I never had the WO spot that far, only to less than 10 km.
That file and data CCIP made for download, is that the values you are using? The MaxRange for visual was only increased to 20 km.
How are you seeing in light fog (which cuts vision) at almost just under 30km?
Are you sure not using Radar? Even the stock radar the Uboat gets is at best is 10 km FuMO391. So I guess no.
What value for Visual MaxRange are you using for Sensors.dat?
I see, 10 km. That is strange. Eat alot of carrots...