From what iv'e read, subs were harder to detect at periscope depth due to the fact ths sonar was aimed 6% below the surface because the waves would interfere with the signal. And im assuming the hydrophones would share the same restrictions.
Ive tinkered with the sensors and now im not bieng attacked every time i hear a ping, in fact i can tell when i have been detected because there will be a loud ping then a quieter one then its rapid loud pinging. but there have been times they pinged their little guts out and never detected me
On the sensors i noticed there is and active and a passive type, were those actualy supposed to be the same unit and not 2 separate ones? I ask because i set like types to have the same detection cones, and so far my experiences are very close to the ones i have read about.