Information for Interest | Pilot Advisory Notes | Restricted Access
Impact on Wives and Families | Work and Sleep Patterns | Implications for Fatigue Management
The work practices of Marine Pilots: a review
1.0 INTRODUCTION
The Great Barrier Reef is the world’s largest coral reef ecosystem, stretching 2,340 kilometers along the north-east Australian coastline. It has been registered on the World Heritage list, and in 1990, was identified by the International Maritime Organisation as the world’s first, and to date only, ‘Particularly Sensitive Sea Area’ (Qld Transport & AMSA 1996). Navigation through the Great Barrier Reef region is made difficult by the narrowness of shipping routes, tidal effects, cross currents, and the reef itself. The high density of small boat traffic and climatic phenomena, such as cyclones, further increase the danger associated with movement through this area. These hazards, and the environmental sensitivity of the reef, resulted in legislation enacted in 1991, which enforced compulsory pilotage on the Inner Route between Cape York (latitude 10o 41’ S) and Cairns (latitude 16o 40’ S) and on Hydrographers Passage (Figure 1). This act applied to vessels 70 meters or more in length and to all ships carrying potential toxic pollutants (e.g. fully loaded oil tankers, chemical carriers and liquefied gas carriers) (Qld Transport & AMSA 1996).
Figure 1 Great Barrier Reef - Torres Strait region (Qld Transport & AMSA 1996)
Prior to July 1993, the Queensland Department of Transport was responsible for the licencing, administration and tariff structure of marine pilotage in the Great Barrier Reef - Torres Strait region (Crone 1994). After July 1993, the regulatory functions were transferred to the Commonwealth government, at which time control over the administration of pilotage was relinquished (Crone 1994). This encouraged competition and, to date, three pilotage companies have emerged (Qld Transport & AMSA 1996). Concern over the impact privatisation of pilotage may have on safety standards has been raised, as past evidence suggests commercial pressures tend to override safety issues, whereas disciplined and regulated pilotage services enhance safety (Crone 1994; NRC 1994; States/BC OSTF 1997).
Of particular concern to regulatory bodies such as the Australian Maritime Safety Authority (AMSA), is the potential impact the work characteristics of Great Barrier Reef pilots (GBRP) may exert on fatigue. As illustrated in Figure 2, work schedules can significantly influence fatigue and stress levels by disrupting sleep, circadian rhythms and information processing. This in turn may manifest in impaired performance capabilities and reduced levels of safety. Hence, the irregular work hours, substantial amounts of night work and long on duty periods experienced by Great Barrier Reef pilots may expose this occupational group to an increased risk of fatigue development. A recent grounding in the Great Barrier Reef region highlighted the impact work practices of pilots can have on fatigue and ship handling performance (Dept. of Transport & Comm. - MIIU 1997).
Although fatigue has been recognised as a potential factor which may contribute to accidents at sea (Couper1996; McCallum et al. 1996; Osler 1997), little is known about the extent and aetiology of fatigue in marine pilots. Evidence from Australian and other seafaring groups suggests that the work and sleep conditions experienced at sea contribute to stress (Parker et al. 1997) and fatigue (Sanquist et al. 1996, 1997). To explore the potential relationship between work, sleep, stress and fatigue in marine pilots, evidence from the literature, which for the most part was not collected from studies of marine pilots, has been examined.
Figure 2 Schematic model of the impact of work schedules on safety (Folkard, 1988)
2.0 WORK PATTERNS OF MARINE PILOTS
Marine pilots are a unique group of seafarers who possess high levels of local area knowledge, ship handling skills and navigational experience. Their role when on board a vessel is to advise the master and navigational officers and/or manoeuvre the vessel, so that a safe passage through the pilotage region/s is achieved. At no time does the pilot’s authority exceed that of the ships’ master; by tradition and by law, the master remains in command at all times and is accountable for the navigation and management of his vessel (AMSA 1993; Crone 1994; NRC 1994). This, however, does not remove pilots from the responsibility they take on when guiding vessels, as their actions and conduct directly impact on the safety of the vessel, crew and surrounding environment.
