Steve Clark

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About Steve Clark

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    Where the water is thin.
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    Human folly.

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  1. If there was no difference between A C34 &AC35 what was all that bitching about Oracle pumping their wing? I understood it if the conventional RRS had been in place, but as they weren't, what was the point? Just to throw another turd on the Oracle sucks flaming dung heap. SHC
  2. The entire choreography of the daggerbards and rudders during a tack or gybe is enormously complex. The timing of the board drop, the reduction of AOA as two boards are now deployed, the rate of rotation, the subsequent increase on AOA as the new leeward board is loaded and the windward board withdrawn, and the subsequent reduction in AOA as the speed builds all has to be right to successfully foil tack. The rule allows you to have processors in the system as long as they are manually initiated. This is why Oracle claims to have 100,000 lines of code on their tacking controls. It seems to me that having the foils curved fore and aft has merits to simplify these problems. The first is that you want to enter the water at 0 degrees AOA or even negative AOA just to reduce the slash and big gulp of air associated with getting the foil submerged. If it enters as close to neutral as possible, it will throw the boat around less. If the strut sweeps forward at the head, the foil will be nose down when up and increase lift as it descends. My guess is you want it to land at the correct orientation for 2 foil flying, and that as it has been lowering the leeward foil is losing AOA at the rate the windward board is gaining it. After the turn, the process should reverse itself, with the windward board progressively unloading as the leeward board gets loaded. The rates of thes things may change for any number of reasons. Clearly, with enough hydraulic fluid and controllers one could program this in a fly by wire protocol, but that is limited in this event, so making the components themselves accomplish some of the necessary adjustments as they go about their normal deployment and retraction, reduces the amount of fluid you need to pump and the number of lines of code you have to write. It is also more elegant. Designers get off on this kind of shit. SHC
  3. I believe the research shows that it always pays to pump. The effect is due to hysteresis, where you can stretch the operating conditions by oscillating the surfaces such that the foil is generating more lift than it would in a steady state. Think fish swimming, birds flying and those guys pumping hydrofoil surfboards around by just bending their knees in the right ways. Birds with their wing still sink like sailplanes, when they flap, their wings generate enough more force that they can climb. Usually in sailing, it gets too hard when the wind gets up and the loads become large, but it always faster. No doubt the aerodymanisits on the forum will correct this, but I am very confident. Beast mode was not physically sustainable in AC 34, and according to the Oracle are cheaters brigade, exceeded what was permissible under Rule 42. Having removed the prohibited actions from Rule 42 for AC 35, the Kiwi may well have devised a way to sustainably flap the flap all the time. It may be that the top of the flap is the most they can sustainably pump given the limits of power. I am sure they studied the opportunities and developed the most promising option. Artimis may have a very active flap as well, but I think this is probably more passive and relies on the springiness of materials. artimis seems to spend less time spinning the handles than the other teams, and this suggests that they have some very refined design of the various elements, or really sophisticated control systems that sip oil where other guzzle. SHC
  4. Fairing have to be considered in to relationship to the wing. Low pressure on the leeward side high pressure on the windward side. Which is almost exactly what you want. The Oracle "keel" down the centerline prevents the two from mixing and creating another drag vortex. On smaller catamarans we have all gone to impermeable trampolines to extend thes effects beyond just the beams. The biggest risk with these boats is almost the inverse of conventional catamarans. Instead of just pitchpoling, the down wind catastrophe is the foils jumping out of the water and then pitchpoling on re-entry. So you kind of want keep the nose down to assure that you have as much range as possible before taking a big gulp of air. Flying makes so many things different. SHC
  5. I think the stated reason for keeping the nose down is to create down force with the forward beam fairing. This improves the righting moment ( or more correctly, resistance to overturning) which means they can use more drive force from the wing. the drag consequences of weight are different for foils than for floating hulls, so there is an advantage to being heavy and having down force generated by the main beam. The stern beam fairings actually generate up and drive force. SHC
