static subs still emits noise?

[Vipper]

I wonder that enemy AI Victor launched couple of torpedoes on me (Improved Kilo) while i was completely standing, engines off, at 130 meters making zero noise. Yet enemy detected and targeted me somehow.

We were very close indeed but still...HOW? And he was moving while targeting. AI cheats?

I reloaded situation again and again and he did find me EVERY TIME.