I am currently working with log files from Expedition to recognize and improve the performance of our boat. However, I do not understand which polar is used to calculate PolBsp and TargBsp or where the difference in calculation is. If I add the same polars to nav, perf and start, TargBsp and PolarBsp are still different. So there is a difference in calculation?

The manual states that Polar Tws % is calculated from the nav Polar (so Polar bsp?) and Targ bsp with the Performance Polar (p. 537/545). But on page 253 it says that Pol bsp is calculated from the Performance Polar.

I have also noticed that -nan(ind) is often logged with PolBsp, but not with TargBsp.

It would be very helpful if someone could explain this to me. Thank you very much!