Can only comment on the sixties and to this day still think that was the best decade to be at sea. As you point out the shipping companies relaxed the rules a bit due to shortage of labour. Once those bloody ACT ships started I could see the beginning of the end for life at sea as we knew it. Like everything else the more advanced and profitable it becomes the worse it gets for the coal face worker.
That's the way the mop flops.
My thanks to Brian for this site.