Facebook

Login

Support Sailonline

If you haven't already - join the SAILONLINE YACHT CLUB!

Please also consider making a donation - all amounts are greatly appreciated!

Board » General Discussion » MOD70 polar development

Page: Previous 1 2 3 4 Next

Posted by
SlashV


Users avatar

Posts
14
Registered at
2009-08-09 22:01:21
2012-12-26 00:33:49 - Re: MOD70 polar development
I've made the following approximation for the krys map:
lat = -2.855E-7 * x^2 - 0.002296592 * x + 69.251568
lon = 0.008093847 * y - 150.31126
Posted by
Tarco


Users avatar

Posts
41
Registered at
2011-11-09 21:54:22
2012-12-26 00:51:55 - Re: MOD70 polar development
This is my first draft : a BWR polar
I think timings are close to what happened, except in Euro-Leg 4, trajectories are not always right, though....
It still needs some corrections.

Don't use for navigation !!! :-)

--- Dernière modification par Tarco le 2012-12-26 00:52:59 ---
Attachments
Posted by
SlashV


Users avatar

Posts
14
Registered at
2009-08-09 22:01:21
2013-01-13 04:24:06 - Re: MOD70 polar development
OK, found some time :) and created a script to parse the addviso xml files and 'enrich' the results with data from the grib files.
I will try to come up with a least squares fit for curves to match the data. Anyone know good basis functions for this?
I am curious how this will turn out. The data doesn't look particularly 'neat'. I attached some plots.
@Tarco. I'll have a look at your file as soon as I have some results of my own.
Attachments
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2013-01-14 15:28:00 - Re: MOD70 polar development
Those look great. Immediate impressions are of deeper vmg downwind and even more light wind speed. It looks like there are interesting things going on headsail reaching as well.
Posted by
Tarco


Users avatar

Posts
41
Registered at
2011-11-09 21:54:22
2013-02-07 20:09:44 - Re: MOD70 polar development
Back after a month...
Is it only me ? I don't have access to Krys Ocean race tracker anymore...

My impression : when they pinch (TWA35), they are able to keep the speed they have build. When they haven't build the speed, they stay at half-ish the top speed they can reach.
That makes 2 sets of speed at low TWA. One set at almost twice the wind speed when they have build the top speed, coming from higher TWA and another set of "low" speed when the speed is not built yet... don't know if I'm clear...
That could probably be simulated by keeping the high speed with a huge loss of speed (50 % or so) when tacking at TWA 50 or less. Or maybe take a top speed of 3/4 of sample speed...

Back to sampling Euro Tour before it disappears too... New results in a few days.
Next races will be in june (Euro Tour) then October 2013 (World Tour in legs)

Posted by
Tarco


Users avatar

Posts
41
Registered at
2011-11-09 21:54:22
2013-04-18 21:04:42 - Re: MOD70 polar development
Back again...
All the trackers have disappeared, so I can't go on with the calcs....

Here are the results I got, up to now. (see attached)

Between brackets, the number of occurences.
When I found several results, too different one from the other, I kept both.

I hope a polar can be created from that.
Attachments
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2013-04-18 22:12:00 - Re: MOD70 polar development
Looks good Tarco - I think we probably have enough data for a good guess. I can help bring it all together, or would you like to do the honours?

They'll be racing the "Route des Princes" in June as 4 shorter legs around Europe. We might not be able to fit all legs in (though it would make a nice series). RC probably has an idea of what's on deck for June, but it's always a busy month. Even if we don't do them in SOL we can "race" the new polar as a final check.

The *big* race will be the Transat in November? I hope they all make it to the start.
Posted by
RainbowChaser


Users avatar

Posts
2656
Registered at
2009-06-14 09:44:50
2013-04-18 22:30:18 - Re: MOD70 polar development
The SOL Racing Year shows what we have pretty much committed to in June .. it is a busy month... but if you can find a way to fit these new races in please feel free to do so! I am all for new ventures :-)

Are the races already in bed with a virtual sailing platform? If so, then that is another issue to be "managed" :-)
Posted by
Tarco


Users avatar

Posts
41
Registered at
2011-11-09 21:54:22
2013-04-19 09:04:39 - Re: MOD70 polar development
I would really love to build the SOL polar.

As June is already overbooked, we should probably not try to run the Princes races. But we can use them to compare the "predicted" speeds to the real ones. They will probably publish a real time tracker on line.
Probably a good way to make corrections to the 'prototype'.

Then, maybe, run a short race in September as a warm-up for crews before the Atlantic race in November. The polar should be ready by then.

