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INTERNATIONAL MARITIME ORGANIZATION
4 ALBERT EMBANKMENT
LONDON SE1 7SR

Telephone:	020 7735 7611
Fax:	020 7587 3210
Telex:	23588 IMOLDN G

                                       
                                      IMO

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Ref. T2/4.2	MSC/Circ.1014
	12 June 2001

                                       
                                       
Guidelines on Fatigue
Module 2
                                       
               SHIPBOARD FATIGUE AND THE OWNER/ OPERATOR/MANAGER



1. IS FATIGUE AN IMPORTANT ISSUE IN SHIPBOARD OPERATIONS? 
   
   Fatigue has been recognized as an important Occupational Health and Safety (OH&S) issue for seafarers. Fatigue has the potential to greatly increase the risk of incidents and injuries in the work place. It disrupts body rhythms and results in poor sleep quality, digestive problems, delusions, confusion, lethargy, respiratory problems, depression, irritability, neurosis and temporary psychosis. Fatigue adversely affects crew performance. It diminishes attentiveness and concentration, slows physical and mental reflexes and impairs rational decision making capability.
   
   An assessment of accidents occurring in the last six months of 1995 indicated that 16% of critical ship casualties, and 33% of injuries, were partly due to human fatigue[1]. Clearly, addressing the issue of fatigue should have a positive effect on personnel safety and has the potential to cut cost for the shipowner, operator or manager by reducing injury and physical damage to high value assets and the environment.
   	 
   Fatigue occurs primarily because an individual cannot get sufficient rest to recover from the effects of having been awake or heavily stressed for a prolonged period. The level of fatigue experienced will be influenced by additional factors apart from the wake period. The type of work undertaken, the environment in which the individual works and lives, and the time of day in which the work is done could all contribute to the level of fatigue experienced. One of the best ways to mitigate the effects of fatigue is through the accumulation of adequate recovery sleep. However, obtaining adequate recovery sleep can be difficult depending on factors like work schedule, circadian rhythm and the physical environment.
   
   The normal sleep-wake cycle of human beings is controlled by a temperature rhythm, referred to as the circadian rhythm. This rhythm actively promotes sleep at night and wakefulness during the day. As a result, work at night is likely to be more fatiguing and an individual is less likely to be able to accumulate restful sleep during the daytime period when they are off watch. These persons will generally get less sleep during the day, than if they were sleeping for an equivalent period at night[2]. Furthermore, day sleepers sleep lightly and are thus easily disturbed by noise, temperature, etc. It is clear the management process must take this factor into account to effectively cope with crew fatigue.  
   
   
2. HOW DOES FATIGUE AFFECT CREW PERFORMANCE?
   
   In order to understand the physiological effects of fatigue, it is useful to describe these effects in relation to a known detriment to performance. In recent studies, the effect of fatigue was found to be comparable to those of alcohol, in terms of negatively impacting performance. One study found that a period of sustained wakefulness of 18 hours was comparable to a Blood Alcohol Concentration (BAC) of 0.05%[3]. As sleep deprivation continued for 24 hours, the effects of fatigue equated to a BAC of 0.10%. What is even more alarming is that the subjects of this study were well-rested students (they had not accumulated a sleep debt prior to the study) who were not required to undertake any hard physical activity during the period. Similar effects can be expected from other populations, and in fact, it might be possible that the effects of sleep deprivation for older individuals would be greater. Both quality of sleep and recovery from fatigue are known to worsen with age. 
   
   Factors, such as the following, will have an effect on the level of fatigue experienced in a given period: (a) the time of day when work was started and completed, (b) the amount and timing of rest over the previous seven days, (c) the activities undertaken during the period of work, and (d) the environment in which work was carried out. If this level of performance degradation was due to alcohol intoxication at sea, this would be considered unacceptable. In view of the similarity between the effects of alcohol and fatigue, it is perhaps appropriate that both be considered in a similar fashion.
   
   Other research has shown that periods of sustained operations for 24 hours result in a drop in performance of about 25%[4]. Specifically, fatigue will have a detrimental effect on higher level mental functions prior to the more obvious effects such as falling asleep on watch or mood change becoming apparent. Loss of higher mental functions will degrade the ability to solve complex problems or rapidly analyze information. A further danger is the likelihood that higher mental skills will be affected before any noticeable reduction in routine or simple activities. 
   
