blunted

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About blunted

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    Super Anarchist
  • Birthday 01/02/1969

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    Toronto
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    Boats with wings are cool, just plain cool

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  1. blunted

    C-Class Little Cup news

    not really? I mean with a tip that pierces that water it runs the risk of ventilation if its too loaded up and its more susceptible to ventilation the more horizontal the foil is, it seems. Invariably you'll get a bit more drag out of any foil at the water / air interface. Essentially lift is a bit of a write-off within two chord lengths of the surface of the water but again that could be a feature as much as a bug when you are trying to control for heave. For me if I saw the inboard tip out of the water it simply meant the system was working. never noticed any global change in boat behavior. Pretty cool if you have Mark Drela giving you input on your third post in a thread. Also a cool dude who most definitely knows his shit. Me on the other hand, I'm taking off to BDA momentarily for a few days of libations and lead sleds, if things go well I imagine I'll have my tip just below the surface some time after sundown. Might end in a wipeout, we'll see what happens.
  2. blunted

    C-Class Little Cup news

    Not to the best of my knowledge. I'd never used them until I sailed on the TF10 this summer. I was lucky I spent a few days working with Pete Melvin on the boats. I explained I hadn't really wrapped my head around the dynamics of z-foils. He was kind enough to explain that they are essentially the same as a v-foil, you've just split the foil and moved it to opposite sides of the boat. I was admittedly skeptical but hey, he's spent far more time than me thinking about it so I went with that. Sure enough, it seems to work pretty much like he described. We were sailing one foil up, upwind, both foils down, downhill. Fun ride, gentle, nice landings etc. for flat out performance I'm not sure what would work better, in that case we were using the WW foil for some downforce so I would imagine it might be more powerful than straight up V-foils.
  3. blunted

    C-Class Little Cup news

    The self regulating of heave is the V-foil configuration itself. Back before anybody understood foiling as we do today, as designers we'd all make the same first step which was the same mistake. We'd start with a vertical foil to keep the boat from going sideways and a horizontal foil to make it go up. In my Archemedian days I would tell you that leeway was a bug not a feature, I wouldn't want leeway because that's giving away pointing ability that we spent years trying to dial in to zero leeway on the course. In making that choice you somewhat separate lift and side forces making them almost discrete. Then you spend all manner of effort figuring out how to control lift. Darwin lead us to wands eventually as a good solution, just pick an alititude you want to fly at and make a mechanical system to force the foils to help you in that goal. But it still leaves a bunch of challenges particularly if you sail over a big range of boat speeds. On a t-foil you always have the same amount of foil in the water if you're going zero or 50 knots or at least up until you have zero foil in the water. So then you have to moderate and control, quite precisely, the lift out of a foil that barely changes shape and never changes size over a huge range of speeds. As such you are faced with making a bunch of compromises starting with your choice of liftoff speed. Want a low speed, you need a bigger foil, you chose bigger foils, congratulations, you get a slower top speed and a more flighty boat. The V-foil configuration flips the script. The genius of it, and it took me more than a few moronic weeks to suss this one out, is that it turns leeway, that old bug, into a feature in the system. If we give up the C-class sacred cow of sailing through the water with no leeway for a second it opens up some possibilities. The most important of which is that the more leeway there is, the more it moderates the vertical lift of the two foils (I consider a V-foil to still be two foils, just happen to be connected). So as the whole show starts to slide sideways a little bit, one, degree, two degrees and so on, it starts becoming less "lifty" while still providing the side force you need. Double plus good is that as you go faster the boat lifts a bit higher and the area of the lifting foils also begins to moderate. This is important because it makes the foil less sensitive to small changes in pitch and far less likely to leap out of the water unexpectedly, which is exactly what a vertical / horizontal combo will do to you, repeatedly, ruthlessly with painful results. So as leeway kicks in, because the boat is flying higher and has less available side force, it also begins to moderate lift and at some point you reach equilibrium of forces. then as an added bonus you remember that leeway doesn't matter any more at that point. why? Well because you're not dragging that stupid hull through the water any longer, you're flying it over the water so who gives a fuck anymore right? If you can't get pregnant who needs a condom? (Maybe there's a hole in that reasoning but we'll come back to STD's later). On a wing boat in particular upwind foiling leeway is a non-issue, you trim the wing to the AWA and nothing else. The bows would actually point more into the wind in this situation which is favorable form an aero-drag perspective. So after all that, what did we get? We got equilibrium, that's the self regulating part of the system. An L-foil essentially cannot ever achieve equilibrium except in some kind of perfect steady state sailing. We did achieve that from time to time and it's fun and slippery but it's gone as soon as you change velocity, or any of a hundred other little things you could change on the boat intentionally or otherwise. Now some wag will come along and tell me how the modern AC50 boats essentially have L-foil systems and seem to do steady state sailing just fine, to which I say, "Sure, try sailing one of those in a straight line for two miles without any AOA input on the foils and see how it goes for you". In short, they use a never ending stream of AOA input to overcome the absence of equilibrium and instead keep many angels dancing on the head of a pin through hyper-exacting foil management which is simply not an option on a boat with only four hands available. I should add that of course part of the system is to be able to change the rake of them, which is a big gross tune factor, and of course their roll angle or how they are trimmed inboard and outboard. The more you angle the foils in, the more aggressive the leeway effect is, but you trade away righting moment and things become draggier, but the ride is more stable. Thus foils are more upright upwind, when we sail in a narrower boat speed range and can afford less heave control, and they roll inboard when going downhill and we have a bigger dynamic range. The "inside angle" I was talking about was the angle between the "vertical" and "horizontal" parts of a V-foil. the smaller that angle, the more heave stable the boat will be but also the more draggy it will be. 90 degrees = sporting, 64 degrees = Franck sailing downhill at 28 knots in chop smiling his shit eating little grin, calm as the day is long. (To be clear, Franck is a cool dude, I respect him greatly and he did an awesome job killing us, I just got a bit fed up of our boat trying to kill us and seeing his transom all the time). So the big development was making heave control intrinsic to the very foils themselves. Condoms optional.
  4. blunted

