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12/27/2022 10:23 am  #1


Polar file clarification VMG or BSP?

The polar charts in the ORR certs issued by US Sailing/ORA include values for best VMG angle and the speed directly parallel to the wind, assuming tacking and gybing.  (Update: This is true for their time allowances, but not for their speed forecasts)

Am I correct, however, that the Expedition polar file format provides boatspeed, rather than VMG, in those columns?  That would be consistent with the other columns, of course. 

Last edited by OAXACA (12/29/2022 9:54 am)

 

12/27/2022 11:52 am  #2


Re: Polar file clarification VMG or BSP?

Yes, see the help too.

 

12/28/2022 6:58 am  #3


Re: Polar file clarification VMG or BSP?

Thanks very much.  I did search the help but was not able to nail it down. I'll look harder.

     Thread Starter
 

12/28/2022 1:16 pm  #4


Re: Polar file clarification VMG or BSP?

The Racing/Polars topic.

The first column always contains the Tws values,
Other columns are in pairs of Twa and Bsp (or heel etc),
Twa must increase across a row,
Tws must increase downwards,

Last edited by Nick (12/28/2022 1:16 pm)

 

12/29/2022 9:53 am  #5


Re: Polar file clarification VMG or BSP?

Got it.  I have written a routine that creates, among other things, Expedition polar files from ORR ratings certificates.  I had been laboring under the misimpression that ORR was providing VMG rather than BSP for its "Optimum Run" and "Optimum Beat" columns. In fact, they DO that for their time allowances, but not for their predicted boat speeds. 

So, it's all good.  Now to sit around and gloat at having several hundred extra polars!

     Thread Starter
 

1/01/2023 6:44 pm  #6


Re: Polar file clarification VMG or BSP?

Nick wrote:

The Racing/Polars topic.
Twa must increase across a row,
Tws must increase downwards,

Must or can we just ignore the popup errors?

 

1/04/2023 8:21 pm  #7


Re: Polar file clarification VMG or BSP?

Definitely you must.

 

5/16/2023 5:00 am  #8


Re: Polar file clarification VMG or BSP?

Apologies if I have missed this in the forum or in the Expedition help: What is vmg% threshold in the Upwind and Downwind tables under the Edit function on the Polars tab? The previous nav set this at 90% and Im not sure why? I presume its different from the %day and %night functions on the Polar tab. Thanks!


The original Wild Oats - 4343!
 

5/16/2023 12:33 pm  #9


Re: Polar file clarification VMG or BSP?

It is just for displaying tests on the polars

 

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