Depending on the whim of the Captain of the voyage, the permanent crew follow one of two watch systems. The current voyage has the easy to understand system of six hours on followed by six off. One watch works eight am/pm to two pm/am, and the other works two am/pm to eight am/pm. In the interest of fairness, the watches swap rosters mid-voyage by the devious mechanism of throwing in three four hour watches one night to ensure that there is at least one time in the voyage where all the crew are guaranteed not to get any significant uninterrupted sleep. Presumably to make up for the fact that for the remainder of the voyage they can settle into a consistent twenty-four hour rhythm, one that musicians would recognise as 4/4 time. 

My mistake. There are three watch systems. There is also the Day Watch. On face value this would appear to be preferable, twelve on, then a glorious twelve off for uninterrupted sleep. The slight snag is that in these southern latitudes it doesn’t get dark(ish) until after eleven pm, and the sun starts to reappear at around two thirty. The corresponding definition of “day” is curiously similar to the hours those unfortunate souls on Day Watch appear to be on duty. 

Anyway, back to the six on six off rhythm. The early risers finish their first shift with breakfast, then get up for lunch before starting the 
afternoon shift, finishing by washing up the dinner plates and going to bed. The late risers have breakfast before starting, finish the shift by washing up the lunch bowls, and have dinner before the evening shift, together with a midnight snack of soup and other leftovers from the galley. One gets dawn, the other sunset. In many ways these are like student lifestyles. Some diligent students do their assignments in the evening, then go to bed shortly after midnight to be up early for lectures. Others are out until breakfast, then sleep until lunch. Except it omits the endless parties and involves regular work seven days a week instead of occasional intense all-nighters just before assignments are due. And it involves cleaning and tidying. Both watches get to clean the ship over the night, the difference being the parts of the ships they clean. Both get to mend things. Both get to plead with/blackmail/cajole the soft Voyage Crew on Watch to leave the warmth of the deckhouse to help with the sailing of the boat - not realising that this is actually the highlight of the watch for the permanent crew because even if it is blowing a gale and snowing, it is still an opportunity to take a break from endless chores to do what they actually signed up for.

I tried to imagine which would be preferable. Sleep early and get up the crack of dawn, or work late and sleep through the morning. Hmmm. Can I have Option C? Unless Option C is the Antarctic Day length watch, in which case I like the sound of Option D, whatever that may be. I did a completely unscientific survey of a few select members of the watches as to which they preferred, and unsurprisingly got no consensus.  Some people are morning people, and some are not. But I did learn the importance of Egg Day and how one watch can enjoy it, and the other cannot. For those who have yet to had the pleasure of being (seasick) on the Europa, Egg Days are those days when eggs are served for breakfast - boiled, fried, scrambled or however else the galley is inspired on that 
particular morning, and Egg Days matter in the fifty metre long world that is Europa. One can only eat so much porridge, granola, cornflakes, ham, cheese and jam. The watch coming on duty at eight has to choose between a leisurely breakfast or a few extra minutes sleep. The latter wins, so there is angst in the breakfast line, and stress if there is a queue for the toaster at 7:53. The other watch has no such trauma, they can savour their breakfast. Rather than bolting down a boiled egg on the run - maybe with a slice of bread - they can sit down, make a couple of slices of toast without worrying if there are three people ahead in the toast queue, add lots of butter and wait for it to melt, then lovingly mash egg all over it, season to perfection and then settle back to enjoy it without a care in the world.
Oh, and the watch finishing at eight also gets to enjoy a drink after dinner, but I’m sure that has nothing to do with any preference between the watches...