It seems you do not know much about naval war games. Do you know what restrictions were placed on the carrier? Do you know if the carrier had to transit a simulated choked point or was other wise was placed in the way of the sub?One of the Aussie subs sunk a USN carrier in war games off the coast of Hawaii a few years back, that is a collins class, which was thought to be obsolete and overly noisy by the time it was commissioned.
It is easy to trot out the periscope pictures and claim "kills" but during war games they are rigged to produce training for both sides.
The Collins class is not obsolete, do some searching on this forum and you will find out just how good they are.