Fatigue - the silent killer

A culture of poor quality sleep and rest amongst ships’ crews is continuing to cause concern. 

A culture of poor quality sleep and rest amongst ships’ crews is continuing to cause concern. 

In 1989, the devastating Exxon Valdez oil spill in Port William Sound, Alaska dramatically exposed shipping’s pervasive and dangerous disregard for crew sleep and rest. Yet now, more than thirty years later, researchers are still having to publish warnings that commercial pressures, increasing work loads and diminishing manpower within the maritime sector are continuing to create a debilitating cocktail of habitual fatigue amongst crews, which, in turn, is leading to poor decision-making, collisions, injuries, and even death.  

According to a recent report by the International Transport Workers' Federation (ITF), an estimated 25 per cent of marine casualties are attributed to crew fatigue, with one in four seafarers admitting that they have fallen asleep involuntarily whilst on duty.  

The ITF research has also found that almost 50 per cent of seafarers taking part in a study reported working more than 85 hours per week — a pressure the seafarers believe is a danger to both their own safety and the safe operation of their vessels. 

Commercial shipping still runs on a traditional four-hour/eight-hour watch shift system — a pattern, which, according to research published in the BMJ medical journal, can leave seafarers with “alarmingly short sleep periods and reduced sleep efficiency, resulting in psychological strain, burnout and exhaustion”. Compared to those who work on land, the research states, seafarers also have to contend with severely chronic social, psychological, emotional and physical stressors, such as having to live and work within a confined community, separated from their family and friends, often for many months on end. 

Long term stress 

SAN DIEGO, CALIFORNIA - DEC 1, 2017 - Crew areas and berths on the USS Midway CV-41 Aircraft Carrier, San Diego, California 

Cabin on a naval patrol ship (Credit: Shutterstock)

“Stress that goes on for a long time will inevitably become exhausting,” explains consultant clinical psychologist Dr Pennie Blackburn, who worked closely with the ITF on its report.  

“The physical and psychological changes during periods of stress use up a lot of our body’s resources and energy, and when that stress is prolonged or repeated, many of the body’s changes will have longer term effects, such as headaches, general aches and pains, stomach and digestion problems, high blood pressure, poor concentration and difficulty in sleeping.  

“Chronic long term stress has also been implicated in more serious health conditions, such as heart disease and stroke as well as a lowered immune system. The psychological effects, meanwhile, include becoming increasingly short-tempered, restless or anxious, and starting to feel trapped, helpless, withdrawn and depressed. So, for all of these reasons, it is very important that ships’ crews learn to recognise the stresses they are being exposed to, and to take measures to manage it. 

“Although you may not be in control of your shift patterns, there are some simple techniques available that can help you get the best from your sleep whilst at sea. 

“The most important thing is to develop good habits around your sleep in order to help you tolerate the times when your sleep is going to be disturbed. Do what you can to make sure that your cabin is cool, comfortable and quiet. And, importantly, there should also be a clear ship’s policy of quiet around the cabins where people are trying to sleep during the day.” 

Circadian rhythms 

The irregular patterns endured by crews can also, according to the BMJ research, eventually lead to serious disruptions of their circadian rhythm — the body’s natural internal clock linked to periods of daylight and darkness — leading to a general sense of sleepiness whilst on duty and prompting a tendency to seek potentially dangerous shortcuts to complete their tasks as quickly as possible.  

Ironically, during waking hours, the monotonous drone of the vessel’s engine and the continuous rhythmic motion of the ship, especially during calm weather, can also instil a degree of sleepiness amongst all of the crew. On the other hand, high levels of exposure to noise and vibration will also increase a crewmember’s problems whilst trying to sleep. 

Project Martha 

An extensive three-year research programme into seafarer fatigue carried out by Solent University — Project Martha — which was presented to delegates at the IMO's human element, training and watchkeeping committee in 2017, revealed that even when the amount of sleep experienced by seafarers remains constant or only slightly decreased, their quality of sleep will eventually become more and more disturbed over the time-frame of a long voyage, resulting in fitful and fragmented sleep and detrimental health issues, such as cardiovascular and metabolic disorders — putting physically, mentally and emotionally depleted crew at an increased risk of accidents and danger. 

Navy initiatives

USS John McCain 

A collision between USS John McCain and a container ship happened just before dawn, “when the body is normally more fatigued and prone to diminished alertness and degraded performance”.  (Picture credit: Gavin Shields)

Recent examples of fatigue-induced shipping collisions include the Atina incident, off the Louisiana coast in October 2020. However, the one maritime organisation that has been most damaged, and embarrassed, by its inability to provide proper rest and sleep for its crews is the US Navy, which has had to adopt urgent new procedures and research following a series of major accidents. 

In August 2017, the 154m (505ft) destroyer USS John McCain collided with a container ship off the coast of Singapore, resulting in the death of ten of its sailors. An accident investigation report by National Transportation Safety Board, published in 2019, found that the destroyer’s bridge watch team had averaged less than five hours of sleep in the 24 hours before the collision and that the ship’s helmsman at the time was suffering from acute fatigue. The report noted that the collision happened just before dawn, a time that sleep experts “consider to be a circadian low, when the body is normally more fatigued and prone to diminished alertness and degraded performance.” 

New initiatives being trialled by the US Navy to combat crew fatigue include the use of high-tech wearable devices which are able to collect data in order to identify and fine tune ways for its sailors and submariners to sleep more soundly. 

“The US Navy is changing its entire culture around sleep,” explains Nita Shattuck, research professor at the US Naval Postgraduate School, who is leading the service’s new sleep programme. “There’s still more work to be done, but I believe huge inroads are now being made.” 

To become a member of the IMarEST Human Element Working Group, or the IMarEST Seafarer Mental Health & Wellbeing Special Interest Group, log into My IMarEST, click on My Special Interest Groups and then tick the boxes of the SIGs you’d like to join. You can then also join the group(s) on Nexus, our networking platform.    


Dennis O’Neill is a freelance journalist specialising in maritime.