Hello,

Targ is the Target TWA, the upwind or downwind target angles. You MUST have these in the polar. Values in parentheses imply tacking or gybing (see the Exp help).

The GFS data is available up to 384 hours (16 days). It will take a while for it to all be made available from NOAA though.

The 'Run time(s)' button will tell you how much is available.

In some cases, the gust field is a surface gust ... which can be lower than the 10m average wind.

Last edited by Nick (11/08/2023 6:56 pm)

Hi Nick --

Thanks for the quick response.  Despite some initial confusion, I think I now understand.  For the benefit of the next user who was confused by this, here's how I now understand it.  

Your polar file contains a table of BSs for combinations of TWA and TWS.  Expedition analyzes your polar file to determine your Target TWA for every wind speed, which is the TWA at which you'll achieve maximum VMG either upwind or downwind at that wind speed.  The routing output table simply shows this calculated optimal TWA for the TWS in each segment.  It has nothing to do with the TWA or TWD of the segment.

Thanks,

Adam




 

Last edited by Saltair (11/09/2023 2:37 pm)

Hi Nick --

I thought I understood it until you mentioned again that we need to specify the target TWA and BSP in the polar.  I think you're saying that of the data points in your polar, one of them must be the target for each TWS and Exp will figure out which of those it is.  But my output file suggests that Exp is doing some interpolation, since my polar file only has data for TWA of 135, 150 and 180 yet my Results file from the router has Targ angles of 179, 134, 138, etc. in it.  What would be causing that if not interpolating to find the actual Target?

Thanks,

Adam

 

Last edited by Saltair (11/10/2023 12:53 am)