  6. I don't know exactly, but the top portion of the flap is probably around 20 square meters. 100 m^2 total wing area, ~50% flap, a bit less than half of it being eased and trimmed. How much energy to you think it takes to move the end of that control rib from neutral to +/- 20 degrees at an apparent wind of ~40 knots? And they seem to be able to do it 30+ times a minute. My estimate is "quite a lot." Perhaps one of our informed participants can tell us how big the "approved" accumulators and what pressures they are allowed to run at to get a handle on how much energy the could harvest and store as a way of grounding this discussion. Facts help. SHC
  7. I just got schooled in a previous thread for not knowing that The defined "illegal actions" had been removed from Rule 42 in this event. Which pretty much opens the door for unlimited kinetics or human propulsion as long as it is attached to the wing, sails, rudders or daggerboards or is otherwise an "act of seamanship." This has completely changed my view of the event. Instead of viewing the athletes as providing power to "normally" adjust the sheets, pull the boards up and down and provide enough juice to adjust the AoA of the main foil, it is now clear that the metabolic energy of the grinders can be used to propel the vessel by pumping the wing or other actions. Some have already poo pooed this, but I think it is significant and gives ETNZ a huge edge. Previously, I believed that an efficient control system and forgiving foil design could compensate for the lack of pure horsepower. Earlier, 800 watts was sighted as the power premium of 4 cyclist versus 4 hand grinders. What was not given is the duration and intensity of the pumping. It is clear from the videos that the grinders are not pumping all the time and are not pumping hard all. Of the time. The cyclist, on the other hand, seem to be spinning the cranks 100% of the time. Does anyone want to hazard a guess what the difference in energy production during the course of a race is? I expect this advantage to manifest itself most in marginal foiling conditions, where ETNZ will foil sooner and longer, and also on the down wind legs where they should be able to foil deeper at the same or better speed. If they can trim faster, they will accelerate off the starting line faster. Finally they should be able to tack and gybe faster simply because the human power will buffer the loss of aerodynamic drive. One horsepower isn't much, except when it really matters. Let me be absolutely clear, I do not regard this as cheating. It is absolutely within the rules as written, but not within the rules as understood by fools like me who thought they knew the rules. I could believe the simplification was done to avoid another charge of cheating against Oracle by ETNZ. I know how hard it is to police kinetics, and it has become customary in many classes to have a wind speed at which the Race Committee can declare "game on" but this is different. ETNZ deserves a golf clap for taking advantage of this opportunity. If anyone can quantify the difference between the arm grinders time producing x power and the cyclists producing y power, I think it would inform all of our appreciation of the events to come. SHC
  8. Alcott Catfish designed by George Patterson , and I was National Champion at the age of something like 14. My mates Adam and Peet Foster and I sailed the piss out of the things. A pretty good pre Hobie design, that probably was faster than a Hobie 14 but Alcort had this thing about using nylon for sails instead of Dacron ( seriously the Sunfish had Nylon sails until the '80s) which turned to shit when the wind blew, but the little beasts could rip pretty good. A lot like a Paper Tiger. The last act of my boat was to put a trapeze on it, which made it my little sister's favorite boat. She never had to come in off the wire and she could keep up with whatever boat one of the boys she was flirting with was sailing. The hardest thing to replace is going to be the rudders. They were Patterson designed cast aluminum heads and blades and really pretty trick. I learned how not to finish aluminum in a salt environment with these things! But they don't exist as spare parts. The UFO does contain some Catfish DNA. Once you look at the two of the it's pretty fucking obvious. The good news is that in the 50 years since mine was sitting under the Christmas tree. (and I DID sail it on Christmas Day) glue has gotten way better and you can build that little hull deck joint reliably. Alcort used some sort of polysulfide goo in those days and 1/8" pop rivets through an aluminum trim strip to keep everything together. On my starboard bow, there was a rivet that had lost it's central mandrel, which made an amusing little fountain when you pressed the bow. I tried to get Dave to include a hole in each bow of the UFO flange for a painter, which would do the same thing before you took off, but he nixed it. I did test it though A long digression to get around to " No. That can't be modified into a UFO." Doesn't have some pretty big pieces in important places to be made to work. One might be able to build a Stunt9 or iFly like foiled out of that platform, but I don't think it is a good place to start. Catfish weren't light, all that strong or all that well built to invest any real effort or money in modifying. If all the pieces were ther and no i.e. 14 sail fit, it would be a fun little boat. But if you want a foiler, either start with something better, or call Dave. SHC
