Navigational safety in the Sound between Denmark and Sweden

Transcription

The Royal Danish Administration of Navigation and Hydrography, The Danish
Maritime Authority and The Swedish Maritime Administration
Navigational safety in the Sound
between Denmark and Sweden
(Øresund)
Risk and cost-benefit analysis
August 2006
The Royal Danish Administration of Navigation and Hydrography, The
Danish Maritime Authority and The Swedish Maritime Administration
Navigational safety in the
Sound between Denmark
and Sweden (Øresund)
Risk and cost-benefit analysis
August 2006
Ref
568125
R568125-002(1)
Version 1
Date 2006-08-24
Prepared by JESP/PTA/SAT
Checked by FMR/SAT/PTA/LWA
Approved by TAN
Report cover: Photograph by Søren Madsen, Øresundbron.
Rambøll Danmark A/S
Teknikerbyen 31
DK-2830 Virum
Danmark
Phone +45 4598 6000
www.ramboll.dk
Table of contents
1.
1.1
1.2
1.3
Introduction
Objective
Limitations
Report overview
2.
2.1
2.2
2.3
2.4
2.5
2.6
2.7
Executive summary
Risk and accident types
Risk acceptance
Data analysis and accident registrations
Hazards and risk control options (FSA step 1 and 3)
Risk analysis (FSA step 2)
Cost benefit analysis (FSA step 4)
Recommendations for decision making (FSA step 5)
5
6
6
6
8
8
9
10
3.
3.1
3.1.1
3.1.2
3.2
3.3
3.3.1
3.4
3.5
3.6
Procedure for analysis
Project definition and information basis
Project definition
Information basis
Hazard identification and risk control options (FSA step 1 and 3)
Risk assessment (FSA step 2)
Frequency and consequence analysis
Risk control options (FSA step 3)
Cost benefit assessment (FSA step 4)
Decision making and recommendations (FSA step 5)
12
13
13
14
14
14
15
15
15
16
4.
4.1
4.2
4.3
4.4
4.5
4.5.1
4.5.2
4.5.3
4.5.4
Basic information
Geographic limitations
Ship traffic overview
Navigational routes
Specific limitations and requirements for navigation in Øresund
Pilot regulations in Øresund
Descriptions for use of Swedish or Danish pilots
Requirements for use of pilot for specific ship cargos or ship sizes
Requirements for use of pilots calling on different harbours in Øresund
IMO recommendations for use of pilot in Øresund
18
19
19
21
21
21
22
22
23
23
5.
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.7.1
5.7.2
Data basis and analysis
Drogden observation station
Leisure boats and fishing ships
Port registrations
Pilot registrations
Ferry lines
VTS-Data
AIS-data
Dynamic data
Static data
25
26
27
29
30
34
34
34
35
36
Ref. 568125/R568125-002(1)
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1
2
4
I
5.8
5.8.1
5.8.2
5.8.3
5.8.4
5.8.5
5.8.6
5.9
5.9.1
5.9.2
5.9.3
5.9.4
5.9.5
5.9.6
5.9.7
5.10
5.10.1
5.10.2
5.10.3
5.10.4
5.11
5.11.1
5.11.2
5.11.3
Validation of data
Quality of the dynamic AIS data
Quality of the static AIS-data
Comparisons of AIS data and data from Drogden observation station
Comparison between AIS and ferry lines between Helsingør/Helsingborg
Comparison between VTS data and Drogden observation station
Data validation summary
Detailed analysis of AIS data
Navigational routes Øresund
The traffic separation zone at Øresund North
The routes east and west of Ven
Kongedybet, Hollænderdybet and Kronløbet
Drogden and Flintrännan
Outside Malmö Harbour
Drogden South
Detailed analysis at Drogden observation station
The number of ships over all registered years
The number of ships registered each month
The number of ships registered each hour of the day
Distribution of GT and draught
Meteorological an oceanographic data
Current
Wind and visibility
Ice
37
37
37
38
39
39
40
40
40
42
45
49
52
59
61
62
62
64
65
66
68
68
69
69
6.
6.1
6.2
6.3
6.4
6.5
6.6
6.7
Accident registrations
Location
Frequency
Causes
Use of pilot
Light conditions
Size of ship (GT)
Consequences
70
70
78
79
80
81
82
83
7.
7.1
7.1.1
7.1.2
7.1.3
7.1.4
7.2
7.2.1
7.2.2
7.3
7.3.1
7.3.2
7.4
Identification of hazards and risk control options (FSA step 1 and 3)
Methods and procedures
Identification method
Frequency and consequence classes
Risk matrix
Risk Register
Hazard identification workshop
Meeting participants
Overview of results from workshop
Risk reduction workshop
Preliminary risk ranking
86
86
86
87
88
89
90
90
91
93
93
94
96
8.
8.1
Frequency models (FSA step 2)
Basic model principles
Ref. 568125/R568125-002(1)
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106
II
8.1.1
8.1.2
8.1.3
8.1.4
8.1.5
8.2
8.2.1
8.2.2
8.3
8.3.1
8.3.2
8.4
8.4.1
8.4.2
8.5
Ship characteristics
Ship traffic distributions
Route characteristics
External conditions
Failure types
Ship-ship collision for passing ship
Description
Assessment of model parameters
Ship-ship collision for crossing ships
Description
Grounding and ship-obstacle collision
Description
Methods for implementation of the frequency models
108
108
111
111
111
114
115
118
119
119
121
122
122
124
124
9.
9.1
9.2
9.2.1
9.2.2
9.2.3
Consequence models (FSA step 2)
Consequence models
Consequence cost evaluation
Fatalities
Property damage
Environmental damage
126
126
128
128
128
130
10.
10.1
10.2
10.3
10.4
Presentation of results from risk analysis (FSA step 2)
Locations and scenarios
Grounding and collision risk results
Expected annual accident costs
Sensitivity analysis
131
131
133
136
139
11.
11.1
11.2
Cost-benefit models (FSA step 4)
Description of cost-benefit model
Assessment of basic cost-benefit parameters
141
141
144
12.
12.1
12.2
12.3
12.4
12.5
Cost-benefit evaluations (FSA step 4)
Total risk changes from implementation of risk reducing measures
Calculated values of the cost-benefit criterion
Ranked list of risk reducing measures
Cost-benefit sensitivity analysis
Control programme for follow-up and updates of results
155
155
156
157
160
163
13.
166
14.
References
170
Appendices
Appendix 1: Hazard identification sheets
Appendix 2: Transverse southbound traffic distributions
Appendix 3: Transverse northbound traffic distributions
Appendix 4: Speed distributions
Appendix 5: Draught distributions
Ref. 568125/R568125-002(1)
i
i
ii
iii
iv
v
III
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
6: Heading distributions
7: Course over ground distributions
8: Fitted distribution parameters for ship location
9: Passage situation distributions
10: Estimation of the number of leisure boats in Øresund
11: Visit to ports in Øresund
12: General description of Bayesian network
13: Bayesian network for frequency models
14: Bayesian network for consequence models
15: Accident costs in Norwegian waters
Ref. 568125/R568125-002(1)
vi
vii
viii
xvi
xxi
xxiv
xxviii
xxix
xxxvi
xxxix
IV
1.
Introduction
1.1
Objective
In March 2005 the Danish and the Swedish authorities met for a general discussion
of the navigational safety in Øresund. At the meeting it was agreed that an overall
description of the navigational safety in Øresund should be established. In order to
do so, a common data basis including registered groundings, collisions and navigational traffic patterns should be made for both Danish and Swedish territorial waters.
In this connection, it was expected that the new AIS-technology could give important
contributions.
A common work group was established that before May 2005 should present a commisorium for this. Both countries emphasised that present activities should not be
delayed from this commisorium. It was decided that all relevant measures to influence the safety level in Øresund (navigational markings, procedures, navigational
limitations etc.) should be included in the analysis.
This co-operation between authorities was a logic continuation of the co-operation
established at the HELCOM minister conference in Copenhagen 2001 and amongst
other issues was initiated through a suggestion from eight Baltic Sea counties concerning new route arrangements in e.g. Bornholmsgattet.
Bearing this in mind, The Royal Danish Administration of Navigation and Hydrography, The Danish Maritime Authority and The Swedish Maritime Administration have
requested Rambøll to carry out a risk analysis of the navigational safety in Øresund.
Øresund is a highly trafficked waterway used by a large number of cargo ships, oil
and chemical tankers, container ships etc. to transport goods from the Baltic Sea to
remaining parts of Europe and overseas destinations. Furthermore, passenger ships
with a high frequency of daily departures transports passengers between Denmark
and Sweden. Finally, a large number of leisure boats are using Øresund as sailing
area in the summer period.
The high intensity of various ship traffic in combination with the relative narrow
navigational routes in some parts of Øresund, will inevitably cause critical situations.
These situations may lead to collisions or groundings and a subsequent potential loss
of lives or environmental damage and several accidents have taken place in Øresund
within the last decade.
In order to ensure that the navigational risk in Øresund is not at an unacceptable
level with respect to human safety, property and environment, the authorities wants
to have a mapping of the risk in various parts of Øresund. This mapping may then
form a basis for decisions on whether to implement risk reducing measures to lower
the risk in critical areas.
1
The objective of the study is to establish a basis for the data analysis and to determine the risk for collisions and groundings in relation to human safety, property and
environment and furthermore to give recommendations for risk reducing measures
that on implementation will lower the risk related to the various risk types given
above.
The risk analysis method applied in this study is prepared such that full accordance
with the International Maritime Organisation (IMO) “Guidelines for formal safety assessment (FSA) for use in the IMO rule-making process“, ref. [1], is achieved.
1.2
Limitations
The study of the navigational safety is limited to Øresund defined by the area between a line from Gilleleje to Kullen and a line between Stevns and Falsterbo in
south, see Figure 1-1. Within this area, potential navigational risks are considered
when occurring outside the port areas.
2
Figure 1-1 Relevant area for the analysis.
3
1.3
Report overview
The study presented in this report covers a number of activities from gathering of
basic information over establishing a data basis, data analysis and risk analysis to
the final presentation of results. An overview of the content of the report is sketched
in Figure 1-2.
Project definition
Information basis
Description and procedure
Chapter 3
Validation and presentation
Chapter 4
AIS: validation and presentation
Chapter 5
Accidents: presentation and analysis
Chapter 6
Procedure
Basic information
Location
Navigational routes
Other information
AIS-data
Accidents
Other data sources
Hazards and risk control options
FSA step 1+3
Workshops
Risk register data
Risk analysis
FSA step 2
Error modelling
Scenario models
Bayesian networks
Cost Benefit
FSA step 4
Assessment of accident
costs
Assessment of costs for
implementing measures
Identification of critical scenarios
Identification of risk control options
Chapter 7
Intial risk ranking
Frequency modelling
Chapter 8
Consequence modelling
Chapter 9
Results
Chapter 10
Cost benefit models
Chapter 11
Human safety
Property
Chapter 12
Enviroment
Ranking
Recommendations
FSA step 5
Recommendations
Recommendations for decisions
making
Chapter 13
Figure 1-2 Report overview
4
2.
Executive summary
The present report presents a data analysis of the vessel traffic as well as a risk
analysis of the navigational safety in the Sound between Denmark and Sweden (Øresund). Figure 2-1 shows a map of the area.
Figure 2-1 Relevant area for the analysis.
The objective of the risk analysis is to establish a basis for the maritime authorities on which they can evaluate and decide which navigational arrangements and measures ought to be introduced in order to minimize or reduce
risks and maintain a sufficiently high safety level for the vessel traffic in Øresund.
5
The methods applied in the present study is in accordance with the International
Maritime Organisation (IMO) “Guidelines for formal safety assessment (FSA) for use
in the IMO rule-making process“, ref. [1]. The summary follows the phases in this
procedure by giving a summary of:
•
•
•
•
•
2.1
Basis for the analysis
o
Risk types
o
Risk acceptance
o
Hazards and Risk control options (FSA step 1 and 3)
Recommendation (FSA step 5)
Risk and accident types
The following risk types are included in the analysis:
•
•
•
Human safety - measured in terms of the expected number of fatalities pr.
year.
Property - measured in terms of expected annual cost.
Environment - measured in terms of annual cost for clean-up. (Long term
costs from adverse effect on the environment are not included).
The accidents considered and for which the risk is calculated for the three risk types
above includes the accident types ship-ship collisions and groundings.
2.2
Risk acceptance
The risk acceptance criteria are based on the approach described in the IMO guidelines for carrying out a Formal Safety Assessment (FSA) in which a ranking of risk
reducing measures on the basis of cost-benefit calculations is proposed. Hence, it is
the societal risk that is considered in the present study.
This is supplemented by verifying that no single locations or areas in Øresund should
contribute significantly to the total risk for the entire Øresund.
2.3
The following data sources have been used in the analysis of the vessel traffic:
•
•
•
•
•
•
•
Ship passages at Drogden lighthouse 1995-2005
Information concerning leisure boats and fishing ships
VTS data in Drogden 1996-1999
Port registrations
Pilot registrations
Ferry line departure tables
AIS data from October and November 2005
6
Through the data analysis the overall navigational routes in Øresund are described.
Based on the traffic intensities on these routes Øresund is divided into six focus areas and the results are presented for each of these areas in terms of:
•
•
•
•
•
The number of passages. An example for Flintrännan and Drogden is shown
in Figure 2-2.
The distribution of the ship locations transverse to the navigational routes in
each focus area.
Direction route distributions where information is given not only of ship location, but also of the ship direction, when passing a chosen line across a navigational route.
Illustrating the passage distances during passages and overtakings (for the
most trafficked areas only).
Distributions of GT and draught.
14300
12700
3400
16400
14800
3300
Figure 2-2 Ship movements in Flintrännan and Drogden.
It is noted that the number of movements are registered at different locations. In
between two registrations there may be changes to the ship traffic due to the pres-
7
ence of a port in the area (e.g there are approximately 2000 ships calling the port of
Dragør each year including the pilot boats at the pilot station in Dragør).
A detailed analysis of the accident registrations in the Øresund area is carried out.
The analysis covers the following aspects:
•
•
•
•
•
•
•
Location of accident
Frequency
Causes
Use of pilot
Light conditions
Size of ship (GT)
Consequences
The results of the analysis of the accident registrations are used to calibrate the established collision and grounding frequency models and to estimate input parameters
for both frequency and consequence models.
2.4
Hazards and risk control options (FSA step 1 and 3)
A hazard identification workshop was held with the objective of identifying hazards
relevant for the navigational safety in Øresund. The hazard identification workshop
resulted in a list of 66 identified hazards.
A preliminary evaluation of frequency and consequence for each risk type for each
hazard was carried out based on input from the workshop participants resulting in a
preliminary risk ranking. This preliminary risk ranking is used as part of the basis for
determining the critical locations in Øresund to be further studied in the risk analysis
(focus areas) and the critical scenarios for the detailed risk analysis.
A second workshop was subsequently held with the objective of identifying risk reducing measures (risk control options) for each of the hazards identified in the first
workshop. The risk reduction workshop resulted in a list of 44 risk reducing measures. The identified risk reducing measures are included in and accounted for in the
cost-benefit analysis.
2.5
Calculation models for estimating risks associated with collision and grounding have
been established for the following accident types:
•
•
•
Ship-ship collisions for passing ship
Ship-ship collisions for crossing ships
Grounding and ship obstacle collision
The basic concept in these models is that the ships may – based on the location on
the considered route – be at collision or grounding course, but will in normal conditions make proper corrections such that an accident does not occur. Only in cases,
where failures occur and no corrections are made, an accident occurs. The models
give estimates of the accident frequencies and the accident consequences. The acci-
8
dent frequencies are given in terms of the number of expected annual accidents. The
consequences are given in terms of the costs of fatalities, property damage and
clearing and clean-up damage.
The economical cost of a fatality related to a ship accident as well as cost related to
clearing and clean-up (environmental damage) is estimated based on information
given in Safedor, ref. [6]. The property damage is estimated based on anonymised
data information from a ship insurance company regarding the insurance sums in
case of ships being involved in accidents.
The areas with dominating risk contributions are the area at Helsingør/Helsingborg
and the Drogden channel. In total it is expected that the average number of annual
collisions is more than one and that the annual number of groundings in Øresund is
approximately 4.
2.6
The cost benefit analysis is performed according to the Danish Ministry of Transports
Guidelines for Social-economical evaluation, ref. [11]. The method implies that cost
of a given risk reducing measure is evaluated against the safety benefits that will be
achieved by implementing the risk reducing measure. The benefit of a given risk
reducing measure is estimated based on the results of the risk model. The cost and
benefit of a given risk reducing measure is combined in the cost-benefit criterion,
which is positive when the measure is cost beneficial. Cost and benefits are calculated on basis of the Net Present Value using a lifetime of 25 years for the implemented risk reducing measures and an interest rate of 6%.
The cost benefit criterion is calculated for different risk reducing measures resulting
in the ranked list of measures shown in Figure 2-3 below.
9
800
Cost/benefit criterion
700
600
500
400
300
200
100
Free pilot service
Funnel shapped entrance to Drogden
ntroduction of VTS (information service)
Excavation of Drogden to make it twice
as wide
IMO pilot recommendations made
compulsory
Precautionary area around Middelgrund
Removal of Drogden lighthouse (incl.
installation of new lighthouse)
mprove marking of Trekroner lighthouse
Introduction of VTS (navigational
assistance service)
Removal of Drogden lighthouse (excl.
Improved marking of Väster Flacket by
buoy
Traffic separation scheme around Ven
Traffic separation scheme between
Ships with smaller draught sailing
outside markers in Drogden
Overtaking forbidden in Drogden
Convoy sailing in Drogden
-100
Move the turn at W4 (HelsingørHelsingborg)
0
Figure 2-3 Graphical presentation of ranked risk reducing measures.
The risk reducing measures in left side of Figure 2-3 from ‘Move turn at W4’ to ‘Introduction of VTS (navigational assistance service)’ have a positive cost benefit criterion.
It should be noted that due to the uncertainty on the model results the present
analysis does not give a clear conclusion on a positive cost benefit criterion for VTS
(navigational assistance service) and Removal of Drogden lighthouse (excluding installation of a new lighthouse).