    C-Class Little Cup news

    Rocker could never point with Alpha due to the symmetric vertical foils on Rocker. So it always had about 3 degrees of leeway relative to Alpha, one reason it was slower upwind. The hulls, The Alpha hull shape was awesome for displacement sailing, could only be outdone by Canaan. I will say this however, when landing at speed, e.g. coming off foils, you really would prefer a contemporary design with a lot of lateral area at the waterline, particularly in the bow. The nice fine bows that go so well in the light stuff do sweet bugger all to stay above the water when you fall off the foils. Its an express route to pitching it in if you're not careful. FYH was far more forgiving coming off the foils than the old Canoe like boats. Differential based on mast rotation? you are breathing rarified air if you think you can link those two things without unintended consequences. As soon as you start foiling you about triple the number of links between forces on the boat. For example, if we were foiling and we happened to have some heel on, say 10-15 degrees, all of a sudden when you turn the rudder you are having big effects on pitch forces because now the vertical surfaces are creating vertical forces in addition to the horizontal forces. That little quick change in pitch all of a sudden can point the bow up a degree more than a second ago and bingo we have liftoff about 2 seconds later as the boat launches fully clear of the water then steps 20' sideways and crashes down. Damping heave response to match the mass of the boat and the skill of the sailors is important. That's the beauty of what ETNZ designed way back in 2013, it's largely self regulating and the regulation can be tailored to the mass and momentum of the boat as well as the speed and capacity of the crew to make trim changes. You'll never be quick enough on the hands adjusting foil rake to keep up with the scene, so it needs some form of self regulation, the smaller the boat, the faster it has to work. Groupama had a safe setup for their foil geometry. The corollary was that they could sail the shit out of the boat with high degrees of confidence even if it was a bit draggier than less safe but more slippery options. On a boat with only two sets of hands there's a lot to be said for something that regulates itself in heave once gross settings are locked in. So their inside angle was something like 64 degrees on their foil which was the most conservative by 20 degrees at the event. Yes it cost drag, but it also freed them up to trim the wing and keep their head out of the boat and to sail. Keep in mind the crew is doing about 85% of the trim functions on the boat, adding the foils is another huge scope creep for crew tasks, plus the foiling foils are heavy and a lot of work to get up and down through each corner. My caloric workload in FYH probably doubled over a day on Canaan. The flap control on rocker never had too much load on it. Look at how long the wand is relative to the opposite side of the rotation axis and you can see it has a lot of leverage to push and pull the flap. Sure, life is better without wands but wands are far lower loads to manage than raking both foils after each tack or gybe.
  5. blunted