Marine pilotage work is largely dependent on shipping demands and as a consequence, work schedules are highly irregular. Work may be undertaken at any time of the day or night, as is evidenced by an investigation revealing that the entire 24 hour period was represented when the starting and finishing times of marine pilotage work were analysed (Shipley & Cook, 1980). Night work is common, with preliminary findings from an analysis of GBRP work schedule files indicating that 54 percent of the ship time is undertaken between the hours of 1818 and 0525 (Parker et al. unpublished observations).
To regulate pilot workload, a number of different work roster systems are used. For example, GBRP operate on a turn system designed to ensure equality between pilots in workload, rest breaks and income, and to match pilot abilities with expected work requirements (Personal Communication - Pilot Advisory Group 4 August 1997). Work schedules involve tours of duty, during which time pilots are on call and perform one or more work assignments. Time between work assignments is spent ashore recuperating and if necessary, travelling to the next port location. For pilots who live in close proximity to their work location, recovery time may be spent at home. However, a number of GBRP live distant from their work and hence, time between work assignments is spent in pilot accommodation houses, hotels or motels. After a tour of duty has been completed, an extended period of rest at home is usually taken (Personal Communication - Pilot Advisory Group 4 August 1997).
As a result of the irregularity of pilotage work and different operations of the three pilotage companies operating in the Great Barrier Reef – Torres Strait region, the duration of tours of duty and work assignments tends to vary somewhat. However preliminary work schedule data indicated that on average, GBRP undertake just over 9 tours of duty per year, with each tour lasting approximately 17 days and involving around 5 work assignments. Work assignments averaged 40.5 hours in duration, while time between work assignments was typically around 53 hours (Parker et al. unpublished observations).
In contrast to GBRP, Port Phillip sea pilots work on a continually rotating roster system (Berger 1983, 1984). Pilots are listed on a register and work assignments are designated to those pilots whose names are at the top of the list. In this way, work assignments are performed by pilots who have had the greatest amount of rest since their last work assignment. After completing a work assignment, the pilot’s name is placed at the bottom of the list.
Around 70 percent of the work performed by Port Phillip sea pilots involves guiding vessels into or out of the Port of Melbourne. Under normal circumstances, a one way voyage entails around 5 hours of navigation. However, work assignments often involve pilots performing two voyages, as the pilot first directs a ship out of the port and then guides a second vessel into the port. The voyages are usually separated by several hours, during which time the pilot tries to rest at the Queenscliff pilot house. Pilots are therefore generally away from home for some 15 hours for each work assignment, with approximately 10 hours of navigation being performed. Time off between work assignments varies, but seems to be around 30 to 40 hours (Berger 1983, 1984).
Stabilised watch systems are another type of work roster used in some pilotage districts in the United Kingdom (Shipley & Cook 1980). These systems involve predetermined on duty and off duty periods, such as 24 hours on, 48 hours off, and are far more predictable than either the turn or rotating roster systems as pilots are informed of their duty periods and time off in advance (Shipley & Cook 1980).
To reach the vessel pilots have been assigned to, it is often necessary for helicopters or launch vessels to be used. Transit times vary depending on the distance to be travelled and transportation mode used, but in some instances in the Great Barrier Reef - Torres Strait region, launch trips may be up to 3 hours in duration (Personal Communication, Iain Steverson 28 August, 1997). The pilot is then required to board the ship, which is still moving, by way of a ladder (AMSA 1993; Australian Reef Pilots Ltd. 1996).
The duration of on duty periods are influenced by a number of factors including the shipping route being travelled, the type, size, draught and speed of the vessel, the prevailing weather and tidal conditions and the amount of shipping traffic encountered (Personal Communication - Pilot Advisory Group 18 September, 1997). The immense size of the area serviced by GBRP means that some on duty periods for this group of pilots are in excess of 60 continuous hours (Dept. of Transport & Comm. - MIIU 1997; Parker et al. unpublished observations). While not all of this time is spent navigating the vessel, pilots are on call at all times while on duty and have no predetermined rest breaks in their schedules.
Throughout a work assignment, the nature of pilotage tasks in terms of physical and mental activity is quite diverse. Acts such as boarding and disembarking are associated with near maximal levels of physical exertion for some of the older pilots (Berger 1983, Shipley 1978), however at other times, physical activity
is minimal. Likewise, the type of cognitive attributes required varies, with close quarters work involving complex decision making and calculations, while watchkeeping and monitoring the ship’s position in open waters necessitates high levels of vigilance.
