The debacle with the Aussie sub was in the late 90's. While I don't doubt our technology has improved some since then I do doubt we know where all their subs are. It wasn't that long ago a NK sub sunk the ROKS Cheonan. That happened during an joint anti-submarine exercise, and the Cheonan was reported to have been using their active sonar at the time.
Save a life. Adopt a greyhound.