The only reason these tankerman are having a problem is because one of them thinks he is a “barge captain” and can get away with anything he wants to. He is an obnoxious jerk that is asserting his authority because he can. If the junior tankerman ignores him and stops making an issue out of his being late for watch, the “barge captain” will probably start showing up on time, but find some other way to show he’s the boss.