[Aktungbby]

TYCZYW! A little required reading: https://fas.org/man/dod-101/navy/docs/fun/part09.htm In a nutshell:

Due to the fact that the principals of sound propagation through the water remain physical constants, in some respects ASW of the future will resemble that of World War II. There will be great differences, however, primarily attributed to the vast improvements in submarine and shipboard quieting technologies. Figure ( ) provides a historical perspective on the relative improvements in source levels of U.S. and Russian submarines. It is clear passive sensing of modern submarines is becoming difficult at best. With no control over target source levels and very little control over ambient noise, it becomes incumbent on systems designers and operators to maximize passive detection thresholds and directivity indices, along with continual implementation of self noise level improvements.

Continued emphasis will be placed on development of new sensor types and radical new concepts applied to current technologies. Some examples of innovation on the research and development forefront include:
- Fiber optic towed array: allowing higher data rates, and longer, lighter cables
- Satellite and aircraft based laser detection: Use of the electro-optic spectrum for ASW detection is receiving much attention. Implementation remains in the distant future, however. - Low frequency active towed arrays: With variable length and depth cables and longer range active sonar sources, the tactical disadvantage of active ASW revealing ownship position is reduced.

...and mind your 'Convergance Zone' at all times https://defence.pk/pdf/threads/tactics-101-anti-submarine-warfare-asw.270380/