Strange Behavior OpenCPN Predictor Line

[Pdxstriper]

Hi,
Referring to the screenshot, I have something weird here with my predictor line(s). My setup is the latest version of OpenCPN on a Windows 11 PC talking to a Vesper 8000. Note that the true direction of my vessel is represented by the line with the longer dashes. The vessel graphic and the shorter dashed line are the problem. As the vessel moves it appears to be crabbing through the water. This is what I see as well as what others see as they track my vessel.

This problem is driving me crazy. It appears to be some setting for an offset/correction of some sort. Does any one know of any setting in either OpenCPN, any OpenCPN plug-in, or the Vesper 8000 that canremedy this situation? Appreciate any ideas.
thanks,
Pete

 

[tiltrider1]

my first guess is the boat is using true north while the heading sensor is on magnetic north.

 

[DDW]

Yes, a difference between heading and course over ground. The latter will be determined from GPS, the former from some boat instrument, perhaps the autopilot. If there is cross current they will not agree, or significant variation in the compass, or different setup as mentioned above. I am using OpenCPN and a Vesper 8000 on my AT34, works fine. I normally have everything set up to use magnetic rather than true.