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Old 31-07-2017, 10:45   #1
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Polar Plugin questions

I have polars. What's the correct formatting so they can be "loaded" in the Polar plugin?

The speeds and angles I have don't correspond to the plugin's setup.

Are the angles in the Polar Plugin True wind or apparent? Same for wind speeds, true or apparent? I looked but can't find information on it.
Thanks.
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Old 31-07-2017, 10:54   #2
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Re: Polar Plugin questions

Look under weather_routing in the plugin manuals. There is a page of notes I made which is not current, but should help.
https://opencpn.org/wiki/dokuwiki/do...ile_conversion

Also do a search on Polars and Weather_routing there is a string of notes about the particular formatting foibles of polars. It is a loose standard, and to get things working with weather_routing_pi, we need to make sure of certain things about the polar file. Sean and Ptulp have done a lot to make the conversion / transfer of polars more seamless, but you should know more about polars anyway. They are quite easy.

Please upload your polar and identify the boat. Also how did you get these polars?
I have found that polars from VPP programs are good as far as they go, but they must be tested vetted, and adjusted for the actual sails and conditions, so recording separate polars while sailing might be less theoretical.

Normally polars are in TW
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Old 31-07-2017, 11:01   #3
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Re: Polar Plugin questions

Quote:
Originally Posted by rgleason View Post
Look under weather_routing in the plugin manuals. There is a page of notes I made which is not current, but should help.
https://opencpn.org/wiki/dokuwiki/do...ile_conversion

Also do a search on Polars and Weather_routing there is a string of notes about the particular formatting foibles of polars. It is a loose standard, and to get things working with weather_routing_pi, we need to make sure of certain things about the polar file. Sean and Ptulp have done a lot to make the conversion / transfer of polars more seamless, but you should know more about polars anyway. They are quite easy.

Please upload your polar and identify the boat. Also how did you get these polars?
I have found that polars from VPP programs are good as far as they go, but they must be tested vetted, and adjusted for the actual sails and conditions, so recording separate polars while sailing might be less theoretical.

Normally polars are in TW
We're racers, so we're using Polars all the time. I have tables in both True and Apparent so whomever is on deck can see what's going on. These are original polars from the designer. We're going to be recording new ones because we have new sails with radically different designs and materials from the original 1985 designs. But we have to start over with something. In the past we used the performance module in MaxSea. We converted over to OpenCPN because of updating issues with MaxSea. I'm trying to get everything back to baseline. In MaxSea I had a small conversion routine that would convert an XLS file to the correct format for their polar input.
Thanks for the quick reply, by the way.
Robb
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Old 31-07-2017, 14:43   #4
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Re: Polar Plugin questions

Good, so you are familiar with this process. If you are using Windows there is a program that is good for recording nmea0183 data and turning it into polars. It is programmed by Patrick and called "Polauto". The other alternative is to simply use the Polar_pi plugin for recording, or to use the VDR plugin to record it all to a file and then process it.

See this thread Nmea recording device needed
which is the result of being on the Marblehead to Halifax with a full set of beautifully detailed VPP Polars, with various sail sets, but it assumed an asym spinnaker that would go downwind at >150 AWA, which ours did not. Since the VPP Polars are "idealized" anyway, we are going to record our own.

I haven't done this yet, but have thought about it. While you are recording polars, use your log book to write down the start & end of recording date/times with a description of sea conditions, bottom conditions, current, sail sets & details, average wind speed etc. This will help you get good polars. Try to pick consistent conditions.

Perhaps you've done this before?

If you attach your polar file below (under Go advanced) (rename it to doc, if it is too big) I will look at it and show you how to fix it for weather routing.

I recently had to convert the VPP polars in Maxsea format to OpenCPN. It was not difficult.

Do you know about Tactics_pi plugin?
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Old 02-08-2017, 13:21   #5
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Re: Polar Plugin questions

I haven't thought about recording the sea state, but that's an excellent idea. On Lake Superior we don't have the variation nor extremes you guys do back home.

I've tried looking into Tactics_pi but haven't had much luck on finding something I can load without have to create a build.

I'll attach what I have for the polars. they're very basic. I'll give you a couple formats, because I dropped them into a table in Apple Pages.
Thanks,
Robb

PS ok so it doesn't like a csv file...
Attached Files
File Type: doc Wylie Polar Tables.doc (9.3 KB, 17 views)
File Type: xls Wylie Polar Spreadsheet.xls (6.7 KB, 17 views)
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Old 04-08-2017, 03:10   #6
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Re: Polar Plugin questions

Oh, Tactics is still a beta plugin, but its been used for at least 2 years. If you use windows, still don't know, there is an executable in Opencpn beta file thingie. Search for that on google and use rguser and rgpass. Go to the tactics directory and download the file
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Old 09-08-2017, 07:58   #7
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Re: Polar Plugin questions

All,
I am just getting started with OpenCPN on an Rpi on the boat. I went thru the OpenPlotter install process and Polars was one of the plugin's that was already loaded (or available) in OpenCPN.

My question is this; is there anything in polars that tells you how to fill out the polars data? Do I just start sailing as close to the wind as possible and continue falling off until I jybe and then move up the other side? It would be nice if it said something like "sail this heading until data is recorded" and when that happens it changes the heading.

thanks,
Ron
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Old 11-08-2017, 20:06   #8
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Re: Polar Plugin questions

Run O & vdr recording or polat_pi. and try to sail in relatively constant conditions for a reasonable periodvof time (wind, sails sey, sea conditions, no to little tide) Then pick another angle of sail and do the same. Make detailed log with start & end for reference later.
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