When I did my first couple of patrols (GWX 1.03) in the north sea I thought (naively) ships went from port to port in roughly straight direction across the sea, not taking too many detours. And that there had to be some chokepoints or high density locations where most of them pass through. I quickly lost any hope of finding those lanes and areas. In the interest of learning how the mission editor works (Yeah right!!! :hmm:

...

honest ), I took a look at the random layer of the campaign. Trust me, enough uncertainty to life up to it's name, or not to count on meeting some ship somewhere anytime soon. Eventhough the north sea is relatively small, the merchants pretty much go all over the place, and have several forks in their waypoints which they choose randomly. Your best bets are on entrances to harbours and along the coast (same as the pic). But those are obviously protected heavily and eventually behind a mine curtain. GWX 2 can only have this uncertainty maximised. I can only guess as I never played it.
Your mileage may vary.