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Friday, 12 November 2010

Fatigue at Sea (LLLLOOOOng POST)

Many decades ago, there was once an uproar over the quality of food on trains as well as separately, the quality of service by telephone operators in India. Since both were Government monopolies, the matter went all the way to the top, and in due course of time, a very precise response was returned, which said that, inter-alia, basis the number of passengers who travelled everyday and the number of phone calls made everyday, the number of complaints was very small. Which further then implied that all was fine. All is well.

Mathematically, this was certainly correct, but all of us know what the quality of railway food and telephone servcies used to be like - regardless of whether we made a complaint or not. All was certainly not well, but most of us chose to keep quiet and ignore matters, suffering the consequences.

Likewise, there is absolutely no co-relation between the number of hours worked at sea in a year by all seafarers and the number of complaints for fatigue by a seafarer, truth be told - if your shipmate prefers a medical visit with a complaint for "fatigue", then other than being laughed out of the smoke-room, he will also probably never be given a job again.

So, when I first discussed this subject of fatigue with batchmates and friends in the ship-management and ship-owning business, I was told variously that:-

a) It was not macho to be concerned about complaints of fatigue on board; after all, life ashore was not easy either, and life on ships was not for the weak and faint-hearted.

b) Any attempt to even try to quantify actual working conditions on board would misfire, since other nationalities were willing to send their people to work even longer hours.

At the root of everything, ofcourse, is the rather controversial 98 hours per week status. As has often been reported, the Merchant Navy is probably the only profession in the world where people have to falsify their work-sheets to show that they have not worked over 98 hours. That, incidentally, is a higher number than most airline crew end up working in the course of a month.

So here are some more fatigue at sea statistics, gathered from a variety of sources:-

# The average sleep duration for mariners at sea is 6.6 hours per 24-hour cycle, in the course of a typical 4 month contract.

# Watchkeepers at sea obtain their sleep in fragments, median time achieved here is less than 5 hours at a stretch.

# The 4-8 watchkeeper has it worst, getting less than a total of 4 hours of sleep for about a quarter of the days on board.
(Source:- Work hours, sleep patterns and fatigue among merchant marine personnel:-


1 Battelle Seattle Research Centre, Seattle, WA, USA 2 United States Coast Guard Research and Development Centre Groton, CT, USA )


Getting straight to the views of governance in India, here is what Mr. P.H. Krishnan, deputy director-general of shipping, said to the newspaper DNA, on the high stress levels and disasters at sea:-

Q:- Every-time there is an accident (now mv Rezzak has gone missing off the Turkish coast) on the high seas, there are theories about how high-stress levels among sailors act as a contributing factor to the disasters. Is there a direct correlation?

A:- Yes, there is. Sailors on board merchant vessels remain on the high seas for six months at a stretch. Internal surveys have revealed that there is a high degree of fatigue among a 16- or 17-member ship crew. Also, there is a dearth of effective co-ordination and communication among the crew as they come from various ethnic backgrounds. All the above factors cumulatively lessen response capabilities in the sailors in times of emergencies, leading to the heightened possibility of disasters due to poor manoeuvring and navigation of the ship.

So now we know what the Government, the same one that ratifies conventions leading to 98 hour working weeks on ships, has to say.


According to the International Maritime Organization (IMO) "fatigue can be defined in many ways. However, it is generally described as a state of feeling tired, weary, or sleepy that results from prolonged mental or physical work, extended periods of anxiety, exposure to harsh environments, or loss of sleep. The result of fatigue is impaired performance and diminished alertness."



There is no universally accepted technical definition for fatigue. However, common to all the definitions is degradation of human performance. The following definition is found in IMO’s MSC/Circ.813/MEPC/Circ.330, List of Human Element Common terms: “A reduction in physical and/or mental capability as the result of physical, mental or emotional exertion which may impair nearly all physical abilities including: strength; speed; reaction time; coordination; decision making; or balance.”


Some inputs from the Exxon Valdez case, now over two decades old, details of which are available free of copyright on the Internet.

One of the findings of the Exxon Valdez (1989) investigation conducted by the U.S. National Transportation Safety Board (NTSB) was that "there were no rested deck officers on the Exxon Valdez available to stand the navigation watch when the vessel departed from the Alyeska Terminal." It is interesting at this time to note that regulations already existed mandating rest periods for watchstanders. With this in mind, the NTSB report recommended "rigorous" enforcement of current regulations concerning watchstander time off, as well as increasing manning levels . . . this report also addressed the growing tendency toward reducing crew sizes by stating the "Exxon Shipping Company manning policies do not adequately consider the increase in workload caused by reduced manning."

