Typically the Merchant Navy watch system divides up our navigation watches between 3 deck officers; chief officer, second officer & third officer. Generally these watches are the same across many types of vessel and place the least experienced officers on watch when the captain is typically expected to be awake. These watches are 4 hours long with 8 hours off which sounds like a good rotation but we have so many other tasks onboard beside a navigation watch.
Once your watch is done, a certain amount of vessel maintenance is expected to be conducted outside of those watch times. The trouble with these ‘four and eight’ watches in my opinion is that they rarely result in anyone getting more that 6 hours sleep per day, when you take into account the maintenance and over-time we are expected to do, meals times and getting up, showered and ready for watch it’s easy to see how over a long trip length that officers can become fatigued especially as there is no such thing as a day off when at sea.
I’m currently working in the offshore industry and typically we have an additional officer onboard so that we can have a doubled up watch when the vessel is in operation using the vessels Dynamic Positioning system (DP). To achieve this, each officer works a 12 hour watch, plus 2 hours overtime so that maintenance can also be covered, I actually find this to be a very good watch system and prefer it to the ‘standard’ watch keeping system as I find I get a good 10-12 hours off so I get genuine downtime and rest. Of course this is only really made possible by the additional officer and many ships simply just don’t have that luxury.
Adjusting to any watch upon joining can be hard and require copious amounts of coffee, personally the watch I find most challenging is 1800-0600 this watch is almost the complete opposite to a normal body clock and depending on what time of the year it is it’s quite possible you can spend a whole trip and never see daylight, this results in perpetual tiredness, can lead to depression in some people and just when you think you have finally adjusted it’s time to go home again!
Studies have shown that it takes a person (on shore), approximately one month to recover from daylight savings time changes or full recovery from jet lag and many ships can change time zones numerous times in a week! This often leads to fatigue and contributes to the difficulties adjusting some sailors face when coming home, especially those whom have spent a long period on night watches. One thing I know for sure is, a sailor can catch up on sleep anywhere!