The navy ocean surveillance systems are designed to detect, identify, and track submarines. They do this by integration over time of the acoustics to see beats and harmonics (like a 30 Hz propeller screw). Onetime events, like whale farts or hull implosions require an analyst to know roughly when the event occurred and be looking for it, since there is no further integration of that one time event by definition.
The autonomous detection by these systems has a library of known threats and the frequency signatures of those threats. While this mini sub had electric propellers before its demise, electrics are especially hard to hear, and they were not likely in the signals of interest the navy systems would be looking for.
So, after the fact, someone could come to the navy and say ‘could you look for something peculiar at this time’. But only by going back through the recordings could you possibly find something.
“Many will now be asking why nothing then was investigated!”
Because it was pointless and confirming it for certain might reveal the extent of our analytical capabilities?
If sound was implosion, then they were all dead.
If not, they already knew a pretty specific area where they were.
Leave it to others to confirm.
Implosion was instant, but wonder what 5 aboard the submersible heard during minutes leading up to implosion.
One report the Navy spokesman said they did not report this at the time because they didn’t want to deter rescue operations until the outcome would be self evident. Take it for what it’s worth.