Patrol order suspected not working

[Silver1974]

After a number of turns now, I have serious questions as to whether the 'Patrol' move for warships actually works properly. I, and some of my allies, have spent months on patrol, both blockading ports and along a coastline, and never ever found an enemy fleet. Then, when making a normal move to return home, or simply a sea transit in other cases, our fleets do frequently find enemy naval forces