2.7
Some risk reducing measures may be implemented very easily without imposing
disturbances to the traffic, whereas implementation of other measures may lead to
various degrees of traffic disturbance or have other effects to be taken into account
(e.g. political) before deciding whether or not to implement the risk reducing measure.
Bearing this in mind, the list of recommendations is given in Table 2-1 below. Further development of the details in these risk reducing measures should be carried
out, and the estimated costs confirmed.
10
No.
Description of recommendation
Comments
35
Move buoy W4 at HelsingørHelsingborg further north to give the
north- and southbound traffic more
time to manoeuvre before meeting
the east/west bound traffic.
This gives a large reduction in
collision frequencies. It is however noted that no collisions
are actually registered at this
location
7
Mark additional lanes in Drogden
outside the existing Drogden channel
to be used for smaller ships with
draughts less than 5 m.
This will give more space to the
large ships in Drogden and will
lead to a reduction in collision
frequencies
43
Improvement of the marking at the
north western area of Väster Flacket
A number of groundings have
been registered at this location,
and a better marking will lead
to improved navigational conditions
Table 2-1 List of recommended risk reducing measures.
Besides the measures above, a number of measures may be recommendable depending on additional clarification before implementation. These recommendations
are:
•
•
•
•
Traffic Separation Scheme in Drogden/Flintrännan
Traffic Separation Scheme at Ven
VTS (navigational assistance service) and Removal of Drogden lighthouse (excluding
installation of a new lighthouse) were found to be cost beneficial in the cost benefit
analysis. However, due to the uncertainty on the model results, the present analysis
does not give a clear recommendation of these measures. Further analysis of both
cost and benefit of these measures might reduce the uncertainty and prove them
beneficial.
11
3.
The objective of the this risk analysis is to establish a basis for the maritime
authorities on which they can evaluate and decide which navigational arrangements and measures ought to be introduced in order to minimize or reduce risks and maintain a sufficiently high safety level for the vessel traffic in
Øresund.
As a fundament for the risk analysis and hence also an objective of the present work,
is the collection and analysis of ship traffic data such that it is ensured that a common basis for the present risk analysis and potential updates is established.
The methods applied in the present study to carry out a navigational risk analysis in
Øresund is in accordance with the International Maritime Organisation (IMO) “Guidelines for formal safety assessment (FSA) for use in the IMO rule-making process“,
ref. [1].
The procedure used in the present study (and as defined by the IMO guideline) is in
line with general applied risk assessment procedures in areas like railway safety,
oil&gas, etc. The assessment is divided into a number of phases:
1.
2.
3.
4.
5.
6.
Project definition / Basis Information
Hazard Identification
Risk Assessment
Risk Control Options
Cost-benefit Assessment
Decision making – recommendation
The interaction between the phases, which are described in detail in the following, is
shown in figure 5-1.
(1)
Project definition /
Basic Information
(2)
Hazard
Identification
FSA step 1
(3)
Risk
Assessment
FSA step 2
(6)
Decision Making
Recommendations
FSA step 5
(4)
Risk Control
Options
FSA step 3
(5)
Cost-benefit
Assessment
FSA step 4
Figure 3-1 Phases in the applied risk analysis
12
The present section outlines the basic concepts for the analysis with regard to the
phases illustrated in Figure 3-1.
3.1
Project definition and information basis
This phase relates to a description of the definitions and limitations of the study and
furthermore to the description of the set of background information that is necessary
in order to carry out the safety assessment.
3.1.1
Project definition
In order to have a common understanding of the basis for the risk analysis, a description of definitions and limitations to the present study are carried out. This concerns:
•
•
Definitions and limitations of the types of risk to consider
Formulation of risk acceptance criteria
Risk types
As a basis for the risk analysis, a set of risk types are defined to be included in the
analysis:
•
•
•
Human safety
Property
Environment
The measures for the different risk types are as follows:
•
•
•
Human safety is measured in terms of the expected number of fatalities pr.
year.
Property is measured in terms of expected annual cost.
Environment is measured in terms of annual cost for clean-up. It is noted,
that these costs do not include long term costs from adverse effect on the
environment.
Hence, a calculation of the risk will address the items above. It is noted that human
safety relates to the safety for the persons onboard ships in Øresund and not to 3rd
party, e.g. the risks for persons being at the Øresund Bridge in case of an accident is
not included.
Risk acceptance
The procedure for Formal Safety Assessment (FSA) as described in the IMO guideline
does not account for any absolute acceptance criteria, i.e. no formulation on upper
bounds for the number of fatalities, for property damage costs of for environmental
costs are defined.
The FSA acceptance criteria relates solely to the ranking of risk reducing measures
made on basis of cost-benefit calculations. Hence, this procedure is used in the present study.
13
It is however noted, that no single locations or areas in Øresund should contribute
significantly to the entire risk. Thus, the results of the risk analysis are given in total
for the entire Øresund and divided into different areas in order to present the distribution of risk on the different areas.
3.1.2
Information basis
The risk analysis is based on the available information about Øresund with respect
to:
•
•
•
•
•
Area description (limitation)
Description of ship traffic
Meteorological information
Existing rules and procedures
A large number of data sources have been investigated. The data analysis is described in details in chapter 5 - both regarding the data analysis of existing traffic
and the analysis of registered accidents in Øresund.
Besides the collected data material, information about the navigational conditions in
Øresund have been detailed described on basis of arranged workshops with invited
attendees having large knowledge of the navigational conditions in Øresund as described in the following section.
3.2
Hazard identification and risk control options (FSA step 1 and 3)
Prior to the risk analysis, an identification process is carried out. The purpose of the
identification process is to identify
•
Critical areas and events relevant for the considered risk types (hazard identification)
•
Risk reducing measures (Risk control options) that will lower the risk related
to the considered risk types
The identification process is carried out on two workshops – one where hazards have
been identified and one where risk reducing measures have been identified. People
having large knowledge of the navigational conditions in Øresund (pilots, ship masters, rule makers etc.) have been invited to attend the workshops. Detailed descriptions of the identification of hazards and risk control options including procedures,
results and lists of attendees are given in chapter 7 and form the basis for the risk
assessment modelling together with the information given from the collected data
and background material.
3.3
Risk assessment (FSA step 2)
On basis of the identified critical areas and critical events as determined from the
hazard identification and analysis of accident registrations, a number of Bayesian
networks have been established to calculate the frequency of occurrence of the
events and the consequence given an event occurrence.
14
3.3.1
Frequency and consequence analysis
In order to determine the yearly frequency of collisions or groundings, models have
been established taking into account a number of parameters. Different main event
categories and subcategories have been defined taking into account one or more of
the events identified at the hazard identification workshops. It is noted that these
are not all relevant for all considered scenarios. Basically, the following general types
of events are analysed:
•
•
•
Ship-Ship collisions
•
Crossing routes
•
Passage situations (passages and overtakings)
Ship-obstacle collisions
Groundings
Frequency and consequence models are made for these categories and are separately adjusted to fit local conditions. Thus, a large number of models are made all
based on the categories above but representing each a specific area of Øresund with
input parameters reflecting the conditions (traffic and navigational) that are relevant
for the selected area. Detailed frequency and consequence modelling are shown in
chapter 8 and chapter 9, respectively.
The total risk for each of the risk types is thus determined as a sum of individual
contributions to the risk of the considered type (human safety, property and environment).
The risk contributions are divided into different areas of Øresund and ranked to ensure that the risk of a single area do not contribute significantly to the total risk.
3.4
Risk control options (FSA step 3)
On basis of the second identification workshop with focus on the risk reducing measures, a list of possible risk reducing measures (risk control options) is established.
The effect of implementing the risk reducing measures are included in the frequency
and consequence models such that it is possible to determine the decrease in risk by
implementing the risk reducing measures.
3.5
Cost benefit assessment (FSA step 4)
The influence on the risk from introducing some of the proposed risk reducing measures are analysed, and on basis of estimates of
•
•
The costs related to implement a measure
The benefit from reducing the risk when the measure is implemented
a ranked list of risk reducing measures is presented. The ranking is made such that
the risk reducing measure which gives the highest cost benefit will be on top of the
list. The methods applied for calculating the cost-benefit for implementing a single
measure involves calculations of the Net Present Value (NPV), i.e. the present value
of an investment (and daily expenses to maintain the investment) and the savings
from avoiding accidents when the measure is implemented.
15
In connection with calculation of NPV-values, values for discount rate and for lifetime
of the considered risk reducing measure are applied. There may be differences in
lifetime for different risk reducing measures. However, for simplicity it is proposed to
use the same lifetime for all considered measures.
3.6
Decision making and recommendations (FSA step 5)
The ranked list of the risk reducing measures is the basis for the decision makers to
choose the most efficient measure for reducing the risk. It is noted that since the
ranked list is based solely on economical considerations there may be other reasons
(political, environmental) that shall be accounted for before it is decided which of the
risk reducing measures that shall be implemented.
In Figure 3-2 the overall process flow in the analysis model is shown.
16
Workshops
Iidentification of hazards
Identification of risk reducing measures
Hum an errors
-Skill based
-Rule based
Technical
errors
Engine failure
Steering failure
Meteoroloical data
Wind
Current
Visibility
Waves
Critical events
Critical locations
Critical error types
Accident reports
-types
-locations
-causes
Ship traffic characteristics
-ship types
-Annual number of
movements
-draught
.........
Location A, Event #1
Location A, Event #2
...............................
Location X, Event #YY
Definition of risk targets
-Human safety
-Property
-Environment
Rules & Procedures
-Markings
-Maps
-Pilots
-VTS
..........
Risk evaluation and ranking
Construction and O&M
costs
Risk reduction and cost benefit
Recommendations
•
Figure 3-2 Overall procedure for risk analysis and cost benefit assessment
17
4.
Basic information
The considered region of the risk analysis is Øresund, i.e., the water between Sweden and Denmark with the border between Sweden and Denmark located right in the
middle of Øresund.
The present section describes characteristics of Øresund with focus on:
•
•
•
•
Navigational routes and potential route limitations
It shall be noted that the risk analysis is limited to Øresund excluding port areas.
Thus, there is no specific description of the large ports in the area.
Prior to the present study, a number of analyses of the navigational safety including
the Øresund region have been carried out. These have had different focus depending
on the purpose of the analysis. The most significant studies are listed below:
•
Operational Risk Analysis for the Øresund Bridge and the Drogden Tunnel,
ref. [35], [20] and [19].
A large number of analyses concerning navigational safety and the 3rd party
risk and environmental risk from establishing the Øresund Link was carried
out.
•
Drogden Feasibility Study, ref. [5].
A study of the advantages and disadvantages obtained from deepening the
Drogden channel.
•
Sund Risk, ref. [2], [3], [23], [24] and [25].
A number of studies carried out by the University of Lund with the purpose of
highlighting different issues of the navigational risk in Øresund
•
Navigational safety in Danish Waters, ref. [14]
A study of critical regions in Denmark and proposals for measures to reduce
the risk.
•
Accident registrations in Øresund 1997-2005, ref. [4]
A statistical description of registered accidents in the Danish part of Øresund.
18
4.1
Øresund is limited of a line from Gilleleje to Kullen in north and a line from Stevns to
Falsterbo in south. The area is illustrated in Figure 1-1.
4.2
Øresund is highly trafficked and leads the ship traffic from Kattegat and the North
sea to the Baltic Sea. The yearly number of ships passing through Øresund is approximately 40.000.
There are several large ports located along the coast in Øresund, amongst these are
the ports of:
•
•
•
•
København
Malmö
Helsingør
Helsingborg
The most frequent visiting ships are ships on various passenger and cargo routes
sailing in Øresund e.g.:
•
•
•
•
•
The ferries between Helsingør and Helsingborg
The ferries from Copenhagen to Oslo and Swinousce
The ferries from Malmö to Swinousce and Germany
The Nordø Link from Malmö to Travemünde
A large number of cruise ships visiting the ports of København and Malmö.
Below is shown some of the ships most frequently passing Øresund.
MS Aurora - a ferry on the route from Helsingør to Helsingborg
19
Wilanov – a ferry on the route between Malmö and Swinoucie
Cruise ships at Langelinie in København
Finnsailor – a cargo ship on the route between Malmö and Travemünde
Besides the ships on regular routes, a large number of various ship types (oil tankers, chemical tankers etc.) are passing through Øresund on their way to or from
ports in the Baltic Sea. Due to limitations in allowable draught in Øresund, a number
of ships are using Storebælt (with larger draught limitation) when sailing loaded and
are using Øresund when sailing in ballast.
20
Finally, a large number of leisure boats and fishing vessels are using Øresund. The
occurrences of these ships are not limited to any specific regions of Øresund, but are
seen all over the region.
Thus, it is seen that the traffic in Øresund consists of a mixture of different ship
types and does thus require good skills and awareness from the navigator on the
ships when passing Øresund.
4.3
Navigational routes
The ships entering Øresund may use different routes on their way through Øresund
depending on the actual draught of the ship or depending on weather conditions etc.
The navigational routes in Øresund are:
•
•
•
•
•
•
4.4
Kongedybet, Hollænderdybet Kronløbet - the port entrance to København
Flintrännan
Drogden
Drogden South
There are large differences in e.g. width of the navigation channels at various places,
in water depth etc. Ships coming into Øresund from north may have a draught of up
to 11.5 m when visiting the port of København and 13,5 m when visiting the port of
Malmö. However, further south - through Drogden and Flintrännan –the water depth
is 8 m and 8.4 m, respectively.
In Flinterännan the elevated bridge of 1090 meters has a span of 490 meters. The
navigable overhead clearance ( air draught ) are 55 meters at MHW. The width of
the navigation channel is 370 m. The water depth in Flinterännan is 8.4 m, and
pilotage is offered for ships not exceeding a draught of 7.0 meter. There is a
maximum air-draught of 55.0 meter at mean water level for crossing the bridge.
In Drogden, the water depth is 8 m at MSL and pilotage is offered for ships up to a
draught of 7.7 m. Ships with air draught above 35 m shall report to Copenhagen
airport
4.5
Pilot regulations in Øresund
Due to the dense traffic and the special navigational conditions in Øresund, a number
of requirements and recommendations for sailing in Øresund with respect to pilot
assistance are established by the Danish and Swedish authorities. The following is a
short description of these requirements and recommendations and includes:
21
•
•
•
•
4.5.1
Requirements for use of pilots for the different harbours in Øresund
The border between Denmark and Sweden is located in the middle of Øresund. For
this reason, guidelines for which national pilotage service must be used have been
established. It is in short described in the following:
•
•
•
•
4.5.2
Both countries can offer pilotage if there is a Danish and a Swedish coast
surrounding the water, where pilotage shall take place, i.e.
Both Danish and Swedish pilots can be used for ship traffic in Flinterännan, west of Ven and through the traffic separation zone at
Helsingør/Helsingborg
Only Danish pilots must be used through Drogden
Only Swedish pilots must be used east of Ven.
Each of the countries pilots offer pilotages to and from own countries ports in
Øresund
Both countries pilots must offer pilotage to/from anchoring position in
neighbouring country.
The navigator/ship owner decides which of the national pilot services shall be
used
Compulsory pilotage shall apply to the following merchant ships when navigating
interior and exterior Danish territorial waters, ref. [36] and includes the following:
•
•
•
•
Oil tankers with cargo.
Chemical tankers carrying cargoes of dangerous liquid chemicals included in
IMO’s chemicals code (International Maritime Organization’s “Code for the
Construction and Equipment of Ships Carrying Dangerous Chemicals in
Bulk”).
Gas tankers.
Ships carrying radioactive cargoes.
Compulsary pilotage for Swedish territorial waters is described in ref. [37] and is in
general similar to the descriptions applying for Danish waters above. Pilotage is, in
general, compulsory for masters on vessels with a length of 70 meters or beam of 14
meters or more.
22
4.5.3
Requirements for use of pilots calling on different harbours in Øresund
The following section gives specific descriptions for pilotage for a number of harbours
in Øresund.
Amagervaerket Harbour
Ships shall use a pilot when arriving at or departing from Amagervaerket Harbour.
This provision shall not apply to:
•
•
Ships with a length of up to 90 metres fitted with a bow propeller and sufficient engine power
Ships commanded by a master who has called at the harbour with the ship in
question at least five times within the past six months.
Helsingør State Port
Tank ships shall use a pilot when arriving at or departing from Helsingør State Port.
This provision shall not apply to tank ships commanded by a master who has called
at Helsingør State Port with the ship in question at least five times within the past six
months provided that a listening watch is maintained on VHF, channels 12 and 16.
Prøvesten Harbour
Ships shall use a pilot when arriving at or departing from Prøvesten Harbour. This
provision shall not apply to:
•
•
Ships with a length of up to 90 metres fitted with a bow propeller and sufficient engine power
Ships commanded by a master who has called at the harbour with the ship in
question at least five times within the past six months.
Malmö Harbour
Requirements for two pilots apply for ships heading for Malmö if the ship has a
length of above 200 m.
4.5.4
In IMO resolution MSC 138(76) on recommendation on navigation through the entrance of the Baltic Sea it is recommended that:
•
•
•
Loaded oil tankers with a draught of 7 m or more
Loaded chemical tankers and gas carriers, irrespective of size, and
Ships carrying a shipment of irradiated nuclear fuel, plutonium and high-level
radioactive wastes (INF-cargoes),
23
when navigating the Sound between a line connecting Svinbaadan Lighthouse and
Hornbaek Harbour and a line connecting Skanör Harbour and Aflandshage (the
southernmost point of Amager Island):
1) to use the pilotage services established by the Governments of Denmark and
Sweden
2) to be aware that anchoring may be necessary owing to the weather and sea conditions in relation to the size and draught of the ship and the sea level and, in
this respect, take special account of the information available from the pilot and
from radio navigation information services in the area.
24
5.
As an important part of input to the risk analysis is detailed descriptions of the existing ship traffic based on a data analysis of available data sources. The objective of
the present chapter is to establish the data basis for existing ship traffic and present
the corresponding data analysis. The purpose of data analysis is primarily to give
qualitative and quantitative input to the risk analysis, and secondly to give background information concerning navigation in Øresund.
