terrafirma
Super Anarchist
Is that based on their ability in those conditions..?
The Ocean Race 2023 leg 3: Capetown to Itajaí, Brazil
- Thread starter Herman
- Start date
Herman
Super Anarchist
- Thread starter
- #1,962
Weather routing March 31st
In the past day HPRB caught up with TM, and took a small lead (2 nm atm).
First I did some polar backtesting, and concluded to power-up all boats. This brought the ETA to Itajai forward as can be expected.
So what is in store for the remaining days?
Pic 2 has the big synoptic pic provided by the Brazilian navy for 00Z. TM and HPRB enjoying light winds sailing due to the HP (1018 hPa) to their east. 11th Hour racing and Biotherm close to the LP zone (1014 hPa which is a high-low) off the coast of Argentina.
Pic 3 has the ASCAT surface winds for 0542Z.
Both wind models have a hard time capturing the weather situation as can be seen in the next 2 pics, when you look closely at the red actual wind vs the projected winds in blue. For TM and HPRB the actual wind direction is +/- 45 degrees off. And they don't agree much for 11 Hr and Biotherm.
Pic 4 ASCAT 0542Z and ECMWF wind and pressure
Pic 5 ASCAT 0542Z and GFS wind and pressure
GFS has that developing LP on the coast of Argentina projected too early in time, and with too much wind.
ECMWF and GFS disagree on what is going to happen in detail today too. A new LP, projected to develop now quickly around Montevideo, according to both GFS and ECMWF, should be moving east and is key this afternoon for the first 2 boats.
GFS pushes their wx routing more to the west and towards the coast, compared to the ECMWF routing. I think this is due to the TWS setting for routing downwind is max 45 kts, and GFS is probably overstating wind speed and thus is pushing them west for less wind force. Being that close to the coast with this amount of wind projected is very doubtful though. If the actual wind is 20 or 30 degrees off, it could turn into a dangerous lee shore.
This LP should turn into a full blown storm when further away on Sat 1st 14Z providing a nice ride north. GFS is projecting more wind, as usual, for the LP than ECMWF.
Pic 6 has the Wx routing and table. As mentioned above in my post both models have the TWD +/- 45 degrees off. Actual TWD was far better for the first two boats. So take the exact ETA's with a pinch of salt. The ETAs for the finish have come forward due to that new LP today to April 1st late in the evening. As can be seen in both weather models the first two boats are projected to finish within minutes of each other. With the windforce going up to the mid 30s again projected for today, while reaching, that could be in the advantage van Team Malizia as we know.
The sea state will worsen to almost 5 meters sig waves according to both WW3 and WAM on April 1st in the very early hours. It will be a rocky ride north, but following seas.
Pic 6 the Wx routing and table. See also pic 9 for the table separatly.
Pic 7 GFS 1645Z zoom
Pic 8 ECMWF 1645Z zoom
Pic 9 wx table
In the past day HPRB caught up with TM, and took a small lead (2 nm atm).
First I did some polar backtesting, and concluded to power-up all boats. This brought the ETA to Itajai forward as can be expected.
So what is in store for the remaining days?
Pic 2 has the big synoptic pic provided by the Brazilian navy for 00Z. TM and HPRB enjoying light winds sailing due to the HP (1018 hPa) to their east. 11th Hour racing and Biotherm close to the LP zone (1014 hPa which is a high-low) off the coast of Argentina.
Pic 3 has the ASCAT surface winds for 0542Z.
Both wind models have a hard time capturing the weather situation as can be seen in the next 2 pics, when you look closely at the red actual wind vs the projected winds in blue. For TM and HPRB the actual wind direction is +/- 45 degrees off. And they don't agree much for 11 Hr and Biotherm.
Pic 4 ASCAT 0542Z and ECMWF wind and pressure
Pic 5 ASCAT 0542Z and GFS wind and pressure
GFS has that developing LP on the coast of Argentina projected too early in time, and with too much wind.
ECMWF and GFS disagree on what is going to happen in detail today too. A new LP, projected to develop now quickly around Montevideo, according to both GFS and ECMWF, should be moving east and is key this afternoon for the first 2 boats.
GFS pushes their wx routing more to the west and towards the coast, compared to the ECMWF routing. I think this is due to the TWS setting for routing downwind is max 45 kts, and GFS is probably overstating wind speed and thus is pushing them west for less wind force. Being that close to the coast with this amount of wind projected is very doubtful though. If the actual wind is 20 or 30 degrees off, it could turn into a dangerous lee shore.
This LP should turn into a full blown storm when further away on Sat 1st 14Z providing a nice ride north. GFS is projecting more wind, as usual, for the LP than ECMWF.
Pic 6 has the Wx routing and table. As mentioned above in my post both models have the TWD +/- 45 degrees off. Actual TWD was far better for the first two boats. So take the exact ETA's with a pinch of salt. The ETAs for the finish have come forward due to that new LP today to April 1st late in the evening. As can be seen in both weather models the first two boats are projected to finish within minutes of each other. With the windforce going up to the mid 30s again projected for today, while reaching, that could be in the advantage van Team Malizia as we know.
