Didn't know how the game handles "virtual" and "real" ships.... Thanks!
The recent concern is that late at night before saving the game I was able to see the convoy sonar bearings and had visual contact matching the bearings in the F11 view, but decided to save the game and go to bed instead of prosecuting the attack... When I reload the saved game the next night in the F3 map view, the sonar bearings are present, but the F11 view is empty and after a minute or two the F3 sonar tracks simultaneously dissolve to a blank map...
