P Flados

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193 F'n Saint

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  1. P Flados

    Team NYYC

    Several were having a discussion about the sequence of the capsize in the Prada Cup thread (post 2366 to post 2392 or so). That thread is probably a better place for the ongoing discussion of what next for racing, so I have jumped over here to continue the look back at the event. After figuring out the data graphical available (https://ac36.herokuapp.com/stats_app, thanks again sailer99), I went in and extracted speed data and tabulate alongside key details you can see from the stern cam video. One note for anyone using the graphical data, the AM TWS data line seems to have completely missed the gust. The really high speeds shown on this line are all after the crash. Race Time Speed Event details (kn) 17:54.00 44.7 Goodie turns to get up 17:55.00 45.3 17:56.00 44.7 17:57.00 43.2 Goodie grabs boom handle 17:58.00 42.4 17:59.00 40.7 Goodie lets go of boom 18:00.00 39.5 Port foil starts down 18:01.00 38.4 Port foil hits water 18:02.00 36.0 Boom starts swing to port side 18:03.00 33.2 18:03.50 31.3 TWA is 0 (head to wind) 18:04.00 29.5 Mid “splash” (lowest height) 18:05.00 27.2 Traveler at stop on port side 18:06.00 26.0 18:07.00 28.0 Starboard foil starts moving up 18:08.00 30.6 Mast looks have gone from negative heel to zero heel 18:09.00 32.0 Starboard foil full up 18:10.00 34.9 Mast heel starts to go slightly positive 18:11.00 39.4 For the duration of this indicated time, mast heel is going positive quickly 18:12.00 43.1 18:13.00 45.3 18:14.00 44.7 18:15.00 40.8 18:16.00 36.7 18:17.00 27.5 18:18.00 25.4
  2. P Flados

    Prada Cup

    Sailor99, Max and others discussing the sequence of the capsize, lets move over to the AM thread and leave this one for the discussion of the current issues with the Prada Cup.
  3. P Flados

    Prada Cup

    S99, Thank you for the additional data. Unless something is screwy with the clock info, the graph of AM TWS seems to have completely missed the gust that we saw hit them when watching videos. This goes along with the the way the AM TWS line looks a lot smoother than would be expected.
  4. P Flados

    Team NYYC

    Look at the video from the stern camera. As they tack the boom swings over and goes full travel right away. About this same time or very soon afterward the other videos seem to show them sheeting way out on the jib.
  5. P Flados

    Prada Cup

    And do not forget that there was probably a big wind shift included in the gust.
  6. P Flados

    Prada Cup

    I tried to extract AM TWS from the above. I got 18:20 23.5 18:25 22.0 18:30 11.5 18:35 6.0 18:40 48.0 Peak for the time zone below: 54 After the down spike, the next spike up is probably bogus with the mast going underwater.
  7. P Flados

    Prada Cup

    Just prior to the -1.5 point above (in the post by Max with the officially sanctioned yellow lines), the boat was in control and accelerating rapidly. The boat heel angle change to +1 is where the boat was just overpowered. It was accelerating but not going fast enough to handle the wind speed increase and direction change. From the image above, I would say that Dean responded to the heel angle change from -1.5 to +1 by turning down. Goody stated in the video by AM that they just "did not get through the power zone fast enough". Normally these boats rapidly accelerate going through this maneuver and get through the "power zone" quickly enough to stay flat. I am not sure how much control they have to depower the rig other than just put the traveler full out (they did) and sheet the jib out (I am pretty sure they did this also). Is there anything they can do to quickly dump power up top to restore heel angle while retaining power down low (as needed to get back to the desired boat speed vs. wind speed)?
  8. P Flados

    Prada Cup

    I agree with the above. Terry had talked about their final set of foils not being on the boat. I wonder where they are in terms of readiness to try out their last set.
  9. P Flados

    Prada Cup

    The basic tack straight into a rounding seems to be a standard "but higher risk" maneuver. The tack, pause briefly and build up speed and then turn down does seem more in control. When the Brits did a bunch of these in earlier races, they made the point of lining up for not being just below the near mark when getting to the top. In hindsight, an earlier tack from the left boundary would have set them up much better. With all of the wind shifts and wind holes, I am not sure how much opportunity they had to plan that far in advance.
  10. P Flados