It is interesting to observe that the concept of fatigue weighs so heavily in recent maritime accident investigations that almost all reports on accidents at sea invariably contain a section on fatigue, even if fatigue played little or no role.


Adopted on 20 November, 1973, IMO Resolution A.285(8), Recommendation on Basic Principles and Operational Guidance Relating to Navigation Watchkeeping, only briefly mentioned fatigue in Annex A(b)(ii) when talking about fitness for duty by stating that "The watch system shall be such that the efficiency of the watchkeeping members of the crew is not impaired by fatigue. Accordingly the duties shall be so organized that the first watch at the commencement of a voyage and the subsequent relieving watches are sufficiently rested and otherwise fit when going on duty."

That sounds very nice. But in actual fact, what does it mean?


IMO issued Resolution A.772(18) on 4 November 1993, entitled Fatigue Factors in Manning and Safety, which was an entire 4 page document dedicated to defining fatigue, identifying specific shipboard related fatigue factors and tasking shipboard management with specific responsibilities in mitigating these factors.

It must be recognized that the seafarer is a captive of the work environment. Firstly, the average seafarer spends between three to six months working and living away from home, on a moving vessel that is subject to unpredictable environmental factors (i.e. weather conditions). Secondly, while serving on board the vessel, there is no clear separation between work and recreation. Thirdly, today’s crew is composed of seafarers from various nationalities and backgrounds who are expected to work and live together for long periods of time. The operational aspects associated with shipping become more complex compared with standard industries, for reasons such as: variety of ship-types, pattern and length of sea passage, port-rotation, and length of time a ship remains in port. All these aspects present a unique combination of potential causes of fatigue.

The most common causes of fatigue known to seafarers are lack of sleep, poor quality of rest, stress and excessive workload.

A. Crew-specific Factors

The crew-specific factors are related to lifestyle behavior, personal habits and individual attributes. However, fatigue varies from one person to another and its effects are often dependent on the particular activity being performed.

The Crew-specific Factors include the following:

• Sleep and Rest:- - Quality, Quantity and Duration of Sleep, - Sleep Disorders/Disturbances, - Rest Breaks
• Biological Clock/Circadian Rhythms
• Psychological and Emotional Factors, including stress:- - Fear, - Monotony and Boredom
• Health:- - Diet, - Illness
• Stress:- - Skill, knowledge and training as it relates to the job, - Personal problems, - Interpersonal relationships
• Ingested Chemicals:- - Alcohol, - Drugs (prescription and non-prescription), - Caffeine
• Age
• Shiftwork and Work Schedules
• Workload (mental/physical)
• Jet Lag

B. Management Factors (ashore and aboard ship)

The Management Factors relate to how ships are managed and operated. These factors can potentially cause stress and an increased workload, ultimately resulting in fatigue. These factors include:

1. Organizational Factors

• Staffing policies and Retention, Role of riders and shore personnel, Paperwork requirements, Economics, Schedules-shift, Overtime, Breaks; Company culture and Management style, Rules and Regulations, Resources, Upkeep of vessel, Training and Selection of crew.

2. Voyage and Scheduling Factors

• Frequency of port calls, Time between ports, Routing, Weather and Sea condition on route, Traffic density on route, Nature of duties/workload while in port.

C. Ship-specific Factors

These factors include ship design features that can affect/cause fatigue. Some ship design features affect workload (i.e. automation, equipment reliability), some affect the crew’s ability to sleep, and others affect the level of physical stress on the crew (i.e. noise, vibration, accommodation spaces, etc.). The following list details ship-specific factors:

• Ship design, Level of Automation, Level of Redundancy, Equipment reliability, Inspection and Maintenance, Age of vessel, Physical comfort in work spaces, Location of quarters, Ship motion, Physical comfort of accommodation spaces.

D. Environmental Factors

Exposure to excess levels of environmental factors, e.g. temperature, humidity,excessive noise levels, can cause or affect fatigue. Long-term exposure may even cause harm to a person’s health. Furthermore, considering that environmental factors may produce physical discomfort, they can also cause or contribute to the disruption of sleep.

