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Hahahahaha! Forget to tighten your wing?

For a heel side turn I'd say she looks pretty closed off to me. When I read that comment in the other thread I was thinking, what picture are you looking at. I can't even see her back shoulder as it's vertically under her head. If you are way up on the boat it seems that the perspective of "open to the boat" can be equivalent to "closed to the course". If she holds that position, by the time she's behind the boat the perception will look much more closed. If that's "open", show me a picture of "closed".

@BraceMaker for a garage operation with no autoclave, no oven, and no press... infusion all the way. Wet bag if I get lazy. Wet lay alone is just a bit too crude for my taste.

If I can find my roll of carbon might finally finish off a trick ski I started about a year ago. Just got the rocker mold finished up.

One point I do disagree with... the concept that 'dynamic flex' is some sort of mystical property that can't be understood falls short. The way a ski flexes under a static load versus under a dynamic load are not independent characteristics. The static stiffness absolutely drives the dynamic stiffness. Unless you are adding our removing significant mass, or if some more complex material property is radically changing, i.e. hysteresis or viscoelastic property, then your dynamic stiffness is very much driven by your static stiffness. The terms 'dynamic flex' or 'dynamic rebound' unfortunately are just close enough to the fringe of common knowledge that they get used, and more commonly misused, for marketing hype more so than real mechanical understanding. It's fun to talk about, even more fun to measure, but I'd argue almost meaningless for any real practical value... at least in comparison to all of the other physical characteristics a ski has. If your ski makes it through a stiff legged offside turn without folding like a banana then you're 'dynamic flex' is probably good to go.

Brilliance is a strong word. I'm thinking it's a healthy dose of meaningful experience, on multiple fronts, with a dash of bullcrap mixed in. There are too many variables at play and not enough data to make a meaningful prediction on a ski by ski basis. So.. we're left with anecdotal information and comparisons to other industries that actually have meaningful data. For anyone with enough curiosity and time on their hands I suggest reading up on S-N curves and fatigue driven stiffness degradation for carbon/epoxy composites. The executive summary goes something like this... yes composites degrade with fatigue loading, but (and it's a big but) it depends highly on the magnitude of the cyclic stress or strain. To that point, most well made higher end composite materials do have an infinite fatigue life threshold, meaning if the stress is small enough it will last forever, in theory. The fact that people break skis more often than companies would like to admit suggests the loads are high enough to at least warrant the conversation. I think the only certainty is that the harder you are on a ski, and the more you ski, the sooner it will break down. Time itself is not so much a factor, you'll want to replace a ski purely due to improvements in technology long before it ages itself to death. So long as nothing catastrophic occurs, fatigue degradation is pretty much only going to soften a ski. (If your ski got stiffer then most likely it wasn't fully cured when it shipped from the factory and a summer in the sun finished it off). Is a slightly softer ski necessarily a bad thing? You probably change the flex characteristics more by screwing around with different binding plates. I would bet for a 'typical use' ski, there is more variability from one ski to the next coming straight out of the factory than how much one ski changes in a year. I'm not saying don't go buy a new ski, I'm just saying there are far more interesting reasons to buy a new ski than concern over fatigue damage. Time to make up some numbers... let's assume a top level pro gets a full season out of a ski. They ski ~5 sets a week at 10 passes each (I have no idea, just trying to stay conservative) and they live in Florida so they ski all year long. That's 2,600 passes. For me, I am lucky to ski 1 set a week, on average, so that's 520 passes. So... I should expect to easily get 5 years out of my ski. Not to mention, I'm not slamming turns at 39off every set out and I've never broken a ski, so my cyclic loading magnitude is probably only 50% - 70% of the 'pro' level, which means I can probably get a good 6 - 7 years out of my ski without any meaningful concern of fatigue damage. I'll want to replace it long before then... or modify it. I suffer from not being able to leave well enough alone.

Just need to stack an isolation mount ontop of an orbit, works great. I use a homemade one, but this should do the trick. If you want more isolation just add mass to the top plate. More mass the better. https://www.amazon.com/STO-Universal-wire-rope-STO-Universal-wire-rope-anti-vibration-mount/dp/B0776BRT39/ref=mp_s_a_1_2?keywords=wire+vibration+mount&qid=1564966205&s=gateway&sr=8-2#

I'm 200'ish when suited up. Ski at 34 mph. Riding a large. Ski feels plenty big, plenty of glide and support. The massive tunnel gives tons of lift and even though the ski is "short" you run the bindings pretty far back, so there's plenty of ski out in front of you. On more traditional skis I'd be at 29.5 to 30.0 binding placement. On this ski I'm right around 28.0" +/- 0.5" depending on whatever settings we're playing with. I can plant my front foot and never really feel like I'm going to stuff the tip. I had to work harder on the c65. The even older versions used to make my elbows sore. The c75 is fairly eaisy on the body, no sore elbows. That being said, it'll push as hard as you want to go mostly in terms of how much angle you want to take. I think this is a lower drag ski overall, you just add or remove wing angle to suit.