   One way to explain how the loss of sleep or rest can affect seafarers is to consider  watchkeeping, operational safety, or security. While on watch, sleep loss has been reported to have effects including, but not limited to, the following:
   
*       Slowed reaction
*       Delayed or false response
*       Failure to respond at the correct time
*       Slowed thinking and diminished memory
*       Poor decision making
*          Increased risk of personal injury (slips, trips, falls, etc.)
   These and other outcomes pose a risk to any position aboard, but especially those that have critical safety and security responsibilities. Should an individual fail to carry out an allotted task due to fatigue, the crew runs the risk of a safety or security incident. Any risk management strategy must focus on mitigating the potential for such hazards to arise by addressing the causes of fatigue. Systems and work procedures should be critically examined to engineer out design deficiencies that could contribute to fatigue. Shipowners, Operators and/or Managers should provide an adequate level of support for managing the risks of fatigue at both the organisational and operational levels.
   
   
   
3. WHAT ELEMENTS OF FATIGUE CAN THE SHIPOWNER, /OPERATOR, OR /MANAGER INFLUENCE?

   While it is not possible for Shipowners, Operators and/or Managers to regulate and oversee the sleeping habits of every seafarer on every ship, it is within their capability to establish a fatigue management system. Hours of rest are presently controlled by a prescriptive formula set out in Chapter VIII of the Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) 1978/1995 as amended. Managers should be aware (when applying these hours of rest) that considering the effects of circadian rhythm and sleep debt are important for ensuring that rest periods are of high quality. It also cannot be too highly stressed that rest means rest, not substituting a different form of work. This should be supported by appropriate systems and processes, so that fatigue risks can be managed in a way that supports safe, compliant and productive operations. Importantly, fatigue risk control measures forming part of Shipowners, Operators and/or Managers  support should ensure:
   
*       Identify and assess fatigue risks;
*       Development and implementation of FRM documentation;
*       "Company" wide fatigue training and awareness;
*       Availability of adequate resources to conduct all ship operations safely; and
*          A healthy shipboard environment.
   
   STCW and MLC require the maintenance of records of rest and work or rest respectively. In addition, t
   
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   aking the effects of circadian rhythm into account can strengthen this approach. Planning tools such as fatigue modeling or rosters (watchkeeping systems) and work arrangements, which take these effects into account, enable management to do the following: 
   
*       Analyze planned work routines by management to ascertain the risk of fatigue
*       Monitor work hours on board the ship to determine whether or not the risk of fatigue is increasing as a result of the work arrangements or from any variations that may have occurred
*       Analyze and comparing information related to hours of work that will determine the effectiveness of employed routines, compared to other alternatives
   
   Such modeling systems are readily available and systems that are applicable to the maritime environment are on the market. It is important to choose a system that has been validated by a number of studies and has been utilized in transport application[6]. Overall, it is important that management adopt a fatigue management system that is tailored to the individual enterprise. 


4. HOW CAN OWNERS/OPERATORS/MANAGERS ENSURE THAT FATIGUE PREVENTION IS PRACTISED ONBOARD?
   
   Management should consider the following in developing fatigue management policies and systems:
   
*       ISM Code requirements for clear, concise guidance on operational procedures on board
*       Assure adequate crewing level
*       The need for joining crews to be adequately rested before assuming duties
*       Scheduling time for proper hand over on crew change
*       Voyage length, time in port, length of service and leave ratios
*       Multicultural issues; language barriers, social, cultural and religious isolation
*       Interpersonal relationships, stress, loneliness, boredom, social deprivation and increased workload as a result of small crew numbers
*       Provision for shore leave and onboard recreation, family communication
*       Watchkeeping arrangements
*       Job rotation
*       Improved sleeping berths and accommodation
*       Adequate quality and quantity of food for proper nutrition
*       Read other Modules for additional potential managerial mitigation tools
*       Modification of present ship design or future designs
*       
   
   Fatigue training and awareness are essential components. The Shipowners, Operators and/or Managers should ensure all personnel have appropriate training. This includes shore-based personnel whose decisions may impact on the management of fatigue (such as those involved in resource planning and duty scheduling decisions) and fatigue-related processes. This is important, as their decisions potentially affect fatigue levels of seafarers and consequently shipboard safety. 
   