    C-Class Little Cup news

    Top surface of the rocker foil is one piece, the part over the hinge IS the hinge. Below that there is a wedge notched out of the foil. On the bottom two flat bits slide past each other making it generally smooth. There is an arrow shaft or similar down the trailing edge of the vertical bit. A push rod travels through the shaft on the vertical bit and connects at the bottom to the flap with a wee little pin connection. I still have the main foil we cut off in 2007 laying about the house. I'll take some pics and vid some time for you. Generally worked pretty well. Obviously the flap twisted somewhat as it was small and not super stiff, so the middle of the foil would always have more trim on than the extremities which was OK by us. We also did two tow tests with Rocker before gambling a wing on it. We just added an extra body to make up for the mass of the missing wing. Unnerving at first, then quite comfortable once you got to trust it. Like I said, we simply started by emulating the best moth technology at the time, easier then re-inventing all four wheels.
  6. blunted

    C-Class Little Cup news

    I remember quite distinctly that day thinking, "fuck we're going to break a forestay if this keeps up". Yes the conditions were bouncy and the rig and platform were all wriggly for sure. Front beam was flexing up and down quite a bit between races. Certainly settled down once we got to racing though. Memorable day.
  7. blunted

    C-Class Little Cup news

    Limits are that the foils need to be "inside the box", e.g. within the 14' beam rule. This is why Rocker was only 12' wide or so, we gave back some platform beam to ensure we could have T-foils under the boat still within the box. Rocker, one more time, had flapped foils operated by wands. No, we were not morons, of course we tried differential setups with the WW pulling down while the leeward pushed up. We tried three legged, we tried 4 on the floor, let the wands do what they want, we tried four on the floor, operate the windward flap manually to get RM out of it. In the plus column, when on foils, Rocker was stable as anything I've ever sailed, rarely if ever pitched in, did not roll quickly at all etc. But over all our conclusion was there was simply too much junk in the water relative to Alpha. Yes we also tried the windward heel etc. Perhaps we were not too smart. I mean we did get it to foil, in fact we got it foiling the first time we took it out in anger with a rig on it, in very little breeze. That was back before anybody figured out how you could use leeway to moderate heave and so really what we had were two moth's flying beside each other. Good times.
  8. blunted

    C-Class Little Cup news

    I can assure that once you have four foils in the water you will indeed care about platform stiffness. Sorting out differential between windward and leeward foils gets tricky if the platform is twisting all over the place. Stiff is most certainly faster, thus we'd put a fair bit of compression into the rig just to stiffen up the boat foiling or not, and we'd also add more in bigger breeze. We needed it lighter in the light stuff just so the wing can rotate appropriately. Torsion, hmm. Are you talking a Cogito style wing with an internal spar that carries the wing on it? Makes a big difference for that spar. Also consider bending moments on the spar, things change dramatically with different approaches to trim. Heavy air modes with deep bottom and bladed or inverted tips put a lot more bending load on the spar than lighter air modes with an evenly loaded wing that has a cantilever effect around the hounds. We nearly red-lined a rig or two trying funky trim options before Steve reeled us in a bit. Righting moment used to be pretty simple to work out but its far more dynamic now with foils that can hike the boat flat. Rig design must be coordinated with foil design and trim. I think the TF10 guys could tell you a thing or two about that. If you want to load up your foils for more RM, better stiffen that tube all round, sky is the limit, just be prepared for everything to weigh more, its a vicious cycle. Shrouds always had about 3-4 times the load of the forestays, purely a geometry issue, plus how stiff the bows were. When really loading up our rigs we'd probably bend the main beam down 1-2" at most. 4 Bolts at each meeting of beams and hulls spread out as far as reasonable and stiff. Shrouds sits about 3-4' behind the beam.
  9. blunted