The sea state will worsen to almost 5 meters sig waves according to both WW3 and WAM on April 1st in the very early hours. It will be a rocky ride north, but following seas.
Pic 6 the Wx routing and table. See also pic 9 for the table separatly.
Pic 7 GFS 1645Z zoom
Pic 8 ECMWF 1645Z zoom
Pic 9 wx table
Last edited:
Fiji Bitter
I love Fiji Bitter
Let's hope we get a finish like 5 years ago, but this time in a lot more wind, according to Herman:
i.stuff.co.nz
Blair Tuke ghosts past Peter Burling in stunning Volvo Ocean Race leg finish
5700 mile Volvo Ocean Race leg comes down to the last 500m as Mapfre steal victory at the finish.
i.stuff.co.nz
Last edited:
Fabricensis
Member
- 92
- 107
So both models agree that the last few 100 nm will be with significant waves and wind, aka Malizia conditions? Or is there a possibility that they can 'coast' with medium waves and 15 kn winds aka Holcim conditions
wildbirdtoo
Member
... another confounding factor might be Holcim's (perceived?) slightly better ability to run nearer to straight downwind .. it will be a very interesting 36 hours!
Herman
Super Anarchist
- Thread starter
- #1,966
My my Leo, are we touchy today? I don't hate mr. Geovoile, those are your words. I tried to find that thread with the discussion we had but was not able to find it.
But there was, and is, imho much room for improvements though. Re-using the same code for a decade for all big RTW races does not show any innovation. We had better trackers in the VOR previously. Navionics marine charts, different weather model overlays, boat projections using VO65 polars to name a few. But now we are back again to the level of quality we complained about in the previous decade. The only thing that has changed since that decade is that the updates are every hour instead of per 3 hours. This could be a budget thing. But it could also be a lack of interest in any product improvements by mr. Geovoile. Or probably both. My 2 cents.
Panoramix
Super Anarchist
On Malizia, they've got Nicolas Lunven on board... may be not a star but he is a very skilled figaro sailor and not sure that Laperche and Escoffier can match him for purely tactical sailing.
Qtrfoil
Member
Well, I wasn't suggesting building an armchair. I know oioi didn't, his suggestion was for auto racing seat shells with no padding at all and I largely agreed with him, adding the idea of 0.5 in closed cell foam. For me, tens of thousands of hours in very high performance vehicles makes me think that flat and hard seats are the worst choice to connect you to the platform and to minimize energy that's getting spent just trying to stay in place.
LeoV
Super Anarchist
Geovoile had a lot of stuff in the past, even position reports in table form. Other trackers leached that off the Geovoile site to build the other ones. Organizers stopped that. Not Geovoile.
PS, I still have the distance measurement tool available.
tiljim
Malizian
- 81
- 104
Kevin should enjoy his last hours at the top of the leaderboard. Boris will roll over him this afternoon. Just recall how Boris said in their approach towards Cape Hoorn that TM just keep the speed of Holcim but could go up to 5kn faster. Now it's his time to prove he was right. 
Thanks Chris, that's what I meant to say!
Qtrfoil
Member
Sometimes I feel just a little guilty for fanboying TM a bit, but I just checked - they've posted 28 videos on YT in last 2 weeks, and Holcim has posted 7. TM is just better at making fans.Kevin should enjoy his last hours at the top of the leaderboard. Boris will roll over him this afternoon. Just recall how Boris said in their approach towards Cape Hoorn that TM just keep the speed of Holcim but could go up to 5kn faster. Now it's his time to prove he was right.
The tracker is a way to draw eyeballs to the race and its sponsors, so they have a tracker which majority focuses on the perceived audience of "less technical" sailors, its why they also go to the trouble to explain things on all the video shows, so really you can't fault the tracker for its simplicity as its doing what it was built to do.
Whats a shame is that the race organisers don't allow other trackers to use the data, its possible to get data from yellow brick for some races and certainly you could build trackers of that but the organisers have requested an obfuscated link for this race that makes that impossible.
What'd be nice is an api from the organisers alongside an agreement that if you use it you show their preferred branding / sponsorship somewhere as an attribution, then let people build what they want
Whats a shame is that the race organisers don't allow other trackers to use the data, its possible to get data from yellow brick for some races and certainly you could build trackers of that but the organisers have requested an obfuscated link for this race that makes that impossible.
What'd be nice is an api from the organisers alongside an agreement that if you use it you show their preferred branding / sponsorship somewhere as an attribution, then let people build what they want
Positions in table form are available on Malizia's version of the tracker :
http://team-malizia.geovoile.com/theoceanrace/2023/leaderboard/?leg=3
It also has ranking on the left part of the screen, measurement tool all the time, spherical projection... Good old geovoile basic version !
And telling an engaging story in general.
I asked my wife, who is not really interested in the race - but forced to sometime watch TOR YT videos on our tv.
From Holcim she could only really recognize Kevin.
From TM she can easily list Boris, Will, Rose and that "silent" guy
I miss viewing the routes in Windy, additionaly
