The principles of preventing navigational errors leading to grounding, collision or other ship disasters are beyond the scope of this book.   The specific contributions of health professionals to preventing such events include advice on those aspects of human factors that are related to navigation, for instance the visual requirements and the task demands of work on a ship’s bridge. They may also contribute to recommendations on crewing levels to avoid problems such as fatigue and insufficient time for safe handover between watches. More specifically they will usually be responsible for assessing the medical aspects of fitness for those undertaking safety critical duties, as well as for identifying those likely to have an excess risk of injury associated with the strains of prolonged periods of work at sea.

 The prevention of work related injury to individuals is based on similar risk assessment approaches to those adopted ashore, and needs to be based on an assessment of hazards and risks in the working environment, with steps taken to mitigate them. Practical difficulties arise because of the conditions at sea, with moving decks, slippery surfaces and unguarded or enclosed spaces. Another feature is the command structure on board which may lack the separate safety supervision functions that are common elsewhere., As a consequence the safety culture on board will depend heavily on that adopted by a few senior officers, who are likely to be under economic and operational pressures that may count against ensuring that precautions and training are adequate. In addition, where crews are multi-ethnic, different sub-groups may each have their own conceptions of risk and safety that may be incompatible with one another’s.

 Occupational injuries in fishing are a particular problem because of the conditions of work, such as deck based casting and hauling of gear, the congested presence of fast moving and heavy cables, beams and weights as well as the winches used to move them. Because of their small size, vessels will respond rapidly to sea conditions and decks will also be slippery from fish and other marine debris.

 Rest time is taken at sea and here there are a range of more domestic risks, such as falls and burns from food preparation. Onshore injury risks while in port or during leave periods may also be domestic in character, but their frequency may be raised by the use of alcohol and the location of the vessel in a hazardous harbour area. Inadequate arrangements for access to vessels, especially fishing vessels, are a significant cause of injuries in harbour.

 When injuries arise at sea, the there is usually no immediate access to specialised treatment facilities. Maritime disasters may require evacuation of a ship using lifeboats or other aids. There can be consequential risks of hypothermia and drowning. Modern evacuation systems go some way towards minimising such risks. However, especially on passenger vessels the safe evacuation of passengers, some of whom may have mobility and other limitations calls for physical strength and a positive psychological attitude. Here, health professionals may play a part in determining criteria that will ensure that crewmembers are capable of such tasks.

 High physical and psychological demands will also be made on crew in the event of a fire on board or when emergency repairs are needed. In both cases the ship will be entirely dependent on the training and capabilities of those who undertake such tasks. Firefighting often requires the use of breathing apparatus, which is heavy and where the duration of the air supply will depend on breathing rates – usually higher in the unfits, the overweight and those who are highly anxious. Fitness criteria used at selection, or more practically, meeting the demands on a firefighting training course, are important ways of reducing the risk of inability to respond in an emergency.