Ship motion is also considered an environmental factor. Motion affects a person’s ability to maintain physical balance. This is due to the extra energy expended to maintain balance while moving, especially during harsh sea conditions. There is a direct relation between a ship’s motion and a person’s ability to work. Excessive ship movement can also cause nausea and motion sickness. Environmental factors can also be divided into factors external to the ship and those internal to the ship. Within the ship, the crew is faced with elements such as noise, vibration and temperature (heat, cold, and humidity). External factors include port and weather condition and vessel traffic.


A. Sleep

Sleep is an active process; when people sleep they are actually in an altered state of consciousness. All sleep does not have the same quality and does not provide the same recuperative benefits. In order to satisfy the needs of the human body, sleep must have three characteristics to be most effective:

• Duration: Everyone’s sleep needs are unique; however, it is generally recommended that a person obtain, on average, 7 to 8 hours of sleep per 24-hour day. A person needs the amount of sleep that produces the feeling of being refreshed and alert. Alertness and performance are directly related to sleep. Insufficient sleep over several consecutive days will impair alertness. Only sleep can maintain or restore performance levels.

• Continuity: The sleep should be uninterrupted. Six one-hour naps do not have the same benefit as one six-hour period of sleep.

• Quality: People need deep sleep. Just being tired is not enough to ensure a good sleep. An individual must begin sleep in synch with the biological clock to ensure quality sleep. If the time of sleep is out of synchronization with his/her biological clock, it is difficult to sleep properly.

B. Biological Clock and Circadian Rhythm

Each individual has a biological clock, and this clock regulates the body’s circadian rhythm. To best understand both of these features, it is first necessary to understand how the circadian rhythm functions. Our bodies move through various physical processes and states within a 24-hour period, such as sleeping/waking, and cyclical changes in body temperature, hormone levels, sensitivity to drugs, etc. This cycle represents the circadian rhythm. The biological clock regulates the circadian rhythm. The biological clock is perfectly synchronised to the traditional pattern of daytime wakefulness and night-time sleep.

For many seafarers, working patterns conflict with their biological clock. Irregular schedules caused by shifting rotations, crossing time zones, etc. cause the circadian rhythms to be out of synchronization.

C. Stress

Stress occurs when a person is confronted with an environment that poses a threat or demand, and the individual becomes aware of his/her inability or difficulty in coping with the environment (a feeling of being overwhelmed). This can result in reduced work performance and health problems.

Stress can be caused by a number of things, including:

• Environmental hardships (noise, vibration, exposure to high and low temperatures, etc), Weather (i.e. ice conditions), Personal problems (family problems, home sickness, etc.), Broken rest, Long working hours, On-board interpersonal relationships.

Fatigue is dangerous in that people are poor judges of their level of fatigue. The following is a sample of fatigue’s known effect on performance.

• Fatigued individuals become more susceptible to errors of attention and memory (for example, it is not uncommon for fatigued individuals to omit steps in a sequence).

• Chronically fatigued individuals will often select strategies that have a high degree of risk on

Fatigue can affect an individual's ability to respond to stimuli, perceive stimuli, interpret or understand stimuli, and it can take longer to react to them once they have been identified. Fatigue also affects problem solving which is an integral part of handling new or novel tasks. Fatigue is known to detrimentally affect a person’s performance and may reduce individual and crew effectiveness and efficiency; decrease productivity; lower standards of work and may lead to errors being made. Unless steps are taken to alleviate the fatigue, it will remain long after the period of sustained attention, posing a hazard to ship safety.

One very important fact to remember is that people who are experiencing fatigue have a very difficult time recognizing the signs of fatigue themselves. It is difficult for a number of reasons, but largely because fatigue can affect your ability to make judgements or solve complex problems. The following list describes how fatigue affects your mind, emotions and body; you may recognize some of these changes in others (with time, you may learn to identify some within yourself):

A. Physically:

• Inability to stay awake (an example is head nodding or falling asleep against your will)
• Difficulty with hand-eye coordination skills (such as, switch selection)
• Speech difficulties (it may be slurred, slowed or garbled)
• Heaviness in the arms and legs or sluggish feeling
• Decreased ability to exert force while lifting, pushing or pulling
• Increased frequency of dropping objects like tools or parts
• Non-specific physical discomfort
• Headaches
• Giddiness
• Heart palpitations / irregular heart beats
• Rapid breathing
• Loss of appetite
• Insomnia
• Sudden sweating fits
• Leg pains or cramps
• Digestion problems