    Prada Cup

    The above post seems mostly correct, but I am not sure about the last paragraph. Early on, I went and reviewed the video with continuous chopper footage for the rounding and the crash (I can not find it now) and the continuous video from the stern. The overhead video lets you get a better feel for boat heading and boat heel, while the other video lets you see the main trim, the steering wheel and it gives boat speed. On a boat that is constantly being balanced on one forward foil and a rudder foil, trimming the main out is your preferred method of controlling heel. Changing boat direction is your secondary method. Early in the rounding the main is trimmed full out (traveler hard up against the stop). It stays there until the boat has crashed. As they go around the mark, they do a little hull splash. This is bad as it drops boat speed. For this kind of rounding, lower boat speeds bring wind AWA aft and give you more sail loading. Coming out of the rounding they are briefly heading down and out toward the side in a stable heel with the boat accelerating rapidly. However, boat speed does not get high enough to allow trimming the main in to regain margin for using the main trim to control heel. After a couple of seconds of hard acceleration and looking good, they get hit with the gust/shift. Normally going downwind, the boat speed is higher than wind speed and letting out the traveler or turning down unloads the sail. With the boat speed not high enough at this point, the traveler is still full out and turning down is the only heel control they have. This is exactly what Dean does, but with the gust / shift, the sail load stays too high and the heel continues to get worse. The boat is riding very high at this point and eventually the rudder loses grip, the stern drops and the boat heads for the sky. The bear away at the top mark is considered to be much higher risk than a normal tack or jibe. The reason is that you have to keep boat speed high enough to keep wind AWA forward enough to not overload the sail. Normally, everything works and if you "drive it hard" you pull it off. This time, the change in wind speed and wind direction was equivalent to "taking your foot off" in that boat speed was lower than typical for the wind speed (because it increased) as they exited the rounding. The wind shift probably contributed in that it made the eventual turn down ineffective at unloading the sail. Dean and Goody did not have any obvious opportunity to do anything "better" as best I could tell. When the gust/shift hit, the main was full out and the boat speed was too low to change course and unload the sail. The boat has limits on how far the main goes out and the timing and magnitude of the wind gust / shift just exceeded their ability to cope with it. They may have failed in their execution, but I am still waiting for a fact based explanation of what action (or inaction) was "wrong" and how this led to the roll over prior to the jump. People are also second guessing that they kept with their prior choice to "stay left". This choice seems to have been made well before they got to the mark based on seeing light wind to the right (with the potential for a race loosing splash down off of the foils) . They may have seen that the wind speed was going to increase. Some wind speed increase is ok. To bail out of this decision at the last minute would mean that they needed to see the magnitude of the speed increase, see that the shift was going to make it worse, processing that these were going to combine to exceed their ability to cope, and do this all in the 5 to 10 seconds prior to Dean sending Goody to the other side. AM has demonstrated that they wanted to be able to drive hard in strong conditions. They practiced hard (both B1 and B2) in lots of wind even when others did not go out. I really want to hear a detailed explanation of the sequence from someone that has experience in top mark roundings in all condition in a boat that does more than 2x wind speed and is greater than 20' in length. Since we seem to have a shortage of posts from these folks, some discussion from those seriously trying to understand the variables and control options for managing heel on these boats is good. However, others seem to be jumping in and second guessing without any real understanding. ,
  11. P Flados

    Luna Rossa Challenge. AC 36

    The lack of reliable boundary info is a big deal. It did not impact the result of any race yet, but easily could. If they can call off a race due to a windshift, should they consider calling off a race where a team is "unfairly handicapped" by lack of boundary info? Alternately, should they disable the feed to the other boat, make them rely on the " boundary light" and cut teams slack for close calls on boundaries.
  12. P Flados

    Team NYYC

    First shot is boat coming out of the water. Second shot is boat having crashed back down. Designing for a huge boat to leap out of the water at 40 knots and crash back down was probably more analytical swag than anything else. Not a lot of historical sensor recordings from a previous / test boat to help them. The fact that it came down on its side was likely a big factor. My guess is that the designers did not get the load cases right. The battery holder may have been adequately strong for up - down and fore - aft loads, but apparently failed due to side loading. Either that, or there was a build (bad joint, bad assembly) or maintenance problem (restraint not properly re-installed).
  13. P Flados

    Team NYYC

    Until the top mark, AM had been looking pretty good for the fist time in a Prada cup race. Up until the problem, it was also a race where they seemed ok without a lot of any real tactician role. AM did as well or better than LR in both straight line boat speed and in getting back up to speed after each maneuver. With the possible exception of light air performance, the performance of the boat was plenty good enough. If AM had consistently made the best tactical choices, they were in a position where they could probably loose a few in the light and still come out on top overall. Yesterday, LR was no slower than Ineos, but LR mad no attempt to cover and allowed Ineos to grab a winning wind shift. I would say that the first day of the Prada Cup and the third day of the Prada cup have shown that the Ineos choice for one less grinder and a dedicated tactician is paying off right now. AM needs to find a reliable source of decision making help for Dean. Once choice woudl be pretty easy. If needed (and when he is on the correct side of the boat) Dean needs to be able to ask Terry for help, followed by Terry stopping his grinding, standing up, looking around and providing needed advice. Someone on the other side of the boat needs to be available for the same function when appropriate. The choice at the top mark may have been "OK but not optimum". The real cause of the disaster was probably more poor execution with a dash of bad luck in "getting caught" with a just wrong wind gust / shift. However, the need for change in better tactical decision making is very very obvious. Hopefully they will get the boat repaired and have some opportunity to try to salvage their campaign.
  14. P Flados

    INEOS Team GB

    Exactly where I was coming from with my "His lack of direction going into the mark can be questioned,". Earlier I noted that Ineos may have better optimized systems that allow for less grinding effort. The alternate explanation is that they are getting as much hydraulics as everyone else but with less grinders. Either way, there choice for less grinders seems to be paying off big time in the tactician department. I have seen no evidence of an effective tactician on board AM. I will go post my thoughts in this regard in the AM thread.