   Initial fatigue-related training should establish a common level of understanding among seafarers and shore based personnel about the dynamics of sleep loss and recovery, the effects of the body clock on circadian rhythms, the influence of workload, and the ways in which these factors interact with operational demands to produce fatigue (covered in Module 1). In addition, it is useful for all seafarers to have information on how to manage their personal fatigue and sleep issues (covered in Module 4 of these guidelines).
   
   From an organisational perspective, it is important to share a common understanding of fatigue issues and its management. Training content should be reviewed based on lessons learned.  
   
   This process, as with any other training, should be ongoing in nature. Hence, training should be conducted on an initial (e.g. prior to commencing any operational duty) and recurrent basis. The interval between training should be determined by the Shipowners, Operators and/or Managers , given their operational characteristics and training needs analysis. 
   
   Adequate Resources (incl. crew)
   
   Adequate resources is one of the primary determinants of seafarers duty hours, workload, duty scheduling, average time off-duty, and other key factors that can have an influence or elevate fatigue. The Shipowners, Operators and/or Managers should ensure that adequate resources are available with a need to proportionally balance varying work and task demands and deal with unexpected surge to reduce the risk of fatigue across shipboard operations. 
   
   Although the master is responsible for managing the ship and its crew, the Shipowners, Operators and/or Managers should ensure that the master is adequately supported and resourced to conduct shipboard duties and operations safely and effectively. This includes having available adequate resources to do so across all shipboard operations. 
   
   Effective operational planning is critical to ensuring adequate resources are available at all times so that operational and other demands placed on the ship and its crew can be managed safely and effectively.  Planning should account for:
   
*       Varying work and task demands within and across days (e.g. amount of time the vessel is travelling through confined and congested waters and less confined open waters);
*       Trading patterns (i.e. number of port calls  -  the more port calls the higher the workload);
*       Planning for disturbances, such as weather, ship movement in port; port entry and exit delays and port surveys and inspections;
*       Ensuring adequate resources are available to cover planned and unplanned aspects such as  training, illnesses, injuries and sickness;
*       Ensuring the Shipowners, Operators and/or Managers contractual obligations that affect the commercial and financial revenue do not impinge or effect safety in any way.
   
   The Shipowners, Operators and/or Managers should consider strategies to deal with periods of high workload and to manage this accordingly. Appropriate strategies may include: 
   
*       The allocation of crew numbers to peak times and demands is a fundamental factor in minimising the exposure to risks associated with extended duty hours. Numbers and types of seafarers should be scheduled on the basis of predictable operational demands to account for daily, weekly, and monthly operational trends;
*       Ensure the master is well resourced and supported to carry out all shipboard tasks safely and to allow for unexpected surge and over-riding operational conditions;
*       Ensure there are adequate resources available to complete shipboard tasks safely without placing excessive demands on seafarers;
*       Augment with shore based support or additional rest when ship is in port such as during loading and unloading, port inspections, etc. to ensure shipboard crew obtain adequate time off for rest and sleep and are fit for duty when the vessel leaves port;
*       Provide shipboard administrative support or a resource for relieving the burden associated with paperwork and related administrative tasks;
*       Where practicable, provide remote support to shipboard crew, in areas such as paperwork, loading/unloading calculations etc. 
*       Utilise other crewing concepts, such as the use of port captains and/or shore based crew;
*       Plan arrival and departures (tides in ports, delays due to weather, pilotage boarding, etc.) to take into account adequate sleep and rest.

   An important aspect that needs to be mentioned is that of Overriding Operational Conditions. In accordance with STCW Section B-VIII/1 `Overriding Operational Conditions' should be construed to mean only essential shipboard work which cannot be delayed for safety, security or environmental reasons or which could not reasonably have been anticipated at the commencement of the voyage. This means that they should not be occurring on a regular basis. Planning, using risk assessment tools and operational experience can foresee these potential disruptions or delays (e.g. weather, port inspections, traffic congestion during departure/arrivals, and sickness of crew members). 
   
   Healthy Shipboard Environment
   
   Unique to shipping is the fact that seafarers are required to not only work but live on board a ship. Hence, ensuring a healthy shipboard environment is crucial to minimising the risks of fatigue. The most important aspects should include:
   
*       Healthy Eating: Healthy nutritious food is available and served on board;
*       Healthy Sleep: The shipboard sleeping environment is commensurate with providing comfortable and good quality sleep (bedding, pillows, mattresses, etc.)
*       Exercise: Adequate exercise facilities are provided (such as well-designed and equipped training facilities and outside spaces), to ensure crew can maintain a healthy lifestyle on-board.
*       Stress: Adequate shipboard measures are in place to recognise and ensure adequate support to seafarers suffering from stress.
   