B. Emotionally:

• Increased willingness to take risks
• Increased intolerance and anti-social behaviour
• Needless worry
• Reduced motivation to work well
• Increased mood changes (examples are irritability, tiredness and depression)

C. Mentally:
• Poor judgement of distance, speed, time, etc.
• Inaccurate interpretation of a situation (examples are focusing on a simple problem or failing to anticipate the gravity of the situation or failing to anticipate danger)
• Slow or no response to normal, abnormal or emergency situations
• Reduced attention span
• Difficulty concentrating and thinking clearly
• Decreased ability to pay attention

Food (timing, frequency, content and quality) Refined sugars (sweets, doughnuts, chocolates, etc.) can cause your blood sugar to rise rapidly to a high level. The downside of such short-term energy is that a rapid drop in blood sugar can follow it. Low blood sugar levels can cause weakness, instability and difficulty in concentrating and in the extreme case unconsciousness. Eating large meals prior to a sleep period may disrupt your sleep.


Now, here are the rules under which, using some cleverly worded options, an active seafarer is presented with a 98-hour work-week on board, when actually, a work week should never have exceeded 91 hours in a week. However, having said that, we need to look closely at Article 5 Paragraph 6:- what are the National Laws for hours of work at the workplace, and why can't these be implemented on Indian ships or even those ships visiting Indian ports?

ILO Convention 180

Art.5 paragraph 1. The limits on hours of work or rest shall be as follows: (a) maximum hours of work shall not exceed: (i) 14 hours in any 24-hour period; and (ii) 72 hours in any seven-day period; or (b) minimum hours of rest shall not be less than: (i) ten hours in any 24-hour period; and (ii) 77 hours in any seven-day period.

Art. 5 paragraph 2. Hours of rest may be divided into no more than two periods, one of which shall be at least six hours in length, and the interval between consecutive periods of rest shall not exceed 14 hours.

Art. 5 paragraph 6. Nothing in paragraphs 1 and 2 shall prevent the Member from having national laws or regulations or a procedure for the competent authority to authorize or register collective agreements permitting exceptions to the limits set out. Such exceptions shall, as far as possible, follow the standards set out but may take account of more frequent or longer leave periods or the granting of compensatory leave for watchkeeping seafarers or seafarers working on board ships on short voyages.

Art. 7 paragraph 1 Nothing in this Convention shall be deemed to impair the right of the master of a ship to require a seafarer to perform any hours of work necessary for the immediate safety of the ship, persons on board or cargo, or for the purpose of giving assistance to other ships or persons in distress at sea.

Art.7 paragraph 3 As soon as practicable after the normal situation has been restored, the master shall ensure that any seafarers who have performed work in a scheduled rest period are provided with an adequate period of rest.


And here's what the STCW convention has to say about things:-

STCW Convention

Section A-VIII/1 of the STCW Code (Mandatory)

1. All persons who are assigned duty as officer in charge of a watch or as a rating forming part of a watch shall be provided a minimum of 10 hours rest in any 24-hour period.

2. The hours of rest may be divided into no more than two periods, one of which shall be at least 6 hours in length.

3. The requirements for rest periods laid down in paragraph 1 and 2 need not be maintained in the case of an emergency or drill or in other overriding operational conditions.

4. Notwithstanding the provisions of paragraphs 1 and 2, the minimum period of ten hours may be reduced to not less than 6 consecutive hours provided that any such reduction shall not extend beyond two days and not less than 70 hours of rest are provided each seven day period.

5. Administrations shall require that watch schedules be posted where they are easily accessible.

3. In applying regulation VIII/1, the following should be taken into account:

.1 provisions made to prevent fatigue should ensure that excessive or unreasonable overall working hours are not undertaken. In particular, the minimum rest periods specified in Section AVIII/1 should not be interpreted as implying that all other hours may be devoted to watchkeeping or other duties;

.2 that the frequency and length of leave periods, and the granting of compensatory leave, are material factors in preventing fatigue from building up over a period of time;

.3 the provisions may be varied for ships on short-sea voyages, provided special safety arrangements are put in place.



Article 11

1. Every ship to which this Convention applies shall be sufficiently, safely and efficiently manned, in accordance with the minimum safe manning document or an equivalent issued by the competent authority.

