There is a slim posibility they spotted my scope. However I only popped it up for a short time, barely above water, and at slow speed (3 knots).
I did pop it up at 5 knots when the track showed the ship was suddenly heading straight for me
I may test this a bit if I can set up a scenario with some set conditions.
Anyone know if the game models reduced passive sonar effectiveness at medium-high speeds? Perhaps it something I can adjust myself.