   Furthermore, initial ship design plays a part in ensuring a healthy operational environment (dealt with in Module 6).
   
   Adequate Sleep Opportunity
   
   Effective fatigue management is predominantly about ensuring that seafarers are provided with adequate sleep opportunity. 
   
   It is not correct to assume that a given rest period from duty will provide a given level of sleep and hence recovery. The length of the rest period is only one key factor. The relationship between the recovery value of off duty periods and the actual amount of sleep obtained in a shipboard environment is increasingly complex. As highlighted in Module 1, sleep quantity and quality (and its restorative value) depends on going through unbroken night time sleep. The more sleep is fragmented by waking-up, the less restorative value sleep has in terms of how seafarers feel and function when they are on duty. 
   
   Shipboard related factors that affect sleep include the design of duty schedules (i.e. length and timing of duty periods, length and timing of breaks within and between a duty period), the type of work being performed (i.e. workload), and the work environment (e.g., heat, humidity, noise, vibration, lighting levels, ship routines, diet, etc.). These can all exert additional downward pressure on the amount of time seafarers are allocated for sleep in a twenty-four-hour day period. 
   
   Room location is important for ensuring adequate opportunity for sleep and should be considered. 
   
   Duty Scheduling and Planning
   
   Duty scheduling and planning is a key factor in managing fatigue [4]. Hence, the Shipowners, Operators and/or Managers should be responsible for ensuring duty schedules provide adequate opportunity for sleep. 
   
   Shipowners, Operators and/or Managers at the very least MUST be in compliance with Regulation VIII/1 of the STCW Convention. 
   
   From a practical perspective, it is important to determine whether a given duty schedule, on average, enables adequate sleep opportunity. There are 5/8? primary duty schedule considerations that should be considered when scheduling. They are:
   
1.       Maximum work hours per 7 days: As total hours worked increase, sleep opportunity decreases. Research has demonstrated that apart from a reduction in performance, extended hours of work are also associated with reduced individual wellbeing, reduced organisational commitment and poor health outcomes. These factors in turn have been linked to declining levels of productivity and safety. Current regulations (MLC) allow for a maximum of 72 hours of work (or minimum of 77 hours of rest) in a 7 day period. 

2.       Maximum work hours per 24 hour period: As indicated in Module 1, as the length of a given period of work increases, the subsequent sleep opportunity decreases. Current regulations (MLC) allow a maximum of 14 hours of work (or minimum 10 hours of rest) in a 24 hour period. Administrative work, shipboard drills, training, ship loading and unloading tasks are all considered to be work hours.

3.       Rest hours (rest periods) between work periods: This is the length of time off between work periods. As the number of rest hours between subsequent work periods decreases, so does the sleep opportunity. Hence, the likelihood of fatigue increases as the number of rest hours decrease in duration. This reflects the fact that seafarers do not simply fall asleep as soon as they are off-duty and wake just before they go back on-duty. Furthermore, seafarers, like all other shore-based workers, have many activities and responsibilities to manage between work periods such as eating, showering, socializing with other crew, relaxing, studying, and writing to and communicating with family members and friends back home. Rest hours should provide for adequate sleep opportunity, be adaptable to the individual circadian rhythm, time to complete those other tasks noted above and account for the effects of sleep inertia after waking. Hence, the interval between two successive work periods should allow sufficient time to obtain adequate sleep before the start of the next work period. Current regulations (STCW) address minimum rest periods.   

4.       Night shift work: As indicated in Module 1, seafarers working during night-time, specifically during the circadian low can experience severe performance degradation initially.   If the seafarer maintains a regular schedule they will adapt over time. However, it is important to provide those seafarers working during night-time a good sleeping opportunity and environment during the day.
   
5.       Short rest breaks within work periods: Short rest breaks benefit performance and help maintain alertness. As indicated in Module 1, one of the most important determinants of fatigue is `time on task'. Frequent short breaks are associated with performance benefits and when the timing of rest is at the discretion of the individual it results in better fatigue management [17-20]. It is recognised that in a shipboard environment this may not always be feasible. It should be noted that the `time on task' effect can also be reduced during the work period by task rotations/substitutions. 