For the present risk analysis the following data sources have been used:
•
•
•
•
•
•
•
Ship passages at Drogden lighthouse 1995-2005
Information concerning leisure boats and fishing ships
VTS data in Drogden 1996-1999
Port registrations
Pilot registrations
Ferry line departure tables
AIS data from October and November 2005
Besides these data, meteorological data (wind, waves, current, and visibility) are
used as input to the risk analysis. Basic parameters based on these data are mainly
taken from other available studies, ref. Drogden Feasibility study, ref. [5], the Sund
Risk studies, ref. [1] and [3].
In the following sections each of the data sources listed above is described and basic
analysis results are presented.
Furthermore, a data validation aiming at ensuring a sufficient quality of the AIS data
is carried out. Finally, detailed analyses of both AIS data and ships passages at
Drogden lighthouse are made.
Data sources not related to ship traffic (meteorological data) are described at the
end of the present section.
An overview of the data handling is seen in Figure 5-1.
25
Data colletion
Data validation
Compare data from
different sources
Drogden
registrations
Leisure boats and
fishing ships
Data analysis
Yearly number of
passages
Transverse route
distribution
VTS data
Passage analysis
Ship characteristic
distributions
(L,B,D,BT, ....)
Port registrations
Ship type distributions
Pilot registrations
Data presentation
Ferry lines
AIS
Figure 5-1 Overview of data analysis procedure
5.1
Drogden observation station
Information concerning the ship traffic in Øresund is registered at the permanently
manned Drogden observation station at Drogden lighthouse. Data in the period from
1995-01-01 to 2005-12-08 is made available for this study.
26
All ship passages (except small leisure boats) crossing a line between the south of
Amager, Drogden lighthouse and Klagshamn in Sweden are registered. For each passage the following information is registered:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Date (year, month and date)
Time (hour, minute, second)
Name (name of ship)
Course (north/south)
Direction (Drogden or Flintrännan)
Class
PTNR (military call sign)
Call sign
Lloyd number
Country
Type
DWT
GT
Velocity
Pilot (is a pilot present)
Draught
Cargo (Yes/No)
Data from
Destination
AIS-error
The fields “pilot”, “draught”, “cargo”, “data from”, “destination” and “AIS-error“ have
only been registered in for the period 2005-07-15 to 2005-12-08.
When AIS-information about the ship is available, this information is used and stored
in the database. If AIS information is not available (most likely due to the fact, that
the ship has no AIS installed), it is noted in the database, and ship characteristics
are found from other sources (Lloyds etc.) if available.
The data from Drogden observation station is validated in sections 5.8.3 and 5.8.5,
and the detailed analysis of the data set is presented in section 5.10.
5.2
Leisure boats and fishing ships
Leisure boats and fishing ships are frequently seen in Øresund, and especially in the
summer period a large number of leisure boats (sailing ships and fishing ships) are
using Øresund. For this reason, estimates have been given for the intensity of these
ship types in Øresund as an input to the risk analysis.
27
To describe this kind of traffic several relevant ports have been contacted. The ports
have supplied information concerning:
•
The number of permanent leisure boats in the harbour
•
The number of "guest nights" (corresponding to leisure boats) in the harbours
A "guest night" is defined as one ship staying in a foreign port for one night. I.e., if
the same ship stays in the foreign harbour for two days, this will count as two guest
nights.
In Table 5-1 is given an overview of the permanent residents and number of guest
nights for some large leisure boat ports in Øresund.
Permanent residents
at harbour
Svanemøllen
Rungsted
Helsingør
Hellerup/Skovshoved
Dragør
Helsingborg
Copenhagen*
Copenhagen County*
1079
800
950
420
750
280
-
Annual number of
guest nights
2063
2700
10 000
2700
7500
3500
15 464*
41 861*
Table 5-1 Annual number of permanent residents and number of guest night
at relevant harbours.
* The summer period (June-August) only.
Based on the number of guest nights and permanent residents in Copenhagen
County a distribution for leisure boats and fishing ships in Øresund is estimated. The
details of the calculations are shown in Appendix 10 Estimation of the number of
leisure boats in Øresund. The overall distribution is as shown in Table 5-2.
28
Month
Ships per day
January
February
March
April
May
June
July
August
September
October
November
December
< 200
< 200
< 200
480
480
2400
2400
2400
480
< 200
< 200
< 200
Table 5-2 Distribution of leisure boats and fishing ships in Øresund.
The numbers given in Table 5-2 cover the entire Øresund region. In Table 5-3 is
shown the assumed distribution at the different locations in Øresund. Note that 10%
of the traffic from leisure boats and fishing vessels are not accounted for, because it
is assumed that they sail outside the mentioned areas. In Table 5-3 the assumed
percentage of the traffic that sail in the sailing routes for the commercial traffic is
also given.
Location
Distribution
Part of traffic in
sailing routes
Øresund south
Drogden
Flintrännan
Ven east
Ven west
Helsingør-Helsingborg
15%
5%
10%
15%
15%
30%
10%
10%
10%
90%
90%
30%
Total
90%
-
Table 5-3 Distribution of leisure boats and fishing ships in Øresund regions.
Based on the numbers in Table 5-2 and Table 5-3 distributions of leisure boats and
fishing ships for each of the areas can be established.
5.3
Port registrations
Information about large ports in Øresund has been retrieved by contacting ports in
the Øresund area. Basically, the annual number of visits to the port have been registered divided into different ship types, ship sizes etc. Where necessary, the information has been supplied with information from Danmarks Statistik, ref. [7].
In Appendix 11 Visit to ports in Øresund is given an overview of the annual number
of visits to the larger ports in Øresund.
29
5.4
Pilot registrations
Information of pilot assistance is important with respect to the risk analysis, because
presence of a pilot onboard a ship could reduce the probability of human failure.
In Øresund there is a pilot service in both Danish and Swedish waters. Pilot registrations have been received from both the Danish as well as the Swedish authorities.
The Danish registrations cover the period 2004 and 2005, where the data from 2004
are more detailed. In the 2004 data set there is a registration for each pilot assistance with information of e.g. pilot route and draught of ship. In the 2005 data set
the registrations are summarised for each pilot route and no information is given
concerning e.g. the draught of the ships.
With respect to the Swedish pilot data specific information concerning the use of pilot
east of Ven was given by The Swedish Maritime Administration. In 2005 there were
500 pilot assistances east of Ven, 300 of these were in transit and the remaining 200
was for Landskrona or Malmö harbour. The Swedish pilot data set for pilot assistances in the entire Øresund was not complete. Thus, for the use of the present risk
analysis pilot data are based on the Danish registrations for 2004. This means that in
Swedish waters pilot data from similar Danish waters are used.
The data analysis is performed for all pilot routes potentially passing through Øresund. Some of these routes (e.g. Skagen-Bornholm) could also pass through Great
Belt, but it has not been possible to determine the specific choice of route for each
pilot assistance.
In Figure 5-3 the number of pilot assistances for each month in 2004 is given.
30
Number of pilot assistance
450
400
350
300
250
200
150
100
50
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
Figure 5-2 Distribution of Danish pilot registrations in the months of 2004.
The pilot data are further analysed with respect to draught of the ships using the
pilot service. In Figure 5-3 the distribution of draught for the ships using the pilot
service are given.
35%
30%
25%
20%
15%
10%
5%
0%
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
>14
Draught [m]
Figure 5-3 Distribution of ships that use pilot based on the size of draught.
Figure 5-3 shows that 75% of all ships using pilot have a draught between 6 and 8
m. Further, since the maximum allowed draught in Øresund is 12.5 m, ships with a
31
draught of 13 m or more is assumed to be ships on a pilot route going through the
Great Belt, rather than Øresund.
For the risk analysis, information concerning the use of pilot in each focus area is
interesting. Since only Danish pilot information is available the following three areas
have been analysed:
• Drogden
• Ven west
• Helsingør-Helsingborg
The relevant pilot routes for each area have been selected and an analysis has been
performed for the selected pilot routes.
In Table 5-4 the number of ships using pilot are given for each draught class in the
three focus areas. This is illustrated in Figure 5-4.
Draught
[m]
0-2
2-4
4-6
6-8
8-10
10-12
12-14
>14
Total
Drogden
Ven west
HelsingørHelsingborg
4
23
405
1553
12
0
6
15
1
13
361
1574
87
17
6
15
0
10
268
1346
90
23
9
15
2003
2059
1746
Table 5-4 Number of ships using pilot in 2004 distributed on draught classes
in three focus areas.
32
2000
1800
No of ships with pilot
1600
1400
1200
1000
800
600
400
200
0
0-2
2-4
4-6
6-8
8-10
10-12
12-14
>14
Draught [m]
Drogden
Ven west
Figure 5-4 Number of ships with pilot in 2004 distributed on draught
classes.
Table 5-4 and Figure 5-4 shows that the largest number of ships using pilot are seen
in the draught class 6-8 m for all three focus areas. This corresponds to what was
seen for the overall picture of Øresund (Figure 5-3).
In the risk analysis the number of ships using pilot can be related to the total number of ships in each draught class to establish a probability of a ship having a pilot
onboard depending on the draught of the ship.
5.4.1
IMO recommendations and pilotage
The Royal Danish Administration of Navigation and Hydrography has counted the
number of ships passing Drogden Lighthouse that should use a pilot according to the
IMO recommendations (see section 4.5.4) but does not. In this counting the 5/6
rule, stating that ships that have passed 5 times within the last 6 months are relieved of pilot duty on the 6th and following passings, has been taken into account.
The counting shows that for a six month period 786 ships has passed Drogden Lighthouse that should use pilot according to the IMO recommendations but did not. 560
of these ships have passed 5 times within the previous 6 month period and are
therefore excused for the use of pilot. Thus, 226 ships during a 6 month period did
not use pilot although IMO recommends it.
The counting is used in the analysis of a risk reducing measure suggesting that IMO
recommendations regarding the use of pilot are made compulsory.
33
5.5
Ferry lines
In Øresund there are several ferry lines and passenger ships:
•
•
•
•
•
•
Helsingør - Helsingborg
Copenhagen – Helsingør – Oslo
Copenhagen - Swinousce
Malmö - Swinousce
The Nordø Link from Malmö to Travemünde
A large number of cruise ships visiting the ports of Copenhagen and Malmö.
The route between Helsingør and Helsingborg is operated by three different ferry
lines and has a substantial amount of daily arrivals, see section 5.8.4.
The route between Helsingør and Helsingborg has been used to validate the number
of AIS-registrations between Helsingør and Helsingborg, see section 5.8.4.
5.6
VTS-Data
A Vessel Traffic Service system (VTS) was introduced during the construction period
of the Øresund Bridge from 1996 to 2000.
The primary tasks of the VTS system were to assist ships sailing through Drogden
and Flintrännan to ensure safe navigation and hence to avoid dangerous navigational
situations in the vicinity of the working areas, see ref. [9] and [10]. Information was
exchanged between the ships and the VTS-stations in Dragør and in Malmö, respectively, via radio contact.
In Table 5-5 annual passages registered by the VTS-stations are summarized.
Year
1996
1997
1998
1999
Drogden
37
38
38
41
597
636
826
028
Flinterännen
4987
Table 5-5 Annual passages through Drogden and Flintrännan based on VTSregistrations in 1996-1999, ref. [9]and [10].
5.7
AIS-data
AIS data is described in detail in ref. [8], and the following sections enclosed in quotation marks are extracts from this reference included to give a description of the
AIS system.
“UAIS (Universal Automatic Identification System), colloquially known as AIS, is
a civilian automatic information system which makes possible the exchange of
data between ships and between ships and land based stations.
A ship equipped with AIS continuously transmits information on e.g. the ships’
name, position, course, speed, draught, type of vessel along with data on the
34
ships’ cargo etc. The information is transmitted via radio communication to
other ships equipped with AIS as well as to land based AIS-stations.
The International Maritime Organization IMO has decided that as of July 1 2002
all new ships with a gross tonnage of 300 and upwards engaged in international
navigation shall be equipped with AIS. At the same time AIS is gradually introduced in older ships so that by the end of 2004 all ships exceeding a gross tonnage of 300 are fitted with AIS equipment.”
The AIS-data are obtained from The Royal Danish Administration of Navigation and
Hydrography and includes registrations in the period from 2005-10-19 to 2005-1208.
The received data are divided into two data files with the following content;
1.
2.
Dynamic information of movement of the ships (information that changes
over time)
Static information (ship characteristics invariant in time).
The AIS unit at the ship broadcasts the information every 2 to 10 seconds while underway depending on velocity, and every 3 minutes while at anchor, whereas the
static data only is recorded with an interval of approximately 6 minutes. The dynamic data (location, speed and heading) are stored automatically, whereas some of
the static data are stored manually by the navigator and is transmitted through the
AIS responder.
5.7.1
Dynamic data
The dynamic data holds the following information:
•
•
•
•
•
•
•
•
•
•
•
•
Year
Month
Day
Hour
Min
Sec
MMSI - is a unique number for each of the registered ships.
Lat - gives the latitude position (in degrees and minutes) of the ship
Lon - gives the longitude position (in degrees and minutes) of the ship
Heading - is the direction at which the ship points, given as an angle in degrees measured clock-wise from north.
COG - is the “course-over-ground”, which is the direction the ship moves,
given as an angle with the same reference as heading.
SOG - is the “speed-over-ground” (the velocity in knots).
The fields year, month, day, hour, min and sec give information about the exact time
of the registration.
35
5.7.2
Static data
The static data is recorded every sixth minute. They hold the following information:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Year
Month
Day
Hour
Min
Sec
MMSI
IMO
Destination
CallSign
TypeOfShipAndCargo
Draught
Size_A
Size_B
Size_C
Size_D
Similar to the dynamic data, the static data stores the time of the registration and
the MMSI number. Even though the time is not considered a static parameter it is
stored along with the static data as a time stamp for the registration. The IMOnumber is a unique registration for a given ship similar to the MMSI number.
The static data holds information about various ship characteristics, e.g., the size of
the draught, the type of ship and cargo, the name, the call sign and the destination.
The quantities Size_A, Size_B, Size_C and Size_D represent ship dimensions as illustrated in Figure 5-1. The point these lengths refer to illustrates the position of the
AIS transmitter.
Figure 5-1 Illustration of the quantities Size_A, Size_B, Size_C and Size_D
36
The information from the static and dynamic data sets are related via the unique
MMSI numbering and the time of the registrations. It is noted that dynamic data can
be observed without having corresponding static data.
5.8
Validation of data
Due to the high level of details in the registered AIS-data, it is considered reasonable
to base the risk analysis on statistics of these data. For this reason, the following
sections describe the quality of the data and compare the data with registrations
from other data sources.
5.8.1
Quality of the dynamic AIS data
Various registrations in the AIS data may be stored incorrectly or may be missing.
Some errors can be quite obvious (e.g. headings larger than 360 degrees), while
others may be difficult to track. Furthermore, some registrations are stored more
than once (duplicate registrations). In Table 5-6 some of the most general errors are
given.
Part of dynamic
registrations
MMSI equal to zero
Heading error (>360 degrees)
Duplicate registrations
1.5 %
19.2%
6.2%
Table 5-6 Ratio of error registrations in dynamic AIS-data
There is also registered lack of data in the data set. Lack of data is identified when
there is a gap in time between two successive registrations of a ship.
In total there are observed 60 gaps in data, which are of a duration of at least two
minutes. 22 of these gaps are 5 minutes or more in duration, while there is one huge
gap of 1684 minutes (approximately 28 hours).
Other types of errors are experienced during the data analysis, these are mainly related to false registrations of the dynamic data. Examples of these types of errors
are:
•
•
•
Ship transmitting wrong MMSI number
Unrealistically large velocity
False coordinates
These error types are detected during the data analysis and are accounted for - either by cross-checking with other registrations of the same ship or by excluding the
false data registrations from the analysis.
5.8.2
Quality of the static AIS-data
There is a difference between the static data and the dynamic data. The static data
requires data input to the AIS transmitter. If the user of the transmitter does not
give any data input of the ship characteristics, these data will not be transmitted.
37
Hence, the static data may lack information as well as contain errors due to human
failures.
In Table 5-7 the errors in the static data are listed. Since these data should be used
to obtain extra information corresponding to the dynamic data, records where MMSI
is equal to zero cannot be used, whenever static data are needed.
Some of the errors related to one static data registration are easy to detect and exclude from further analysis and still take advantage of the remaining registrations.
Examples of such errors and their extension are shown in Table 5-7.
Part of static
registrations
Draught = 0
Draught > 25 m
No ship type
No ship dimension
No MMSI
1.8%
1.6%
3.5%
9.2%
1.1%
Table 5-7 Quality of the static AIS-data.
As seen from Table 5-7, the information of the dimensions of the ship is not available
in all cases. However, the remaining information from those registrations can be
used. Since the extent of the errors reported in Table 5-7 is relatively small, the data
quality is considered sufficient for the risk analysis.
5.8.3
Comparisons of AIS data and data from Drogden observation station
The registrations made at Drogden registration station cover the same period as the
period where AIS data is available. Thus, a comparison of the number of total registered ship movements in Drogden and in Flintrännan are carried out and the result is
shown in Table 5-8.
Location
Drogden, northbound
Drogden, southbound
Flintrännan, northbound
Flintrännan, southbound
Total
No. of registrations
Drogden
AIS
station
2014
2324
401
444
5183
1879
2088
414
437
4818
Ratio
93%
90%
103%
99%
93%
Table 5-8 Registrations at the Drogden registration station compared to AIS
registrations.
In Table 5-8 it is seen that there is a good agreement between the two set of registrations, and that the AIS registrations accounts for 93% of the registrations from
Drogden observation station.
38
It is noted that registrations from Drogden observation station also includes information from AIS data. It is registered whether or not AIS-information is available. Approximately 7% of the data is without any AIS-information.
Hence, it is concluded that the AIS data is in good agreement with the data from
Drogden observation station.
5.8.4
Comparison between AIS and ferry lines between Helsingør/Helsingborg
The ferry route between Helsingør and Helsingborg is operated by three different
ferry lines and has a substantial amount of daily departures. Since the daily departures are given in various time tables, departures during the AIS-registration period
can be estimated. quite accurately.
Comparisons between AIS-registrations of the ferries and time table countings are
given in Table 5-9 below.
