[CA] [CA11] Wind readings become incorrect after a few hours of sailing

[stephen_i_w]

When I first set out sailing, on my Catalina 315, the wind data (wind direction and speed) appear to be correct. The wind instrument reads the same wind direction as the Windex on both the i60 and the e7 MFD.

After a few hours of sailing, the wind readings become incorrect. The readings can be as much as 180 degrees away from the actual wind direction and the wind speed reads as --- on the i60. I also notice that the same incorrect reading for wind direction will be the same on both the e7 MFD and the i60 wind display. When this happens, the wind instrument wind vane and the Windex, atop the mast, still point in the same direction.

I tried rebooting the everything on the network and the error persists. Thinking that a voltage drop might be responsible, I moved the battery selector to draw power from both batteries. The incorrect readings persisted. I started the engine to draw power off of the engine alternator and the incorrect readings still persisted.

The next time I take the boat out, the wind data again reads correctly. This has happened on several trips on my sailboat. I have attached a schematic of my boat's network.

I thank you for any help you can give.