6 on / 6 off is absolutely ridiculous and governments / IMO should be acting to stop it, at least on the short sea ferries more and more ships are going to 12 on / 12 off, which is not so bad on short sea routes because all of the arrivals and departures break up the monotony a bit, bur watchkeepers should be doing no more than 8 hours per day on watch with and extra time being purely maintenance or admin tasks, every study ever carried out into fatigue has shown that working 6 on / 6 off very quickly leads to a reduction in efficiency. Shipowners know this, governments know this, classification societies know this and yet when accidents happen everyone wrings their hands in horror, points at the poor seafarer and asks "who could you have allowed this to happen?"
I get more and more disillusioned with both the marine industry and the governments which regulate it by the day.