This isnt sailing related but since polyphasic sleep is being refered to above.
I worked in Taiwan for about 8 years and the custom there is to sleep at lunch time for about 15-20 min. Office workers keep a small pillow for the head down on the desk slumber and on building sites and in factories, you can see pieces of cardboard stored at various places, workers pull them out and lay on them for their snooze. It is quite a universal practice and when foreign customers show up they think it's hilarious seeing the whole building asleep. But I took up the practice too. Put your head down for 15 min after eating lunch means no more drowsiness feeling at 3pm. It is brilliant, I try to practice it today, which I can since my office is at home. No chance to do it in a regular office in Australia, you'd be laughed at.
But there are several practices that only get noticed in the west if there is first a scientific "discovery" for something which is already known about and taken for granted in the East, and polyphasic sleep is one of them.