AC 37 -like before but with a little less and a little more...

Discussion in 'Sailboats' started by Skyak, Nov 18, 2021.

  1. Skyak
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    Skyak Senior Member

    Last edited: Nov 18, 2021
  2. sharpii2
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    sharpii2 Senior Member

    It appears that foiling monohulls are here to stay. At least for The AC.

    The technology works reasonably well, and is a way of keeping with monohulls (catamarans are faster foilers).

    Indeed, foiling seems to be the last word in scalable sailboat performance.

    So, it's only natural for the AC to embrace it.

    But it seems different from the 12 meter class old days. I find myself more and more indifferent to the competition, as it seems to be dominated by a small mafia of sailors who seem to be completely mercenary.

    I suppose this is at least partly because most sailors will never own or even sail on a foiler. They are incredibly fast, but must be kept extremely light in order to work.
     
  3. Flotation
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    Flotation Junior Member

    Why would catamarans be faster foilers by definition? As speeds increase air drag gets more important and cats drag a whole lot of draggy structure trough the air.
     
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  4. wet feet
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    wet feet Senior Member

    True enough.On the other hand the lifting foils on a cat can have a greater amount of lateral separation from the rig and the windward hull is even further away,which helps the righting moment.I would be very interested if anybody could dig out reliable comparative aero drag figures for both types.I don't doubt it would be too confidential to share and have no realistic expectation of seeing solid data.
     
  5. Skyak
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    Skyak Senior Member

    I don't see any good comparison of multi to monohull foilers because these AC 75s are using stored power for ballast management and the configuration is multihull if you go by the foil hull equivalency. Bi-foilers like the Moth are true monohulls.

    The real accomplishment of foiling is decoupling speed from size. The new foiling speed limit is cavitation. Below that speed limit is the battle to manage the fairly binary performance -staying up and in control of small high aspect foils. The foils have gotten so small that air drag is more significant.
     
  6. DogCavalry
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    DogCavalry I aim to misbehave.

    When not on the foils, monohulls still need ballast, to not just flop over. So presumably the cat is still lighter, once the boat is big enough that constant motion from the crew isn't enough to keep it upright.
     
  7. DogCavalry
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    DogCavalry I aim to misbehave.

    Must agree though. I simply don't care anymore. It hasn't been relevant to the art of making seaworthy boats for a very long time. If they set the dates a year and advance, and ran the races absolutely without regard for the weather that day, I'd pay some attention.

    I'd love to see some of these decadent monstrosities fighting it out in sea state 5. Or cowering in port while some folks in a real boat take it all.
     
  8. Skyak
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    Skyak Senior Member

    I am quite pleased with the foiling cat one design series and none of them would exist without the SF AC. The "Sail GP" is a great show -particularly in borderline conditions that they don't have much experience in.

    The "new" AC 75s are the least interesting aspect of the protocol behind
    -new AC 40s to be raced in youth and women's tournaments.
    -the chase boats are to be hydrogen powered -this is a big opportunity for fuel cell electric boat development. GM just made a move on electric boat power. They should be best positioned for this chase boat contract with their fuel cell tech.
     
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  9. sharpii2
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    sharpii2 Senior Member

    For two reasons:

    1.) No.ballast, so less weight, and
    2.) Greater distance between the main lifting foils.

    Also, two slim hulls are easier to push through the air than one wider one, even if the beams of the two narrow hulls add up to be the same as the wider hull.

    Although there will definitely be more friction drag (because of more surface area for the catamaran), that is nothing compared to the parasitic drag of the wide single hull.

    Either sailing on the water, or foiling through the air, the multihull offers the most bang for the buck when it comes to speed.

    But the AC has never been about bang for the buck. It's often been about the opposit.
     
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  10. DogCavalry
    Joined: Sep 2019
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    DogCavalry I aim to misbehave.

    Yes. Make sure to spend as much bucks as possible, to keep out the lower classes.

    The '88 races were extremely interesting. Just for the look on Michael Fay's face.
     

  11. schakel
    Joined: Jul 2008
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    schakel environmental project Msc

    I have an idea that I already launched on Sailing Anarchy the day they issued the new protocol.
    Protocol for the 37th America’s Cup https://forums.sailinganarchy.com/index.php?/topic/227617-protocol-for-the-37th-america%E2%80%99s-cup/&do=findComment&comment=7732586

    Here is the idea, It's bloody simpel. Use photo electric Voltcells molted into the deck as an extra bonus for battery 60 volt charge.
    ac 40.png
    Use the same cells of the solarchallege if you do not want to do research, but in case of endless financial supply, invent a better one and be usefull for the planet.
    Vattenfall solar team.PNG
    They reacted somewhat positive maybe Dalts is considering to take the extra option into the final, not draft, version. He stated there were al lot of days not sunny in for instance Portsmouth.
    Also the final location in the cup, Auckland has a lot of not sunny days.
    My idea is as follows but has to be described in the regattarules.
    Make a green flag when lurking (extra shore power ) is prohibited.

    As counter argument they came up with the extra weight disadvantage.
    That's not a problem if every team is obliged to do so.
    Most effective PV cells might be to costly and too vunerable for water leaking.
    CellPVeff(rev210104).png
    How do my fellow engineers feel about this plan?
    It might safe the weight of grinders in the best case.
    grinders.jpg
    grinders 2.jpg

    Looking forward to constructive remarks....
     
    Last edited: Nov 26, 2021 at 10:11 AM
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