    i touch myself

    You must work in a fucking human resources department. this is precisely the response I was suggesting would be exceptionally stupid. Why, because that's the kind of shit that will end up being hyper-policed by a bunch of non-sailors who know fuck all about the sport and will default to fending off any and all possible liability from the MNA. they'll start "disciplining" people with a stupid, non-accountable, hyper-lawerized mechanism that will only serve the interests of the MNA. Sooner or later it'll end up looking like a Title IX Kangaroo court. Since when should the MNA or related authority be proactively policing personal interactions between members or athlete's? Got a complaint about a pro on your boat? Call the fucking loft and say to the boss "Bob was being a skeezy dickhead on the boat, kindly ask him to reel it in and act like a professional please". Better yet, call it out when it happens, "Bob, you're married with kids, stop hitting on me, it's not going to happen and it's making you look stupid, just cut it the fuck out and stick to sailing please". If the woman in question has even a scintilla of respect from the owner and the crew, it'll be a quiet next leg on the course and Bob will STFU and cut that shit out.
  10. blunted

    i touch myself

    Just sail on boats with just wings, you'll never have these pesky sexist sailmaker issues. Per Ajax above, I understand his sentiment. I got hauled in front of a disciplinary committee a few years ago for a non-sailing related member to member interaction. It was me interacting with a guy half my age. Suffice to say there has it seems, evolved a very large gap in how different generations seem to feel squabbles should be adjudicated. The member in question wanted me thrown out of the club forever for simply giving him offense over an issue pertaining to privacy (He was violating my and my families privacy, substantially). I ended up having to write a written apology and the committee members apologized to me for even asking that of me in the circumstance. Really it was an olive branch to the other member essentially to say, "We have heard your complaint and acknowledge it". What I came away with was a sense that the offense taken by the other member and what he expected through his appeal to authority, was wildly out of proportion with the disagreement we had shared. It left me feeling that the spirit of the club was in no way going to be able to endure any measure of that kind of grievance mongering in the long run. It also left me pretty alienated from the club, I was frankly pissed off about the entire episode so much so that I, like Ajax, pulled back on my club engagement in general. I was also disappointed in the other member to the extent that while I felt I was right in the matter, I had gone to great lengths to try and resolve the issue in an amicable and collegial manner which was entirely rebuffed by the young man. Fair enough I say, but it does not bode well for collegiality between members and sailors when you cannot have a beer, work out your differences and put the issue to bed. I'm happy to report that most people I know of that age cohort in the sailing scene do not seem to share such sensitive skin but it doesn't take much of that kind of snowflaking to make twitchy managers and boards write wildly restrictive and frankly stupid policies in reaction to that kind of stuff. To the detriment of all affected. Per the original thread, I have not in the last 15 years seen any explicitly shitty sexist behavior alluded to in the anecdote provided in any of a wide variety of boats and crews that have women participating in them, that I have sailed with. Sure there is occasionally a clumsy pass at a girl that ranks as a fail, occasionally a poorly delivered joke that leaves you face palming. Broadly speaking however I see meritocracy at work on a wide variety of crews. Many women / girls are given plenty of chances to participate in different ways on boats, sooner or later some roles require grunty strength and they eventually fall to very strong women, a rarity, or a young buck who has the energy for the role. Sooner or later skills come out on top in various roles on the boat. It would be a shame to see wicked up identity politics and "offense culture" injected into the sport. It won't build it up, it won't "cure" it, it won't do much other then piss off a bunch of people who will simply walk away, perfectly reasonable pleasant people who are today an asset to the sport.
  11. blunted

    Show your boat not sailing

    In the spirit of boats not sailing.... Main Duck Island in the middle of Lake Ontario. we managed to get the whole island to ourselves for the evening this past summer. Very quiet
  12. blunted

    Show your boat not sailing

    That was me who edited the link, I didn't want to give them any free traffic. Look at the original post if you really want to see what the link was.
  13. blunted

    Show your boat not sailing

    Hmmm, a fine looking Yacht. I grew up racing Vision, KC3, a 1930 Camper and Nicholson 8M. I have a soft spot for 1930 8M. Ambitious putting the rig up on that thing with a Gin pole.
  14. blunted

    Show your boat not sailing

    there is only one correct response at SA. SHOW US YOUR TITS!
  15. blunted

    J24: Anyone ever DIY pull a deck?

    Sell it to a Mexican Drug Cartel as a drug Mule boat.