HH-Ferries
Sundbusserne
Scandlines
Total
Time table
3679
2175
6264
12 118
AIS
3644
2148
5872
Ratio
99%
99%
94%
Difference
1%
1%
6%
11 664
97%
3%
Table 5-9 Registrations for the ferries at the route Helsingør/Helsingborg
From the table it is seen that the correspondence between the time tables of ferry
lines and the AIS registrations are very good, indicating that the AIS-data is a sufficient basis to use in the risk analysis.
5.8.5
Comparison between VTS data and Drogden observation station
Since VTS data is registered in a construction period with potential changes in normal ship traffic patterns, it is not possible to compare these data directly to AIS.
However, it is possible to compare the VTS data registered in 1997 with the observations from the Drogden observation station during the same period to verify the
completeness of the data from Drogden observation station, and hence indirectly
confirm the quality of the AIS data. Registered annual passages in Drogden and in
Flintrännan for the two data sets are shown in Table 5-10.
VTS
Drogden
Flintrännan
38 689
4987
Drogden station
34 239
4395
Ratio
88%
88%
Table 5-10 VTS and Drogden observation station registrations for 1997.
A fair accordance between the two data sets is seen. One reason for the difference is
that the registrations are carried out in two different areas. The VTS data contain
registrations for east-west traffic between Copenhagen and Sweden, registrations
that are not included in the registered data from Drogden observation station.
39
5.8.6
Data validation summary
On basis of the quality analysis of the AIS-data and the validation toward other data
sources as shown in the previous sections, it is concluded that the AIS data has a
sufficient quality and that the AIS-data represents a significant part of the ship traffic
in Øresund. Thus, it is concluded that the data can be used as a basis for the risk
analysis.
Note, that error in e.g. draught of an AIS registration only results in the registration
being discarded with respect to the analysis of draught. In other data analyses the
registration is included.
5.9
Detailed analysis of AIS data
In the following sections results from the detailed analysis of the AIS data are presented.
The overall navigational routes in Øresund are described first. Based on these routes
Øresund is divided into six focus areas, and the results of the detailed AIS analysis
are subsequently presented for each of these areas. The analysis results consist of:
•
The number of passages.
•
The distribution of the ship locations transverse to the navigational routes
in each focus area. The plot is shown as a bar chart and is a good illustration of the transverse distribution of ships.
•
Direction route distributions where information is given not only of ship location, but also of the ship direction, when passing a chosen line. This plot
is shown as directed arrows with a length equal to the number of ships
passing the line in a given bar and a direction equal to the average direction of ships in the bar. The plot is primarily a good illustration of the direction of the ships across the line, but also shows the transverse location.
•
For the most trafficked areas distributions illustrating the passage distances
during passages and overtakings are also given.
Direction route distributions hold the same information concerning transverse location of the ships,
5.9.1
Navigational routes Øresund
In Figure 5-5 ship intensity plots from different ship movements over a short time
period is shown. The plot is generated by the Royal Danish Administration of Navigation and Hydrography.
40
1. The traffic separation
zone at Øresund north
3. Kongedybet,
Hollænderdybet and
Kronløbet
2. The area around Ven
4. Drogden and Flintrännan
5. North of Port of
Malmö
6. Øresund south and
Drogden entrance
Figure 5-5 Ship tracks on different navigational routes in Øresund
Figure 5-5 shows that the ship traffic follows specific routes in various regions of
Øresund. Øresund is divided into six focus areas (based on the accident registrations
and the hazard identification) for the detailed AIS analysis and these areas are as
shown in Figure 5-5:
1.
2.
3.
4.
5.
6.
The traffic separation zone at Øresund north
The area around Ven
Kongedybet, Hollænderdyet and Kronløbet
North of the Port of Malmö
Øresund south and the south entrance to Drogden
In the following section the results from the detailed AIS analysis is presented for
each focus area.
41
5.9.2
The area between Helsingør and Helsingborg is a narrow strait which is the northern
entrance to Øresund. The area is furthermore characterized by a large number of
ferry routes pendling between Helsingør and Helsingborg. Since there is ship traffic
in different directions a Traffic Separation Scheme is established in the area to separate north and south bound ship traffic. The separation zone is defined in a region
from north of Helsingør/Helsingborg to south of Helsingør/Helsingborg.
A map of the area is given in Figure 5-6 with annual ship flows for the overall navigational routes indicated.
14500
16300
47200
46700
16100
17900
Figure 5-6 Navigational conditions in the area around Helsingør and
Helsingborg with annual ship flows on navigational routes.
The complicated traffic pattern in the area is easily seen from the route plot in Figure
5-7 visualizing the routes for the east-west going traffic for a 12 hour period.
42
Figure 5-7 Plot of routes for a 12 hour period visualizing the east-west going traffic.
From Figure 5-7 it is seen that the ferries heading in eastern direction goes north of
the ferries heading in western direction. This can also be seen from the distributions
of the ship traffic location in east-west direction in Figure 5-8.
Figure 5-8 Distributions of ship location and direction for the ferries in eastwest direction at Helsingør-Helsingborg.
43
The ships in south/north direction sail as noted earlier in a traffic separation zone
why it is expected that the south- and northbound traffic is well separated. In Figure
5-9 it is seen that there is a good separation of the ship traffic. However, it is also
seen that outside Helsingør a small part of ships goes north before crossing the
separation zone.
Furthermore, it is clearly seen from the direction plots in Figure 5-9 that some ships
have a direction that leads them west of Ven while others have a direction leading
them east of Ven.
Figure 5-9 Distribution of ship location and direction for north-southbound
traffic at Helsingør-Helsingborg.
Similar plots to those shown in Figure 5-9 are given in Figure 5-10. The plots are
made here just at the bend on the navigation route.
44
Figure 5-10 Distributions of ship location and direction for ship passages
north-south at Helsingør-Helsingborg.
5.9.3
At the southern border of the traffic separation zone, south bound ships may choose
a route east or west of the island Ven. Ships with large draughts may choose the
eastern route of Ven due to the large water depths in this area.
The ships using Danish pilots use the route west of Ven – both south- and
northbound – while ships using Swedish pilots use the route both east and west of
Ven.
A map of the area is given in Figure 5-11 with annual ship flows on overall navigational routes indicated.
45
15100
14400
3300
800
3500
1900
Figure 5-11 Navigational conditions in the area around Ven with annual
ship flows on navigational routes.
The ships can choose to go both ways – east or west – around Ven. However, the
majority of the northbound ships chooses the way east of Ven, while the southbound
ships chooses the way west of Ven.
However, two exceptions from the usual choice of routes are:
•
•
Southbound ships heading for the port of Malmö may choose the route east
of Ven due to the shorter distance and due to the large waterdepths at the
eastern side of Ven.
The northbound ships with Danish pilots must – due to procedural requirements (see section 4.4) – take the route west of Ven.
Hence, the traffic distributions round Ven consists mainly of separated traffic - nortbound east of Ven and southbound west of Ven – and a small part of the traffic taking opposite routes. This is clearly shown in Figure 5-12.
46
Figure 5-12 Distributions of ship location and direction around Ven.
Besides the north- and southbound ship traffic around Ven, also ferry traffic from
Landskrona to Ven is registered. There are 4 different ferries serving this route and
in 2004 there were a total of 4041 trips between Ven and Landskrona. At the route
plot in Figure 5-13 is shown an example of the ship traffic pattern in the Ven region.
Figure 5-13 Route plot in the Ven area for a period of 12 hours.
47
Besides analyses of the transverse traffic distributions, also distributions of passage
distances are analysed east and west of Ven. In Figure 5-14 and in Figure 5-15 the
considered region for the passage analysis and corresponding passage distributions
are shown.
12
Number of
passages
10
8
6
4
2
e
or
M
90
0
10
20
78
0
66
0
54
0
42
0
30
0
60
18
0
0
Minimum distance [m]
Figure 5-14 Distribution of passage distances for ship passings or overtakings east of Ven
12
10
passages
Number of
8
6
4
2
e
or
M
50
00
15
13
00
12
50
10
0
0
0
0
0
90
75
60
45
15
30
0
0
M in im u m d is tan ce [ m ]
Figure 5-15 Distribution of passage distances for ship passings or overtakings west of Ven
48
5.9.4
Kongedybet, Hollænderdybet and Kronløbet
Ships approaching the port of Copenhagen will from north use Kronløbet and from
south use Kongedybet (or Hollænderdybet and Kronløbet) on their way to the port.
These are all narrow marked channels where the light house angles assists in the
navigation. A map of the area is given in Figure 5-16 with annual ship flows on overall navigational routes indicated.
4900
4800
13500
11900
1100
1000
2550
Figure 5-16 Navigational conditions in the area outside the port of Copenhagen with annual ship flows on navigational routes.
49
Kongedybet
Kongedybet is a narrow channel in the northern part of Drogden used by ships to
and from the port of Copenhagen. In Figure 5-17 is shown transverse distributions
for the location and direction of the ships using Kongedybet.
Figure 5-17 Distributions of ship location and direction in Kongedybet.
It is seen from Figure 5-17 that the ships at this location only deviate very little from
the central part of the navigation channel.
50
Hollænderdybet
Hollænderdybet is the northern continuation of Drogden. Ships using Drogden on
their way through Øresund will pass Hollænderdybet. In Figure 5-17 is shown transverse distributions for the location and direction of the ships using Hollænderdybet.
Figure 5-18 Distributions of ship location and direction in Hollænderdybet.
51
Kronløbet - Approaching and leaving Port of Copenhagen
Kronløbet is frequently used by ships entering or leaving the port of Copenhagen. In
Kronløbet, the northbound ships have different courses depending on the planned
route. A part of the ships take the route east of Buoy 21 (shown in upper right corner of Figure 5-19) before heading north, while others go north as soon as a sufficient water depth is obtained. Similarly, ships approaching from north have different
courses depending on whether or not they have been east of buoy 21. These things
are clearly seen on Figure 5-19.
Figure 5-19 Distributions of ship location and direction in Kronløbet.
5.9.5
Drogden is a narrow channel marked with buoys and a width of 300 m. Drogden is
located in the area between Nordre Røse lighthouse in north and Drogden Lighthouse
in south.
A submersed tunnel crosses underneath Drogden at a line between Peberholm and
Amager. The draught limitation in Drogden is 7.7 m. A large number of ships – approximately 30 000 pr. year - uses Drogden on their way through Øresund.
The southern entrance to Drogden is right north of the Drogden lighthouse. In this
region, a strong transverse current is often experienced. The yearly number of ship
movements in Flintrännan and Drogden is illustrated in Figure 5-20.
52
14300
12700
3400
16400
14800
3300
Figure 5-20 Ship movements in Flintrännan and Drogden.
In the following, ship location distributions are analysed at the locations:
•
•
•
Drogden Lighthouse
Buoy 16
Buoy 6
At Drogden lighthouse, the northbound ships will usually go east around the lighthouse. However, as seen from the route plot in Figure 5-21, some ships will go west
around the lighthouse.
53
Figure 5-21 Route plots at Drogden Lighthouse
In Figure 5-22 it is clearly seen that a small part of the northbound ship traffic goes
west around the lighthouse. Furthermore, it is seen that after passing the lighthouse
all ships are heading towards the navigation channel.
Figure 5-22 Distributions of ship location and direction at Drogden Lighthouse.
At buoy 16, the ships have just entered Drogden, and not all ships are at this location properly located in the navigation channel. Buoy 16 is frequently hit by ships. It
is seen from Figure 5-23, that a part of the ship traffic is located outside the marked
channel with the possibility of hitting buoy 16.
54
Figure 5-23 Distributions of ship location and direction at buoy 16 in Drogden.
At buoy 6 further north in Drogden the ships have found their place in the navigation
channel which makes the ship location distribution more narrow compared to the
distributions in the southern part of Drogden.
55
Figure 5-24 Distributions of ship location and direction at buoy 6 in Drogden.
Besides analyses of the transverse traffic distributions, also distributions of passage
distances are analysed. In Figure 5-25 the considered region for the passage analysis and corresponding passage distributions are shown.
350
300
Number of
passages
250
200
150
100
50
42
0
38
0
34
0
30
0
26
0
22
0
18
0
14
0
10
0
60
20
0
Minimum distance [m]
Figure 5-25 Distribution of passage distances for ship passings or overtakings in Drogden
56
It is seen that most of the passages occurs within a distance of 200 m, and that a
few passages have distances less than 20 m. Detailed probability distributions and
corresponding ship dimensions are given in Appendix 9 Passage situation distributions. Results from these distributions are described more detailed in section 8.2.
Flintrännan and Trindelrenden
Flintrännan is the navigational channel east of the island Saltholm crossing the Øresund Bridge. Flintrännan is marked with fixed beacons and has a width of 370 m and
a limited height of 55 m through the navigation span between the main pylons.
A small channel from the port of Malmö named Trindelrenden also crosses the Øresund Bridge. The channel has a width of 100 m through the navigation span and a
limited height of 40 m. Details of the navigation channels when crossing the bridge is
shown in Figure 5-26 below.
Figure 5-26 Navigational conditions in the vicinity of the Øresund bridge
Specific considerations concerning safety in regard to the ship traffic passing the
Øresund bridge are made. Besides the marking etc. as described in 5.9.5, a number
of protective islands are established with the purpose of avoiding ship collisions with
the piers closest to the navigation channel.
Route plots and distributions of ship locations and directions are shown in Figure
5-27 and Figure 5-28, respectively.
57
Figure 5-27 Route plots for a 12 hour period at the Øresund Bridge.
Figure 5-28 Distribution of ship location and direction at the Øresund
Bridge.
In relation to ship collisions with the bridge piers (and bridge girders for high air
draft ships), the distributions of the distance between passing ships are studied. The
passing distance distribution are shown in Figure 5-29.
58
14
12
Number of
passages
10
8
6
4
2
37
0
M
or
e
34
0
31
0
28
0
25
0
22
0
19
0
16
0
13
0
10
0
0
Minimum Distance [m]
Figure 5-29 Distributions of passage distances at the Øresund Bridge.
From Figure 5-29 it is seen that the majority of ships passes each other within 250
m in order to have a safe distance to the piers in the navigation span. A small part of
ship passages are approximately 400 m. These passages are registered in cases,
where one is using Trindelrännan and one is using Flintrännan.
5.9.6
Outside Malmö Harbour
North of the port of Malmö (east of Sjollen) the ships from Flintrännan heading north
is advised to go east of the buoy before heading north in order not to meet south
bound ships at this location. In order to determine whether or not the north bond
ships follows the recommendations, analyses of distributions of the ship location at
this place are carried out.
In Figure 5-30 (left) is seen a passage distribution based on the three lines (left).
The ship passages visualized (right) have all passed the three lines during a short
time period.
59
Figure 5-30 Distributions of ship location at passages outside Malmö harbour.
It is seen that the south bound ships takes the short route. A part of the northbound
ship traffic follows the recommendations and goes east of the buoy. However, it is
seen that a part of the ships takes the shortcut with the risk of meeting a south
bound ship.
It is noted, that the ship traffic intensity at this location is not very high. Hence, the
risk of meeting ships is not significant.
60
5.9.7
Drogden South
Traffic from Drogden and Flintrännan meets south of Drogden Lighthouse. In an area
around the roundabout mixing traffic to and from the Baltic Sea with the traffic to or
from Femern Bælt, a traffic separation zone is established as shown in Figure 5-31.
In the figure with annual ship flows on navigational routes are indicated.
18700
16900
Figure 5-31 Navigational conditions in the area around the roundabout with
annual ship flows on navigational routes.
The roundabout is located outside the Øresund region. Critical events in this region
have been identified, but the risk assessment related to the navigation in this area is
not included in the present study.
61
5.10
Detailed analysis at Drogden observation station
The content of the data registered at Drogden observation station is described in 5.1.
In the following, results of the analysis of these data are given with respect to the
distributions of
•
•
•
•
The
The
The
The
number of
number of
number of
size of the
ships over all registered years
ships registered each month
ships registered each hour of the day
GT and ship draught
The reason for using these data to estimate time dependant distributions is that the
data is registered over a period of 10 years. AIS-data is only available for a period of
50 days which makes AIS-data less suited for estimating this type of distributions.
The number of ships over all registered years
In the following the number of ships passing through Øresund each year in the period from 1995 to 2005 is shown. Furthermore, a subdivision of these ship on directions (north/south) and on the routes (Drogden/Flintrännan) is given. These are
shown in Figure 5-32, Figure 5-33 and Figure 5-34.
45,000
40,000
35,000
5.10.1
30,000
25,000
20,000
15,000
10,000
5,000
0
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Year
Figure 5-32 Ships passing through Øresund per year
62
25,000
Northgoing
Southgoing
20,000
15,000
10,000
5,000
0
1995
1996
1997
1998
1999
2000
Year
2001
2002
2003
2004
2005
Figure 5-33 Ships passing through Øresund per year in each direction
40,000
35,000
Drogden
Flintränna
30,000
25,000
20,000
15,000
10,000
5,000
0
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Year
Figure 5-34 Ships per year in Drogden and Flintrännan
It is seen from Figure 5-32 that the total number of ships passing through Øresund
varies between 30 000 and 40 000 ships per year. Furthermore, it is seen that there
is no significant increase or decrease in the ship traffic over this period.
63
From Figure 5-33 it is seen that approximately 10% of the ship traffic in Øresund
uses Flintrännan on their way through Øresund, while the rest uses Drogden.
From Figure 5-34 it is seen that there is more ships using Øresund going south than
north. This is probably due to the fact that some large ships from Russia and the
Baltic states are loaded on their out of the Baltic Sea and has a ship draught exceeding the limits for using Øresund. On their way back these ships are in ballast and
may then be allowed to use Øresund due to the smaller ballast draught.
The number of ships registered each month
Countings over the registration period of the average number of ships passing each
month are shown in From Figure 5-35.
4000
3500
Average number of registrations
5.10.2
3000
2500
2000
1500
1000
500
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
Figure 5-35 Ships movements per month in Øresund
From Figure 5-35 it is seen that there is no (or only very little) seasonal variation in
ship traffic. However, it is noted that leisure boats are not included in these registrations (see section 5.2 for estimates regarding number of leisure boats). These boats
account for a large variation over the year and have a substantial number of daily
passages in the summer period.
