LA - TAHITI Routing stability and...... by the way....... Who is going to win?
Post by iconPost by nsp | 2020-05-29 | 17:24:01

Hi all.

And specially Cvetan, because on this matter you are the Master.

In this race I have been experiencing something weird.

Of course we know there are weather chart files updates at certain hours of the day, no doubt, we all know that and we use to pay special atention tto those moments.

Of course we know Zezo updates the projected optimal course calculated taking into account several variables, charts, polars, rig, start and destination point, wind force etc etc...we all know that and there is no doubts.

Of course sometimes we see hesitations in sugested route, even to the point already discussed to sometimes go north or south of some areas.
this does not happen often, but happens. And sometimes for some periods od 10 minutes zezo points one way and then returns back to the previous projected course.

However, in this race I am experiencing a different thing. It is like if Zezo is unstable. It frequently changes "ideas" sometimes making us think in a strategy of a flat 140 twa degres then he changes for a totally different thing of a mix of 135/140..wich I understand...but then to out of the blue gybe for 1h40.

I am feeling this strange behaviour since start with slight changes and hickups. And now this Gybe thing. And let me tell you this not syncronized with any weather chart update.

Are you aware of anything going on?

.....


The other theme..who will win....this time defenitelly EAST pack :)))

Thanks

Fair winds all

Nuno


commenticon 36 Comments
Post by iconPost by Zorba777 | 2020-05-29 | 21:11:15
Router is working normal here. Maybe try a page refresh or clean cache?

East side will have stronger wind for some days, but is also going a longer way. West side is taking a slow start but is expected to catch good winds later on. I am trying a bit East of the middle, passed right at Guadalupe. Around June 2-3 look like the deciding days ... GL

Post by iconPost by zezo | 2020-05-29 | 21:17:27
@nsp Guess it's just the weather pattern. A lot of instability causing the router to change its mind every 5 minutes.

Guess you've read that other thread about why that happens.

Also guess you're on the South route. I'm still sailing the opposite direction myself, and it's quite stable there, but maybe not for good.
Post by iconPost by YC6211 | 2020-05-30 | 08:00:23
East group is currently looking about 4-5 hours ahead. But that's still way too close to call at 9 days out.
Post by iconPost by zezo | 2020-05-30 | 10:36:28
But the difference persists between updates, which is usually a bad sign.
Post by iconPost by chelonia | 2020-05-30 | 11:32:42
Hi Cvetan, "A lot of instability causing the router to change its mind every 5 minutes."

How is that even possible when weather circumstances stay the same from one update until the next weather update? Or is the weather chancing all the time. Sorry if this has been answered already but I´ve been away for a while ... and the search function, well .... :-)
Post by iconPost by BooBill | 2020-05-30 | 16:36:30
Multiple routes can get you to the same destination at almost exactly the same time. Tiny differences in your initial conditions can result in the optimizer algorithm selecting a different route than it did just a few minutes ago. When you click the compass icon to generate a route it takes your position from the last 5-minute update. You might have moved a mile since then. For that reason, I always wait till an update posts to run a route. That way my starting postion is as close as possible to my actual game position.

If it is swinging between two vastly different strategies, say going one side or the other of a major system, then you have a real decision to make. Those situations are the whole reason I enjoy this game.
Post by iconPost by chelonia | 2020-05-30 | 18:33:35
Thank you @bmertens. Yes of course, that makes sense. The boat position/condition is the only variable (router)input between weather updates, and the 1-16day forecast option which will indeed make the router re-calibrate.

But in essence, when you fix/plot your position as close as possible and leave the forecast setting the same then the router track should be good to go until the next weather update, and no new routing request would be needed until the new update (07:00, 13:00, 19:00 CET). Especially on these long term ocean runs.

Or do you also plot new positions in between weather updates? Perhaps when sailing close quarter?

Fair winds!




Post by iconPost by zezo | 2020-05-30 | 18:40:47
There was a thread a week ago where I explained in detail why the router output is not really deterministic, even between the updates. There are other things that change, so the result can be a bit different every 5 minutes. Or a lot different, sometimes

You can find the discussion here http://zezo.org/forum.pl?tid=7897. You may want to skip the first sub-thread, 10 messages or so.

About how often to run the routing - as often as you want, but if it suggest another tack every time keep your common sense. That's also discussed there.


Post by iconPost by chelonia | 2020-05-30 | 18:48:34
Appreciated Cvetan. Thanks!
Post by iconPost by turtle 1663 | 2020-06-02 | 15:14:41
Just ran some calculations and it´s very close between SE and NW group. I would say that SE has a small lead over NW of about an hour, but hard to tell at this point in time. SE is +/- 700 NM closer to the Mataiva. Weather for NW seems to be more stable. If I had to choose I would bet on NW ... Good luck!
Post by iconPost by YC6211 | 2020-06-02 | 23:32:47
The NW group sails the rest of the race at a faster angle. What concerns me is that the NW group has had an ETA of 1-5 slower than the main group for the entire race. Once the SE group passes the convergence today, we'll know pretty much exactly when they'll finish. The NW group still has to get through there.
Post by iconPost by turtle 1663 | 2020-06-03 | 06:30:42
Yep, today NW is having a pretty good day, tomorrow will be important, if not decisive, going through the rubble, fingers crossed. Good fun though!!
Post by iconPost by BooBill | 2020-06-03 | 00:06:26
If you had a nicely formed North Pacific high that route might have worked. It's only really forming now. South group is having an easy transition of the convergence. Queue the fat lady.
Post by iconPost by turtle 1663 | 2020-06-03 | 06:45:16
Current difference ETA west of Mataiva +/-1h in favor of SE, NW closing in ... tomorrow will be d-day, convergence for NW looking pretty good but need to become better 🤞

Post by iconPost by Zuelometro | 2020-06-03 | 18:28:41
'Of course we know there are weather chart files updates at certain hours of the day, no doubt, we all know that and we use to pay special atention tto those moments.'

