-
Announcements
-
Abbreviated rules 07/28/2017
Underdawg did an excellent job of explaining the rules. Here's the simplified version: Don't insinuate Pedo. Warning and or timeout for a first offense. PermaFlick for any subsequent offenses Don't out members. See above for penalties. Caveat: if you have ever used your own real name or personal information here on the forums since, like, ever - it doesn't count and you are fair game. If you see spam posts, report it to the mods. We do not hang out in every thread 24/7 If you see any of the above, report it to the mods by hitting the Report button in the offending post. We do not take action for foul language, off-subject content, or abusive behavior unless it escalates to persistent stalking. There may be times that we might warn someone or flick someone for something particularly egregious. There is no standard, we will know it when we see it. If you continually report things that do not fall into rules #1 or 2 above, you may very well get a timeout yourself for annoying the Mods with repeated whining. Use your best judgement. Warnings, timeouts, suspensions and flicks are arbitrary and capricious. Deal with it. Welcome to anarchy. If you are a newbie, there are unwritten rules to adhere to. They will be explained to you soon enough.
-
dorox
Members-
Content count
56 -
Joined
-
Last visited
Recent Profile Visitors
560 profile views
-
I can assure you - you woudn't see a potential AC founder there
-
Nobody cares about sailing in Russia. It is just too far from being a national sport. And the oligarchs are having fun in RC44 which they can actually sail, as opposed to modern AC. There is also a language barrirer and the price of oil. There was an interesting endeavour of Gazprom with ESS, but it failed.
-
Today's data. Oracle had non symmetric foils - look at the speed difference on the polar - port foil was worse. Not much of the straight line speed difference I would say. Probably tacking is killing them.
-
Yes, and the median TWS is higher for NZL, which supports the point. I don't see much speed differential, not at all. Probably the most gains were created by maneuvers. I need to find the way to analyse that.
-
Today's portion of "analytics": Tactics: median TWS for NZL - 8.7kn, USA - 8.5kn. Tacking: average VMG at TWA<30deg: NZL-13.8, USA- 13.13 Gibing: average VMG at TWA>160deg: NZL - 23.86, USA - 17.86
-
Today's portion of "analytics": Tactics: median TWS for NZL - 8.7kn, USA - 8.5kn. Tacking: average VMG at TWA<30deg: NZL-13.8, USA- 13.13 Gibing: average VMG at TWA>160deg: NZL - 23.86, USA - 17.86
-
Today's portion of "analytics": Tactics: median TWS for NZL - 8.7kn, USA - 8.5kn. Tacking: average VMG at TWA<30deg: NZL-13.8, USA- 13.13 Gibing: average VMG at TWA>160deg: NZL - 23.86, USA - 17.86
-
New interpretations on rudder wings with nice pictures: https://docs.google.com/a/acracemgt.com/viewer?a=v&pid=sites&srcid=YWNyYWNlbWd0LmNvbXxub3RpY2Vib2FyZHxneDozOTUzMTc4ZGI2ZGFhOGFl https://docs.google.com/a/acracemgt.com/viewer?a=v&pid=sites&srcid=YWNyYWNlbWd0LmNvbXxub3RpY2Vib2FyZHxneDo3ZGE3NzkyOWM2NzU1Y2Vm
-
I don`t know exactly, but my guess is that because there is larger heeling moment from the wing. This heeling is balanced by higher lift on the foil when compared to downwind. And higher lift equals to bigger angle of attack which leads to lower pressure around the foil. In simplier terms, for downwind foil is used to support only weight of the boat. For upwind it supports weight plus increases righting moment which requires higher lift.
-
What I found interesting is the top limit they hit at high wind speed: appr. 15kn VMG or 25 kn SOG. I think this should be cavitation speed in upwind mode. Keep in mind that cavitation causes damage to appendages - they do not want to sail 100% unless it is their last cup race
-
The dots I plotted are at "steady state" sailing. It is defined as change of average SOG over 10 s is less than 0.1kn and change of a COG over 10s is less than 0.1deg. Look at the polars - the course is changing within 20 deg when going upwind: sometimes they sail lower/higher, or they might put more or less pressure on the boat by adjusting the wing (they dont need to go 100% all the time, just enough to beat SWE)- this affects VMG.
-
That's just one race. Every point represents a steady state straight line sailing for 10 sec. When all races are plotted on one graph it gets very messy.
-
Well, polar graph on the top shows speed in knots at different sailing angles. 0 - dead upwind, 180- dead downwind. The lots of dots between 30 and 60 is the starboard upwind tack. Dots between 210 and 240 represent port downwind. Those two directions they sailed most of the time because the wind shifted right quite a lot. The bottom one is basically proportional to the lift to drag ratio of the wing and foil combined. The typical value for a keelboat would be 0.2 - 0.3. You see how Artemis is worse than NZL in light wind. And also is interesting how both teams basically hit the limit at high wind speed.
-
Today NZL average upwind VMG of 14.8 against 13.4 of SWE. This difference of 1.4 kn equals to 200 m gain over 5 min of upwind sailing - pretty much what we saw today.
-
Today's analysis. NZL is much faster upwind: average VMG of 14.8 against 13.4 of SWE. This difference of 1.4 kn equals to 200 m gain over 5 min of upwind sailing - pretty much what we saw today.