When both are on overtime, seniority prevails and the senior guy should be able to stay. We fought this battle and won multiple times. If they force the senior guy out, document the fact that the junior guy was on the dock and the exact time that this took place, file a grievance and you'll win. But the dock/part-timers is a different story. If they set their start times up properly, they WON'T be on O/T, so the senior man is going home because of it. Cutting that o/t is their whole intent. Be sure to document everything though, because it took over a year for the grievances to be heard, and it's easy to forget the details.
