Stress and fatigue are common and difficult problems to deal with onboard ships. A range of factors contributes to fatigue. One of the most obvious ones is workload. However, workload is complex; should it be considered in terms of external demands placed on someone or on how an individual subjectively experiences their work? With no good measures of the relationship between external demands, subjective appraisals and physiological indications of stress10 it is actually very difficult to define objective limits. Workload can relate to a short intensive peak period of work - say off-loading and taking on cargo - or to the cumulative effects of a monotonous lengthy sea passage. Thus having too little to do can be just as fatiguing as having too much to do.

 The widespread policy of reduced manning in the shipping industry, an organisational policy that aims to increase efficiency, often made possible through automation10, has produced some high-profile consequences, such as the Exxon Valdez striking Bligh Reef off Alaska, spilling 11 million tons of crude oil over 11,000 square miles. It was found by the US National Transportation Safety Bureau’s accident investigators that the company ’did not adequately consider the increase in workload caused by reduced manning’10 (p 47). However, on a daily basis, the same factors that contributed to the Exxon Valdez accident, are experienced by seafarers around the world, and whether these result in accidents or not, it is likely that they take a more personal toll on at least some seafarers. A range of factors contribute to stress and fatigue at sea and there is much that can be done to monitor and manage these. They include: sleep debt (see below), experience of risk situations, degree of interest and engagement in work activities, diet, fitness and opportunities to move around, the time of day people are working (see below), and the environment.

The Cardiff Fatigue Study impressively indicated the links between fatigue, health and performance, and the association between these and reduced manning practices. A number of striking findings of the study included that 1 in 4 seafarers reported falling asleep on watch; 50% said that they had worked 85 hours a week or more; half said that their working hours had increased over the last ten years; half considered their large number of working hours to present a risk to their personal safety; and 37% felt it posed a danger to the safe operation of their ship11. In a sense then, technological advancements have dictated increased workloads for crews, but these have not been supported by advancements in ameliorating fatigue, monitoring health, or indeed promoting the health and wellbeing of crews.