Fatigue at Sea: A field study in Swedish shipping

The purpose of this study was to collect data about the fatigue level of bridge watch keepers to use for revising earlier sleep models, and devise innovative solutions for the shipping industry. Data collection included interviews with shipping companies and a field study onboard 13 cargo vessels. 32 participants took part in representing two watch systems; 2-watch and 3-watch. Subjective sleepiness and stress estimations were performed once every hour. EOG was used to record eye movement behaviour. Reaction time test was made to examine performance. 3-watch participants are more satisfied with their working hours and working situation. Tendencies indicate that 2-watch participants are a bit more tired, whereas the stress is the same. All are less sleepy and less stressed at home. Time on shift had effect on sleepiness. The highest KSS scores were recorded in the late night and early morning. After night shift the reaction times have higher variance and more long reaction times are present. The mean value after night shift was significantly higher than after day shift. All thirteen shipping companies agreed that officers on the bridge always have tasks sensitive to fatigue but no company experienced fatigue as a problem during normal conditions. All were positive to monitoring devices, mentioning safety matters