Thanks, BigWalleye!
Another question. While playing a bit this am before heading out to work I had a few odd reports. I was crusing on surface, west of Scapa Flow, daylight, clear weather, time compression 512, warning silhouette green. All has been quiet, skies and ocean clear. Suddenly I get the report "we've been spotted", silhouette blinks red for a second and back to green. No reports of ship or plane spotted, no attacks on my sub, nothing else. First couple times I dropped to real time and searched sky and ocean, nothing. Other times (maybe 4 or 5 total) I ignored it and sailed on with nothing happening.

Am I missing something? I don't recall that happening before. I am on my 6th patrol I believe. Running 57% realism.
Also, in my game, on the map, reported contacts are in color. Blue seems to be friendly ships, Green I think is neutral and red are hostile. Is this normal due to my realism settings? I've noticed others on here asking about identifying target ships.