64
The number of ships registered each hour of the day
The total number of ship movements each hour of the day is shown in Figure 5-36.
20,000
18,000
16,000
14,000
Registrations per year
5.10.3
12,000
10,000
8,000
6,000
4,000
2,000
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Hour
Figure 5-36 Ships movements per hour in Øresund
It is seen from Figure 5-36 that there is only very little variations over the day.
65
Distribution of GT and draught
Distributions of ship characteristics are used in the risk analysis to evaluate both
frequencies and consequences of collisions and groundings. Thus, it is important to
obtain knowledge of these distributions – both regarding the shape of the distributions and the possible changes over time.
Distribution of GT is given in Figure 5-37.
100%
90%
80%
70%
Probability distribution
5.10.4
60%
50%
40%
30%
20%
10%
0%
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
GT
Figure 5-37 GT distributions in Øresund (1995-2005).
From Figure 5-37 it is seen that there are ships in Øresund up to more than 50000
GT and even significant higher. However, it is also seen that approximately 95% is
below 30000 GT and 80% is below 10000 GT.
The ship size increase over the years is estimated based on the reported GT for all
ships during the registration period. The results are shown in Figure 5-38.
66
100%
1995
90%
1996
80%
1997
70%
1998
1999
60%
2000
50%
2001
40%
2001
30%
2002
20%
2003
10%
2004
2005
0%
0
5000
10000
15000
20000
25000
GT
Figure 5-38 GT-increase 1995-2005 in Øresund
It is seen that the ship size (GT) have increased in the last 10 years. From the figure, the 80%- and 90%-percentile is calculated and shown in Table 5-11 together
with the increase ratio compared to the initial ship size percentiles in 1995.
Year
80%
Increase
compared
to 1995
90%
Increase
compared
to 1995
1995
5968
0.0%
9286
0.0%
1996
5968
0.0%
12 120
23.4%
1997
6613
9.8%
12 113
23.3%
1998
7410
19.5%
12 110
23.3%
1999
7744
22.9%
12 251
24.2%
2000
8980
33.5%
14 929
37.8%
2001
8519
29.9%
14 903
37.7%
2002
9950
40.0%
13 640
31.9%
2003
10 203
41.5%
16 543
43.9%
2004
10 271
41.9%
19 891
53.3%
2005
10 543
43.4%
21 142
56.1%
Table 5-11 80%- and 90%-percentiles for GT in Øresund 1995-2005
It is seen from Table 5-11 that a significant increase in GT has taken place. Over the
considered 10-year period the ship size have increased approximately 50% - depending on which percentiles the increase ratios are based on.
67
The distribution of ship draught based on the registrations at Drogden observation
station is given in Figure 5-39.
Draught
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0
2
4
6
8
10
12
14
16
m
Figure 5-39 Draught distributions in Øresund (1995-2005).
From Figure 5-39 it is seen that practically all ships have draughts below 8 m. This is
due to the fact that the registrations are made south of Drogden and Flintrännan
where draughts should not exceed 7,7 m and 8,4 m, respectively.
It is noted that the draught distributions at the northern part of Øresund is significantly different since draught limitations for the ships in the northern part is higher
(up to 13,5 m for ships heading towards the port of Malmö).
In the risk analysis, the draught distributions taken into account are based on AIS
registrations at the specific locations. These distributions are shown in Appendix 5
Draught distributions.
5.11
Meteorological an oceanographic data
Meteorological parameters (current, wind and visibility) have an influence on the
navigational patterns and safety. Hence, basic knowledge of these parameters gives
input to the risk analysis.
5.11.1
Current
In Øresund the current measurements are available only from the Drogden observation station at Drogden lighthouse. Current data have been obtained from the period
68
2003-2005, and the data have been analysed with respect to determination of minimum and maximum currents, time series analysis etc.
However, the current varies substantially over the Øresund area and knowledge of
the current condition at one location is not sufficient to determine the size and direction of the current at any other location in Øresund. Thus, input to the risk analyses
concerning current is instead based on expert assessments of areas with critical current conditions.
In general, the current is influenced by the high- and low pressure conditions in over
the North Sea and the Baltic Sea rather than by wind and tide.
5.11.2
Wind and visibility
The wind and visibility conditions have been analysed in details in connection with
establishment of the Øresund Fixed Link, ref. [20]. The parameters in the risk analysis are based on this reference.
5.11.3
Ice
There may be climatic conditions at winter time where ice formations will take place.
This is for instance the case at the area west of Ven. In such cases, ships may need
assistance in order to navigate properly.
69
6.
Analyses of accident registrations from Øresund are valuable information with regard
to calibration of frequency models and estimation of input parameters for both frequency and consequence models.
Accident registrations have been obtained from The Danish Maritime Authority and
The Swedish Maritime Administration covering both Danish and Swedish registrations. The Danish registrations cover the period 1997-2005, whereas the Swedish
registrations cover the period from 1988-2005.
The accident registrations are categorized into three main categories:
• Ship-ship collisions (in the following referred to as collisions)
• Groundings
• Ship-obstacle collisions
Note, that the Danish registrations do not contain the category ship-obstacle collisions. Furthermore, the Swedish registrations for ship-obstacle collisions are very
sparse after 2002. The reason for this is unknown.
In the following the accident registrations along with several statistical analyses are
presented.
6.1
Location
Figure 6-1 shows a map of Øresund with the all accident registrations plotted on it.
However, 26 of the received registrations (primarily Danish) are not plotted on the
map, because no coordinates were given for these accidents. In total 329 different
accident registrations were received and 303 of these are plotted in Figure 6-1.
70
Groundings
Ship-ship collisions
Ship-obstacle collisions
Boxes with other colours are related to the map and are not essential in this plot.1
Figure 6-1 Accident registrations in the Øresund area.
1
Caused by the limitations of the application “Det Levende Søkort 2” used for the visualization, plotting of accident registra-
tions in the same area causes some of the boxes to be misplaced. This is especially the case, when several registrations lie in
the same area.
71
In the subsequent statistical analyses of the accident registrations only accident registrations which are located within the relevant area for the present risk analysis are
included. Thus, registrations south of a line connecting Stevns and Falsterbo or north
of a line connecting Gilleleje and Kullen are omitted. This excludes 55 of the 303
registrations, leaving 248 registrations. Furthermore, registrations which are categorized either as ‘Harbour area’ or ‘At quay’ are also omitted. This excludes 77 registrations, leaving 171 registrations.
Further, the Swedish registrations are from the period 1988 to 2005, while the Danish registrations are from the period 1997 to 2005, i.e. only in the period 1997-2005
is the data material complete. Thus all registrations before 1997 have been left out
(57 registrations) which results in a data set of 114 registrations. Finally, for the
statistical analyses registrations without coordinates (and fulfilling the above mentioned criteria) have also been included (25 registrations), thus giving a total of 139
registrations for the analyses.
These 139 relevant accident registrations have been analysed and the 114 registrations with coordinates are plotted on charts. In the following, detailed maps of each
of the focus areas in Øresund are given with the relevant accident registrations
shown.
72
Ship-ship collision (2000-2005)
Grounding (2000-2005)
Ship-obstacle collision (2000-2005)
Miscellaneous (2000-2005)
Figure 6-2 Relevant accident registrations in Drogden south.
73
Figure 6-3 Relevant accident registrations in Drogden north.
74
Figure 6-4 Relevant accident registrations in Flintrännan.
75
Figure 6-5 Relevant accident registrations in area around Ven.
76
Figure 6-6 Relevant accident registrations in Helsingør-Helsingborg area.
77
The following statistical calculations of the accident registration data are presented in
the subsequent sections:
•
•
•
•
•
•
6.2
Frequency
Accident causes
Use of pilot
Light conditions
Size of ship (GT)
Consequence
Frequency
On basis of the accident registrations the frequency of each type of accident can be
calculated. The different types are:
•
•
•
•
Grounding
Ship-ship collision (referred to as collision)
Ship-obstacle collision
Miscellaneous (including e.g. capsize and pollution)
The frequencies based on the set of 139 accident registrations are shown in Table
6-1.
Accident type
Grounding
Collision
Miscellaneous
All
No. of
registrations
92
28
12
7
139
No. of
years
9
9
9
9
9
Frequency
[per year]
10.2
3.1
1.3
0.8
16.7
Table 6-1 Frequency of accidents in period 1997-2005 in the relevant area.
To investigate whether construction of the Øresund Bridge has had any impact on
the number of accidents the frequency is also calculated for the time period 20002005, corresponding to after construction of the bridge. For this time period there
are 71 accident registrations. The calculated frequencies for these 71 registrations
are shown in Table 6-2.
78
Accident type
No. of
registrations
No. of
years
Frequency
[per year]
Change in
frequency
Grounding
Collision
Ship-obstacle collision*
Miscellaneous
53
11
1
6
6
6
6
6
8.8
1.8
0.2
1.0
-13.6%
-41.1%
-87.5%
28.6%
All accidents
71
6
12.2
-23.4%
* The Swedish registrations for ship-obstacle collisions are very sparse after 2002. The
reason for this is unknown.
Table 6-2 Frequency of accidents after construction of the Øresund Bridge
(2000-2005).
Figure 6-7 shows a plot of the accident frequency for the entire period (1997-2005)
and for the period after construction of the bridge.
18
16
Frequency [per year]
14
12
10
8
6
4
2
0
Grounding
Collision
Ship-obstacle
collision
Miscellaneous
All accidents
Accident type
1997-2005
2000-2005 (after Øresundsbro)
Figure 6-7 Frequency of accident for each accident type.
From Table 6-2 and Figure 6-7 it is seen that the accident frequency after construction of the Øresund Bridge appear to be lower for all accident types except ‘Miscellaneous’. Thus the frequencies related to after construction of the Øresund Bridge will
be used as reference in the present risk analysis.
6.3
Causes
Based on the data set of 139 accident registrations the cause of the accidents can be
examined. In the 139 registration 17 different primary causes are listed. These
causes can be seen in Table 6-3 along with the percentage of accident registrations
for each cause and for each accident type.
79
Cause
Grounding
Human factor
Communication
Alcohol
Water conditions
Fatigue (of personnel)
Failure of propulsion machinery
Failure of navigational instrument
Failure of steering machinery
Navigational equipment not used
Poor planning
Lack of look-out
Navigational failure
Erroneous handling of other ship
Operational failure of other ship
Lack of or too late duty to give way
Collision with floating object
Unknown
Collision
Shipobstacle
collision
Miscellaneous
All accidents
21.7%
1.1%
2.2%
1.1%
6.5%
1.1%
1.1%
2.2%
2.2%
1.1%
1.1%
3.3%
0.0%
0.0%
0.0%
0.0%
55.4%
17.9%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
3.6%
0.0%
0.0%
7.1%
0.0%
3.6%
10.7%
3.6%
0.0%
53.6%
75.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
8.3%
0.0%
0.0%
0.0%
0.0%
0.0%
8.3%
0.0%
8.3%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
14.3%
0.0%
0.0%
0.0%
0.0%
0.0%
28.6%
14.3%
0.0%
42.9%
24.5%
0.7%
1.4%
0.7%
4.3%
0.7%
0.7%
3.6%
1.4%
0.7%
2.2%
2.2%
0.7%
4.3%
1.4%
0.7%
49.6%
100.0%
100.0%
100.0%
100.0%
100.0%
Table 6-3 Cause of accidents for each accident type.
From Table 6-3 it is seen that for approximately half of the registrations the cause of
the accident is unknown. Apart from this, the most domination cause of an accident
is conditions related to the human factor.
6.4
Use of pilot
For each accident registration it is stated whether or not a pilot was onboard (if
known) at the time of the accident. It should be noted, that with regard to the Danish registrations the use of pilot was prior to 2005-01-01 only registered if it was
judged to be relevant for the unravelling of the accident.
For 60 of the registrations this information is not given or marked as unknown, thus
approximately 60% of the registrations have information concerning the use of pilot.
In Table 6-4 and Figure 6-8 the use of pilot for each accident type is presented.
Use of
pilot
Grounding
No.
%
Collision
No.
%
Yes
No
Unknown
4
43
45
4.3%
46.7%
48.9%
1
18
9
3.6%
64.3%
32.1%
Total
92
100.0%
28
100.0%
Ship-obstacle
collision
No.
%
No.
1
9
2
8.3%
75.0%
16.7%
0
3
4
0.0%
42.9%
57.1%
100.0%
7
100.0%
12
Miscellaneous
%
All accidents
No.
6
73
60
139
%
4.3%
52.5%
43.2%
100.0%
Table 6-4 The use of pilot for each accident type.
80
80%
70%
Percentage of accidents
60%
50%
40%
30%
20%
10%
0%
Yes
No
Unknown
Pilot onboard
Grounding
Collision
Miscellaneous
All accidents
Figure 6-8 Percentage of accidents with pilot onboard for each accident
type.
From Table 6-4 and Figure 6-8 it is seen that in approximately half of the registrations no pilot was onboard the ship at the time of the accident (for collisions this
means that no pilot was onboard either of the ships) and in 40% of the registrations
the use of pilot is not known. Thus, a pilot was onboard in 4% of all of the relevant
registrations, corresponding to 7% of the registrations where the use of pilot is
known.
6.5
Light conditions
In the accident registrations the light condition at the time of the accident can be
noted. In Table 6-5 and Figure 6-9 this information is presented for the 139 accident
registrations.
Light
condition
Grounding
No.
%
Collision
No.
%
Light
Dark
Dawn
Unknown
20
22
2
48
21.7%
23.9%
2.2%
52.2%
7
9
2
10
25.0%
32.1%
7.1%
35.7%
Total
92
100.0%
28
100.0%
Ship-obstacle
collision
No.
%
6
5
0
1
12
Miscellaneous
No.
%
50.0%
41.7%
0.0%
8.3%
3
1
0
3
42.9%
14.3%
0.0%
42.9%
100.0%
7
100.0%
All accidents
No.
36
37
4
62
139
%
25.9%
26.6%
2.9%
44.6%
100.0%
Table 6-5 Light condition for each accident type.
81
50%
Part of accidents
40%
30%
20%
10%
0%
Light
Dark
Grounding
Collision
Dawn
Miscellaneous
Unknown
All accidents
Figure 6-9 Percentage of accidents distributed on the different light conditions.
From Table 6-5 and Figure 6-9 it is seen that for 40% of the registrations the light
condition is not known. For the remaining 60% it is further seen, that for each accident type there are approximately the same share of accidents with light as with
dark light condition.
6.6
Size of ship (GT)
In the accident registrations the size (GT) of the ship involved in the accident is registered. For the 139 registrations the GT has been divided into 5 classes (similarly to
ref. [4]) and the results are shown in Table 6-6 and Figure 6-10.
GT
Grounding
Collision
Ship-obstacle
collision
No.
%
Miscellaneous
No.
%
No.
%
No.
%
< 500
500 – 3000
3000 – 10000
10000 – 20000
> 20000
Unknown
13
36
21
3
5
14
14.1%
39.1%
22.8%
3.3%
5.4%
15.2%
9
12
4
2
0
1
32.1%
42.9%
14.3%
7.1%
0.0%
3.6%
5
2
2
0
2
1
41.7%
16.7%
16.7%
0.0%
16.7%
8.3%
3
1
0
1
0
2
Total
92
100%
28
100%
12
100%
7
All accidents
No.
%
42.9%
14.3%
0.0%
14.3%
0.0%
28.6%
30
51
27
6
7
18
21.6%
36.7%
19.4%
4.3%
5.0%
12.9%
100%
139
100%
Table 6-6 GT class for each accident type.
82
45%
40%
Part of accidents
35%
30%
25%
20%
15%
10%
5%
0%
< 500
500 - 3000
3000 - 10000
10000 - 20000
> 20000
Unknown
GT
Grounding
Collision
Miscellaneous
All accidents
Figure 6-10 Percentage of accidents in each GT class for each accident type.
6.7
Consequences
In the Swedish accident registrations the consequences of the accident is registered,
for the Danish registrations this information is not given. Based on the Swedish registrations the following consequences have been analysed:
•
•
•
Personal injury:
•
Number of injured
•
Number of fatalities
•
Number of lost persons
Whether or not there was a hull damage
Whether or not there was a leakage.
Personal injury
Personal injury has been registered for 57 accidents in the considered time period
(1997-2005), but only for two accidents has there been any injuries:
•
•
5 fatalities at a ship-ship collision on March 28, 2000 at the northern exit of
Øresund (close to Kullen).
1 injured at a ship-obstacle collision on September 26, 2000 at Höllviken
(near Falsterbo).
For the remaining 55 accidents there were no personal injuries.
83
Hull damage and leakage
For 54 accident registrations hull damage and leakage was registered. The analyses
of hull damage and leakage are given in Table 6-7, Table 6-8, Figure 6-11 and Figure
6-12.
Hull damage
Grounding
No.
%
Collision
No.
Ship-obstacle
collision
No.
%
%
Miscellaneous
All accidents
No.
No.
%
%
Yes
No
Unknown
19
18
55
20.7%
19.6%
59.8%
4
2
22
14.3%
7.1%
78.6%
6
5
1
50.0%
41.7%
8.3%
0
0
7
0.0%
0.0%
100.0%
29
25
85
20.9%
18.0%
61.2%
Total
92
100%
28
100%
12
100%
7
100%
139
100%
Table 6-7 Hull damage for each accident type.
100%
90%
80%
% of accidents
70%
60%
50%
40%
30%
20%
10%
0%
Yes
No
Unknown
Hull damage
All accidents
Groundings
Collision
Ship-obstacle
Miscellaneous
Figure 6-11 Percentage of accidents with hull damage.
When only considering accidents where hull damage has been registered, it can be
seen for both groundings and ship-obstacle collisions that there is hull damage in
approximately half of the accidents. For collisions there is only registered whether or
not there was a hull damage in 6 accidents and in 4 of these a hull damage was registered.
84
Leakage
Grounding
No.
%
Collision
No.
Ship-obstacle
collision
No.
%
%
Miscellaneous
All accidents
No.
No.
%
%
Yes
No
Unknown
4
33
55
4.3%
35.9%
59.8%
0
6
22
0.0%
21.4%
78.6%
1
10
1
8.3%
83.3%
8.3%
0
0
7
0.0%
0.0%
100.0%
5
49
85
3.6%
35.3%
61.2%
Total
92
100%
28
100%
12
100%
7
100%
139
100%
Table 6-8 Leakage for each accident type.
