Face Ocean
Post by iconPost by Thierry-R | 2017-05-19 | 19:20:36

Hi Cvetan!

Will You support Face Ocean?

Regards
Thierry

commenticon 7 Comments
Post by iconPost by toxcct | 2017-05-19 | 20:17:38
already opened... check the combobox in the home page :)
Post by iconPost by zezo | 2017-05-19 | 21:02:04
Yep, http://zezo.org/faceocean/chart.pl

With the current forecast you better check "Ignore gates" because the best route seems to go South of the mark and then back up (the gate logic does not allow crossing the gate latitude East of the mark)
Post by iconPost by Thierry-R | 2017-05-20 | 09:46:40
Once more thanks for all
Thierry
Post by iconPost by YourMomSA | 2017-05-24 | 20:55:58
Hi Cvetan -

Thanks as always for your work. I was one of many boats that didn't notice your comment here about "ignore gates" until it was too late. I finally realized something was wrong when it was telling me to short-tack along the mark's latitude, and then came here and saw the comment. No big deal - I'm racing without options, so I wasn't going to be with the lead pack anyway.

I'd like to ask for some clarification, though, so that I can hopefully avoid making the same mistake in future races. Can you please clarify the purpose of the gates, and how you decide where to insert them? What was the goal of the gate in this particular case, for example?

Thanks,
Mom
Post by iconPost by zezo | 2017-05-24 | 21:45:05
I'm trying to make the router as much point-and-click as possible. That works for certain courses, bit it's impossible to make it work in all cases (at least not without information from the game if the boat has cleared certain game or not)

The logic for this particular gate says "can't cross the mark latitude unless you are West of the mark"

Which would work in other weather conditions but not right now.

In other weather conditions it could be quite useful (if the optimum route passed further West of the mark you would not know it if routing straight for the mark)
Post by iconPost by frhopker | 2017-05-25 | 06:12:55
Hi Cvetan,
In this 'fan page', I'm one of your fans that thank you for this wonderfull tool.
One thing that I noticed on the last regattas, is that the suggested courses come with a kind of zigzag each 10 minutes, ranging in 5 degrees difference each time.
The questions are:
- why the tool produced this result (the zigzag)?
- this zigzag really helps on the long term courses?
- the penalty of two minutes on the course changes will not affect the overall performance?
Thanks for your attention!!
Congrats for your hard work!
Post by iconPost by zezo | 2017-05-25 | 11:59:53
Hi

Good questions!

The simple answer is quite simple - the router tries to sail at every 5 degrees TWA, so if your destination happens to lie at TWA say 57 it will alternate between 55 and 60 every 5 minutes or so. You should be pretty safe sailing at 57 most of the time. Alternating should be safe too as long as it does not cause sail changes, but in theory should be slightly slower because you sail slightly longer distance.


There are few exceptions to the simple case:

- Optimum upwind and downwind angles are tried exactly, so if it says 42 it's 42. But sometimes it decides to sail at 45 even if the optimum VMG is 42 ;-)

- Sometimes there are flat spots in the polars which actually have to be avoided, but then the correct headings will be 10 or 15 degrees apart.

- The worse flat spots are at the sail crossover points. The sail change penalty should prevent the 5-minute zig-zag, but in the worst crossover cases a sail change every hour or so may be better than sailing in the minimum.

In the end the polars and the "track tool" are your best friends. Sometimes I don't bother checking the black dot inf at all, just observe the behavior of the dots on the red/green lines compared to the isochrones.

P.S. I was smoothing those small differences and not placing black dots on them, but people were complaining that the numbers don't add to 360.
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