Suggestion: improved spotting system

[neistridlar]

Can you explain what behaviors a suspicious warship would exhibit?

I left that open because I don't have any historical sources to go off. But The first thing that comes to mind is to change course and speed more often. Possibly point the ship towards the suspected location for better sonar performance, maybe send off a ping or two. I'm guessing the escorts would not stray too far from the convoy to investigate though without a firm contact.