6.       Naps: are an effective countermeasure to fatigue, exhaustion from long work hours, and restricted sleep. Whether before an anticipated short night's sleep or after, brief naps improve performance and alertness, and delay fatigue-induced performance degradation. Overall research has shown that the benefits of controlled napping out-weigh the potential risks associated with sleep inertia.

7.       Recovery Sleep: The provision for sufficient recovery time following periods of sleep debt is important.  It should be noted that provision of minimum rest periods may not sufficiently acknowledge the critical role that the circadian timing plays in the rate at which fatigue accumulates and the rate at which people recover.  When a seafarer commences their work they need to be sufficiently rested so as to be able to sustain their work activities over the designated duration of the next work period. To work safely across a given duty and to then return to the next work period sufficiently recovered requires that the seafarer obtains sufficient quantity and quality of sleep between work periods. While one or two recovery sleeps of eight hours or more are generally enough following a period of acute sleep loss (one night), recovery following a period of sleep debt (two or more nights of sleep loss) may take in excess of three nights. Sleep opportunities during the circadian low are preferable because sleep that occurs during the circadian low 	provides the most recuperative value. It is recognised that in a shipboard environment this may not always be feasible.  

8.       Reset Breaks: Given that risk of fatigue increases over a span of successive work days of sleep debt, it seems logical that some "recovery" must take place over spans of rest days otherwise the risk of fatigue would continue to rise. This is typically an issue at sea as seafarers are exposed to potentially arduous duty schedules over a long period of time (in excess of seven days, sometimes months on end) without the possibility of a reset 	break. It is recognised that in a shipboard environment this is likely not practical, however this may be a factor to consider when determining crew rotation. 

   Fatigue management should consider napping and short break policies. 
   
   Fatigue management should also acknowledge impairment through sleep inertia, specifically for seafarers who are woken up suddenly in the middle of their sleep period (for emergency or other purposes) or need to wake up during the circadian low to take over a duty period. 

   Tools to Assess Fatigue in Scheduling: The planning of duty schedules based on fatigue science as well as operational requirements permits predictive identification of fatigue hazards. This assists in allocating adequate rest periods that provide sufficient sleep opportunity.  
   
   These can be useful additional tools for the management of fatigue. However, it should be noted that they should not be used in isolation nor be the main driver for duty scheduling decisions as they are not sufficient to determine the full extent of fatigue-related risk. They should always be supported by other operational data. Their main purpose should be limited to identifying potentially fatigue inducing duty schedules or scheduling hot spots and allow for better decisions in the selection of duty schedules. This is because numerous unforeseen circumstances can cause changes to planned schedules, for example, weather conditions, unexpected technical problems, or crew illnesses. It is noted that many companies already account for fatigue informally during planning activities. Seafarer fatigue relates to what is actually worked, not what is planned. Thus another proactive approach for identifying fatigue hazards is to analyse actual duty schedules in operation.
   
*       Fatigue Risk Assessment Tool: The risk level of a specific duty schedule may be assessed via a fatigue risk score. 

*       Fatigue Predictive Software Tools: Models and related software to predict fatigue levels for specific operations can be useful additional tools for the management of fatigue risks.
   
   Workload Management 
   
   As discussed in Module 1, mental and physical demands of work can contribute to a seafarer becoming impaired by fatigue in a number of ways. Concentrating for extended periods of time, performing repetitious or monotonous work and performing work that requires continued physical effort can increase the risk of fatigue. Mental fatigue and physical fatigue are different and a seafarer can experience them at the same time. It is important to be aware of a seafarers' optimal level of workload and stress and to have realistic attitudes towards these. Understanding that different people react differently to stressful situations (such as emergencies, family problems at home, job related) is critical for effective interventions. Hence, the use of effective communication with seafarers and monitoring  and observing any behaviours that may indicate a change to a seafarer's fatigue as a result of workload is important (see fatigue signs and symptoms in Module 1) .
   
   Typical techniques for managing workload while on duty include: prioritisation of tasks, task delegation, task rotation and crew rotation, task shedding. A list of risk control strategies that should be used in managing workload may include: 
   
*       Carefully consider task design according to the workload and resources available;
*       Reducing the amount of time seafarers need to spend performing sustained physically and mentally demanding work (tank cleaning, navigation through congested waters, etc.);
*       Where possible, planning for a minimum of two crewmembers  together on navigational watch, specifically during night time;
*       Managing workload and work-pace change caused by machinery breakdowns and planned and unplanned sicknesses and illnesses;
*       Where practicable, minimising routine and administrative tasks or redesigning them to ensure seafarers can focus on core duties in their working time;
*       Minimise repetitive or monotonous tasks by using task rotation, where practicable 
*       Where practicable, defer non-urgent work to allow appropriate rest and recovery.
   
