The pirates are simply criminals of opportunity. Sail out and attempt to grab a ship if it comes into view. If not, sail back home and try again tomorrow.
I surprised that the Naval Forces in the area haven't pulled their collective heads out of their fourth points and instituted the one thing that would stop the pirates cold.
Convoys.
Achmed, Mohammad and the boys in the oversized bass boats wouldn't stand a chance against a 5-20 ship convoy protected by ONE Frigate, Destroyer, or Patrol Ship armed with anything larger then 20mm autocannon. Have designated points (North/East bound, South/West bound) for ships to meet up with an escort vessel. If you want to go it alone, then good luck, but you're on your own, we're not answering 911 calls as all lines are currently busy, please try your call again later.
Should be simple to coordinate, rather then having ships from 10-20 different navies trying not to run into each other as they steam in circles off the Horn of Africa....