2. When determining, approving or revising manning levels, the competent authority shall take into account:

(a) the need to avoid or minimize, as far as practicable, excessive hours of work, to ensure sufficient rest and to limit fatigue; and

(b) the international instruments identified in the Preamble.



Article 13

The shipowner shall ensure that the master is provided with the necessary resources for the purpose of compliance with obligations under this Convention, including those relating to the appropriate manning of the ship. The master shall take all necessary steps to ensure that the requirements on seafarers' hours of work and rest arising from this Convention are complied with.


Case reports:-

chief maritime investigator, UK, Stephen Meyer in his annual report, said:-

"With only two watchkeepers, even if they did nothing but their bridge watches, they would work an 84-hour week," Mr Meyer said. "But with routine paperwork, cargo work, maintenance, entering and leaving harbours, inspections, loading/unloading, passage planning etc., their actual working hours are much longer. "It is an anachronism in the 21st Century, that seafarers are falsifying their timesheets to prove that they are working only a 98-hour week."


Case Study from the Chemical Trade

V/1 loaded from Malaysian and Indonesian ports arrived Europe with heated cargo of different grades of palm oil in winters. En-route passage nothing much except Suez transit and heating of cargo. Total passage to N. Europe is about 25 days. After coming along side v/l will be discharging 4 parcels along side and 4 parcels to coasters. Head office kept well informed about berths and coaster arrival schedules. Coasters are arranged by owners and as per instructions received should not have any delay when coming alongside for loading. Boarding supervisor on board to monitor cargo operations and tank cleaning. Any slackness on part of crew is added as remarks in report. Total crew on board includes Chief Officer, 2 duty officers, 3 ABs, 1 OS, Pump man, Boson and two cadets. Due to hectic schedule and freezing nature of cargo chief officer is all the time in CCR to monitor cargo operations. Duty officers are continuously on six on six off. Crew are distributed as follows: 06:00 - 12:00, 18:00 - 24:00 - Pumpman, AB1, AB2, Cadet; 12:00 - 18:00, 00:00 - 06:00 - Boson, AB3, OS, Cadet.

Except for fatty acids all cargoes require squeezing while stripping. This requires crew to go inside hot tanks and do manual squeezing. Coils are hot and tanks are slippery. Any delay in squeezing can freeze cargo at bottom and this can lead to ROB or delay by several hours in discharge of cargoes. From each watch pump man and 1 cadet stay on top for operations and crew go inside for squeezing. But with only 2 crewmembers it is not possible to complete squeezing. View this all crew members (including off watch are called for squeezing tanks). It is important to give gap in stripping of tanks however at times gap can't be more then 15mins and immediately on completion crew has to enter into another tanks. Work load increases in case cargo stops going due to freezing when level of cargoes goes below heating coils. On completion of discharge v/l to proceed to North Sea for tank cleaning. Next cargo is chemicals including some fine chemicals like Paraxylene, MEK, Acetone, Iso-Butane etc. Loading to take place in 3 consecutive ports. Time allocated for cleaning of 28 tanks is 4 days. To wash tanks with hot water followed by detergent and finally rinsing. Duty officer can't participate in tank cleaning view they are doing navigational watches. Chief Officer after completion of discharge is busy with tank cleaning schedule. Almost 3 days go in washing tanks and one day to prepare tanks for loading. Once about to complete you plan to return back for loading to avoid any delays. Tank cleaning involves manual cleaning after initial pre wash to remove traces of last cargo. Sometimes acid tanks need re-cleaning if not properly cleaned. Once again prior to arrival you will receive schedule of berth rotation and coasters in first loading port. Immediately on arrival Surveyors come on first berth to take wall wash tanks to avoid delays at other berths. This shifting on berth and loading takes about 3 days in port. After loading v/l to proceed to two other nearby loading ports. After first port, pressure reduces as number of tanks to be loaded reduces. Total Discharge-Tank Cleaning and back loading takes about 12 days. So in all, those 12 days of tank cleaning and back loading is full of work with no proper rest! Rest hours violation becomes common. With so much work in hand one has to worry about tank passing by surveyors and reports given by the boarding supervisor!!

On chemical tanker additional duty officer should be a must, who can assist chief officer in tank cleaning operations.

