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      Abbreviated rules   07/28/2017

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coxcreek

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About coxcreek

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  1. Artemis?

    Usually the rudder horizontal foil with its asymmetric lifting shape, provides lift, not down force, although purely through speed through water, the inverted T's are locked in so in a way, they're providing lift but also fixed level force at the same time, meaning they're not going to lift out. Also they are virtually fixed around 0 angle of attack, therefore providing lift (from asymmetry) - carrying around 20% of the platform weight. You're right about if set at minus 1/2/3 whatever degrees, this would force the bows down but at negative angles, you're also creating drag. Imo they're not doing that. And the rudders do not usually let go (unless sailing through very aerated water). I thought a canard set up was bow steering (also lifting), like a land yacht (steering) and also the early sailing foil designs like Don Niggs', triangular with the single foil forward and central, two spead foils (wheels) aft. The AC designs are aeroplane, except the windward main foil is lifted most of the time - so they are really aeroplane with half a wing.
  2. Artemis?

    Agreed, FarquerU. Do you know the blokes involved and any more information reguarding the SL33 foil positioning experimentation? ... because kudos to them; maybe the breakthrough that wins the cup
  3. Artemis?

    The main foil positioning is VERY interesting. In the past most foils have been placed a little ahead of CLR to lower the chance of bow rocking forward and pitch poling yet ETNZ have their mains on the halfway mark, pretty much the same as a conventional boat with daggers. That from many viewpoints, is RADICAL but they must have sorted this position out from testing on the SL33's. If that positioning is correct, AND IT IS, we've been wrong for decades. To me, Oracle's look to be in the right position yet they foil very erratically whereas ETNZ foil as if on rails. Maybe O's are lifting the needle bows okay, then the platform begins warping and the arse goes down, then up and overpowers the main foil ... and it all turns to defecation.
  4. Artemis?

    Hoom, that Christian Fevrier shot of Yellow Pages' wing is with the complete slotted foil rig set in the parked position, everything cranked up to windward, so it won't foil powerfully as a complete unit; if it was set the opposite with the elements set to leeward, the cat would be fiercely sailing about ... on land. My point about the triple element, double slot, barn door flaps is that when the C Class were racing in those days, Victoria and YP were unbeatable downwind, like a large percentage faster ... and able to sail deeper too. So when the platform is sorted, you may expect (just a guess) to see a similar Vic/YP, but more modern, multiple element wing rig setup appear on Artemis.
  5. Artemis?

    That high flying backlit shot; how satisfying, looks like a slim Oracle but without the revolting platform twist. Yes, acknowledged, is flat water on SF lake. Aside from dragging her mast support entrails when level, looks very good. And nothing wrong with the Cunningham flap system. They'll get it sorted. Now, amongst the sour puss haters, who really finds this AC fleet boring? Best thing that could ever have occurred to the Cup. Light years ahead of the monos.
  6. Artemis?

    I have no figures but the hulls appear to have harder, more abrupt turns in the bilge areas, and guessing, just from looking at shots, the hulls may have wider beam than the other AC72's, also looks lower wooded, close to Oracle ... so although the ass ends looks draggy, maybe that's the way Juan K wanted them to be. It is not as if we haven't seen low, squarish sterns before; Biscuits Cantreau, either 3 or 4, had a wide main hull stern that sat, at rest, below WL. Different story when powered up though.
  7. Artemis?

    Steve Clark is absolutely right about forward foil positioning. In my own whispering way I have been saying exactly the same thing. Although this information gives many diarrhea, will reiterate: the horrible flexing platform was the reason for Oracle's poor foiling performance (and semi-demise) ... although of course, as Jimmy said, will bounce back stronger, maybe? But flexing platform fucked up the windward rudder angle of attack. Their foil position is/was the right way to go if retaining the low buoyancy bows. IF their platform had been even halfway stiff, Oracle would have been a completely different (and successful) design. Look for them to continue the same foil forward philosophy with O2... but with stiffened platform.
  8. Ben Lexcens designs

    From the Jim Young book: So I was really put off and disappointed by not getting this design and duly I met Bob Miller, who became the famous Ben Lexcen. Somewhere I have a loose design drawing of Volante that is not even fair. It was an idea, not really a working drawing. And I said to him about the sketch, “That’s an enormous amount of wetted surface.” And he replied, and I’ll always remember this,” To hell with silly wetted surface, it doesn’t matter a damn!”