100%
90%
80%
% of accidents
70%
60%
50%
40%
30%
20%
10%
0%
Yes
No
Unknown
Leakage
All accidents
Grounding
Collision
Ship-obstacle
Miscellaneous
Figure 6-12 Percentage of accidents with leakage.
Table 6-8 shows that there has only been registered a leakage in 5 accidents (out of
the 57 where leakage is registered). Four of these accidents are groundings and the
last is a ship obstacle collision.
In ref. [1] oil spill in Øresund are reported for the period 1967-1996. The total
amount of oil spilled was 2 495 400 tons. The frequency of major oil spills was 0.83
per year with an average of 83 180 tons spilled per year, i.e., the average amount of
oil spill per accident was 99 816 tons.
85
7.
Identification of hazards and risk control options (FSA step
1 and 3)
A hazard identification has been performed as part of the risk analysis. The objective
of the analysis was to identify hazards relevant for the navigational safety in Øresund, make an initial risk evaluation of each hazard and identify risk reducing measures (risk control options).
The identification process and the results are presented in the following.
7.1
Methods and procedures
As a basis for the hazard identification, various categorisations were made, including
amongst others
•
•
•
•
Risk types
Accident types
Characteristic navigational regions in Øresund
Error types
Furthermore, prior to the identification, a detailed review of existing accident registrations was carried out.
In order to have a systematic approach to the identification process, two workshops
were established, one focusing on the actual identification of hazard and one focusing on risk reducing measures related to the identified hazards. The workshops were
carried out by use of standard identification techniques, i.e. free and structured
what-if techniques, taking advantage of the established categories and the registered accidents. The workshops was leaded by a chairman and assisted by a secretary to register all input from the workshop attendees.
The hazard identification has been based on the analysis of the registered accidents
in the Øresund area (see chapter 6) and on a structured brain-storm process. The
hazard identification is documented in a Risk Register.
In the following the identification method (section 7.1.1), the quantification of hazards (sections 7.1.2 and 7.1.3) and the documentation of the hazard identification
(section 7.1.4) is described.
7.1.1
Identification method
The structured brain-storm process was carried out in accordance with IMO guidelines and was performed through two workshops:
•
Hazard identification workshop, see section 7.2
•
Risk reduction workshop, see section 7.3
86
Both of the workshops with participation of experts within fields relevant for the
identification process, e.g. pilots, captains and people from the Danish and Swedish
authorities. At the workshops the brain-storming process was supported by the use
of prompt lists and charts with accidents registrations marked on.
The categorization of identified hazards/events focused on the following main accident types:
•
•
•
Ship-ship collision
Grounding
Further, the consequences of the identified hazards were categorized according to
the following risk types:
•
•
•
Loss of life
Property
Environment
The definition of these risk types are as given in section 3.1.
7.1.2
Frequency and consequence classes
The ranking of hazards were done according to frequency and consequence classes
as suggested by IMO guide lines. The frequency classes are given in Table 7-1 and
the consequence classes are given in Table 7-2.
Frequency
Index (FI)
Description
Definition
F
[per ship year]
7
Frequent
Likely to occur once per month on one ship
10
5
Reasonably
probable
Likely to occur once per year in a fleet of several
ships, i.e. likely to occur several times during
the ships life.
0.1
3
Remote
Likely to occur once per year in a fleet of several
tens of ships, i.e. likely to occur in the total life
of several similar ships
10-3
1
Extremely
remote
Likely to occur once in 10 years in the world
fleet of several hundred ships.
10-5
Table 7-1 Frequency classes
87
Consequence
index (CI)
Description
Human safety
Property
Environment,
[DKK]
1
Minor
Single or minor injuries
Local equipment
damage
0-1 million
2
Significant
Multiple or severe
injuries
Non-severe ship
damage
1-10 million
3
Severe
Single fatality or multiple severe injuries
Severe casualty
10-100 million
4
Catastrophic
Multiple fatalities
Total loss
>100 million
Table 7-2 Consequence classes for each risk type.
7.1.3
Risk matrix
The risk of a hazard is defined as the frequency multiplied by the consequence:
Risk = Frequency × Consequence
Since the quantification of classes are based on a logarithmic scale the risk index
(RI) for ranking purposes can be found by summation of the frequency and consequence index:
RI = Frequency index + Consequence index
E.g. a hazard rated remote (frequency index 3) and consequence severe (consequence index 3) would have a risk index of 6.
Thus, the risk matrix based on the frequency and consequence classes described in
the previous section are as shown in Table 7-3 with risk indices shown.
Minor
CI 1
Frequency
Consequence
Moderate
Serious
CI 2
CI 3
Catastrophic
CI 5
Frequent
FI 7
8
9
10
11
Reasonably possible
FI 5
6
7
8
9
Remote
FI 3
4
5
6
7
Extremely remote
FI 1
2
3
4
5
High
Medium
Low
Table 7-3 Risk matrix with corresponding risk indices shown.
The colouring in Table 7-3 refers to the risk level of the hazards. Hazards with a risk
index between 2 and 4 are considered ‘low’, hazards with a risk index between 5 and
88
8 are considered ‘medium’ and hazards with a risk index between 9 and 11 are considered ‘high’. See also section 3.1.1 for a discussion of risk acceptance.
7.1.4
Risk Register
The hazard identification is documented in a Risk Register, which is a database system available for storing and keeping track of the identified hazards and corresponding risk assessments.
Hazard descriptions, risk quantifications and risk reducing measures together with
various categorisations are stored in the database facilities to accommodate future
requirements for follow-up and review by issuing lists, risk matrices etc. for the current risk status.
The risk register is illustrated in Figure 7-1..
Description and definition of overall risk targets
Window to edit (describe, categorise, quantify)
existing hazards and to add new hazard
Setting search and filter criterias for the hazards
Various summart statistics presentation possibilities
(risk matrices, risk history, criticality lists)
Information on relevant persons (risk owners, riks
identifiers)
Options for changing frequency and consequence
classes, risk types categories etc.
Close database
Figure 7-1 Risk register main menu
89
7.2
Hazard identification workshop
The first workshop held as part of the hazard identification process took place in
January 2006 and the objective of the workshop was to identify, to categorize and to
make a preliminary evaluation of hazards relevant for the navigational safety in Øresund. The Øresund area was divided into six areas and the relevant hazards were
identified for each hazard by brain-storming supported by prompt lists.
7.2.1
A list of all the participants in the workshop is given in Table 7-4.
Name
Company / work field
Organisation / invited by
Peter Ulriksen
Authority
Claus Jacob Bang
Authority
Jeppe Juhl
Carsten Jensen
Markus Lundkvist
Henrik Lorentzen
Authority
Authority
Authority
Shipmaster
Erik W. Thomsen
Pilot, Sound Pilot
Anders Alestam
Traffic area leader and
former pilot
Chief officer, M.s. CROWN
OF SCANDINAVIA
Senior captain, Scandlines
Navigator, Bunker vessel
Master at mercahnt vessel, Furetank Rederi AB
Captain on ferry, Finnlines
Ship Management
Commercial fisherman,
Ven
First lieutenant, Naval
Home Guard
Professor, Navigational
safety
Risk and safety engineer,
Hazid chairman
Hazid secretary
Risk and safety engineer
Royal Danish Administration of Navigation and Hydrography
Danish Maritime Authority
Swedish Maritime Administration
Lars Skjold Hansen
Preben Bæk Nielsen
Hans Jørgen Klim
Bo Höglund
Anders Hamming
Ola Bengtson
Mogens Timler,
Peter Friis-Hansen
Søren Randrup- Thomsen
Pernille Thorup Adeler
Jesper Pedersen
DTU
Rambøll
Rambøll
Rambøll
Table 7-4 Participants in hazard identification workshop.
90
7.2.2
The hazard identification workshop resulted in a list of 66 identified hazards given in
Table 7-5.
Hazard
no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Description
Ship-ship collision at Falsterborev due to crossing ship traffic.
Ship-ship collision at Falsterborev due to inattention in connection with the use of radar
navigation.
Ship-ship collision north of Drogden lighthouse due to limited space when two northbound
ships enter Drogden at the same time.
Ship-ship collision north of Drogden lighthouse due to a ship being set by the current.
Ship colliding with buoy 16 north of Drogden lighthouse.
Ship-ship collision at the south entrance of Drogden.
Grounding at Quartus ground due to limited space for passing of ships in Drogden.
Grounding at Quartus ground because buoy 16 is missing.
Ship-ship collision where Drogden meets Flintrännan.
Ship looses the manoeuvring ability and drifts towards areas where the water depth is not
sufficient and grounds.
Ship looses the manoeuvring ability and drifts towards obstacle.
Grounding at Sandflyttan when northbound ship takes a shortcut on the route.
Ship looses the manoeuvring ability and drifts towards another ship and collides.
Ship-ship collision in Drogden because ships are passing too close to each other.
Leisure boats grounding at Saltholm.
A ship with difference between true heading and course over ground collides with passing
ship.
Ships colliding with protective islands surrounding the central piers of the Øresund Bridge.
Collision of the girder between two bridge piers of Øresund Bridge.
Collision of the girder between two piers of the Øresund Bridge because a ship with a too
large air draught (deck house height) tries to pass the bridge outside the channel.
Grounding in the marked route in Flintrännan passing the Øresund Bridge.
Ship-ship collision north of Port of Malmö (east of Sjollen) because northbound ships do not
follow the recommended route and thus pass close to southbound traffic.
Grounding in the entrance to Port of Malmö.
Grounding at Middelpult.
Ship-ship collision at Middelpult.
Ship-ship collision in Kongedybet.
Grounding due to interference between ship radar and the instruments landing system (ILS)
of the Copenhagen Airport.
Ship-ship collision due to interference between ship radar and the instruments landing system (ILS) of the Copenhagen Airport.
Ship-obstacle collision due to interference between ship radar and the instruments landing
system (ILS) of the Copenhagen Airport.
Ship colliding with stone wall in the entrance/exit of the Port of Copenhagen.
Ship-ship collision at exit of Port of Copenhagen (in area where light house sectors cross)
due to crossing traffic.
91
Hazard
no.
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
Description
Grounding in the entrance to Port of Copenhagen.
Ship-ship collision with ships leaving anchor site no. 2.
Ship-ship collision with leisure boats.
Grounding at Lous Flak.
Grounding by southbound ships that should pass east of Pinhättan but instead pass on the
west where the water depth is down to 7m.
Ship-ship collision at buoy outside Landskrona.
Grounding between Pinhättan and Landskrona at Stengrund.
Ship-ship collision west of Ven due to sudden change of course.
Ship-ship collision due to ships sailing close to each other in waters around Ven because of
narrow lighthouse sectors.
Grounding around Ven.
Grounding at Väster Flacket off of Landskrona.
Ship-ship collision with coaster in the Helsingør-Helsingborg area.
Grounding on the Swedish coast north of Helsingør-Helsingborg due to ships not turning at
the buoy in the middle of the channel.
Grounding on the Swedish coast north of Helsingør-Helsingborg due to northbound current.
Ship-ship collision between the Helsingør-Helsingborg ferries.
Ship-ship collision with a fishing vessel fishing in the lane.
Ship-ship collision in waters north of Helsingør-Helsingborg.
Collision with sports divers in area around Helsingør-Helsingborg and around Ven.
Ship-ship collision with fishing vessel in waters around Ven.
Ship-ship collision in waters around Ven.
Ship-ship collision in Drogden if a large ship in ballast meets another ship when the wind is
strong.
Ship-ship collision in Drogden due to queue up of ships.
Grounding in Drogden due to queue up of ships.
Ship-ship collision in traffic separation system at Helsingør due to slowly sailing ships.
Grounding in traffic separation system at Helsingør due to slowly sailing ships.
Ship-ship collision in traffic separation system at Helsingør due to blurring of radar image.
Ship-ship collision between southbound ships in traffic separation and Helsingør-Helsingborg
ferries.
Ship-ship collision in Drogden due to missing buoy.
Grounding in Drogden due to missing buoy.
Ship-obstacle collision in Drogden due to missing buoy.
Grounding in Drogden because of a too large draught.
Grounding at Sundby Hage.
Ship-ship collision outside Helsingborg due to background lightning.
Ships colliding with the piers of the Øresund Bridge.
Air plane colliding with ship with large air draught.
Table 7-5 List of identified hazards.
92
During the workshop the participants gave their evaluation of frequency and consequence of the hazards. These evaluations are subjective and cover a range of frequencies and consequences from the initiating event to the final accident. Thus, a
compilation of the evaluations was afterwards performed and the data was structured into a simple event description for each hazard. These event descriptions
formed the basis for the ranking of frequency and consequence for the final accident
for each hazard. In the risk register of the hazards (see section 7.1.4) the event descriptions are also included along with the ranking.
In Appendix 1 Hazard identification sheets detailed information for each of the hazards are given. The detailed information includes:
•
•
•
•
7.3
Accident type
Hazard description
Description of causes and comments including event description used for
evaluating frequency and consequences as described in above.
Risk evaluation (frequency and consequence) for each relevant risk type
(human safety, property and environment).
Risk reduction workshop
The second workshop held as part of the hazard identification process took place in
February 2006 and the objective of the workshop was to identify risk reducing
measures (risk control options) for each of the hazards identified in the first workshop.
The risk reducing measures were identified by going through all the identified hazards in each of the six areas in Øresund.
7.3.1
A list of all the participants in the second workshop is given in Table 7-6.
93
Name
Company / work field
Organisation / invited by
Peter Ulriksen
Authority
Claus Jacob Bang
Authority
Aron Sørensen
Jeppe Juhl
Carsten Jensen
Markus Lundkvist
Torbjörn Edenius
Henrik Lorentzen
Authority
Authority
Authority
Authority
Authority
Shipmaster
Peter Herskind
Pilot, Sound Pilot
Anders Alestam
Trafikområdechef and
former pilot
Captain on ferry, Finnlines
Ship Management
Navigator
Navigator
Driftledare Sydkustens
trafikområde, future chief
of VTS
Hazid chairman
Hazid secretary
Anders Hamming
Benny Anderson
Carl-Göran Rosén
Lennart Anderson
Søren Randrup- Thomsen
Pernille Thorup Adeler
Rambøll
Rambøll
Table 7-6 Participants in risk reduction workshop.
7.3.2
The risk reduction workshop resulted in a list of 44 risk reducing measures, see
Table 7-7.
94
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Description
Traffic Separation Scheme between Drogden and Flintrännan. Northbound ships use Flintrännan.
Fixed beacons in Drogden
Traffic regulation in Drogden
VTS
Removal of Drogden lighthouse
Ships with smaller draught sailing outside existing markers in Drogden
Move buoy 16
Funnel shaped entrance to Drogden by new buoy marking
Weather service (maybe coupled to VTS)
Emergency anchoring
Skilled personnel (loosing manoeuvring ability)
Engine and software backup (loosing manoeuvring ability)
ECDIS
Free pilot service
Excavation of Drogden to make it twice as wide
Pilots participating at the VTS station
Equip pilots with mobile AIS
One fixed buoy (instead of floating)
Improve marking of Trekroner lighthouse
Marking of route for ships with large draught in passage guide
Renaming of buoy at entrance of Port of Copenhagen (buoy 21)
Information campaign for leisure boats
Improved control of leisure boats and their sailing
Restricted areas for leisure boats
Excavation at Staffans Banke
Traffic separation at Staffans Banke
Swedish coast should guide leisure boats away from Ven
Guidance from VTS about sailing around Ven
Traffic separation around Ven
Deep-water route on east side of Ven
Shorten traffic separation zone at Helsingør-Helsingborg
Move the turn at W4 (Helsingør-Helsingborg)
Marking in passage guide that large draught southbound ship tend to go west of W5 (Helsingør)
Forbidden to fish in traffic separation
More attention from coast guard toward fishing vessels in the lane
Introduction of fines for fishing in the lane
Mid channel marking on north west side of Ven
Marking of ferry routes in charts
Improvement of marking at Gräsrännan
Marking of Väster Flacket by buoy
removal of wreck on west side of Ven
Table 7-7 List of risk reducing measures.
95
The risk reducing measures may relate to one specific hazard or to a group of hazards. In Appendix 1 Hazard identification sheets the relevant risk reducing measures
in Table 7-7 are listed for each identified hazard.
7.4
Preliminary risk ranking
For each hazard an evaluation was performed for each risk type (human safety,
property and environment) as described in section 7.2.2. Thus, a risk index has been
established for each risk type for each hazard. Based on the risk index a ranking of
the identified hazards can be given. This is considered to be a preliminary risk ranking, since it is based on the subjective opinion of the workshop participants prior to
the risk analysis.
The risk ranking is illustrated by risk matrices for each risk type and by a ranked list
of each hazard for each risk type. The risk matrices illustrates the number of identified hazards located in each of the 16 predefined matrix regions. The risk matrices
are shown in Table 7-8, Table 7-10 and Table 7-12 for human safety, property and
environment, respectively. The corresponding ranked lists of hazards are given in
Table 7-9, Table 7-11 and Table 7-13.
Minor
CI 1
Frequency
Consequence
Moderate
Serious
CI 2
CI 3
Catastrophic
CI 5
Frequent
FI 7
0
0
0
0
Reasonably possible
FI 5
0
0
2
0
Remote
FI 3
3
4
33
6
Extremely remote
FI 1
2
1
14
1
High
Medium
Low
Table 7-8 Risk matrix for human safety with the number of hazards shown
in each field.
The preliminary ranked list of hazards for human safety is given in Table 7-9.
96
Risk
index
8
FI
CI
5
3
Hazard
no.
43
8
5
3
44
7
3
4
2
Description
Grounding on the Swedish coast north of Helsingør-Helsingborg due to ships not
turning at the buoy in the middle of the channel.
Grounding on the Swedish coast north of Helsingør-Helsingborg due to
northbound current.
Ship-ship collision at Falsterborev due to inattention in connection with the use of
radar navigation.
7
3
4
9
7
3
4
42
7
3
4
45
7
3
4
48
7
3
4
58
6
3
3
3
6
3
3
4
6
3
3
6
Collision with sports divers in area around Helsingør-Helsingborg and around
Ven.
