Kristiansen Svein. Maritime Transportation: Safety Management and Risk Analysis
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Perrow (1999) also gives an interesting discussion of three basic forms of rationality:
‘absolute’, enjoyed by economist and engineers, ‘bounded or limited’ ration ality proposed
in cognitive science and organizational psychology, and ‘cultural or social’ rationality
mainly practised by the public. The author delivers many interesting arguments for these
alternatives to absolute rationality.
16 CHAPTER 1 INTR O DUCTIO N
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Maritime Policy and Management, Vol. 25(2), 157–174.
Kouabenan, D. R., 1998, Beliefs and the perception of risks and accidents. Risk Analysis, Vol. 18(3),
243–252.
Kristensen, H. O., 2002, Cargo transport by sea and road – technical and economic environmental
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Perrow, C., 1999, Normal Accidents. Princeton University Press, Princeton, NJ.
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Vassalos, D., 1999, Shaping ship safety: the face of the future. Marine Technology, Vol. 36(2), 61–76.
17
2
MARITIME RISK PICTURE
2.1 INTRODUCTION
An accident can be defined as an undesirable event that results in damage to humans,
assets and/or the environment. In order to get an understanding of the characteristics of
maritime accidents we need insight into the maritime risk picture, and this chapter present s
some of the key issues and central elements of this risk picture, including some
introductory observations on why accidents happen in the maritime domain. Among
other things, this chapter will indicate that accidents generally are complex phenomena.
It will also be shown that the level of risk does vary significantly between various
maritime activities.
2.2 DEFINITIONS
This textbook will examine a wide range of related issues, such as reliability analysis, risk
analysis and safety management, and in this context some definitions of key concepts must
be presented (Stephenson, 1991):
. Hazards: possible events and conditions that may result in severity, i.e. cause sig-
nificant harm.
. RAM analysis: reliability, avail ability and maintainability analysis.
. Reliability: the ability of a system or component to perform certain define d
functions.
. Risk: an evaluation of hazards in terms of severity and probability.
. Safety: the degree of freedom from danger and harm. Safety is achieved by doing
things right the first time and every time.
. Safety management: keeping an operation safe through systemat ic and safety-minded
organization and management of both human and physical resources.
. Systems safety: the discipline that utilizes systems engineering and management
techniques to make systems safe throughout their life-cycle.
19
2.3 MARITI ME A CTIVITY
Maritime activities have had, and still have, an impor tant role in the busines s, trade and
economy of many countries. The key areas of maritime activities include:
. Maritime transport:
*
Coastal shipping
*
Transport of people both inland and overseas
*
International shipping
*
Cruise shipping
. Fishing
. Marine farming
. Continental shelf operations (i.e. oil and gas):
*
Rig operations
*
Supply services
*
Pipeline laying
*
Underwater activities
. Science and survey
These activities have several positive attributes, such as employment, production,
creation of values and fortune, spreading economic consequences, positive influences
on currency and exchange transactions, etc. There is, however, a price for these benefits in
terms of negative effects. Some of the typical hazards found in maritime activities are
outlined in Table 2.1.
Maritime accidents may lead to three different kinds of consequences:
. Harm to human beings: injuries and fatalities.
. Environmental pollution.
. Economic losses: damage or loss of vessel and cargo, lost income, etc.
If we limit our studies to maritime accidents we may distinguish between concept
accidents, work accidents and maloperations, as outlined in Figure 2.1.
There is no simple answer to why accidents happen in maritime activities. It will be
pointed out later in this chapter that accidents are complex phenomena, and usually no
simple solutions exist to prevent them.
2.4 CONCEPTOF ACCIDENT TYPES
Ship accidents are usually classified according to the type of energy release involved. The
typical accident phenomena/types are shown in Table 2.2.
In order to understand the nature of ship accidents, one must study the failure
mechanisms related to systems or functions. A ship includes several systems and functions
that are necessary for it to perform its mission, and some of these are presented in Table 2.3.
Both reliability, availability and maintainability (RAM) analysis and risk analysis are
20 CH A PTER 2 MARITIME RIS K PICTU R E
Ta b l e 2 .1 . Threats and hazards in maritime activities
Maritime sector Hazards
Shipping Dangerous cargo: fire, explosion, poisoning, environmental damage
Ocean environment and weather
Substandard ships and substandard shipowners
Difficult to control safety due to its international character
Fishing Relatively small vessels with critical features (e.g. hatches)
Ocean environment and weather
Operation in coastal waters – grounding and steep waves
Partly one-person activities (increases vulnerability if something happens)
Development of damage and flooding is fast
Lack of training
Offshore Many new kinds of activities, limited experience and knowledge
High pace of development work and construction
Continuous development of technology and ways of operation
Large concentrations of energy resulting in high fire and explosion risk
High utilization of the space on platforms
Diving Increasing water depth (high pressures, difficult to control)
Lack of knowledge about physiological factors
Ocean environment – splash zone risks
New work processes
Figur e 2.1. Maritime accident types and consequences.
2.4 CONCEPT OF ACCIDENT T YPES 21
performed on these systems and functions to keep them available (i.e. to reduce the
probability of failures) and to minimize the effects of failures.
A common characteristic of accidental outcomes is the release and/or transformation
of energy. Figure 2.2 gives examples of energies involved in shipping.