In summary, marine pilots are a unique group of seafarers who possess high levels of local area knowledge, ship handling skills and navigational experience. Their work tends to be irregular, both in terms of its timing during the 24 hour cycle, and in relation to the duration of on duty periods and time off between work assignments. This is, to a large extent, determined by the characteristics of the pilotage region (i.e. length of shipping routes and shipping demands), however work roster systems may also influence the regularity of the work. The nature of pilotage work in terms of physical and mental activity, varies considerably throughout a work assignment.
3.0 WORK AND SLEEP
Occupations involving work outside normal hours can have a profound effect on sleep quantity and quality (Akerstedt 1991, 1995; Folkard 1996a; Knauth & Costa 1996). Sleep taken after night work and to a lesser extent, before morning work, tends to be significantly shorter and of inferior recuperative value compared with sleep taken following afternoon work (Folkard & Barton 1993; Kecklund et al. 1997; Tilley et al. 1982). Subjective ratings of sleepiness and fatigue are subsequently greater during night and morning shifts (Akerstedt 1995; Kecklund & Akerstedt 1993; Kecklund et al. 1997; Luna et al. 1997), and in some instances, sleepiness is severe enough to result in night workers unintentionally falling asleep while on duty (Gold et al. 1992; Luna et al. 1997).
The irregular work schedules of marine pilots impact on sleep. When on duty, 31 percent of pilots servicing the Great Barrier Reef - Torres Strait region attained an average of less than 4 hours sleep per day, while 65 percent secured between 4 to 6 hours per day (Parker et al. 1997). Thus some 96 percent of GBRP were working after experiencing, at best, 6 hours of daily sleep. The sleep obtained when on duty also tended to be of inferior quality, with over 55 percent of the pilots rating their sleep as fair, poor or very poor (Parker et al. 1997). In contrast, when the same group of pilots were at home, over 75 percent reported 7 to 8 hours of sleep which was of good to very good quality (Parker et al. 1997). These findings seem to indicate that the reduced amounts of sleep experienced by GBRP when on-duty are a function of the work conditions, rather than personal choice.
Marine pilots from the United Kingdom (Shipley & Cook 1980), the Netherlands (de Vries-Grierer 1982), the United States (Sparks 1992) and the Port Phillip region of Australia (Berger 1984) have reported similar sleep problems. The irregularity of pilotage work also appears to contribute to a higher prevalence of sleep disorders, as 7 to 36 percent of marine pilots were self-reported insomniacs (Berger 1984; Shipley 1978; Sparks 1992). In comparison, only 5 to 6 percent of the general population classified themselves similarly (Lack et al. 1988; Wilson & Lack 1983).
Other occupational groups operating on irregular work schedules have also reported compromised sleep (Bisson et al. 1993). Three groups of military personnel involved in Operation Desert Shield were studied over a single 7 to 9 day round trip involving 2 to 3 flights in the United States to pick up passengers or cargo, an eastbound flight to Europe, a quick return flight to Saudia Arabia, a westbound flight back to the United States and an additional flight to home station. Duty days of 20 hours were common, with flights being performed at various times of the night and day. Crews were often required to sleep during local daylight hours, in sleeping and billeting facilities which were sometimes less than ideal. These conditions, which are similar to the conditions experienced by marine pilots, resulted in many crew members finding it difficult to obtain 4 or more hours of continuous sleep, and often crew were awake for some 7.5 to 10.3 hours prior to beginning duty. As a consequence, fatigue ratings during subsequent flights were substantially increased and there was some evidence of impaired performance (Bisson et al. 1993).
Some of the difficulties associated with achieving adequate sleep when work is performed during unconventional hours can be explained by the fact that sleep displays a strong time of day effect. Sleep onset that occurs after midnight results in a progressive shortening of sleep length, such that a 1400 to 1800 hour bedtime culminates in only approximately 2 hours sleep (Figure 3). This effect has been attributed to underlying circadian cycles and in particular, the close relationship between sleep duration and the body temperature rhythm (Akerstedt 1995; Folkard 1996a; Scott & Ladou 1990). As a consequence, morning sleep after night work is naturally shortened.