Ship-ship collision between southbound ships in traffic separation and HelsingørHelsingborg ferries.
Ship-ship collision north of Drogden lighthouse due to limited space when two
northbound ships enter Drogden at the same time.
Ship-ship collision north of Drogden lighthouse due to a ship being set by the
current.
6
3
3
10
6
3
3
11
Ship looses the manoeuvring ability and drifts towards areas where the water
depth is not sufficient and grounds.
6
3
3
13
6
3
3
14
6
3
3
19
6
3
3
22
Collision of the girder between two piers of the Øresund Bridge because a ship
with a too large air draught (deck house height) tries to pass the bridge outside
the channel.
6
3
3
23
6
3
3
24
6
3
3
25
6
3
3
29
6
3
3
30
Ship-ship collision at exit of Port of Copenhagen (in area where light house sectors cross) due to crossing traffic.
6
3
3
31
6
3
3
33
6
3
3
34
Ship-ship collision with leisure boats. There are a lot of leisure boats in the entire
Øresund area, especially in the summer.
6
3
3
37
6
3
3
39
6
3
3
40
Ship-ship collision due to ships sailing close to each other in waters around Ven
because of narrow lighthouse sectors.
6
3
3
41
6
3
3
46
6
3
3
47
6
3
3
49
6
3
3
50
97
Risk
index
6
FI
CI
3
3
Hazard
no.
52
6
3
3
53
Description
Ship-ship collision in Drogden if a large ship in ballast meets another ship when
the wind is strong.
6
3
3
54
6
3
3
55
Ship-ship collision in traffic separation system at Helsingør due to slowly sailing
ships.
6
3
3
56
6
3
3
57
6
3
3
60
6
3
3
64
5
1
4
1
5
3
2
7
5
3
2
8
5
3
2
15
5
3
2
17
4
3
1
5
4
1
3
16
4
1
3
18
4
1
3
21
4
1
3
26
4
1
3
27
4
1
3
32
4
1
3
35
4
1
3
36
Grounding by southbound ships that should pass east of Pinhättan but instead
pass on the west where the water depth is down to 7m.
4
1
3
38
4
3
1
51
4
1
3
59
4
3
1
61
4
1
3
62
4
1
3
63
4
1
3
65
4
1
3
66
3
1
2
20
2
1
1
12
2
1
1
28
A ship with difference between true heading and course over ground collides with
passing ship.
Ship-ship collision north of Port of Malmö (east of Sjollen) because northbound
ships do not follow the recommended route and thus pass close to southbound
traffic.
Grounding due to interference between ship radar and the instruments landing
Ship-ship collision due to interference between ship radar and the instruments
landing system (ILS) of the Copenhagen Airport.
Ship-obstacle collision due to interference between ship radar and the instruments landing system (ILS) of the Copenhagen Airport.
Table 7-9 Ranked list of hazards for human safety.
98
Minor
CI 1
Frequency
Consequence
Moderate
Serious
CI 2
CI 3
Catastrophic
CI 5
Frequent
FI 7
0
0
0
0
Reasonably possible
FI 5
0
2
2
0
Remote
FI 3
1
2
39
1
Extremely remote
FI 1
0
3
15
0
High
Medium
Low
Table 7-10 Risk matrix for property with the number of hazards shown in
each field.
The preliminary ranked list of hazards for property is given in Table 7-11.
99
Risk
index
8
FI
CI
5
3
Hazard
No
43
Description
8
5
3
44
7
5
2
5
northbound current.
7
3
4
9
7
5
2
51
6
3
3
2
6
3
3
3
6
3
3
4
6
3
3
6
6
3
3
7
6
3
3
8
6
3
3
10
6
3
3
11
6
3
3
13
6
3
3
14
6
3
3
19
6
3
3
22
Collision of the girder between two piers of the Øresund Bridge because a ship
with a too large air draught (deck house height) tries to pass the bridge outside
the channel.
radar navigation.
current.
6
3
3
23
6
3
3
24
6
3
3
25
6
3
3
29
6
3
3
30
6
3
3
31
6
3
3
33
6
3
3
34
6
3
3
37
6
3
3
39
6
3
3
40
6
3
3
41
6
3
3
42
6
3
3
45
6
3
3
46
6
3
3
47
6
3
3
49
100
Risk
index
6
FI
CI
3
3
Hazard
No
50
6
3
3
52
Description
6
3
3
53
the wind is strong.
6
3
3
54
6
3
3
55
6
3
3
56
ships.
6
3
3
57
6
3
3
58
6
3
3
60
6
3
3
64
5
3
2
17
5
3
2
61
4
1
3
1
4
3
1
15
4
1
3
16
4
1
3
18
passing ship.
4
1
3
21
4
1
3
26
4
1
3
27
4
1
3
32
4
1
3
35
4
1
3
36
traffic.
4
1
3
38
4
1
3
59
4
1
3
62
4
1
3
63
4
1
3
65
4
1
3
66
3
1
2
12
3
1
2
20
3
1
2
28
Table 7-11 Ranked list of hazards for property.
101
Minor
CI 1
Frequency
Consequence
Moderate
Serious
CI 2
CI 3
Catastrophic
CI 5
Frequent
FI 7
0
0
0
0
Reasonably possible
FI 5
0
0
2
0
Remote
FI 3
1
7
29
0
Extremely remote
FI 1
0
7
13
0
High
Medium
Low
Table 7-12 Risk matrix for environment with the number of hazards shown
in each field.
The preliminary ranked list of hazards for environment is given in Table 7-13.
102
Risk
index
8
FI
CI
5
3
Hazard
No
43
8
5
3
44
6
3
3
3
6
3
3
4
6
3
3
6
6
3
3
7
6
3
3
8
6
3
3
10
Description
northbound current.
current.
6
3
3
13
6
3
3
14
6
3
3
22
6
3
3
23
6
3
3
24
6
3
3
25
6
3
3
29
6
3
3
30
6
3
3
31
6
3
3
34
6
3
3
37
6
3
3
39
6
3
3
40
6
3
3
41
6
3
3
47
6
3
3
50
6
3
3
52
6
3
3
54
the wind is strong.
6
3
3
55
6
3
3
56
6
3
3
58
6
3
3
60
6
3
3
64
5
3
2
9
5
3
2
17
5
3
2
46
ships.
103
Risk
index
5
FI
CI
3
2
Hazard
No
49
Description
5
3
2
53
5
3
2
57
5
3
2
61
4
3
1
2
4
1
3
11
4
1
3
16
4
1
3
21
4
1
3
26
4
1
3
27
4
1
3
32
4
1
3
35
4
1
3
36
radar navigation.
passing ship.
traffic.
4
1
3
38
4
1
3
59
4
1
3
62
4
1
3
63
4
1
3
65
3
1
2
1
3
1
2
5
3
1
2
12
3
1
2
20
3
1
2
28
3
1
2
33
3
1
2
51
Table 7-13 Ranked list of hazards for environment.
104
As a summary the risk matrix for all risk types is shown in Table 7-14.
Minor
CI 1
Frequency
Consequence
Moderate
Serious
CI 2
CI 3
Catastrophic
CI 5
Frequent
FI 7
0
0
0
0
Reasonably possible
FI 5
0
2
6
0
Remote
FI 3
5
13
101
7
Extremely remote
FI 1
2
11
42
1
High
Medium
Low
Table 7-14 Risk matrix for all risk types with the number of hazards shown
in each field.
It is seen from the risk matrices that no hazards are located in the high risk region.
However, a large number of hazards are located in the medium risk area. For those
hazards it may be reasonable to implement some of the proposed risk reducing
measures based on the established cost-benefit considerations.
The preliminary risk ranking is used as part of the basis for determining
•
The critical locations in Øresund to be studied in the risk analysis (focus areas).
•
Critical scenarios for the detailed risk analysis
The identified risk control options are taken into account in the cost-benefit analysis.
105
8.
Frequency models (FSA step 2)
On basis of the descriptions of the basic information (data, geographical areas etc.),
models for estimating collision and grounding frequencies have been established for
the following accident types:
•
•
•
Ship-ship collisions for passing ship
Ship-ship collisions for crossing ships
Grounding and ship obstacle collision
The ship-ship collision models are for the interaction between two ships. the interaction between three or more ships are not modelled.
In the present section, the basic principles of the applied models are described. It is
noted that some features of the models are common for all applied models, whereas
other features relates solely to one explicit model.
Furthermore, the calculation methods used to implement the models are described.
8.1
Basic model principles
The models applied in the present study are based on a mathematical modelling of
ship traffic movements and interactions and was originally suggested by Fujii, ref.
[15] and also detailed described by Terndrup Pedersen, ref. [17]. The models have
been applied on risk studies made in connection with the construction of the Øresund
bridge, ref. [20]. In this connection studies were made to validate the model. The
model was validated towards actual registered accidents, and good correspondence
between model results and registered accidents were proven, ref. [18].
The basic concept in these models is that the ships may – based on the location on
the considered route – be at collision or grounding course, but will in normal conditions make proper corrections such that an accident does not occur. Only in cases,
where failures occur and no corrections are made, an accident occurs. Hence, the
frequency of an accident relates to the two probability contributions
1.
2.
The probability of a ship being on collision or grounding course
The probability that the navigator do not make correction in due time
Detailed descriptions of the Fujii models applied to the different scenarios (collisions
from passages, crossing routes and groundings) are given in sections 8.2, 8.3 and
8.4. The modelling includes descriptions of the following items:
•
•
•
Ship characteristics (length, width, draught, speed, heading)
Ship traffic distributions and yearly volume
Route characteristics (water depths, obstacles, markings)
106
•
•
External conditions (weather, current)
Failure types
The general form of a model is sketched in Figure 8-1. Note, that the figure shows a
sketch of a collision model. In the grounding/ship-obstacle model there are no ships
in direction 2, instead there are parameters describing the obstruction that the ships
are approaching.
Time of year
Ship direction 1
Ship direction 2
Route markings
Route width
Route bends
Water depths
Ship Location on route
Route markings
Route width
Route bends
Water depths
Ship Location on route
Characteristics:
length
breadth
draught
speed
Characteristics:
length
breadth
draught
speed
Human failure
Weather:
current
visibility
Technical
failures
Evasive
manouvre
Accident
candidates
Accident
Figure 8-1 Sketch of a ship collision model
107
It is noted that Figure 8-1 only shows a sketch of the flow in the models. The individual models are more complicated and are adjusted to the considered scenarios
and locations. However, the model in Figure 8-1 shows the overall structure of the
model. In the following, some general descriptions covering the issues shown in
Figure 8-1 are given.
8.1.1
Ship characteristics
Different states of the ship traffic are described. This includes:
•
•
•
•
•
•
Ship types
The number of different ship types are relatively large, why a grouping of all
ship types have been performed, such that the following ship types are used:
Leisure boats and fishing vessels
Assisting vessels (dredging and pilot vessels)
Passenger ships
Cargo ships
Tanker (including oil and chemical tankers)
Other
Ship speed (m/s)
Ship width and length (m)
Ship draught (m)
Location on the route
Heading and course over ground
Hence, the model includes specifications of different characteristic ship types. It is
therefore possible to identify the influence from various ship types considered to
contribute significantly to the overall risk, either in terms of environmental risk (oil
tankers, chemical tankers, single hull tankers) or in terms of human safety (large
passenger ships, cruise ships etc.).
Detailed probability distributions with respect to speed, draught, heading, course
over ground and location are for all ship types at all considered locations shown in
Appendix 2 – Appendix 7. Distributions for ship width and length are computed
based on the static AIS data.
8.1.2
Ship traffic distributions
For the distributions of the location of ships at a given line, fitted distributions have
been applied on basis of the registered distributions as given in Appendix 2 Transverse southbound traffic distributions and 3 Transverse northbound distributions.
Fitting models have been used in previous navigational risk analyses, see ref. [9],
[10], [14], [15] and [19]. A basics assumption on fitting data has been that ship
traffic locations at a line fit a combination of a normal distribution and a uniform distribution.
108
It is required that the fitting model on basis of registered observations determines
the normal distribution parameters mean and variance, the uniform parameters upper and lower bound and the ratio of ships following the uniform distribution.
Thus, the distributions Floc(x) for ship locations are determined as
Floc (x) = θ U(x; a, b) + (1 − θ) N(x; μ, σ)
where
θ
Ratio of ships following the uniform distribution
U(x; a, b)
N(x; μ, σ)
Uniform distribution at x with lower bound a and upper bound b
Normal distribution at x with mean μ and standard dev. σ
The analyses have been made on a selected set of data from Drogden, Flintrännan,
Ven East and Ven West. The midpoint of the navigation channel is used as origo.
Thus, mean values are the average distance from the mid point of the navigation
channel. West and east of Ven, the navigation channel width is taken as the distance
from the shore line of Denmark/Sweden to the shore line of Ven. Examples of observed and fitted distributions in Drogden are shown in Figure 8-2.
0.014
Registrations
Mixed distribution
0.012
0.014
0.01
0.008
0.008
0.006
0.006
-1
- 150
- 138
- 126
- 114
0
-9 2
- 70
- 68
- 56
- 44
- 32
- 10
8
-6
6
18
30
42
54
66
78
9
100
112
124
136
158
0
0
0.004
0.002
0
-1
-150
-138
-126
-114
0
-92
-70
-68
-56
-44
-32
-10
8
-6
6
18
30
42
54
66
78
9
100
112
124
136
158
0
0.002
Mixed distribution
0.012
0.01
0.004
Registrations
Figure 8-2 Observed and fitted location distributions – Left: Drogden
southbound – right: Drogden northbound
Summarised values of the fitting parameters for 4 characteristic locations in Øresund
are shown in Table 8-1.
109
Location
Direction
Drogden
S
Flintrännan
Ven West
Ven East
Mean
[m]
Standard
deviation
[m]
Uniform
ratio
-56
34
0.04
N
51
35
0.06
S
-53
43
0.06
N
33
37
0.05
S
2679
401
0.07
N
3078
280
0.14
S
-1655
278
0.28
N
-1439
273
0.07
Channel
width
[m]
300
390
9250
4300
Table 8-1 Fitted distribution parameters for ship locations
In the fitting procedure no considerations have been taken to distinguish between
ship types or ship characteristics. Hence, the distributions are applied to the overall
number of registered ships at the location considered. This approach is judged to be
conservative (in the sense that it gives a frequency estimate that is high compared
to the situation, where a more detailed approach have been included), since large
ships and ships appearing frequently at the same place tends to keep closer to the
average location than other ships.
It is seen from Table 8-1 that the uniform ratio in narrow channels like Drogden and
Flintrännan is approximately 5%. This is not differing significantly from other former
studies in Øresund, ref. [19], which suggests values from 3-5%. In the present
analysis a uniform ratio of 5% is applied.
For the parameters associated with the normal distribution – mean and standard
deviations – it is estimated on basis of the results shown in Table 8-1, that the following relations apply:
•
•
The mean value is located 1/3 of the channel width away from the starboard
side of the navigation channel
The standard deviation is 10% of the navigation channel width.
These estimates are in good agreements with the data analysis in Flintrännan and in
Drogden. Furthermore, if the navigation width at Ven is reduced so that it is not the
total width from shore to shore but rather limited by the 10 m curves west of Ven
and the buoy at Staffans Banke east of Ven, there is good agreement for those locations as well. The complete fitted distribution results are shown in Appendix 8 Fitted
distribution parameters for ship location.
It is noted that the distribution applies solely to the AIS registered ship traffic. Thus,
the leisure boats and fishing boats are modelled separately to form a complete ship
traffic distribution.
110
It is shown earlier that the ship traffic is distributed evenly on the months and the
time of day, such that different seasons do not influence the ship traffic patterns for
the commercial ship traffic. However, leisure boat traffic is only to a limited extent
present in winter, spring and fall. Thus, seasonal variations are included in the model
to account for leisure boat traffic in the total ship traffic volume and in the ship traffic distributions.
8.1.3
Route characteristics
A detailed modelling of the selected locations in Øresund, where risk analyses have
been applied, is carried out with respect to:
•
•
•
•
•
Route width
Route bends
Markings and other sailing arrangements
Obstacles
Water depth
The modelling of the ship locations on the route must be seen in close connection
with the actual route characteristics which also is indicated by the different values of
location parameters given in Table 8-1.
8.1.4
External conditions
Besides actual information of the ships and the navigation areas, various external
conditions give input to the risk models in terms of
•
•
Current conditions
Visibility
From the hazard identification workshops, critical areas where the current have influence on the navigation are identified (e.g. southern entrance to Drogden). The
current will in these areas move the ship from the ideal line. This effect is modelled
by shifting the actual location of the ship in case adverse current conditions are present. It is noted, that the influence from the current is modelled qualitatively on basis of statements from the attendees at the workshop. At the southern entrance at
Drogden it is assumed that the current in 5% of the time is transverse to the sailing
direction and has a speed that disturbs the navigation.
The visibility influences the use of radar and the possible probability of visual detection of another ship in due time.
8.1.5
Failure types
The basic concept in the Fujii models is that the ships may be at collision or grounding course, but will in normal conditions make proper corrections such that an accident does not occur. The reasons for not making proper corrections are due to:
111
•
•
Technical failures
Human failures
General descriptions of these error types are given in the following.
Technical failures
Technical failures are related failures on the machinery on board a ship leading to
situations, where the navigator looses control of the ship and is unable to make corrections to a ship on collision or grounding course. Basically, two technical error
types are considered:
•
•
Failure of steering system
Failure of propulsion machinery
The frequency of failure of the steering system fsteering has in a U.S. investigation, ref.
[32], been estimated to
fsteering = 0.41 failure per year pr ship
With 270 effective sailing days per year assumed representative for the commercial
ships in Øresund, the frequency per hour of failure of the steering system is 6.3·10−5
failures per hour. This frequency or rate of steering failure is adopted for all types of
ships and is assumed constant throughout the passage of the Øresund. The failure
rate is considered a conservative estimate (in the sense that it gives a frequency
estimate that is high compared to the situation, where a more detailed approach
have been included).
