One thing that occurred to me - are there sites and maps that show were vessels are? Even submarines? Like with aircraft? Seems as though someone - mil surveillance, satellite - would have been able to see what submarines were in the area at that time. Someone has to know (beside the one who did it).
-—see what submarines: FWIW and for future reference if one of our subs was there no one would know. That’s how we build them and it’s what we do. But this job didn’t require a sub. Not even one with a bottom grabber like the Seadragon or the NR-1 would be used. Certainly not one with an outside diving chamber. Blowing that pipe(s) is just not that complicated.
Only if they are transmitting. If they don’t want to be found they won’t be. Ships not transmitting have to be found on the sea and under it...under it is just harder.
Here’s a ship tracker....some USN ships are on it, but only if they want to be - same with aircraft if the military doesn’t want to be found they aren’t.
Commercial subs will transmit so that 1) they aren’t mistaken for the enemy and 2) they can be found in case something goes wrong. Others not so much.
https://www.marinetraffic.com/en/ais/home/centerx:-76.0/centery:36.9/zoom:8