Why a secret Cold War submarine sinking is hard to conceal

Could a submarine lost to enemy action during the Cold War have been kept secret?

It would be very difficult because implosion noise, hydrophone networks, third-party detection, and the administrative trail of a missing boat create independent evidence.

A submarine loss is not silent because hull failure creates a powerful acoustic event that can travel through the ocean. Cold War listening systems covered strategic passages such as the GIUK Gap, and neutral or allied sensors could record the same incident. The disappearance of a crew and boat would also create personnel, maintenance, and patrol records that many people must explain. Accidental or hostile losses can remain genuine historical mysteries, while a confirmed enemy action would be difficult to hide indefinitely.