What if a pirate is targeting a sub when its out of your sonar range. Like if u send ur pirate at a sub that it should catch inside your sonar but he gets an admiral or u lose an outpost so u cant see his sub anymore.

Your pirate would still chase it. If they get an admiral and can make it to their base safely, then your pirate would try to go the long way around the map to dodge it. However, if you simply lose sight the pirate will continue on its path.