Re >> "the French Ministry of Defense reported that the submarine had suffered a collision with an βan immersed object (probably a container).β"
and
Re >> "At some point, the two navies compared notes"
I get that ballistic submarines want to stay secret and use passive sonar, instead of active sonar. But I also would have thought - if a submarine mysteriously ran into something under water that they did not expect to be there, that they'd start taking a more "active" approach to figuring out what was going on. It'd be like if I tried to walk blindfolded through a large & empty conference room: if I bumped into a whole wall after walking only 3 or 4 steps, I'd be very confused!
The trouble is whom and how to ask. The submarine world is a giant, international cat and mouse game, and asking around gives away operational details that may involve compromising other things (e.g., special operations deployments) if you say "at exactly X coordinates at time T we bumped into something. Anybody know?"
Also, since the dawn of militaries, much of what occurs is posturing. You want the other side to think you are big, bad, competent professionals. "We ran into something and we don't know what" makes you less superhuman in the eyes of the public and potential adversaries.
It sounds like both subs took damage around their sonar systems, so it's possible they couldn't use active sonar after the collision even if they wanted to.
and
Re >> "At some point, the two navies compared notes"
I get that ballistic submarines want to stay secret and use passive sonar, instead of active sonar. But I also would have thought - if a submarine mysteriously ran into something under water that they did not expect to be there, that they'd start taking a more "active" approach to figuring out what was going on. It'd be like if I tried to walk blindfolded through a large & empty conference room: if I bumped into a whole wall after walking only 3 or 4 steps, I'd be very confused!