Given the B777 range ring on the 40 deg line I imagine that the P3 will be limited in its search time at the extremities of the range ring. Any P3 drivers able to comment. I would suggest an aircraft carrier is going to be the only option unless there can be some descent sat coverage.
Staging out of Cocos Islands should give them good endurance?
http://goo.gl/maps/4cDSX