naturally, we're stupid that way
It's very distraughtening (is that a word?) to see the big fat tanker you're planning to sink suddenly turn towards you and come straight for you.
they also change course after having travelled a specific distance. I don't know whether they do both, that is to say whether one convoy can change course at both instances.
I'm currently shadowing a convoy that has lost it's juiciest target but still has some fat merchants left for next evening so I'll try to figure it out
I'm sure mr. BigBoyWooly can enlighten us. but maybe he shouldn't because of metagame thinking being bad