   Work and Living Environment
   
   The work and living environment is important for ensuring adequate opportunity for sleep and should be considered. Because good quality sleep is critical, Shipowners, Operators and/or Managers should develop procedures to minimize interruptions to seafarers' sleep. Opportunities for implementing countermeasures in this area vary from shipboard environmental, procedural to operational changes. For example most environmental aspects such as noise can be better addressed during ship design (Module 6). However, there are control measures that the Shipowners, Operators and/or Managers  can implement to assist in reducing noise levels in the sleeping environment [25]. 
   
   Environmental, procedural and operational measures may also range from low cost solutions, such as porthole blinds and door baffles, to high cost solutions, such as re-fitting the vessel exhaust or air conditioning systems. 
   
   Operational and procedural changes may include developing napping policies or defining blocks of time (sleep opportunities) during which seafarers are not contacted except in emergencies. These protected sleep opportunities need to be known to all relevant personnel. Depending on the situation, changes should be made to those areas that will have the most impact, and following evaluation, consideration to other changes can then be made.
   
   Environmental control measures may include, but are not limited to:
   
*       Adequate facilities for rest, sleep and meal breaks and other essential requirements, such as bathroom facilities and personal storage;
*       Making sleeping areas darker, quieter, and more comfortable and increasing lighting in certain areas of the ship, such as:
      oo Providing a dark sleeping atmosphere using black out blinds for portholes or berths in sleeping spaces;
      oo Installing-insulation baffles over cabin door louvers;
      oo Improving air conditioning (ambient temperature) and air flow;
      oo Supplying good quality and comfortable bedding such as mattresses and pillows;
*       Making sleeping spaces a priority in retro-fitting and new ship construction;
*       Ensuring adequate personal storage space is available for seafarer's personal effects.

   Procedural and operational control measures may include, but are not limited to: 

*       Increasing access to healthier food choices by ensuring nutritious food is served on-board;
*       Providing information and advice on healthy eating and physical fitness;
*       Making exercise equipment and facilities available to seafarers;
*       Providing and maintaining a quiet atmosphere for sleep. Develop a `do not disturb' policy for sleeping seafarers;
*       Where practicable, calls for drills should be conducted in a manner that minimizes the disturbance of  rest periods as they can be extremely disruptive;
*       Putting in place short breaks within duty periods, including napping policies;
*       Ensuring ship routines such as meal times are commensurate with seafarer working schedules. This includes providing personnel working at night with appropriate meal choices;
*       Providing access to counselling services to assist in any issues arising from the disruption to individual, family or social patterns and shipboard related aspects. Implement a consistent stress management program;
*       Have a policy in place to support seafarers experiencing elevated levels of workload;
*       If possible, avoid assigning seasick and ill seafarers shipboard work;
*       Provide shipboard phone use and Internet and e-mail access to all crew; and
*       Where possible, ensure that maintenance work does not disrupt personnel sleeping.
   
Adequate Sleep Obtained 
   
   Given that sleep loss is a primary contributor to fatigue, Shipowners, Operators and/or Managers should determine whether adequate sleep is obtained. 
   
   Situations may arise where a seafarer is provided with an adequate sleep opportunity, but they may not get adequate sleep. Hence, while an adequate sleep opportunity provides an indication of the quantity of sleep likely to be obtained, it is important to know whether adequate sleep has actually been obtained. Seafarers, should be provided the opportunity to report back situations when they have been unable to obtain adequate sleep or feel at risk of making fatigue-related errors, 
   In general, seafarers are responsible to use adequate sleep opportunity appropriately, so they are alert and capable of performing assigned shipboard work safely. However, there are a number of reasons why seafarers may not obtain adequate sleep. Aspects mentioned below can all affect the amount and quality of sleep obtained:
   
*       a seafarer working during the night may have difficulty getting quality sleep;
*       seafarer upon joining the ship may experience difficulty adjusting to the sleep schedule;
*       seafarer travelling for an extended time to the ship should not be required to report to work immediately until adequate rest is obtained;
*       untreated sleep disorders as highlighted in Module 1;
*       emotional stress; 
*       the sleeping environment (comfort, noise, darkness, ship motion, privacy) may not allow for adequate sleep;
*       the type of food consumed; 
*       medication or use of prescribed/over the counter/natural remedies; 
*       consumption of  stimulants such as caffeine and amphetamines; 
*       use of personal electronic devices before sleep, which may delay the onset of sleep and not allow adequate sleep to be obtained.
   
