Zezo forum: Figaro 3 Polars Winches

Figaro 3 Polars Winches

Post by toxcct | 2021-05-06 | 22:15:30

Hi all,

Did anyone notice the "winch" section of the polars json from VR changed from what it used to be ?

We still have the usual "stdTimerSec", "stdRatio", "proTimerSec" and "proRatio" properties, but now, we also have 2 new objects present for all 3 type of winch usage ("tack", "gybe", "sailChange") :

Do anyone know how it affects the behavior of the boat ?
@Cvetan/zezo ?
@Michael/Hardtack ?

23 Comments

Post by zezo | 2021-05-07 | 06:59:20

Looks like there will be separate penalties for gybe, tack and sail changes, in high and low winds

The Maxi too. And the numbers are a lot worse - 600-900-1200 seconds. Which makes sense - it's a lot harder to change sails on a large boat than on a Figaro.

Post by toxcct | 2021-05-07 | 07:29:33

ah, lw==low winds and hw==high winds !

yes, that makes sense ; I just couldn't understand what they were heading to.
Well, it seems there is not much to do on my side, but you will have to put you hands under the hood of the router again ;)

Post by Hardtack | 2021-05-07 | 07:45:25

Interesting. Let#s see if the new penalty times show up in the dashboard. It won't be very easy to see because of the long update interval, and Dashboard oly displays the remaining time.

Post by DeskSailor | 2021-05-07 | 09:06:34

Has this occurred mid-record attempt giving unfair advantage to those who have gone before?

Post by toxcct | 2021-05-07 | 13:38:46

No, this is a new polar published for a yet unstarted race AFAIK

Post by DeskSailor | 2021-05-08 | 17:32:51

Thanks.

Post by BooBill | 2021-05-07 | 11:26:06

There will be only 3 or 4 sail changes the entire race, so any advantage would be insignificant.

Post by YourMomSA | 2021-05-07 | 13:20:02

What wind thresholds define "low" vs "high"? And does it pro-rate the impact, or does it suddenly change if you're above or below the threshold?

They've also changed the impact of the pro winches... instead of making the change faster, it makes the speed during the change less penalized.

Post by BooBill | 2021-05-07 | 14:39:53

Let's not lose sight of, that once again, they've made changes to the game, that affect competition, without any communication whatsoever.

Thanks to toxcct for some eagle eyes.

Post by 43South | 2021-05-07 | 18:47:06

Looks to me like the 'low v high' would be applied, dependent on what sail you are using at the time of the tack/gybe.

Post by toxcct | 2021-05-07 | 19:24:16

No, these numbers are located in the "winch" part of the polars.
That means they will affect speed only when the winches are used, which means on gybe, tack or sail change only.

However, as YMSA pointed out, there is a difference between low and high winds, but we don't know where the threshold is.
That will affect the routing for sure, and Cvetan will have to implement it somehow in zezo, but I guess we will have to inspect the faces in the dashboard, and report here what we experience of the speed penalties so we can identify where the limit is between low and high wind speeds...

Post by Reves_de_gosse | 2021-05-07 | 19:38:03

It's not clear at all for me.
If you have two winds, low and high, you need only one limit between them.
But we have two, hsw: 30 and lws: 10
Strange.

Post by Reves_de_gosse | 2021-05-10 | 15:14:40

It's not clear at all for me.
If you have two winds, low and high, you need only one limit between them.
But we have two, hsw: 30 and lws: 10
Strange.

Coefficients for Odyssey :
globalSpeedRatio : 1
iceSpeedRatio : 0,3
Foil foilSpeedRatio : 1,04
twaMin : 80
twaMax : 160
twaMerge : 10
twsMin : 16
twsMax : 35
twsMerge : 5

