Neither a P8 or P3 is going to pick up a sunken sub. They track subs using passive listening devices/buoys, although they do have active buoys that they can use to actively track a sub with sonar. Perhaps the passive ones could hear banging on the hull if that was happening. Otherwise I suspect they would need surface ships with specialized gear that can map the bottom with sonar in order to find it. Unless of course there is a "black box" deployed that is giving off a signal.
One slight addition, the P3's have a Magnetic Anomaly Detector (that boom sticking out the back) that can detect a sunken sub if they flew almost directly over it. Not sure what a P8 has for that type equipment.
Neither a P8 or P3 is going to pick up a sunken sub. They track subs using passive listening devices/buoys, although they do have active buoys that they can use to actively track a sub with sonar. Perhaps the passive ones could hear banging on the hull if that was happening. Otherwise I suspect they would need surface ships with specialized gear that can map the bottom with sonar in order to find it. Unless of course there is a "black box" deployed that is giving off a signal.
One slight addition, the P3's have a Magnetic Anomaly Detector (that boom sticking out the back) that can detect a sunken sub if they flew almost directly over it. Not sure what a P8 has for that type equipment.