  9. See above. It is a moving target from time to time and fleet to fleet. The difficulty of enforcing Rule 42 lead to the P5 provisions where sailors are more or less permitted to go nuts on kinetics. SHC
  10. After looking at the notice board, I stand corrected. There is no way, short of complete mismanagement of the yacht and campaign that ETNZ can lose. I would have to work the sums, but it is as if they have more sail area. That answers that. Back to our regularly scheduled programming. SHC
  11. Where are the amended racing rules used in the America's Cup published or are they secret?Rule 42 has been on the books for as long as I have been racing, so over 50 years. I didn't make it up. Conceptually it defines how much metabolism you can attach to the sails and hulls and still be sailing. The way this is usually judged is by looking at the fleet and identifying someone whose rig is moving more than the others, or whose boat is moving in an unusual way relative to the boats around them. Or by sailors policing themselves and protesting. The point is that it is a "what you can get away with" standard. You do as much as you think you can eat away with, are yelled at, and then do slightly less. ETNZ seems to have invested in the capability to manipulate the top of their wing more and faster than the other teams. In my book this is about the same as a team having the capacity to trim and ease their mainsheet twice as fast as the other boats. It raises a question the way a 300 pound Samoan one to one sheeting a TP 52 mainsail. He may not be pumping more than is legal, but I sure am going to keep a close watch to see if he does. When I chose to raise the point of ETNZ's wing trimming, which I happen to understand and is perfectly obvious to me given that I have been sailing wings since 19fucking 85, I looked up the definitions on World Sailings web site to make sure I wasn't misquoting something. I guess I missed the memo that says that propulsion rules are different in the AC . If you are right, they are a bunch of pansies and pumping anywhere near enough! SHC
  12. I am asking the question. One can sheet and ease fast and not violate Rule 42. We do it all the time. If ETNZ has the capacity to fan the top of their wing, they have to understand that if they "do it too much" they are vulnerable to a Rule 42 protest. SHC
  13. The stop right in front of them ploy is a Favorite of Duncan MacLane's "Captain Asshole" playbook of catamaran match racing starts. After he used in Dennis in 1988, all succeeding starts were rabbit starts. If you want to play that game, you are accepting that you are going to get hit, but the other team will be disqualified. There is almost no way out In other news, let's just accept that the racing rules are going to be tested by these events simply because. The boats are so fast and can turn so quickly. There has never been a contest between boats like this.....ever. So everyone needs to cut the teams a bit of slack as they try to manage the racing rules at 5 times the speed they were written for. SHC
  14. What would you say if a crew was pumping the vang on a 505 causing the upper leach to fan in and out about a foot? It would not look like conventional pumping, but if the crew was working out with the kicker tackle from the wire, I bet you would tell him to stop. The effect is exactly the same, momentary increase in lift to the point of stall, rapid ease to reattach flow followed by another rapid trim. It does not matter what mechanism is used, what matters is the action of the sail. Now ( and this is where it gets really fun) it is happening automatically as Ex-yachie suggests, theme I think they are afoul of Rule 52 which says that all adjustments have to be initiated by a manual input of some sort. Oh and Nav, I am so sorry. SHC
  15. Tempest was dropped and the Star reinstated. the selection of Olympic classes is more bizarre than most recognize. The first step is selecting the events. Such as "Men's Singlehanded", " Two Woman Dinghy" and so forth. This bit is done by the Olympic Yachting Committee and is fairly straightforward sports politics. Where it gets odd is that the actual classes that are used to compete these events are voted on by the Member Organizations. These all vote in their self interest according to their national strength in any class. So if Australia feels they have a better chance of getting a medal in the Star than they do in the Tempest, they will vote for the Star. Countries who have no horses in either race trade votes to assure that their favored slate is included. So when push came to shove, the USYRU concluded that they had a better chance of winning a Star gold than. Tempest gold and voted to defund reinstate the Star as the two man boat. Much later there would be much hate and discontent when US Sailing voted with the majority to remove the Tornado. This was simply because they didn't see a medal in the immediate future and the best US teams were getting old. Like many things, the long story is better than the sound bite. SHC