Hours of work at sea: watchkeeping schedules, circadian rhythms and efficiency

This review is concerned with the hours of work of personnel engaged in watchkeeping duties on board ocean-going vessels plying between distant ports. After an introduction to the general problem, existing research findings are considered in the context of the degree of adjustment shown by physiological and performance rhythms to the various watchkeeping systems in use on different types of ship. The findings are discussed in relation to a proposed programme of research aimed at determining the optimal system for maintaining efficiency in crews operating the modern, fully automated vessels now coming into service.