Nautical Institute Fatigue Forum Report, 06/001


The results of a 6 year research programme into seafarer fatigue, Seafarer Fatigue: The Cardiff Research Programme were published in November 2006. Adequate Crewing and Seafarer Fatigue: The International Perspective has just been released. The first of these reports, supported by the UK Maritime and Coastguard Agency, the Health and Safety Executive, Nautilus UK and the Seafarers' Research Centre, Cardiff seeks to predict worst-case scenarios for fatigue, health and injury; to develop best practice recommendations appropriate to ship type and trade and to produce advice packages for seafarers, regulators and policy makers.

The research took the form of a literature review, a survey of 1,856 seafarers, diary studies and objective testing on board. In addition to the clear confirmation that fatigue is a very real problem at sea, the studies also exposed a tendency of many seafarers to under-record their working hours. Major findings: n One in four seafarers said they had fallen asleep while on watch Almost 50% of seafarers taking part in the study reported working weeks of 85 hours or moren Around half said their working hours had increased over the past 10 years, despite new regulations intended to combat fatigue and Almost 50% of seafarers taking part in the study consider their working hours present a danger to their personal safety n Some 37% said their working hours sometimes posed a danger to the safe operations of their ship Many reported that they had worked to the point of collapse and fallen asleep at the wheel and over half of the sample believed that their personal safety was at risk because of fatigue.

(Seafarer Fatigue: The Cardiff Research Programme.)


The 1989 grounding of the Exxon Valdez caused the release of 11.2 million gallons of crude oil. It was a true environmental disaster, the world's worst ever oil spill. The US National Transportation Safety Board later determined that the probable causes included “the failure of the third mate to properly manoeuvre the vessel because of fatigue and excessive workload” and “the failure of the Exxon shipping company to provide a fit master and a rested and sufficient crew for the Exxon Valdez”.

A typical example of watchkeeper fatigue occurred at 05:15 on a June morning when a 1,990gt general cargo vessel ran aground on the west coast of Scotland. The chief officer had been on watch since midnight and was suffering the cumulative effects of fatigue generated by the 6 on 6 off watchkeeping routine punctuated by regular port visits where he was expected to oversee all cargo operations. The chief officer fell asleep standing at the controls between 04:05 and 04:15 and missed a planned alteration of course. He woke an hour later, still standing, as the vessel grounded.


Studies show that there are comparable effects between fatigue and alcohol intake on a persons ability to function. Guidance in the STCW Convention (Section B-VIII/2 part 5 – annex 5) prescribes a maximum of 0.08% blood alcohol level during watchkeeping and prohibits the consumption of alcohol 4 hours before a watch. A number of States are planning initiatives to further limit alcohol intake on board and many shipowners already operate vessels with total bans. Curiously, although studies have established that fatigue is prevalent at sea and that its effects are in fact worse than those caused by alcohol, there would appear to be much less enthusiasm within the industry for addressing the problem of fatigue.

Fatigue, Alcohol and Performance Impairment Reduced opportunity for sleep and reduced sleep quality are frequently related to accidents involving shift-workers. Poor-quality sleep and inadequate ecovery leads to increased fatigue, decreased alertness and impaired performance in a variety of cognitive psychomotor tests. However, the risks associated with fatigue are not well quantified. Here we equate the performance impairment caused by fatigue with that due to alcohol intoxication, and show that moderate levels of fatigue produce higher levels of impairment than the proscribed level of alcohol intoxication. Forty subjects participated in two counterbalanced experiments. In one they were kept awake for 28 hours (from 8:00 until 12:00 the following day), and in the other they were asked to consume 10- 15g alcohol at 30-min intervals from 8:00 until their mean blood alcohol concentration reached 0.10%.

We measured cognitive psychomotor performance at half-hourly intervals using a computer-administered test of hand-eye coordination (an unpredictable tracking task). Results are expressed as a percentage of performance at the start of the session. Performance decreased significantly in both conditions. Between the tenth and twenty-sixth hours of wakefulness, mean relative performance on the tracking task decreased by 0.74% per hour. Regression analysis in the sustained wakefulness condition revealed a linear correlation between mean relative performance and hours of wakefulness that accounted for roughly 90% of the variance. Regression analysis in the alcohol condition indicated a significant linear correlation between subject's mean blood alcohol concentration and mean relative performance that accounted for roughly 70% of the variance. For each 0.01% increase in blood alcohol, performance decreased by 1.16%. Thus, at a mean blood alcohol concentration of 0.10%, mean relative performance on the tracking task decreased, on average by 11.6%. Equating the two rates at which performance declined (percentage decline per hour of wakefulness and percentage decline with change in blood alcohol concentration), we calculated that the performance decrement for each hour of wakefulness between 10 and 26 hours was equivalent to the performance decrement observed with a 0.004% rise in blood alcohol concentration.