   Regardless of the circumstances causing insufficient or poor quality sleep, these should preferably be identified through proactive measures and treated as a potential shipboard hazard. 

   
   
   
   
   
   
   
5. WHAT RULES AND REGULATIONS ARE IN PLACE TO PREVENT AND DEAL WITH FATIGUE (INTERNATIONAL, NATIONAL AND MANAGEMENT)? 
   
   As discussed in the previous sections, Chapter VIII (Fitness for duty) of the STCW convention sets minimum rest requirements for watchkeeping personnel and those whose duties involve designated safety, security and prevention of pollution duties. However, it does not stipulate minimum requirements for other persons. The limits described in Regulation VIII/1 of the convention have been incorporated into national regulation in some countries. This action was taken in order to comply with the requirement of the STCW convention so that "each administration shall, for the purpose of preventing fatigue... establish and enforce rest periods for watchkeeping personnel and those whose duties involve designated safety, security and prevention of pollution duties." 
   
   In addition to the STCW convention, the International Labour Organisation has developed MLC 2006. This convention requires governments to establish a work hour regime for crew members based on either minimum rest hours or maximum working hours, which can be undertaken in a single day or over a seven-day period. 
   
   
   STCW 78/95 as amended and MLC 2006 are relevant to the implementation of the ISM code in so much as the code requires operators to "maintain their ship in conformity with the provisions of the relevant rules and regulations." Ensuring that those on board are fit to undertake their duty is relevant to the maintenance of the ship in this context as it has an effect upon the seaworthiness of the ship. 
   
   Experience with the limits  --  set by STCW and MLC 2006  --  is needed to verify which conditions require supplemental information or modifications. However, these requirements must be examined with respect to other factors such as sleep propensity at given times of the day. A rest break taken between the hours of 0000 and 1200 may result in a sleep of 7 to 8 hours compared to a duration of only 5 to 6 hours for a rest break taken in the latter half of the day. 
   
   For countries that have independent OH&S legislation for their maritime industry, this factor will become more significant with wider acceptance of fatigue modeling and fatigue risk management. Under such circumstances, compliance with the requirements and the use of risk management tools, where available, will become necessary. 
   Appropriately manned in order to encompass all aspects of maintaining safe operations on board (in accordance with the Principles of minimum safe manning, adopted by the Organization by resolution A.1047(27)).
   
   ISM code reference in seafarers add here too. 
   
   
                                  References
                                       
    McCallum M.C, Raby M and Rothblum A.M (1996)  -  Procedures for Investigating and Reporting Human Factors and Fatigue Contributions to Marine Casualties. Report No CG-D-09-97. National Technical Information Service  -  Virginia, United States.
   
   2 Folkard S and Barton J (1993)  -  Does the `Forbidden Zone' for sleep onset influence morning shift sleep duration?  -  Ergonomics. 36(1-3): 85-91 - Australia.
   
   3 Dawson D, Lamond N, Donkin K and Reid K (1997)  -  Quantitative Similarity between the Cognitive Psychomotor Performance Decrement Associated with Sustained Wakefulness and Alcohol Intoxication  -  From the minutes of the AAPMA 36[th] Biennial Conference 1998 - Australia.
   
   4 Belenky G, Balkin T.J, Redmond D.P, Sing H.P, Thomas M.L, Thorne D.R and Wesensten N.J (1998)  -  Sustaining Performance during Continuous Operations: The US army's Sleep Management System - taken from The 3[rd] International Conference on fatigue and Transportation 1998 - Australia.
   
   5 Dawson D, Fletcher A and Hussey F (1999)  -  Fatigue and Transport, Report to the Neville Committee  -  The Centre for sleep Research, University of South Australia - Australia.
   
   6 Reid T, Roberts T. and Dawson D. (1997)  -  Improving Shiftwork management II:  Shiftwork and Health  -  Occupation Health and Safety 1997, 13(5):  439-450  -  Australia/New Zealand.

                                          
                                       

