[jedc]

(former US submariner here)

Also commented downthread, but sonar IS always on at all times. https://news.ycombinator.com/item?id=35780124

Honestly, I'm extraordinarily surprised that the USS San Francisco didn't sink killing everyone onboard. Have you seen the photos? https://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)#/m...

The only reason that the submarine was able to get to the surface and stay there after this was because the damage was just on the port (left) side. Even with that luck, they were only able to stay on the surface because a piece of equipment was able to stay running for several times longer than it was designed to do.

You can read more about it in various places (like here: https://nationalinterest.org/blog/reboot/what-happens-when-s... ) but imagine being at work and suddenly getting thrown toward a wall at 20++mph. Damages and injuries everywhere, and its a miracle only one person died.

[officeplant]

>but sonar IS always on at all times

Yeah completely forgot there is both active and passive sonar.