Back in the 60s, my dad, who was not much of a drinker used to claim that half of the captains on the ore carriers were half in the bottle about half of the time. He was probably about half right.
Times were a bit different then, even on the highways. The run from upper Superior to the lower lakes every week for 25 years was a pretty monotonous job, even if it paid pretty well. He claimed it was sometimes difficult to keep captains on that job.
He was not overly critical of them as he understood the difficultly of the job and being away from home most of the year. He just did not appreciate having them in that state when on duty.