Been skiing on one of the prototypes for several weeks. It's good, really good. Seems to glide and carry more speed than the c65 but still settles in really well approching the ball. It'll grab as much angle as your willing to take while still providing loads of support. Probably the most fun I've had on a ski yet. I'll run a 35off, 34mph on a good day. There's been more good days with this one. I've had the settings all over the place trying to help provide some feedback to the extent that I can. Pretty much been ridable over a very broad range, but it gets really good when the settings get dialed. My last move was a 0.2" dft adjustment. I was very happy with my previous settings but the new ones are sweet.

Too much space infront of 1 ball..... threw your timing all off

Caldwell is an animal, no doubt about it. I ran up to Trophy a few weeks back to get an early look at the c75 and sat in the boat to watch him experiment with different fin settings, it went something like... fin tweak/38off/39off, fin tweak/38off/39off, repeat, repeat, repeat... the guy didn't miss a pass. And the fin tweaks weren't exactly tweaks, more like full range of adjustment. I stole one of the prototypes on my way out, I'm a few sets in at this point. And yeah, it works for mortals and hacks too! Some initial thoughts... it's a shorter ski, but you don't really notice since you run the boots so far back. The tunnel has so much lift and support, feels like plenty of ski under foot. I'm 195 lbs and riding a Large. If skis are too small they beat me up, elbows start to hurt, can't glide as needed, the c75 has none of that. It's a very easy ski to ride. Some of the very early Denali's (circa v3.1 v3.4) could be a bit twitchy if the setup was off, the c75 is smooooth. It's nutty what it lets you get away with and yet still end up with space before the next ball. After a couple fin adjustments, ran my first 35off of the year and with more space into the ball than I've ever experienced. @Wish you lost me with your diagram, what I feel is much much more as Adam sketched. Very fast behind the boat, up on the boat (wide) early, and space before the ball. I've had some decent success on previous Denali models, but yeah.... not giving this one back anytime soon,,, or ever. It's just too much fun.

Did you run out of carbon?

That's fantastic. Never heard of such a thing.

Had a random idea that I'll never get around to actually trying out, maybe someone with more time on their hands... @Gloersen got me thinking about ways for a driver to real time 'monitor' their boat path. I'm thinking Boat Wiskers. It would consist of two or three lengths of wiskers that are attached to toggle switchs at their root, the wisker array would be attached to the starboard and port sides of the hull with a suction cup base. The toggle switches would then be hard wired LEDs that could be placed on the dash right infront of the driver. The wisker array would be placed such that they would tag the boat path bouys if you got too close to them. The wisker lengths would be staggered so that you trip more wiskers the closer you are to the boat guide and thereby light up more LEDs. A very simple, no brains system, just some switches, a battery and some LEDs. Won't provide any feedback between the boat guides, but would provide great instant feedback at the boatguides.

You can always just file the inside of the fin block down a bit to expose more of the tail end of the fin. Keep in mind that Denali is trying to accommodate every other companies' fin block, not super easy in an industry with no defined standards. On another note, that style of fin block in the pictures is wonderfully simplistic in design, but not terribly robust. It has a design flaw that can result in a loose fin. If you're swapping fins in and out you should also check to make sure you're actually clamping the fin and not the set screws. Because the set screws are in the slot, if the machining tolerances drift out of favor you'll end up clamping the screws and not the fin. To check, make sure your set screws turn freely after you have your fin clamped tight. If you can't freely turn your set screws then you're not fully clamping your fin and it may want to move. If this is a problem just remove the set screws altogether right before you fully tighten down the clamping screws. I believe the CG fin is on the thicker side of life so this should not be a problem, but super easy to check so might as well. I've actually seen this a few times with normal stock fins. And while you're at it, file down the sharp tip of your set screws to allow your fin to slide along the set screws instead of the set screws diggong into the fin. I have no idea why skis come with cupped (sharp) style set screws, ball points would make so much more sense.

As far as a skiers paradise, it's hard to beat Jacksonville. Just look at that wind coverage.

Big fan of the ski dock orbit. The ease of use with rope changes is pretty hard to beat. Also, it's a reasonably sturdy mount. With just a phone directly on the orbit it had a lot of vibration that made the videos pretty hard to watch. So, I made an isolation mount to filter out all of the higher frequency content. It works great and the orbit is rigid enough to the pylon to prevent excessive low frequency motion. I still get a bit of rope induced motion, but it's pretty minor. Never used a wakeye mount, but their phone app is fantastic. The top plate is supported by rubber tubbing that is very low stiffness for lateral motion but still reasonably stiff for vertical loads to support the weight of the top plate and attached phone. The orange foam is just a snubber incase someone decides to push on it, it's not in contact with the top plate.