The concept of the ‘forbidden zone’ of sleep has also shed some light on why sleep prior to early morning work tends to be of reduced quantity. Previously it was assumed that conflicting social, domestic and/or family demands resulted in shiftworkers failing to adjust their bedtime to take into account their early rising time when working morning shifts. However, an alternative explanation proposed by some researchers is that circadian influences may greatly reduce sleep propensity during the evening hours preceding an individual’s habitual bedtime (Akerstedt 1995; Cabon et al. 1991; Folkard 1996a; Folkard & Barton 1993; Lavie 1991). This period of decreased sleep propensity has been termed the ‘forbidden zone’ and makes the early initiation of sleep extremely difficult (Akerstedt 1995; Folkard 1996a; Lavie 1991).
Additionally, the importance of the sleeping environment on sleep quality and quantity cannot be underestimated. Ideally, sleep should be taken in a dark quiet room, which is comfortable in temperature and has an adequate flow of fresh air (Rosekind et al. 1996; TSB 1997). However, it is not always possible to achieve such conditions during daytime sleep or when sleeping in alternative accommodation as GBRP are frequently required to do. Exogenous factors such as increasing temperatures and natural sunlight can make the sleep environment uncomfortable and outside noise and activity commonly cause disruptions (Akerstedt 1995; Cabon et al. 1991, 1993; Rutenfranz et al. 1988).
When insufficient amounts of sleep are obtained over several consecutive days, a cumulative sleep debt is incurred (Folkard 1996b; Gillberg 1995; Knauth 1993, 1996; TSB 1997). Evidence supporting this concept can be sought from the work of Tilley and colleagues (1982) who noted that nightworkers obtained significantly less sleep and exhibited a progressive impairment in reaction time performance over the course of a working week as compared to day and afternoon workers. This finding was thought to represent an accumulation of partial sleep deficits and the resultant build up of fatigue (Knauth 1996; Folkard 1996b; Tilley et al. 1982). In light of these findings, it has been suggested that shiftwork schedules should not involve anymore than three night shifts in succession (Knauth 1993, 1996).
By comparing the average sleep duration of GBRP when at home and when on duty, it can be noted that during work assignments pilots incurred an average sleep debt of 2.8 hours per night (Parker et al. unpublished observations). This result was more than double the figures reported for other Australian seafarers (Parker et al. unpublished observations) and American merchant marine personnel (Sanquist et al. 1996). Hence, it is possible that over the course of longer work assignments, GBRP may be susceptible to exhibiting fatigue-related performance decrements induced by a cumulative sleep debt.
That pilots are on call at all times when on duty may also adversely affect sleep. Torsvall and colleagues (1987, 1988) documented reductions in the duration and perceived quality of sleep of on call ships’ engineers, even when sleep was not disturbed. Additionally, adjustments in temporal patterning of sleep and elevated resting heart rates were observed. As a consequence, ratings of fatigue were increased the following day. These results led the authors to conclude that the apprehension associated with this type of work induces substandard sleep (Torsvall et al. 1987; Torsvall & Akerstedt 1988). Comparable results have also been noted in physicians on night call duty (Arnetz et al. 1990) and in on call transplant co-ordinators (Smithers 1995).
Additionally, the short and fragmented nature of sleep obtained by pilots when on duty can significantly reduce recuperative value. A study examining the sleep patterns of US merchant marine personnel identified that those personnel involved in a 4 hours on, 8 hours off watchkeeping system were more likely to attain their sleep in 2 or more separate episodes and to report lower quality sleep as compared to personnel in command, daywork and steward departments (Sanquist et al. 1996). This finding was attributed to the fact that the latter groups of personnel generally obtained a single block of sleep during the night and hence, were sleeping at times which were more consistent with normal human physiology (Sanquist et al. 1996). Studies of European merchant marine watchkeepers (Rutenfranz et al. 1988) and long haul truck drivers (Hopkins 1992) have revealed similar results.
Hence it would seem that several aspects of marine pilotage work may adversely affect sleep. The irregular timing of the work, the fragmented nature of sleep obtained when on duty, and the variable quality of sleeping facilities available to pilots when staying in alternative accommodation on ship and ashore can reduce both the quantity and quality of their sleep. The reasons for this principally seem to be endogenous in nature (i.e. related to underlying circadian rhythms), however exogenous factors such as noise, light and heat may also contribute.