One way the PBY would be useful is that if it spotted a CV, that boat would then become visible on the map for a given length of time, with its estimated course (say a line just like your own country's CV, but only showing a randomly generated waypoint along its current heading). The position would NOT update unless the PBY maintained contact.
So lets say a Rook Catalina spots a Nit CV about 50 miles outside an airfield and the icon becomes visible, showing the boat headed SE. The PBY shadows the CV for a bit as it approaches its target base before the Nits send up a CAP to shoot it down. The icon would then remain in its last known position, showing its last known course, for the next half hour or so. Meanwhile the Rooks organize a CV-killer strike and head out towards the last reported location and heading, while the Nits, knowing their boat has been spotted, turn the CV.
Now, much like historical CV battles, as the Rooks arrive the CV may not be in its original location, requiring a final position fix.