Hull hullSpeedRatio : 1,003

Winch lws : 10 Wind
hws : 30 Low High
tackStdTimerSec : 300 600 900
tackStdRatio : 0,5 1 1
tackProTimerSec : 75 600 900
tackProRatio : 0,5 0,7 0,7
gybeStdTimerSec : 300 600 900
gybeStdRatio : 0,5 0,5 0,5
gybeProTimerSec : 75 600 900
gybeProRatio : 0,5 0,7 0,7
sailChangeStdTimerSec : 300 900 1200
sailChangeStdRatio : 0,5 0,5 0,5
sailChangeProTimerSec : 75 900 1200
sailChangeProRatio : 0,5 0,7 0

Post by Bacemoi | 2021-05-07 | 21:01:35

Hi everyone,

Are we sure that these new parameters will be used?
If yes, it seems that the advantage of pro winches will be reduced.
For example with a boat sailing at 20kts, the difference between std and pro is 0.625 NM with the current algorithm (10 kts during 225s).
If we do understand correctly, with the new algorithm, the difference will be 0.2 NM (4 kts during 180s).

Please let me know if I made a mistake in my analysis.

Post by apfrit | 2021-05-11 | 21:58:21

Hello,

it looks like former fix penalties will be added to new adaptative ones, two wind values are provided for linear interpolation to calculate penalties for any wind force.

Do yo have the same understanding ?

Are the new penalties already computed in the zezo's routing options ?

Thank you

Post by CRISTAU | 2021-06-09 | 02:49:35

Hi CVETAN, wondering how you calculate the effect of Winch Pro for the routing? Actual calculation or a percentage? I thought the penalty was half speed during 5mn instead of 1mn which means 2mn penalty, did it change? On TARA I see 27 changes, therefore WP should save 54mn, but when I compare the routing with lights, and with or without Winch Pro, I get a difference of 5 hours at arrival (263h/ 268h), you get much more than my estimate!

Post by Inicio | 2021-06-09 | 06:47:46

Now the gap is 9 h.

Post by Inicio | 2021-06-09 | 07:05:49

Anyone knows if the new penalties work for Olympic or Tara?

Post by shockwave11 | 2021-06-09 | 10:04:28

Post by zezo | 2021-06-09 | 17:25:20

@CRISTAU The router still uses the old default penalties.

Problem with PRO winches is the algorithm does not really optimize towards maneuvering. That would add another dimension of complexity (and order of magnitude of the execution time)

Ignoring the sail changes and tacks would give a global optimum. Adding small penalty (like 10% for 10 minute step) is not that bad and is still close to the optimum. Adding a big penalty does not work very well.

Post by CRISTAU | 2021-06-11 | 03:03:33

When I check now from my position (I am with Lights only), I still have 6 hours difference at Grand-Ilet with or without Winch Pro which is quite surprising as when I calculate the penalty, it should be 15* 2mn= 0.5h. I understand that if I arrive late to a point because of past penalties, I may loose good winds and loose more than 0.5h at the end, but such a 6h difference surprised me. As the system calculates every 10mn, you mean you presently apply 5% during these 10mn as the penalty is 0,5mn (half speed during 1mn) and 25% for normal winch (half speed during 5mn)? When the new sails are applied it will add some complexity but not that much.

Post by Inicio | 2021-06-13 | 10:21:14

And I have also seen that great difference between the time of the routes with or without Winches Pro. The difference is much greater than the savings in maneuvers.

The idea that I have come up with is that Zezo calculates better when tacking or gybing is allowed without the burden of penalties. And he chooses a faster route when you check the Winches box ... even if you don't have them.

Post by YourMomSA | 2021-06-18 | 11:53:04

Did they also do something to force botspeeds in "wrong sail" situations while waiting for the autosails to trigger the change... to force the "wrong sail" to use the better sail's speed?

In Olympic yesterday, when everyone was eventually shifting from TWA <115 to TWA 120, I noticed autosails wasn't changing people from C0 to LG, so I sailed TWA 125 for a minute to force the change. And then I was surprised to see (after my sailchange penalty) that my speed, in the same windspeed, matched those around me. Toxxct's polars suggested C0 in TWA 120 should have been slightly slower than LG.

I noticed something similar on my own boat a couple days prior, when I discovered Autosails hadn't made a change yet that Dashboard said was due, bur my speed matched the polar speed of the better sail anyway.