Zezo forum:

Post by YourMomSA | 2018-02-28 | 17:09:30

Finally a good race for spending some credits. :-)

Cvetan, are you able to see in this race how much wind is needed for foils and/or heavy sails to be useful? I'm guessing this race won't have a need for HS. Maybe foils if they kick in at like 11 knots windspeed, but my recollection is that you need more like 14 kts, and I doubt we'll see that much.

44 Comments

Post by zezo | 2018-02-28 | 17:15:58

The boat is Class 40, same as RORC 600. I'll check it now, but it's not like gale-force around those places.

Post by zezo | 2018-02-28 | 17:25:19

Grrrrr the forecast says 4 knot minimum wind almost all of the time. Not going to be very fun race.

Post by YourMomSA | 2018-02-28 | 18:12:37

Well, the good news is that it's only 300 nm, and if that forecast holds, we won't need foils or heavy sails, so we can spend the credits on cards instead. Although I guess with it being Category 6, the Full Pack doesn't cost much anyway.

Post by zezo | 2018-02-28 | 18:16:16

http://zezo.org/muscat/chart.pl

300 nm at 5 knots average speed is a lot of time spent online.

A bit about the RORC 600, but for different reason.

You have a point about spending free credits if foils don't kick in, but you still need a C0 and the light sails.

Post by YourMomSA | 2018-02-28 | 19:49:53

Thanks, Cvetan. Looks like we need 18.9 kts windspeed for HS to be worthwhile. Do you know what the minimum windspeed is for foils to be helpful?

(Does the answer to that question vary from boat to boat, or do the foils behave the same regardless of whether it's a C40, IMOCA, Happy, Maxi Trimaran, etc)?

Post by mak08 | 2018-02-28 | 20:28:36

I am taking the liberty to answer in Cvetan's place.

So far, all boat types used the same foiling parameters. From the Meta_GetPolar message:

"foil":{"speedRatio":1.04,"twaMin":80,"twaMax":160,"twaMerge":10,"twsMin":16,"twsMax":35,"twsMerge":5}

Foils start working gradually from TWS = 16-5 = 11kn and TWA = 80-10 = 70�. Full effect +4% speed from 16 to 35kn etc.

Only the actual sail speeds differ from boat to boat in the GetPolar messages.

Post by YourMomSA | 2018-02-28 | 20:55:34

Thanks! So... if this race starts looking like it might have 11 kts wind at some point, then foils would be worthwhile.

Here's the way I've noted the conclusions of your analysis, FWIW...

- Partial benefit starts with TWS 11 kts and wind angles aft of 70 degrees.
- Full benefit is reached at TWS 16 kts and wind angles aft of 80 degrees.
- Benefit ceases if windspeed exceeds 35 kts or you decide for some reason to sail with wind angle aft of 160.

Very handy to know that's completely independent of which type of boat you're sailing. Thanks again.

Post by mak08 | 2018-02-28 | 21:14:29

Yes, except that the speed increase does not cease but is symmetrically reduced to zero as TWS increases from 35kts to 40kts and/or TWA increases from 160� to 170�.

Post by Ursus Maritimus | 2018-03-02 | 11:54:57

you can see the foils operating range at the polars by toxcct
http://toxcct.free.fr/polars_beta/

Post by Ursus Maritimus | 2018-03-03 | 13:12:29

I know the router doesn't like sharp bends.
Is there way to route around the corner, all the way to the finish?

Post by zezo | 2018-03-03 | 14:53:47

It does not like sailing back towards the origin. Absolutely can'd do ut because the optimizer goal function is progress from the start.

With the SE forecast the port tack gets you closer and the router can's sail it.

To avoid the limitation you can move the starting point along the North shore of the strait, at a point that gives you about the same time to the mark.

Post by Ursus Maritimus | 2018-03-03 | 19:45:34

So we're gonna need twice as much time for this one with the 2 kts wind limit ;)

Post by zezo | 2018-03-03 | 19:56:17

Not that bad, but it's possible that part of the time will be spent between 2 and 4 knots.

Post by JohnT | 2018-03-03 | 20:13:40

Cvetan, Not sure it's worth your time, but cloning the functionality you added to the JV (to vary a start time) would be a great option for routing round the corner...
And thanks again for continuing to keep up with all the insane VR changes, and to the members of this forum as a whole for collectively keeping us updated.
John aka Truffle Hunter

Post by zezo | 2018-03-03 | 21:40:16

It's not about implementing it but about usability for new users and support questions asked when (and we've all been there) you click the drop-down at dark o'clock and the forecast gets terribly off.

That's why I prefer to keep it simple. The routing will fix itself once you approach the mark, and the forecast will change a lot in the meantime, so it's not like you can plan the entire route right from the start, program it and go to bed.

Post by JohnT | 2018-03-03 | 22:26:08

Totally agree with your logic - especially after doing exactly that a couple of times in the Southern Ocean. FYI, I wasn't thinking so much about use during the race as getting better input on which set of sails to select with my free cards...moving the start solved the challenge:)

Post by zezo | 2018-03-04 | 13:32:23

I know, but you need both C0 and light sails anyway, because LS work upwind and downwind, and "reaching sail" works in low wind speeds too.

I had enough free credits left to do exactly that. Should pay back about the same amount even without much effort spent on the race.