It's mostly the ski..... but yea the fin is pretty sweet. Surprisingly forgiving to settings, I move it pretty much every other set and so far it's been skiable no matter where I put it, and I'm not talking a few thou. I've had the length from 6.8" to 7.1", some settings are better than others for sure but all have been very usable.

@Gloersen @DefectiveDave you guys got me thinking. I ran a load cell and positional tracker so I can split the total measured line load into the centripetal force and the 'applied' force then plot both of those out. Might help illustrate @AdamCord 's point. Then... we could use the two values as a pseudo means to measure skier efficiency by looking at a ratio value of centripetal force (output) / 'applied' force (input), if all that makes sense. It'll be a few days before I get the time, but could be interesting.

@dchristman that's pretty neat. I assume what I'm looking at is a phone on a pylon mount and you're tracking the orientation at which the phone is pointing (please correct me if I'm wrong). Were you using only the on board gyroscope or some combination of sensors?

@david_quail are you looking to setup a means to collect data real time to interface with the AI, or are you just looking for some available data sets to feed it? Over the last couple years I've randomly experimented with a few different methods of data collection: pixel tracking, accels, load cells, rope angle, strain gauged pylon etc. I even got @adamhcaldwell to ski once with a data cable zip tied all the way down the rope connected to a couple of strain gauges on his ski. It got a little interesting when I realized I accounted for a quick release connector if he let go of the handle, but neglected to account for a quick release connection between his leg and the ski... good thing he didn't fall. So far, the best system in terms of data quality I've been able to come up with is direct line load measurement using a load cell and line angle measurement using a homemade angle-to-voltage sensor and a portable DAQ. My opinion is if you have line load and line angle you pretty much have, or can calculate, everything you would want to know. It's been super interesting and insightful, but up until now I've only logged the data real time then did all the post processing off line. I actually just starting playing with this again a couple weeks ago to setup a real time graphical interface to make the data much more useful, i.e. real time feedback instead of taking a couple hours to generate all of the graphs. I've found that the data is way more interesting to people if they can see it real time. I also have aspirations to hook up a third sensor to the boat to measure rpm at the same time. I'm super curious to see if I can measure the lag and intensity of the rpm vs. skier load for the different ABC/123 zero off settings. Feel free to email me, I'd be happy to share the setup if it means more data. I really like @adamhcaldwell 's idea of a data collection weekend at Trophy if you happen to be in the southeast. I can also send you some data files to get you started if it's anything that's meaningful to you.

@Gloersen Neat video! After watching that 12 months doesn't seem quite as long.

@thager For the vast majority it's mostly just a thought exercise to help get through the winter. But for those few who just can't help themselves from trying to figure out exactly how something works, like fin tuning, it's another tool in the box to play with. I've heard many a time someone bring up the idea of tuning based on the centroid of the fin but have yet to see anyone actually post the math to enable such a thing. Whether or not there's value in tuning based on the centriod, I'll leave that to guys like @adamhcaldwell . But just for example... lets say for some reason you've got it in your head that you want to add .020" of length to your fin but don't want to take out surface area. Your current fin is set to 6.850/2.490. You can use the surface area equation to know exactly how much depth to take out to maintain the same surface area, in this case .011" making your new fin settings 6.870/2.479. Use of the centroid equations follow the same pattern, however the reasoning behind such a desire gets pretty deep. But you asked 'how', not 'why'. The only reason we tune by length/depth/dft is because they are easy to measure. If surface area and centroid location were just as easy to measure I suspect some of the mystery of fin tuning my disappear. It may even allow you to start comparing fin numbers from one fin shape to another.

@eleeski I honestly can't tell if you're being serious or sarcastic.

Equations for finding the Centroid of your Fin... turns out these are pretty linear as well. Centroid, the geometric center of a shape. New Term Definitions: Cx, Centroid Distance From Back of Fin (X-Axis). Cy, Centroid Distance From Bottom of Ski (Y-Axis). Cx can be used with your DFT measurement and Boot measurement to calculate the distance of the fin's centroid along the x-axis to either the tail of the ski or to your boot placement. CxDFT, Centroid Distance From Tail of Ski (X-Axis): CxDFT = Cx + DFT CxDFB, Centroid Distance From Boot (X-Axis): CxDFB = Boot - CxDFT Cx = (0.4300 * Length) + (-0.0783 * Depth) + 0.2119 Cy = (-0.0358 * Length) + (-0.3823 * Depth) + 0.1993 Both equations are based on linear regressions with R-Squared values of 0.9991 and 0.9997 for Cx and Cy respectively. In other words, really good fits. Point data from CAD: This is pretty much all of the data the spreadsheets contain, but if anyone wants a copy of the Excel file I'd be happy to share. But don't expect me to make it all pretty.