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:

Chesapeake and Potomac TIMED Race 2026

Welcome to the Chesapeake Bay, the sailing capital of the United States. Feast on Maryland crab cakes or crabs seasoned with Old Bay spice before sailing down the Bay aboard a Formula 18 catamaran on a 128 nm course that will take you up the Potomac River finishing at Quantico, Virginia. This is a TIMEDrace so you may RE-REGISTER HEREto try again after finishing a run. You will have two weeks to test your skill and decision making after the race opens.
Race #2032
INFOby brainaid.de
Formula 18 catamaran Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ2 - TRCH - SYC
RACE CLOSE: Saturday,
23 May at 23:00 UTC
Race starts: May 10th 12:00 Registration will open soon
▶ Flash
GO TO RACE

Tobruk to Iskenderun 2026

Welcome to the fourth of our nine races across the length and breadth of the Magical Mediterranean Sea, and the second that is not in partnership with a real-life event, this time for good reason, which we won’t get into here. From Tobruk to Iskenderun it’s 670nm in length, with the added complication that the island of Cyprus will be in your way. Hoping, possibly forlornly, for plenty of downwind sailing, we’ll take the Lagoon 55 for the voyage!
Race #1976
INFO by brainaid.de
Lagoon 55 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: MED - SYC
Race starts: May 05th 15:00 Registration Open!

▶ Flash
GO TO RACE

Tasmania to Kamchatka 2026

Welcome to yet another all-new route. Tasmania to Kamchatka, part of our Ocean Championship and also the third leg of the ROW (Round the Old World) series. Be aware of the obstacles on the way, likely to split the fleet. It's like X:mas to X:mas, crossing the same waters, navigating the same archipelagos. This second race of OCQ2 2026 will be sailed in our revised 'version 2' Imoca 60 Foil. Race #2031
INFO by brainaid.de
Imoca 60 Foil v2 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - ROW - OCCH - SYC
Race starts: May 04th 11:00 Registration Open!
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member WRmirekd
  2. Sailonline Yacht Club Member CriticalHippo
  3. Sailonline Yacht Club Member rumskib
  4. Sailonline Yacht Club Member Panpyc
  5. Sailonline Yacht Club Member rafa
  6. Sailonline Yacht Club Member KaSToR
  7. Sailonline Yacht Club Member CollegeFund
  8. Sailonline Yacht Club Member bonknhoot
  9. Sailonline Yacht Club Member vida
  10. Sailonline Yacht Club Member sassy63

View full list

Series

Mobile Client

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

The mobile client