>>518975887
>Nuclear subs are noisy as FUG
You have not kept up with modern sub design.

>>518975592
>Type 212CD submarines are undetectable even for the US navy
>>518975592
>could sink
>a US carrier fleet)
Passively listening is not the only way to detect a submarine. Blue-green laser, MAD (magnetic anomaly), and good-old fashioned active SONAR are much better in certain circumstances. Once the non-Nuke boat is detected, it's ability to evade is sharply limited and it goes deaf as it speeds up.
One engagement scenario: Active ping, ASROC torpedo on it's location, helo drops another on its evasion path once it's too fast to hear it.

A non-Nuke boat is essentially a manned CAPTOR mine.