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Back to SSG 12
Illustration: Tove Svensson
73 per cent admit sleeping on watch
The final reference group meeting in the Fatigue at Sea study was held at the World Maritime University in Malmö, on May 23. The project status and results were presented, followed by a workshop where results and recommendations were discussed.
Margareta Lützhöft, researcher and former captain, is leading the study. The project is a part of the Vinnova Maritime safety programme and is a joint venture between the Swedish National Road and Transportation Research Institute (VTI) and the Karolinska Institute, Sweden’s largest centre for medical research. The project started in the autumn of 2005 and will end in September this year.
Safe manning
The purpose of the study was to collect data about sleepiness, stress and performance levels of watchkeeping officers. On the basis of these results, researchers in cooperation with maritime stakeholders aim to develop solutions to pass on to appropriate instances. The ultimate purpose is to construct solutions that lead to safe manning of ships while acknowledging financial constraints.
Several incidents and accidents can be attributed to fatigue, and a recent study performed by the Swedish Maritime Administration (SMA) indicates that the number may be even larger than reported. In a closed voting session at a Swedish maritime day 73 per cent of the participants (all maritime officers) admitted to having fallen asleep one or more times on watch.
Onshore research in industries and in the traffic environment shows that fatigue is a safety issue, particularly during the night. Fatigue and sleep deprivation do not only contribute to the increased risk of accidents on a short-term scale. There is also evidence of long-term health effects with an increased risk of cardio-vascular problems, an already over-represented health problem among seafarers. The mind is also affected, leading to stress symptoms, lack of concentration and memory degradation.
The Fatigue at Sea study contained an onboard study and a simulator study. 29 deck officers participated in the onboard study, representing both the two-watch and the three-watch system. In the simulator ten seafarers sailed the two different watch systems for six days in a simulated environment as close to reality as possible.
Before the studies, all the officers were asked to answer a questionnaire regarding their work situation and general sleeping pattern. During the study they were monitored with non-invasive instruments to get an objective reading of the participant’s activity level and eye blink behaviour. The duration and frequency of the human eye blink is correlated to stress and sleepiness.
Alarming results
The officers also kept a work and rest log. In the log they were asked to state their level of stress and alertness respectively on the Karolinska Sleepiness Scale (KSS). On the nine-graded scale, grade one represents “very alert” and grade nine “very sleepy, have to fight sleep”. The study showed somewhat alarming results. On 82 occasions, the participants scored KSS seven and above, which – according to the researchers – represent a hazardous state for persons in charge of manoeuvring machinery.
In 38 of these occurrences the score was eight or nine, indicating that during 38 of the studied 1,390 hours, the officer on watch had difficulty not falling asleep while manoeuvring the ship.
In 84 per cent of the occurrences where very high KSS values were scored, the participant worked in a two-watch system.
For the stress scores, the analysis gave no statistically significant results, but a trend towards higher results for the two-watch system was evident.
Not yet complete
The analysis of the data from monitoring the activity level and sleep efficiency has not yet been completed. Preliminary results show that sleep efficiency is around 75 per cent for officers in the two-watch system and 79 per cent for officers in the three-watch system. The findings are low, according to Mats Gillberg at the Karolinska Institute.
“Sleep efficiency should be around 85 to 90 per cent to be considered a good sleep. The values we found here are equal to what we see among people with sleep disturbances”.
The project runs through September, after which the final report will be presented. The research team will also produce a popular science publication directed to the shipping companies and seafarers, where the problem and potential solutions are discussed.
//Cecilia Österman
Latest update 13-06-2007 15:58
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