It should be kept in mind that any one failure might lead to different consequences
with different degrees of seriousness. Different degrees of seriousness with respect to
consequences include:
. An accident
. An incident
. An operating disturbance
. A non-conformance
Ta b l e 2 . 2 . Accident phenomena
Type Comments
Collision Striking between ships
Contact/impact Striking between ship and other surface objects
Grounding and stranding Hitting the seabed or shore
Foundering and flooding Opening and flooding of hull
Hull and machinery failure Hull or machinery failure is directly responsible
for the accident
Fire and explosion Fire, explosion or dangerous goods release
Missing
Other miscellaneous
Table 2.3. Some generic ship systems and functions
Systems Functions
Accommodation and hotel service Anchoring
Communications Carriage of payload
Control Communications
Electrical Emergency response and control
Ballast Habitable environment
Lifting Manoeuvrability
Machinery and propulsion Mooring
Management support systems Navigation
Positioning, thrusters Pollution prevention
Radar Power and propulsion
Piping and pumping Bunkering as storing
Pressure plant, hydraulics Stability
Safety Structure
22 C H A PTER 2 MA R ITI ME RIS K PICTURE
In the introduction to this chapter, an accident was defined as an undesirable event
that results in damage to humans, assets and/or the environment. Incidents are, on the
other hand, undesirable events that are detected, brought under control or neutralized
before they result in accidental outcomes. If incidents (e.g. small fires in the machinery
space of a ship) occur frequently, this indicates an inadequate level of safety. Suddenly one
may not be able to bring one of these undesirable events under control, resulting in an
accident with harm to personnel, property and/or the environment.
An operating disturbance may take different forms but may be defined as a situation
where the operating criteria for a system or component are violated. Typical operating
disturbances include:
. Reduced efficiency
. Reduced capacity
. Loss of function
. Operating in emergency mode
. Outside operating performance limits (vibration, wear)
. Temporarily idle
A non-conformance is usually defined as a situation where the operation is outside
certain criteria that define what is acceptable.
The causes of accidental outcomes may be highly diverse and are often a combination
of several factors. The main groups of accidental causes are listed in Table 2.4.
The main objective of performing a risk analysis is to measure the importance of the
possible causes for a system and its functions, and to generate and implement safety
measures preventing these causes from occurring and/or reducing the consequences if
they occur.
The nature of vessel accidents will be discussed at length in a later chapter.
Figure 2.2. Examples of energies involved in shipping.
2.4 CONCEPT OF ACCIDENT T YPES 23
2 .5 Q UANTIT A TIVE RISK PICTURE
2.5.1 Vesse l Acc i d ents
The different types of ship accidents (identified in Table 2.2) show considerable variation
in terms of frequency. The number of total losses for ships greater than 1000 grt (i.e.
gross tonnes) was 137 in 2001. The distribution in percent by accident type is shown in
Figure 2.3, and from this figure it is clear that the accident type resulting in most losses is
foundering, being a result of flooding and loss of hull integrity. Foundering may be the
result of a wide range of initiating factors, e.g. extreme weather conditions, failure of hull,
engine breakdown, etc.
It is important to consider the underlying data basis of any statistics showing the
distribution of different accident types/phenomena. The accident type distribution given
in Figure 2.3 was based exclusively on total losses, but in some statistics both losses
and serious casualties are combined. Figure 2.4 is an example of the latter type of
statistics based on accident and loss data from the period from 1980 to 89. As can be
seen from this figure, the inclusion of serious accidents changes the relative importance
of different accident types. The most striking difference between Figures 2.3 and 2.4 is
that foundering is less dominating in the latter case. This may, however, be expected
by the fact that the statistical database used has a large group of accidents not leading
to total loss (foundering is, by definition, total loss). It is also interesting to observe
that the relative importance of accidents involving grounding/stranding and contact/
impact is greater. A dominating category of accidents in Figure 2.4 is ‘Hul l/
Machinery’. This category represents hull and machinery failures that do not result in
total loss.
Another complication in comparing accident distributions is the effect of vessel size
and type. It is a well-known fact that smaller vessels operati ng in coastal waters are more
prone to certain types of accidents than large vessels operating mainly in open water cross-
trades. In Norway there are two ship registers, NOR and NIS and, as shown in Figure 2.5,
these two registers may be studied to reveal differences in the accident statistics between
smaller coastal vessels and larger vessels operating in international trade. The NOR and
NIS registers have the following characteristics:
. NOR : Norway’s ordinary register consisting mainly of its native coastal fleet,
i.e. primarily smaller vessels.
Ta b l e 2 . 4 . Ge neri c accid ental causes
Human causes (e.g. failure to read navigational equipment correctly)
Mechanical causes (e.g. failure of pumps)
Fire and explosion (e.g. loss of visibility due to smoke)
Structural causes (e.g. failure of bow doors)
Weather-related causes (e.g. high ambient temperature or strong wind)
Miscellaneous
24 CH A PTER 2 MARITIME RIS K PICTU R E
. NIS: the Norwegian ‘open’ register consisting primarily of larger vessels operating in
international trades.
In Figure 2.5 the total number of accidents studied is somewhat limited due to the fact
that only two years were taken as the basis for the accident type distribution. Nevertheless,
the following observations can be made:
. The coastal fleet (NOR) is much more prone to grounding. This should not
be surprising given that the vessels included in NOR mainly operate close to the
coast/shore.
. The inter national fleet (NIS) experiences, relatively speaking, more collisions. This
may, for example, be due to the difficulties related to navigating and operating such
large vessels in narrow and busy ports and fairways.
. Relatively, NIS vessels have more fires and explosions than vessels in NOR.
Figure 2.3. Percentage distribution of accident types leading to total loss, world fleet in 2001. (Source:
W orld Casualty Statistics, Lloyd’s Register of Shipping (1962^93), (1994 ^98).)
Figure 2.4. Serious ship casualties, world fleet 1980 ^ 89. (Source: Lloyd’ s Register of Shipping ( 1962^93) ,
(1994 ^98).)
2.5 QUANTITATIVE RISK PICTURE 25