    Confirmed Teams
    ETNZ Defender

    Artemis Racing
    Oracle Team USA
    Team BAR
    Softbank Team Japan
    Groupama Team France

    Unconfirmed teams:
    Prada Challenger of Record?
    Team Heineken?
    Team Australia?
    Team Alinghi?

    Anyone more information?
    The 35th Americas Cup Official Online Store http://shop.americascup.com/stores/americascup/en

    And about 100 percent foiling is a no no with these monofoilers.
    I can't imagine how a tack procedure will look like.
    But perhaps I'am gonna regret this last comment.:)
     
  5. Dolfiman
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    Dolfiman Junior Member

    The races format is really an issue, connected with the boat capabilities. Personally, I dislike traditional match racing, when I see hundreds of true/false tack changes, I switch off my TV. For me, it is not gentlemen racing.
     
  6. michaeljc
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    michaeljc Senior Member

    There is a basic problem - ballast. Water ballast will eliminate rapid tacking and rapid tacking is a fundamental part of match racing. Manually transferring the water required is way beyond human power within the required time

    Do the physics allow foiling completely out of the water given the required weight of ballast on a conventional keel? Maybe downwind. Foils could assist righting force upwind which makes for an intriguing situation

    My gut feeling is that they will be conventional with an allowance to use foils any way the crew sees fit. It all makes for an exciting scenario IMO. The engineering challenges are mind boggling
     
  7. Doug Lord
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    Doug Lord Flight Ready

    I think an ideal Auckland monofoiler might be something like the latest Hugo Boss with rudder T-foils-maybe with some mods to allow light air foiling as well.

     
  8. michaeljc
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    michaeljc Senior Member

    Wow Doug - I think you have nailed it! Who can say that this boat is not exciting? It appears to have a swing keel which makes sense
     
  9. CT249
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    CT249 Senior Member

    Exciting on a windy reach, yes. But how often will you get a windy reach in an AC? And will they end up going straight out to the layline, tacking slowly, and then going straight to the windward mark because tacking costs too much?
     
  10. michaeljc
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    michaeljc Senior Member

    Na - Auckland has plenty of wind, swell and chop. They don't need to stay in the harbour
     
  11. OzFred
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    OzFred Senior Member

    What seems likely so far is that the boats will be very similar to the 2019-20 Volvo Ocean Race boats. The next AC boats are supposed to race in Italy prior to wherever the AC is held, so that leaves maybe 3 years to have the final boats on the water and ready to race. Not much time if everyone doesn't even know what to start developing until next month, so the boats need to be largely based on things that exist now.

    [​IMG]

    Water ballast, canting keels, canting rigs all take time in manoeuvres so destroy any chance of close racing—who will push the limits of a port/starboard in a boat that can't turn quickly, knowing that the slightest error will end disastrously for both boats? So they seem to be out. Plus they infer an engine to provide reliable hydraulic power, and the next boats are supposed to be all human powered by sailors, not stored energy or cyclers.

    "Light air foiling" is a nebulous concept with no definition or even accepted limit. Boats will be designed to maximise performance in the expected conditions—whether that's floating, foiling or somewhere in between. A 20m monohull that is designed to foil upwind (say 45° TWA) in 10kn would be a serious handful, perhaps un–sailable, in 25kn.
     
  12. michaeljc
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    michaeljc Senior Member

  13. fastsailing
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    fastsailing Junior Member

    Since human body is over 90% water, I include sailors themselves as form of water ballast in technical sense and point of view of sailing physics. 49er can be scaled up, if so wanted to, with no other form of ballast than sailors. That can be done with or without upwards lifting foils. Is there any point of doing so is another question.
    I don't think any conventional ballast keel being useful if not canting and out of the water in a foiler. In that condition it is not lowering center of gravity of the boat, it is causing everything above it to be higher than it otherwise would be and thus reducing stability. If the ballast keel is kept in the water it does improve stability but is it necessary for an inshore boat?
    It is far more about what the rules will require than what is possible and what not.
     
  14. Gary Baigent
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    Gary Baigent Senior Member

    The Open 60 types are poor dog windward performers, the latest bunch being even worse than the earlier generation ... so how is that going to fit with AC windward course race sections?
    Talk of large no ballast 49er or Moths is nonsense; even a 40 foot version of these two types would fall over so a 60 or 70 would be completely and utterly useless. Like with 25 crew trapezing to keep the thing upright. Get real. No, these retrograde old world designs will be carrying lead, and deep lead at that, on a pendulum keel, sailing slow (compared to AC50), off Takapuna and watching out for the shallows.
     

  15. jonas a
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    jonas a Junior Member

    Maximum beam and number of allowed appendices will be key. Canting keel is standard on the Melges 40, and works well on a course. However, I am quite sure that there won't be any ballast tanks. Makes sense offshore only. The Imocas are designed to only work well on a reach, so they're not the best model for an AC mono. A better approach would be to use a 70ft mini maxi as a starting point.

    Not sure if a moth like boat would work, but if the boat is very wide, it could theoretically perform almost like the previous gen cats

    If the leeward foil provides enough lift, maybe the bulb weight could be reduced ?
     
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