dorox

The last one, headsail (without mast, single skin): L/D = 14.208 Hmm, I guess I'm calculating L/D wrongly there, numbers aren't making much sense. will redo it another day. It would be helpful if someone gives me the cross section dimensions for ac50 wing, and ac75 mast and sail - that would make the simulation a bit more relevant

While having a little time to procrastinate I have tried to see the difference in lift-to-drag ratio(L/D) between different wing and mast designs - lets see your opinions. The simulation is for a 10 m/s wind at an angle of 6deg to the wing (sail). Symmetrical single wing: L/D = 8.8243 Non-symmetrical wing (it is similar to double-skin sail): L/D = 9.0541 Circular mast with a single skin sail : L/D = 22.934

Seems like Artemis is taking part in the work on the design rule. Did they officially announce the challenge? Or is it a random person wearing an artemis hat? (screenshot from the recent ETNZ video)

Nope, this guy is not a commodore of St Peterburg YC. He is the owner of watste processing company, alcohol producer, and a lecturer in a university . It does not seem like he has any connections to Gazprom. Valentin is actually the leader of the Synergy racing team - the one which participated in ACWS in 2011 under the name of "Ё-Challange" according to russian press https://itboat.com/articles/263-kubok-ameriki-rossiya-uchastvuet. I can not confirm this as I did not follow AC at that time, but there is a picture of the boat (could be photoshopped). The interesting thing is that Synergy wanted to compete in 34th AC, but the cost was too high."The cost has grown from 20 millions euro for 32 AC to 60millions for 34 AC... I am not sure that there is anybody willing to compete at that price in Russia" https://itboat.com/articles/183-kogda-nibud-my-ego-zaberem

Waiting for Russian hackers to steal ETNZ's simulation software

Good job asking about the bulb. Now one can imagine their 2 options are: with and without ballasted keel (?)

Will the videos from ac34 and ac35 be published on youtube? Will the race management publish boats telemetry as it has been done before?

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

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.

Yes you are right - probably as with most of the sailboats you tend to sail lower upwind in lighter winds. And the opposite for downwind. Picture below strengthens this point. The data is from all the races NZL done so far. Color represents true wind angle: red - higher, blue - deeper. more graphs is in "too much data" topic

In the 6-14 kn wind range NZL dominated yesterday. Lets see if artemis can improve today. The plot is for upwind.