Post by JohnT | 2018-03-04 | 17:00:21

But to stay to the PDD no money racing, you have to choose one of those. I've gone with LS, so that should guarantee lots of reaching ;)

Post by JohnT | 2018-03-04 | 17:00:22

But to stay to the PDD no money racing, you have to choose one of those. I've gone with LS, so that should guarantee lots of reaching ;)

Post by YourMomSA | 2018-03-07 | 13:42:20

Hmm... If the latest forecast holds, we might get 11-12 kts for a couple hours right after the start. It's possible we might also see more than 11 later in the race, depending on how the forecast and timing evolve. So... there could be some benefit to foils. But not much. Probably a gain of 0.5-1% on a 9-kt boatspeed for maybe 1.5-2 hours... Maybe about 0.1 nm gain... One sailchange is worth just as much, and and single good or bad decision is worth a lot more. But... if it lasts a couple more hours and/or gets to 12 or 13 kts, then suddenly foils would be important.

Post by lorenzo | 2018-03-07 | 14:10:00

for the group I_am_not_giving_a_single_penny_more_to_this_people_until_they_become_adults I am using my 400 credits just for navig cards.
I agree with Mom, a missed tack during night will cost more than any extra option

Post by user1234 | 2018-03-07 | 16:29:43

Just an observation. Whit no options i get routing of 64 hours and some minutes. With C0 box checked i get a routing of 65 hours and some minutes. 1hour more with c0. I think theres something funny happening.
Maybe its the cape the routing has to go around. The observation was made 16:20 utc, with gfs 06z+ t12z+57h weather.

Post by Xeelee | 2018-03-07 | 16:46:58

Did you also count the isochrones from the last waypoint to the destination ?

Post by user1234 | 2018-03-07 | 21:28:17

No. I didn't count the isochrones the whole way.
I made the observation by looking at the black dot, and the infobox the dot provides.this was on the last dark blue isochrone. I also counted light blue lines after the last dark blue "6 hour " isochrone, and there was one light blue "1 hour" line more with code0 checked.
And btw i didn't have the "time shift" checked when this observation was made.

Post by Lasse | 2018-03-07 | 21:04:41

I have never managed to get zezo to make the route all the way to the finish line. Not with "timeshift" checked. For me it looks like this just now:

Post by Lasse | 2018-03-07 | 21:06:58

I remember reading in some thread that zezo refuses to track closer to the start, i.e. backwards.

Post by Lasse | 2018-03-07 | 21:12:13

About buying foils or not, I checked the winds closer to the finish in the future and saw that it eventually started to get more windy (> 11kts). So, I quickly decided to buy foils.

Then I realized that by that time I will probably have ended the race...

LOL!

Post by zezo | 2018-03-07 | 21:57:20

Yep. The router can't route back to the origin. It does not affect the end result, but you have to be awake 12 hours after the start to see the end of the track.

You should be awake anyway, because there are 2 forecasts between the start and the Hormuz buoy.

Post by JohnT | 2018-03-07 | 22:17:20

The 12 hrs after the start isn't a big issue when the race starts @ 02:00 local time...but making sure I haven't revisited Iran enroute looks to be more of a challenge given the total unwillingness of the lottery machine to provide any programming assistance; and my obstinate refusal to fork out real money to VR for this race.

Post by YourMomSA | 2018-03-07 | 23:28:42

If I understand things correctly, the fleet won't have to wait until we arrive at Hormuz to see routings to Muscat. I believe once we're within a few hours of Hormuz, it'll start recognizing the waters beyond Hormuz as "not doubling back". Probably somewhere around where it's currently proposing a gybe.

Post by zezo | 2018-03-08 | 10:13:38

Polars say 9 knots, UI says 9 knots server says 7.2 knots.

WTF?

Post by toxcct | 2018-03-08 | 10:15:44

Cvetan/Mak08,

The race just began, and I'm noticing that there is quite a difference between the Theorical Speed from the polars (9.01 kts) and the Reported Speed (7.21) in my current attitude (TWS=11.4, TWA=130�).

I don't seem to suffer from any penalty (no sail change, no gybe/tack), so I don't understand why it keeps going on a lower speed...

I even tried to close the game tab ; nothing better.

Post by mak08 | 2018-03-08 | 12:09:07

Yep. Thanks for the note. Probably we should display *all* the game parameters in the dashboard. I'll take a look tonight.

Post by Sambaopreis | 2018-03-08 | 10:16:09

I have the same. Posted a new topic for this. So i am not the only one.

Post by YourMomSA | 2018-03-09 | 23:55:42

Just checked the real race's tracker... 15 entries... 5 have officially retired, and a couple are going the wrong way and appear to simply have not called in their retirement yet. The orange boat that's going straight upwind toward Muscat... is motoring, having retired already... but VR hasn't removed the retired trackers from the game (yet). The real leaders are slogging it out up by Hormuz. This real-life race is a serious test of patience. By the time it's done, they might only have 4 or 5 finishers.

Post by zezo | 2018-03-10 | 06:31:08

Dunno when it happened but the finish circle was moved East. Just noticed that the direction differs by 5 degrees and fixed it.

Post by Ursus Maritimus | 2018-03-10 | 17:07:04

yeah, saw the same and than noticed you synchronised the waypoint in zezo. Great job !!

It's gonna be a tricky finish ...

Post by WaterHammer | 2018-03-10 | 18:01:10

Hi Cvetan, a 200% and 400% zoom level would be nice now in the Dubai-Muscat race. :-)

Post by Ursus Maritimus | 2018-03-10 | 23:24:07

Post by Ursus Maritimus | 2018-03-10 | 23:24:50

probably more often with 2 kts wind

Post by Ursus Maritimus | 2018-03-11 | 05:39:17

what a lousy windshift at two hours before the line. suddenly trajectory shifted 12 degrees and tacking becomes a must :(

Dropped back from 13th as NMS-saylor to whatever.