The only problem is that "How to create SOL polar for dummies" is not published yet... :-)
I'll probably (certainly) need some help... :-)
Posted by
Tarco


Users avatar

Posts
41
Registered at
2011-11-09 21:54:22
2013-04-24 06:20:19 - Re: MOD70 polar development
76T, on second thought, I reckon you should create the "guessed" polar, so we could try it on a short race in may. And compare it to the real "Route des Princes" legs in June.

I believe that would take you a few hours when I would need weeks, if not more, just to understand how to do...

But I would like you to explain me afterwards, if you've got time to. :-)


--- Dernière modification par Tarco le 2013-04-24 09:49:59 ---

Page: Previous 1 2 3 4 Next

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Red Eye - Frisian Isles Trophy 2025

For our final “Red Eye” race, we invite you to cross the Noord Zee to the Wadden Zee, where a 160nm course around a few sandy islands raced on SOL only once before in 2010 awaits you. We don’t have a replica of Erskine Childers’ Dulcibella in our boathouse, and in any case if we took her out, we might well contract more than one “Red Eye”, so instead we’ll race our very own riddle of the sands in Farr 400s!
Race #1848
INFOby brainaid.de
Farr 400 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - RED

Race starts: Nov 05th 12:00 Registration Open!
▶ Flash
GO TO RACE

Fernando de Noronha to Faroe 2025

The RWW Series concludes with a spectacular journey from Fernando de Noronha to the Faroe Islands, a legendary destination in the wild North Atlantic. Panning 4,100 nautical miles, this leg will be a true test of endurance, strategy, and sheer determination. Also the penultimate leg of the 2025 Ocean Championship, it’s your chance to prove your mettle against the sea, the wind, and yourself. We’ll be racing aboard the Ragamuffin 100, a vessel built for speed and challenge — demanding planning, precision and grit from every sailor on deck. Do you have what it takes to master the Northern Atlantic?.
PRIZE: SMPF
Race #1960
INFO by brainaid.de
Ragamuffin 100 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RWW - OCQ4 - OCCH - SUPSOL - SYC
Race starts: Nov 03rd 11:00 Registration Open!
▶ Flash
GO TO RACE

Mistli's Birthday BBQ Race 2025


Welcome to one of Sailonline's great traditions - the ofttimes slightly untimely celebration of SOLer Mistli's birthday on November 1, by way of a tricky race through the Stockholm Archipelago. To match the day that’s in it, this year correctly, we are providing you with a fleet of sleek 11 metre 1-designs (get it?) to slice through these (at least) 61.5nm of SLI-infested waters, and give you a fair chance that there will still be some beer left by the time you moor up by the jetty at Trosa!
Race #1947
INFO by brainaid.de
11m OD PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
RACE CLOSE: Wednesday,
November 5 at 2300 UTC.
Race starts: Nov 01st 14:00 Registration Open!
▶ Flash
GO TO RACE

ORCV Melbourne to Devonport Race 2025

Welcome to the legendary Rudder Cup, Australia’s oldest and most storied yacht race—sailed for over 110 years across the challenging Bass Strait from Melbourne to Tasmania. Organized by the Ocean Racing Club of Victoria, this 195nm classic tests sailors’ skill, strategy, and endurance against the unpredictable Southern Ocean. This year, our SOLers will be racing the timeless Swan 36, Nautor’s very first production yacht—a Sparkman & Stephens masterpiece renowned for her elegance, balance, and seaworthy performance. Get ready for a true ocean racing adventure!
Race #1951
INFO by brainaid.de
Swan 36 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
RACE CLOSE: Saturday,
November 8 at 2300 UTC.
Race starts: Oct 31st 03:30 Registration Closed
▶ Flash
GO TO RACE

Sinbad by Balloon 2025 - Carnarvon to Dondra


From here, our home in Bharatavarṣa is now north west of us – said Sinbad to his fellow balloonists. Perhaps we can ride the wind first further north, and then catch the winds that every year bring the rain, perhaps not. It’s 2600nm and we could be aloft awhile, so, Master el-Quarters, victuals only, no sandbags, provisioning the giant hamper. It will be not a picnic!
Race #1886
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - SBB
Race starts: Oct 15th 11:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member KaSToR
  2. Sailonline Yacht Club Member CriticalHippo
  3. Sailonline Yacht Club Member WRmirekd
  4. Sailonline Yacht Club Member vida
  5. Sailonline Yacht Club Member rafa
  6. Sailonline Yacht Club Member CollegeFund
  7. Sailonline Yacht Club Member Panpyc
  8. Sailonline Yacht Club Member FreyjaUSA
  9. Sailonline Yacht Club Member BRENTGRAY
  10. Sailonline Yacht Club Member Sax747

View full list

Series

Mobile Client

SYC members have the benefit of access to our mobile/lightweight web client!

The mobile client