Can someone tell me the time of the weather update? Is it only in zezo or also in VR weather?

I'm on West team, apparently we're not crossing, probably finishing in 2nd line, all depends on that low pressure zone in front.

Good luck all.
Post by iconPost by BooBill | 2020-06-03 | 20:59:48
That "low pressure zone" in front of you is called the intertropical convergence zone or doldrums, or pot noir, or where race strategies go to die. 🤣
Post by iconPost by turtle 1663 | 2020-06-03 | 19:07:04
From what I understand:

Weather updates in game are at 07:00h, 13:00h, 19:00, 01:00, Central European Time (CET)

Zezo seems to be 30min/1h earlier.

More info at:

http://zezo.org/qa.html


Post by iconPost by lorenzo | 2020-06-03 | 21:54:20
more details
http://zezo.org/forum.pl?tid=6109
Post by iconPost by turtle 1663 | 2020-06-04 | 09:49:45
All is lost
Post by iconPost by Hardtack | 2020-06-04 | 09:59:15
We're still going.

So is La_Sémillante, in a way :-)
Post by iconPost by turtle 1663 | 2020-06-04 | 10:25:00
fuck me, where did you just come from ... that´s me thinking I was doing just fine among the usual suspects in the NW group :-) go goo gooooo
Post by iconPost by Hardtack | 2020-06-04 | 11:06:21
La_Sémillante of course is the semi-retired ranking leader who occasionally comes back to win a race, just like that. In the other races she does funny things like this.

Me, I'll enjoy it while it lasts. Unfortunately the east fleet ETA is still 2.5 hours ahead of mine.



Post by iconPost by turtle 1663 | 2020-06-04 | 12:02:32
👍🤞
Post by iconPost by Hardtack | 2020-06-05 | 07:26:13
Ouch. The two last forecasts were devastating. No more router needed to tell who's in front now.
Post by iconPost by turtle 1663 | 2020-06-04 | 10:22:06
Lol ...
Post by iconPost by LinusVanpelt | 2020-06-04 | 14:03:08
Hi very regarding race, my learning continues.
Having nothing to lose I chose this option telling myself that I was not immune to a good surprise. Some surprises we had, but not really good, never compared to south group, and not really surprise: they are the doldrums.
But if I had to do it again I would take this option again, more fun than to follow the top ranked, so very enjoying (in a few time perhaps).

Post by iconPost by turtle 1663 | 2020-06-04 | 16:39:59
Yes, agreed. Much more fun then following the herd. One day it will pay off, until then, enjoy the ride :-)
Post by iconPost by BooBill | 2020-06-04 | 22:10:00
Seems you've discovered one of the ways that VR can surprise you Turtle 1663. You can only see who you follow, who's currently in the lead or who VR chooses to show you. There are 20,000 other boats out there you can't see until they slide in front.

I led the main pack of the RORC Transat for 2 days. Had written my speech and picked out what tie I was going to wear to the ceremony. Then bang, a whole group shows up that came down from the north. Totally off the radar until suddenly they took the lead.

It pays to follow some of the oddballs who like to try different strategies.
Post by iconPost by turtle 1663 | 2020-06-05 | 07:56:29
Oh I know buddy, there´s (almost) always another one in front of you. Sorry to hear about your Transat disappointment. Take care
Post by iconPost by YC6211 | 2020-06-05 | 10:39:07
I think this latest forecast is the final nail in our coffin. We now have to push straight through this light air that the east can route around. Such is life when you go for the all or nothing route.
Post by iconPost by LinusVanpelt | 2020-06-05 | 11:18:02
"Drink the chalice to the dregs" 😂
& we haven't crossed the line yet 🤣
Post by iconPost by turtle 1663 | 2020-06-05 | 11:19:19
Yup, I´m heading more southwest (119o port) hoping the high will fall straight in the middle of the two groups. I saw you doing the same. What else can you do :-)
Post by iconPost by turtle 1663 | 2020-06-05 | 11:24:01
But it´s over and out, SE can be dead in the water for at least 12 hours and still win. We tried and it was good fun.
Post by iconPost by Zorba777 | 2020-06-06 | 16:54:50
I am now 9 hours behind the leaders, which is not too terrible with only light sails and hull polish. But there were at least two occasions the others were flying away from me on C0. So, next time I will try with C0 and foils, which is often more useful in a long race like this. Live and learn... Will the next doldrums change the race outcome? Or is a 3NM lead (by Tigrou) enough?
Post by iconPost by LinusVanpelt | 2020-06-06 | 19:41:12
Hi Zorba, i think that many FPs would dream to be at your place. For the choice of options you can make simulations before departure of the race, on zezo, and thus make the best compromise, I don't think there is a universal combination.
And for the race outcome ...
Good winds
Post by iconPost by Zorba777 | 2020-06-07 | 13:32:06
Yes. I will try FP some day. For now I usually start with the sails most needed in the first days and then I see along the way. If I find myself in a very good position I can always buy C0 or whatever is needed...
I took a few chances by sailing deeper to the South after the gybing in slow winds a week ago. But the weather did not develop as needed to support that plan, so I found myself back on the main route a few days later. One can sail a good result by always going with best path per router. But it's more satisfying to try a few things along the way.
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