Therefore, after 17 hours of sustained wakefulness (3:00) cognitive psychomotor performance decreased to a level equivalent to the performance impairment observed at a blood alcohol concentration of 0.05%. This is the proscribed level of alcohol intoxication in many western industrialized countries. After 24 hours of sustained wakefulness (8:00) cognitive psychomotor performance decreased to a level equivalent to the performance deficit observed at a blood alcohol concentration of roughly 0.10%. Plotting mean relative performance and blood alcohol concentration 'equivalent' against hours of wakefulness, it is clear that the effects of moderate sleep loss on performance are similar to moderate alcohol intoxication. As about 50% of shift-workers do not sleep on the day before the first night-shift, and levels of fatigue on subsequent night-shifts can be even higher, our data indicate that the performance impairment associated with shift-work could be even greater than reported here. (Nature, Volume 388, July-August 1997 )


Strong association between fatigue and accidents:-

Accident statistics show a strong association with factors that increase the risk of fatigue, such as under manning and long working hours.

Objective measures of performance efficiency are also influenced by fatigue and this suggests that it is not just watch-keepers who are likely to be affected but other members of the crew as well. Fatigue increases human error which not only increases the risk of collisions or groundings but also increases the risk of personal injury and injury to others. A recent MAIB report of an accident in which an A/B tragically died determined that the seafarer was crushed due to unsafe equipment design, lack of appropriate training and insufficient maintenance. However, the comments regarding manning levels and hours of rest make for interesting reading: Complement of Neermoor had a total crew of six, comprising master, mate, chief engineer, two AB deckhands and an OS/cook. At sea, the master and mate worked 6 on/6 off navigational watches, with the master keeping the 6 - 12 watches and the mate the 12 - 6 watches.

The two ABs were employed on deck and as lookouts as required, assisted by the OS/cook when he was not busy with his catering duties. The chief engineer was solely responsible for the engine room and other technical issues. The crew were all serving on short term renewable contracts, arranged through a third-party manning agency. This complement was in accordance with the minimum manning level specified in the vessel's MSMC. However, the ship had previously operated with a crew of 7… Hours of rest records Although hours of rest records were kept on board Neermoor, the records for the week preceding the accident were not available at the time of the accident, and they have not since been produced. While full details of crew hours just before the accident are not available, conclusions have been drawn from logbook entries, voyage reports and other sources.

The master and mate, as the only two navigating officers on board, worked a 6-on/6-off watchkeeping routine while on passage. In addition, they were required to work standby periods for arrival and departure from port, as well as administrative/ship's business and cargo related duties while in port. The crew had a similar workload, as shown by the narrative of this accident. After the short passage from Dordrecht to Southampton, they were required for arrival and then berthing duties. The logbook shows that a security watch, in accordance with the requirements of the ISPSC, was maintained during the time spent discharging in Southampton. Once they had completed their unberthing duties, the ABs were set to work cleaning the hold; this took most of the night and they were barely finished on arrival at Teignmouth. from the MAIB investigation of the fatal accident due to collapse of a portable bulkhead onboard mv Neermoor at Teignmouth, UK on 27 April 2006.


Fatigue was clearly established as the principal causal factor in the case of an 80m long bulk carrier, which ran aground on rocks in the Western Islands of Scotland at 01:50 on an October morning. The vessel only had two watchkeeping officers including the master. Towards the end of his 18:00 to 24:00 watch, the master left the bridge and called the chief officer to relieve him. He returned to the bridge, plotted a position on the chart and sat in the wheelhouse chair to await the arrival of his relief. He fell asleep, and the chief officer remained asleep in his cabin. They both woke up as the vessel grounded. There had been no watch alarm fitted to the vessel and there had been no seaman on lookout duty.

