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Board » Flag Officers » Races » New York to San Francisco Record Attempt

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Posted by
NZL_Scotsman


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2008-10-04 07:59:40
2013-03-27 04:08:20 - Re: New York to San Francisco Record Attempt
You may have noticed that Gilles' DTG increased after passing the Cape Horn mark. This is due to the course between next mark and the finish. This issue has been discussed at length on chat before. The mark near the was to create a better race course. Unfortunately, this has resulted in the DTG calculation showing unusual results. This is likely to continue until the boats are near San Francisco.

A more complete explanation and discussion is posted here.
_______________
edited to make link out of url

--- Last Edited by RainbowChaser at 2013-03-27 07:58:32 ---
Posted by
NZL_Scotsman


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2013-03-27 05:17:42 - Re: New York to San Francisco Record Attempt
Race Report Day 20
Our race leader Gilles has passed Cape Horn and is therefore past half way to the finish. Soldini took over 21.5 days to round the cape, so Gilles is two days ahead of the record pace after averaging about 14 kts since departing New York. From here it is “uphill” as we head north towards San Francisco.

The South Atlantic was more straightforward than the North, but still had its challenges. The route taken by Gilles generally followed the rhumb line but locally required careful navigation through or around the weather systems crossing the mid-latitudes. These systems can behave unpredictably, which plays havoc with the best made plans. Gilles made a superb move three days ago when he decided to aim more directly for Cape Horn and even passed through the middle of the Falklands Islands.

The fleet has spread out with over 160nm between first and tenth. The southernmost point of the Americas is also where the Atlantic meets the Pacific. As attention moves towards the Pacific the chasers will be looking for passing opportunities. Whilst Gilles’ lead is a strong one, he will still be looking over his stern to keep a close watch.
Posted by
RainbowChaser


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2009-06-14 09:44:50
2013-03-27 08:16:07 - Re: New York to San Francisco Record Attempt
Re DTF issue this is what I just said in race chat:

RainbowChaser 7:54 morning all.. it IS possible to remove the waypoint at Pillar Point but if we do, your finish line will not sit across the bay but will be perpendicular to the rhumb line...

and

RainbowChaser 7:55 the position of the finish point, however, is needed for the record I understand so if you are all happy to have a skewed finish line then I can go ahead an remove Pillar Point (or Jeroen can) ;-)

We have a long way to go so my view is to remove the Pillar Point mark and move on.

What do you all think?

:-)
___________

--- Last Edited by RainbowChaser at 2013-03-27 09:10:43 ---
Posted by
Svein


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2009-05-04 15:09:20
2013-03-27 09:14:14 - Re: New York to San Francisco Record Attempt
Well IMO, the direction of the finish line is basically a cosmetic issue (in a long race like this with longish intervals between finishes) and should not be considered, more importan is as relevant as possible pos#/dtf.
Posted by
hmm


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2011-11-03 13:35:22
2013-03-27 11:22:48 - Re: New York to San Francisco Record Attempt
SOL uses great circle lines for the DTF calculation which can be tricky in long races like this.

If you test drawing a GC line from Cape Horn to SFO you can see that the line actually curves like an S when it crosses equator which shows that it is difficult to anticipate on a flat map how the shortest distance goes in different situations.

However the combination of a long leg, shallow turn and short leg (to finish) is not handled well by the method SOL uses for calculation so in my opinion removing the Pillar Point waypoint would be the best fix for this issue.

In racing point of view, the issue is actually cosmetical as the distances sailed by the boats are still the same. The problem is in the way SOL tries to anticipate the point where boats will round the Pillar point.
Posted by
WIN


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2009-07-09 23:32:07
2013-03-27 11:24:02 - Re: New York to San Francisco Record Attempt
Ciao ALL my friends ;)

although I am not in this race , I would like to make a couple of contributions , being the DTF , and the race course quality check two subjects that apply to all races specially Ocean.

1)
The DTF mechanicals in SOL are at present the best we can have , but we know they are far from being realistic when thinking IRL sail racing. We all know that rankings in SOL are valid only if all boats are on one reaching line and close enough to the finish ( LOL ) .......SO : YES !! RC ...please remove that mark that furtherly and dramatically deteriorates the realism !....Perhaps in a not too distant future we can study better ways .....now let's play with what we have got at best .

2)
The pre race quality check is very important and is responsibility of each and everyone of us , specially the Mavericks of the SOL mechnaicals. Some has pointed fingers at Admins for the snag ..... IMO admins only have to be praised for keeping SOL alive , and I would love to see this firmly in our minds .
BTW ...I am NOT a maverick of the behind the scenes in SOL ....I do NOT understand the effect of that WP on the DTF ( LOL ) ....thus I was not able to spot the problem , but there is a number of Solers who DO ....it would be great if they could help the admins in quality checks.

Till soon ;))

Piero
(WIN)
Posted by
A2


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2009-10-26 00:39:42
2013-03-27 13:34:25 - Re: New York to San Francisco Record Attempt
For Markku Hänninen:

I certainly will defer to your familiarity with the nitty gritty of the way things work in this matter, however I was under the impression that the DTF calc used the Rhumbline distance as boats in shorter races are often placed higher who stick close to the redline
None so blind
Posted by
javakeda


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2013-03-01 03:18:22
2013-03-28 07:44:11 - Re: New York to San Francisco Record Attempt
It seems clear that, as long as we have marks to be left to port or starboard [as opposed to marks that must be sailed to], rankings in intermediate legs are problematic. As a prior poster suggested, how wide a skipper leaves a mark is a tactical decision. Proximity to a mark does not necessarily translate to an advantage.

With that background, here are some off-the-wall thoughts on 'classification':

1) Basic classification should be based on a combination of marks rounded and GC-[sail to] distance to the next mark. There should be no way that a boat that has rounded a mark [e.g. Cape Horn] is classified below a boat that has yet to round that mark.

2) The lat/lon of all boats should be published by SOL in conjunction with the Wx. This corresponds to the "check-in" requirements of many real-life races -- although most races do not require check-in every six hours..

3) We should develop additional share-ware tools to help all skippers analyze their tactical position vis-a-vis other boats. [I would gladly share any analytical spreadsheets I might develop.]

All of this is based on the thought that 'rankings' in a ocean race are somewhat subjective. Rather than striving for a 'perfect' objective function, I suggest we embrace the subjectivity ... and the ambiguity that implies.



Posted by
dikkehenk


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2012-02-24 15:03:37
2013-03-29 10:47:46 - Re: New York to San Francisco Record Attempt
on request, here is the polar for QT..

have fun :)



--- Last Edited by DIKKEHENK at 2013-03-29 10:48:29 ---
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Posted by
Eddie C. Dost


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2008-08-23 11:40:29
2013-03-30 13:30:59 - Re: New York to San Francisco Record Attempt
I have added QtVlm polar downloads to my sailonline toolbox, please test and tell me whether this works with QtVlm.

If the downloaded files are good for QtVlm, please spread the word to others.

Thanks!

Cheers,
Eddie

P.S. The toolbox is at http://sol.brainaid.de/sailonline/toolbox

--- Last Edited by Eddie C. Dost at 2013-03-30 13:31:49 ---
_/)_/)_/)
The sea is lovely, dark, and deep, But I have promises to keep, And miles to sail before I sleep, And miles to sail before I sleep.

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