Zezo forum: Avoid change of sails (SPI) going from LG to HG (through SPI)

Avoid change of sails (SPI) going from LG to HG (through SPI)

Post by bibi63 | 2021-06-30 | 02:57:41

When you are going TWA 140+ and wind change from 17knt to 20 ant you go through 2 sails change (at 17.7 you go from LG to SPi and 18.8kn you go from SPI to HG. If wind change quickly you can do 2 sail change in 15 or 20 minutes.

After calculate the 3% I thought I was OK to stay auto because the difference of speed would stay below 3% so it would go LG tp HG and I was fine in auto. Well it almost worked but at the last moment, as I was closed to change to HG it changed SPI instead and stay there for a while until changing to HG.

I think it stayed within 3% of tolerance but seems like it didn't want to skip the SPI sail and go directly to HG.

I know you can turn manual off that would be one option but by looking at the dashboard I noticed that some sailors (not all) were able to stay in auto (at least as shown in dashboard) and go directly from LG to HG without going through SPI. I am not sure how they do that ?

One option I am thinking is 1) they stay auto in LG 2) at a certain time (not sure when) they change in manual and go the HG 3) they come back in auto. All within the 5 minutes window. I don't know if it would work, do you have experiences, suggestions ?

Thanks

8 Comments

Post by MidnightFoiler | 2021-06-30 | 05:09:03

So you are saying that you saw the current sail change in dashboard in the correct reported speed column (not the polar derived one)? You would have also seen the speed drop for the penalty. If you just saw it in the VR client then that does not really mean anything!

Assuming that you saw it in dashboard I would say you must have just hit the tolerance - did you check the polars for the TWS and TWA reported in dashboard for the difference between LG and Spi?

I pretty sure I have successfully done as you intended and it skipped the intermediate sail (different boat though - maxi in vela cup I think) simply keeping it on auto sails - and the beauty is on auto you get the best speed of all 3 sails all the time but only 1 penalty.

Only other thing I can think of is if something triggered it to re-evaluate the correct sail like a gybe - but I believe even that should not matter.

And maybe they have adjusted the tolerance again?

Post by bibi63 | 2021-06-30 | 09:50:59

Well it indicated SPI in the fleet dashboard for 2 or 3 intervals of 5 minutes (while it didn't for other sailors). Also in the log the column VC appeared in yellow with a lower speed indicating SPI.

I am not sure if it counted or not as I am not familiar with reading the log column and its impact.

Thanks
Yves

Post by bibi63 | 2021-06-30 | 09:52:36

Also looking at the fleet dashboard I saw some bots going from LG to HG directly and most others going LG to SPI to HG within the 15 20 minutes of transition.

Thanks
Yves

Post by MidnightFoiler | 2021-06-30 | 12:09:55

The important column here is vR - reported - the sail listed there is the one the server has you using - but with autosails the speed reported should be the same as the optimum sail even if you have not actually changed to it.

Yellow vC - calculated - means it can't explain the difference between vC and vR or vT but this includes when vC is faster due to it using the speed for the faster sail than reported by vR - but in this case vC would be higher not lower. From memory I think vT shows the speed of the faster sail and that sail and that would match vC.

The fleet tab should be accurate - do you have VIP so that it updates every update cycle or where you manually refreshing? (I assume that is still the same).

A screenshot of your race log would help but not easy to post here.

Post by bibi63 | 2021-06-30 | 13:47:56

Thanks Midnightfoller

I am not sure I understand everything in the log. Looks like when you change sails it only appear in VC column not VR but I will check again.

I have VIP and it updates every 5 minutes. On the fleet tab I clearly went through SPI for a few 5 minutes iterations. Other players did not (or at least I think that is what I saw)

Now we just did it again but this time it took 50 min to go LG-SPI-HG (and not 20 minutes as before) and pretty much everybody had to do the 2 changes (HG-> SPI -> LG).

Strange because if you calculate we should be within the 3% margin but not sure.

Yves

Post by MidnightFoiler | 2021-07-04 | 12:19:26

Aha, mystery solved. I was just checking things with our team and the tolerance is 1.4% and used to be 0.3% not 3%. I had forgotten the numbers sInce this thread http://zezo.org/forum.pl?tid=8395 or I would have said so earlier.

We were also looking at the sail changes in the Horta race and it seemed the only way to avoid the extra sail change was to switch to manual and yes I think your original theory on how to do it is correct. If it hovers around the switchover wind speed for a long time then of course it may not be worth trying to avoid the extra change.

I haven�t actually done it but I imagine the ideal would be to leave it on auto until just before it would switch to Spi on auto and then in the same minute set it to manual and select the next sail up/down. If it were me I would probably leave it on manual unless auto was needed before the next weather update

Post by bibi63 | 2021-07-06 | 02:51:48

Thanks, that helps.

I tried i. I changed to manual just before it changed in VR but at a time where it was already showing spirit as the preferred sail. As soon as I changed to manual, it changed to SPI and defeated the purpose. I thought boy changing it back to LG but I was not sure if the system change to SPI and I change it back immediately, would I be penalized by 2 changes ?

As I was not sure I let it go. I wonder if you change to a sail and change it back immediately within a minute, are you penalized ?

Post by MidnightFoiler | 2021-07-08 | 12:32:03

So, if it had not auto changed on the server to Spi and it sent Spi on switching off auto and you managed to manually switch it within the same minute (same minute timestamp in dashboard) then it should ignore the first sail command from switching off auto and either do no penalty because you put it to the same sail or just one penalty to a different sail.

If it has auto changed on the server just before then you will get 2 penalties - so it is safer to switch to manual before you are worried the server might auto switch.