In the previous 4 days, the master and the chief officer's workload had been arduous and they had not achieved more than 6 hours off duty at any one time. The quality of sleep during some of their rest periods had also been poor because of the uncomfortable movement of the ship in a seaway. In port, their off-duty periods had been disrupted by the need to shift berths because of cargo loading requirements, and at sea the pressures of paperwork and meal times affected their ability to rest. (MAIB Bridge Watchkeeping and Safety Study, 2004)


A growing cause for concern. In recent years, the Association has noted an increase in incidents involving crew members who appear to be suffering from some form of psychological difficulty. This can range from mild anxiety attacks to aggressive behaviour to fellow crewmembers, including extreme physical violence. More tragically it can lead to suicide. It is not clear what the main causes are, but a possible factor is the length of time spent away from home and sometimes an inability to get relieved from a ship. At the same time, there may be family pressure to remain at sea longer in order to earn more money and continue sending funds home. In the modern world of shipping, turnaround times in port are also much quicker, creating more work for both officers and crew and less opportunity to relax, resulting in fatigue and stress… (North of England P&I Club, Signals Issue: 64 July 2006)


So, what's it like with fatigue and you, at sea or ashore?


The way forward

Treat fatigue as a serious health and safety issue.

A large proportion of work-related death, injury and ill-health amongst seafarers arises from failure to manage health and safety effectively. This failure is exacerbated by changes that have taken place in the structure and organisation of the industry internationally over the last quarter of a century that both increase risks to health and safety and make prevention of harm to workers more difficult to regulate or manage. Industry wide, cultural change is needed to address fatigue. There are serious risks and consequences associated with fatigued seafarers such as the potential for more environmental disasters and loss of life, the economic losses due to accidents, and the impact on the health and well being of the seafarers. The first stage of dealing with fatigue is to get the relevant people to acknowledge that there is a problem to address.

A more robust approach to regulation and manning A starting point for improving the situation must be a more robust approach to regulation. It is important to ensure that potential fatigue is taken into account when setting appropriate manning levels. Manning levels need to be addressed in a realistic way that prevents economic advantage accruing to those who operate with bare minimums. Such an approach must consider more than the minimum levels necessary to operate a vessel; rather it must address the need for maintenance, recovery time, redundancy, and the additional burden of the paperwork and drills associated with security and environmental issues. More transparent regulatory models need to be developed to allow such an approach. Enforcement of existing legislation, elimination of false record-keeping, and better training and guidance It is essential that existing guidelines are enforced with mandatory provisions and that effective measures are taken to overcome the problem of false record-keeping.

One possibility could be to link the guidance in IMO A890 to the ISM Code. This must be supplemented with a serious attempt to promote a culture of safety on board ships. As long as seafarers feel compelled to falsify records of their hours of work, the problem will be hard to address. Appropriate training and guidance regarding avoidance of fatigue and optimum working conditions is needed. Lessons can be learned from other transport industries and it is important to seek examples of best practice and apply these in an effective way to the maritime sector.

One of these is to seek the involvement of all stakeholders in developing solutions to the problem. Methods of addressing issues specific to seafaring are now quite advanced and a holistic approach to the issue of fatigue can lead to a culture that benefits the industry as a whole. If nothing is done now, the maritime industry may find itself compelled to respond to external drivers such as the environmental lobby or those pushing the security agenda. Learn from best practice in the maritime sector and in other comparable industries It is important to learn by example and adopt those strategies that ill lead to a culture of “best practice” and an elimination of “worst case scenarios”.

This approach will require the collaborative efforts of all stakeholders and good models of such teams (the work force, owners, regulators, and academics) have been developed in other areas of transport.

For more detailed information on the outcomes of the recent research quoted in this document see: Smith,

A., Adequate Manning and Seafarers' Fatigue: The International Perspective January 2007 Smith, A., Allen, P., Wadsworth, E., Seafarer Fatigue: The Cardiff Research Programme November 2006

For more details of fatigue related accident reports see:

MAIB Bridge Watchkeeping Safety Study July 2004



Followup article is here:-

1 comment:

  1. Dear Veeresh,
    Good article.As a chemical master I found the bit on a chem tankers typical port schedule ringing particularly true.Sometimes I feel most of the reports by the MAIB and their ilk amounts to so much mental masturbation as nothing really changes for the better for us at sea.Kind of like a bunch of intllectuals pontificating in an air conditioned New Delhi auditorium on how to "reform"rural India.Fake from the start.
    Cheers and keep your writing going.