Sailonline.org - Online Sailing

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!

Tweets by @sailonline

Board » General Discussion » MOD70 polar development

Posted by SlashV 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 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 0_MOD70_Draft.pol (2.9 KB)
Posted by SlashV 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 et_1_foncia.png (127.4 KB) krys_foncia.png (119.0 KB)
Posted by 76Trombones 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 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 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 MOD70_tracker.ods (11.9 KB)
Posted by 76Trombones 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 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 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 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:

Manilla to Calbayog 2024

After six years, we welcome you to the race created by sassy63 for the second time. He takes us to the Philippines to race around islands on a 380 nm course. We sail the Italia 14.98 and in Calbayog we'll enjoy our well-deserved Palatan dish and drink it with San Miguel.
Race #1803
INFO from brainaid.de
Italia 14.98 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ2 - ARCH - SUPSOL - SYC
RACE CLOSE: Tuesday,
April 30 at 2300 UTC.
Race starts: Apr 22nd 17:00 Registration Open!

▶ Flash

GO TO RACE

Melbourne to Osaka Prelude 2024

Welcome once again to what these days is Sailonline’s almost annual virtual Melbourne to Osaka Yacht Race. In real life, this double-handed 5500 nm race between these two sister cities, one deep in the southern hemisphere, the other high in the northern hemisphere, is run every four to five years, and is planned to be held again in 2025, so this race is a Prelude in partnership with the Melbourne Osaka Cup 2025 organising committee collaborating with the Ocean Racing Club of Victoria (ORCV), and the Sandringham (SYC) and Osaka Hokko (OHYC) yacht clubs. On this occasion, we’ll be racing the well-known First 40, a popular size of boat for a long-distance double-handed race. With the doldrums unavoidably lying across the track, you can expect to be at virtual sea for at least a month!
Race #1669
INFO by brainaid.de
First 40 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: Apr 20th 00:00 Registration Open!

▶ Flash

GO TO RACE

St Nazaire Chasse TIMED Race 2024

Welcome to a "chasse" (hunt) from St. Nazaire to La Baule on the west coast of France! This race was designed by SOLer FR_flouflou in 2010. The KER 40 was introduced to SOL in 2016 by SOLer psail, and the Sol-KER was a welcome addition to SOL’s fleet of 40- footers, as it was to the IRL Ker fleet of eponymous - like KERonimo, KukuKERchu and Ice BreaKER. This is a TIMEDrace, so you may RE-REGISTER HERE to try again, after finishing a run. You will have 13 days and 11 hours to show your skill and decision making after the race opens.
Race #1797
INFOby brainaid.de
Ker 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ2 - TRCH - SUPSOL - SYC
RACE CLOSE: Saturday,
27 April at 23:00 UTC
Race starts: Apr 14th 12:00 Registration Open!

▶ Flash

GO TO RACE

Cape Town to Auckland 2024

Welcome to the second leg of this Round The World series 2024. It's also the April edition of this year's ocean race championship. The course is the same as the one sailed in 2023, but this year we sail the iconic Swan 65, as suggested in the concluding RTW race last year.
Prepare yourselves for an epic 30-day journey, navigating through the unpredictable waters of the South Seas. It's essential to take care of provisioning to ensure a smooth and enjoyable race experience. With the longer duration, we anticipate plenty of opportunities for camaraderie, competition, and unforgettable memories.
PRIZE: SMPF
Race# 1789
INFO from brainaid.de
Swan 65 PARTICULARS
WX updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - RTW - OCCH - SUPSOL - SYC
RACE CLOSE: Sunday,
May 5 at 2300 UTC.
Race starts: Apr 01st 11:00 Registration Closed

▶ Flash

GO TO RACE

Go to race archive

SYC Ranking

View full list

Series

Mobile Client

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

The mobile client