Assessment of the fixed 4-hours on/8-hours off watchstanding schedule on a surface vessel of the Swedish Royal Navy

Abstract

We assessed the utility of the 3-section, fixed, 4hrs-on/8hrs-off watchstanding schedule on a ship of the Swedish Royal Navy (HSwMS ORIOΝ). Data from the ORIOΝ (n=12 sailors) were compared with data from three USN vessels (n=22). Daily sleep duration, number of sleep episodes/day, and daily work duration were equivalent in the two samples. Compared to their USN peers, however, sailors on the ORION were more alert, reported better sleep quality, less severe insomnia symptoms, and better mood. Also, sailors on the ORION were faster and made fewer errors on the psychomotor vigilance task (PVT). Analysis of daily activities suggests that Swedish sailors may have felt and performed better because sailors working night shifts were allowed to wake up later. Our findings suggest the sailor well-being when standing watch on the fixed 4/8 can be improved when sailors are allowed flexible wake up times in the morning after a night shift.