Carrier or sub?
During wartime a sub is tracked much differently than peacetime, you know that. Especially inside of hostile territorial waters.
This was not in hostile waters. It was during a fleet exercise.
The sub in the example given above having popped up next to a carrier, I suspect we had assets, not seen, that knew her exact location all the time.
You 'suspect'? Having been on the 'underwater' side of exercises, I can say that it is a piece of cake for a submarine to sneak up on a carrier. The only defense the carrier has is it's speed.
Do you doubt there was a SSN right behind that ChiCOM sub? Do you think we would reveal to the world the effectiveness of "other" methods to track subs and their little display of hubris meant nothing?