Page 2 of 2

Re: Vrtool, Vendée and TIMEZONES = version 2.11

PostPosted: Tue Dec 11, 2012 9:33 pm
by par2005
Hi,

2.11 works fine here as well.

Does the case that you cannot use full polars for decent weather routing on vrtool still apply? (read in some old posts).
There are two polar files available in http://www.vrtoutoulz.fr/polars/
Not sure which one to use?

Could somebody (for example omar) share their methods of how you guys use weather routing when sailing? What is the procedure you follow? Do you do any additional manual track planning or simply calculate with weather routing and follow that route? Any particular sequences you follow? I.e. long term route and short term route .. ? Would love to hear all those small details.

Re: Vrtool, Vendée and TIMEZONES = version 2.11

PostPosted: Wed Dec 12, 2012 10:53 am
by omar
par2005 wrote:Does the case that you cannot use full polars for decent weather routing on vrtool still apply?

Yes it does. The so called full polars have one line (a TWA and a bunch of TWS/boatspeed pairs) for each TWA degree. That's 180 lines. The classique polars have one TWA line for each 5 degrees, with a smaller interval (2 degrees) in the close hauled area. Both produce very similar results, since you can interpolate the missing angles in the classique database.

WR algorithm uses the polar chart vertices in the branching process that checks the domain of track possibilities. If you use full polars, a given number branches will cover a much smaller set of tracks than the same number of angles from a classique polar.
This is how it currently works. :roll:

Vrtoutoulz offers both types. Use the classique with interpolation.