Reliable statistical data have not been identified for how often the propulsion machinery on a ship fails and the ship potentially may be unable to control. However,
according to general ship engineering judgement, the propulsion machinery on a
ship is assumed to fail approximately once during a year in service. Assuming furthermore 270 effective sailing days per year to be relevant for the commercial ships
sailing through Øresund, the frequency of failure of the propulsion machinery becomes:
fdrift = 1.5·10−4 failure per hour pr. ship
The frequency of failure of the propulsion machinery is a rough estimate based on
statements from navigators etc. and is adopted for all types of ships, although differences in reserve power and backup systems are present. Furthermore, the frequency is assumed constant throughout the passage of Øresund.
Besides technical failures to the ship also failures to the radar equipment have been
used. The failure of radar equipment is taken as in former similar analysis, ref. [15]
112
and [20], where a failure probability of 6.7·10-4 have been used. This failure has in
particular influence in combinations with low visibility conditions.
Human failures
Human failure modelling can be made in various details all depending on the purpose
of the study. In the present study, an overall approach to the human failure modelling is made taking into account a number of factors all adding up to the total human
failure probability. This approach is described by e.g. Macduff, ref. [16]. Introduction
of human errors may then be due to the following causes:
•
•
•
•
•
•
Absence from bridge (absent)
Present but distracted (distracted)
Present but incapacitated due to accident or illness (accident)
Present but asleep from fatigue (asleep)
Present but incapacitated from alcohol (alcohol)
Man machine interface (failure in using equipment)
It is for the purpose of the present study considered sufficient with the modelling
including the causes above. More detailed man-machine interface modelling as described in e.g. ref. [24] will give accurate guidance on the design and equipment of
machinery, but are considered outside the scope of this work.
The generic values to apply to the listed causes above are also suggested in ref. [16]
and are in good correspondence with values given by Kirwan, ref. [21]. These values
are ranging between 10-2 and 10-4 pr. action all depending on the type of action to
carry out (routine actions, special actions etc.) and also depending on the alertness
and awareness of the operator when carrying out the action. Hence, external conditions may change the probability of failure, e.g. presence of VTS, awareness for sailing in difficult waters etc. In the present study, values of 10-4 is applied to the various failure types but are changed at specific locations in order to reflect the conditions at that location.
A graphical presentation of the human failure using the Bayesian network modelling
technique described later is shown in Figure 8-3.
113
Figure 8-3 Model of human failure probability
As indicated in Figure 8-3, risk control options (VTS) may affect the human failure
probability. This is described in later sections.
8.2
Ship-ship collision for passing ship
This model is applied for ships passing each other in a channel (wide or narrow)
where the ship traffic is not separated. Hence, this is the case in many locations in
Øresund, but is in particular studied at the following locations:
•
•
•
•
Drogden
Flintrännan
Ven East
Ven West
There is other locations (Kongedybet, Kronløbet etc.) where ships are passing each
other, but at the locations listed above, the highly trafficked and narrow channel
(Drogden) or the occurrence of special obstacles (the bridge in Flintrännan) or the
occurrence of leisure boats and fishing vessels makes the risk of collisions more significant.
At Helsingør/Helsingborg, only collision frequencies from crossing ships have been
included, see section 8.3. Passage situations at this location is not considered due to
the traffic separation zone, and due to the fact that the ferries crossing the strait are
passing each other with large distances.
114
8.2.1
Description
The model for estimating collision frequencies during ship passages are as mentioned
earlier described in e.g. ref. [16] and [17]. These models operate basically with the
following
•
•
A distribution of the ship traffic for ships in both directions
A ship domain – a geometrical domain around the ship
It is assumed that if the domains of the two ships interact, there will be a prbability
of collision in case no evasive manoeuvres are taken. Whether or not evasive manoeuvres are taken depends on if any human or technical failures are made. If there
is no interaction between the two domains, the passage is considered safe.
Hence, the model includes the distance between two ships when passing each other
– in opposite or same direction. These two situations are denoted passings and overtakings, respectively. A situation with passing ships is sketched in Figure 8-4.
115
Ship class
v, L, B, D
.Dist
Ship class
v, L, B, D
Navigation channel
Figure 8-4 Passing ships
As seen from Figure 8-4, the following parameters give input to the calculation of the
collision frequency:
•
•
•
•
•
Ship traffic distribution in the considered navigation channel
Distance between the ships when passing each other
The number of passages pr. year
Knowledge of ship characteristics (length, width, speed) of the ships
Navigation channel characteristics (width, bend on route, marking of route)
116
The theories applied for this scenario was originally made by Fujii, ref. [15]. In this
work, the domain around the ships was estimated based on registered ship traffic
movements in open straits. These models suggest an ellipse-formed domain around
the ship with a rather large width. It is suggested to reduce this width in narrow
straits (like Drogden and Flintrännan) such that the domains of the two ships interact
if the distance Dcrit between the ships is given as
Dcrit < 2,1 ⋅ ( L1 + L2 )
where L1 and L2 is the length of ship 1 and ship 2, respectively.
In order to estimate parameters valid for the different routes in Øresund, an analysis
of the actual distance for passing ships is carried out. The probability distribution for
the distance between passing ships in Drogden is given in Figure 8-5.
Drogden
100%
90%
Probability
80%
70%
60%
50%
40%
30%
20%
10%
0%
0
100
200
300
400
500
600
Passage distance [m]
Figure 8-5 Passage distance in Drogden
It is seen from Figure 8-5 that most passages occur within the Drogden channel (distance less than 300 m) and that most passages occur within a distance less than 200
m. This distance is somewhat smaller than the distance proposed by Fujii. In order to
use a more realistic measure of the critical passage distance, it is estimated that not
more than 10% of the passages can be considered critical. Hence, the critical passage distance (corresponding to an interaction of ship domains) is estimated to be
the 10%-percentile in the passage probability distribution.
It is noted, that this will give a reduction in collision frequencies compared to the
originally values proposed by Fujii. It is however considered to be more realistic to
use the 10% percentile for the narrow straits in Øresund.
117
It is furthermore noted, that there is no significant correlation between passage distance and length/width of the passing ships.
Calculated passage distance distributions and corresponding width of the ships are
shown in Appendix 9 for all considered areas.
The yearly frequency fcoll of collision during passages on a navigation route is determined as the product of the number of critical passages and the probability of not
making an evasive manoeuvre during a critical passage:
f coll = N pass ⋅ P(d < d crit ) ⋅ (1 − Pevasive )
where
Npass
is the number of passages per year in a considered area.
Over a distance of Lw, the number of passages is determined as
Lw ⋅ ⎛⎜ 1 + 1 ⎞⎟ ⋅ N 1 ⋅ N 2
v2 ⎠
⎝ v1
P(d<dcrit)
is the probability that passage occurs with a distance
less than the critical distance
1-Pevasive
is the probability of not making an evasive manoeuvre
due to human or technical failures
The probability of having passages within the critical passage distance is calculated
on basis of the probability distributions of the ship location on the route. These distributions are estimated on basis of the modelling described in section 8.1.2.
The parameters to use in each of the considered areas are given in the following
section.
8.2.2
A number of input parameters to the model are given based on either the data basis
given in Chapter 5 or assessments for the different locations. The parameters give
input to the estimates of the number of collision candidates or to the probability of
making an evasive manoeuvre if a ship is on collision course. The input parameters –
description and relevant report section for finding values- are taken as given in Table
8-2.
118
Parameter
Report section
Ship traffic distribution parameters
Passage distance
Number of ships
Number of leisure boats
Pilot on board
Ship type distribution
Breadth of waterway
Distance at time of observation
Section 8.1.2
Section 8.2.1
Chapter 5
Section 5.2
Section 5.4
Appendix 2 or 3
Assessed for each location
Table 8-2 Passing ships – input parameters.
8.3
Ship-ship collision for crossing ships
This model is applied for ships approaching each other on two crossing routes. The
model is set up where two routes meet at the following locations:
•
•
•
•
8.3.1
Drogden and Flintrännan meeting south of Drogden lighthouse.
Northbound ships going east of Drogden lighthouse meeting northbound
ships going west of Drogden lighthouse.
Eastbound ships in Kronløbet meeting north- and southbound ships in
Hollænderdybet.
East-westbound ships at Helsingør/Helsingborg (primarily ferries) meeting
north- and southbound ships at Helsingør/Helsingborg.
Description
The model for estimating collision frequencies on crossing routes are as mentioned
earlier described in e.g. ref. [16] and [17]. The model operates basically with the
following:
•
•
•
A distribution of the ship traffic for ships in both directions
A domain where the two routes crosses (risk area)
A geometrical collision diameter within which two ship can meet based on
their direction, speed, length and width.
The model is sketched in Figure 8-6.
119
Risk area
Ship class
v, L, B, D
Ship class
v, L, B, D
Angle
Figure 8-6 Distribution for approaching ships on crossing routes.
As seen from Figure 8-6, ship distributions and ship characteristics are input to the
model. Furthermore, definition of the geometrical collision diameter in terms of ship
velocities and the area in which crossing takes place are input to the model.
Hence, the frequency of a collision are determined as
f coll = N Q ⋅ (1 − Pevasive )
where
NQ
is the number of collision candidates
1-Pevasive
The number of collision candidates is determined as:
Na = ∑
i
Q1i Q2 j
∑ ∫∫ V
j
A
i
(1)
Vj
( 2)
(1)
f i ( zi ) f j
( 2)
( z j )Vij Dij dA ⋅Δt
where
120
i,j
Ship type indices indicating the ship type (passenger ships,
tankers etc.) as described in section 8.1.1
Vij
is the relative speed between two ships
Dij
is the geometrical collision diameter (described in details in
ref. [17])
i,j
are ship class indices
fi, fj
are the distribution of location in the channel for class i,j
Vi, Vj
are the velocities of ships in class i,j
A
is the considered area of crossing traffic
The probability distribution parameters of the ship location on the route are estimated on basis of the modelling described in section 8.1.2. Ship characteristics are
determined on basis of the data analysis and are given in Appendix 4 to Appendix 7.
8.3.2
input to the estimates of the number of collision candidates or to the probability of
making an evasive manoeuvre if a ship is on collision course. The input parameters –
description and relevant report section for finding values- are taken as given in Table
8-3.
Parameter
Report section
Ship traffic distribution parameters in each direction
Number of ships
Number of leisure boats
Pilot on board
Speed distribution for ships in each direction
Draught distribution for ships in e ach direction
Ship type distribution for each direction
Angle between directions
Breadth of waterway
Distance at time of observation
Section 8.1.2
Chapter 5
Section 5.2
Section 5.4
Appendix 4
Appendix 5
Appendix 2 or 3
Table 8-3 Crossing ships – input parameters.
121
8.4
Grounding and ship-obstacle collision
This model is applied for two different situations - ships being on grounding course
or ships being on collision course with a fixed obstacle. The reason for using the
same model to describe these two situations is that collision with a fixed obstacle can
be interpreted as grounding on a zero water depth curve. The consequences are off
course different, but the frequency modelling is identical for the two situations. The
model for groundings is set up at the following locations:
•
•
•
•
•
•
North coast of Helsingborg.
Quartus grund at south entrance to Drogden.
Middelpult in Kongedybet.
Lous Flak south west of Ven.
Väster Flacket south east of Ven.
Stengrund on the northbound route from Flintrännan to Ven east.
The model for ship obstacle-collision is set up at the following location:
•
Øresund Bridge in Flintrännan
A description of the grounding/ship-obstacle model is given in the following section.
8.4.1
Description
The grounding and ship-obstacle collision model is identical to the other collision
models in the sense that it consists of two contributions to the yearly frequency –
first a determination of the yearly number of ships being on grounding or collision
course and secondly a determination of the probability of making an evasive manoeuvre.
The model for determining the number of ships on grounding or collision course consists of one or two contributions depending on the nature of the navigation route:
I.
II.
Straight route before meeting shoal or obstacle:
All ships at collision course not making an evasive manoeuvre are grounding/collision candidates
Bend on the route before meeting shoal or obstacle:
All ships on collision/grounding course before the bend not making a turn in
the bend are collision/grounding candidates.
It is noted, that the two situations may be combined in the sense that ships actually
making a turn (avoiding situation II) but being on collision course after the turn are
collision candidates. The situations are illustrated in Figure 8-7 (situation I) and
Figure 8-8 (situation II).
122
Obstacle
Depth curve
Ship class
v, L, B, D
Ship class
v, L, B, D
Figure 8-7 Grounding (left)/collision (right) candidates for ships on a
straight route (situation I).
Ship class
v, L, B, D
Obstruction
Ship class
v, L, B, D
Figure 8-8 Collision/grounding candidates for ships on a route with a bend
(situation II).
123
Hence, the frequency of grounding (or collision) can be determined as
f coll / ground = N Q ⋅ (1 − Pevasive )
where
NQ
is the number of collision candidates
1-Pevasive
In a scenario where the two situations (I and II) are combined the frequency is calculated separately for the two situations and the total is found by adding the two
contributions.
8.4.2
input to the estimates of the number of grounding/collision candidates or to the
probability of making an evasive manoeuvre if a ship is on grounding/collision
course. The input parameters – description and relevant report section for finding
values- are taken as given in Table 8-4.
Parameter
Report section
Ship traffic distribution parameters
Number of ships
Pilot on board
Speed distribution for ships
Draught distribution for ships
Ship type distribution for each direction
Location of shoal or obstacle
Water depth at shoal or obstacle
Distance from bend to shoal or location
Section 8.1.2
Chapter 5
Section 5.4
Appendix 4
Appendix 5
Appendix 2 or 3
Assessed by charts
Assessed by charts
Table 8-4 Grounding ships – input parameters.
8.5
Methods for implementation of the frequency models
The frequency models are made as Bayesian network models. The principle in a
Bayesian network is to define probabilities of various system states (ship location,
ship type distributions, human failure probability etc.) in various nodes. The nodes
are related by arcs to defining conditional probabilities. An example of a frequency
model for a ship collision is illustrated in Figure 8-9
124
Figure 8-9 Bayesian network for assessing collision frequencies.
An overall description of Bayesian networks are shown in Appendix 12: ‘General description of Baysian Network’, and Bayesian networks for all collision and grounding
frequency models as described in the present chapter are shown in Appendix 13:
‘Bayesian Network for frequency models’ and in Appendix 14: ‘Bayesian Network for
consequence models’.
125
9.
Consequence models (FSA step 2)
The frequency models described in the previous chapter calculates the frequencies of
the considered scenarios. In the present chapter descriptions are given of the consequences if one of the considered accidents occurs.
There is distinguished between various types of ship collisions (front-front, front-side
and front-back collisions) and of groundings. Consequences have been estimated for
the three consequence types:
•
•
•
Fatalities
Property damage
The consequence model determines the degree of damage according to the list
above and transforms the degree of damage into a cost related to the considered
consequence. The environmental damage is restricted to address only costs for
clearing and clean-up. Thus, no evaluations of long-term economical effect are included.
Furthermore, it is noted that no considerations to the safety and rescue installations
in Øresund are included in the analysis.
The following sections describe the consequence modelling and the subsequent cost
evaluation.
9.1
Consequence models
The consequence models are coupled to the frequency models such that input to the
consequence models are based on the condition, that a collision or grounding has
occurred. Thus, the model inherits the configuration of ship characteristics most
likely leading to a collision/grounding. Hence, the consequence model takes the following input characteristics given a collision or grounding:
•
•
•
•
Ship types
Ship width, draught and length
Ship velocity
Angle between ships
126
Furthermore, on basis of the above items, the following enters the model:
•
•
•
•
Amount of fuel on board the ships (both bunker fuel and stored fuel on tankers)
Bulb (is the ship with or without bulb – this has an influence on the consequnce of a collision since this will most likely lead to a damage below sea
level end thus increased risk of spillage into the water)
Hull type (single or double hull – it is assumed that 90% of all oil tankers are
double hull type. This has an effect on the amount of spillage following an
accident)
Number of persons on board the ships (varying from 1 person in small ships
to many thousands on the large cruise ships)
On basis of these inputs, a model is established to evaluate:
•
•
•
The number of fatalities
The property damage
Clearing and clean-up costs
All consequence models are shown in Appendix 14 Bayesian network for consequence models. The model for collisions is shown in Figure 9-1.
Figure 9-1 Bayesian network for assessing collision consequences.
127
It is seen from Figure 9-1 that the ship characteristics affect the degree of damage
to the ship and ends up in three consequences:
•
•
•
Total damage to persons
Total property damage
Total release size
Total damage to persons is given as the number fatalities in different intervals (0,01,1-3,3-5,….) and a related probability that the number of fatalities occurs.
Total property damage is given as a number of states (none, very small, small, …)
and a related probability that the state occurs.
Total release size is given as a number of states (none, very small, small, …) and a
related probability that the state occurs.
The interpretation of the states in economical terms is described in the following.
9.2
Consequence cost evaluation
The present section outlines the economical consequence of the considered risk
types:
•
•
•
9.2.1
Fatalities
Property damage
Fatalities
The economical consequence of a fatality related to a ship accident is taken directly
from Risk Evaluation Criteria, Safedor, ref. [6] where values between 1.5 and 6 million US$ are mentioned and the value of 3 million USD is proposed. The amount of
money for one fatality is on this basis taken as 18 million DKK2.
No risk aversion is taken into account, i.e. the cost of 10 fatalities is ten times the
cost of one fatality.
9.2.2
Property damage
The property damage is estimated based on anonymous information from a ship insurance company regarding the insurance sums in case of ships being involved in
accidents.
Distribution functions of the insurance costs for both grounding and collision show,
that there is a wide range of costs ranging from many smaller cost to a few very
large costs.
2
Exchange rate: 1 USD = 6 DKK
128
The distribution functions for the insurance costs of both collisions and groundings
are shown in Figure 9-2.
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
Collisions
Groundings (incl. zero)
0%
0
200,000
400,000
600,000
Groundings
Collisions (incl. zero)
800,000
1,000,000
100 USD
Figure 9-2 Probability distributions for the insurance costs of collision and
groundings.
It is noted that there is graphs denoted ‘incl. zero’. These graphs represent the accident costs including also the accidents, where no costs are seen. These zero costs
are most likely related to accidents where the insurance company havd no expenses,
and may not be relevant for the accident.
The average costs for the cost distribution functions shown in Figure 9-2 amount to
•
•
Grounding: 276 million DKK
Collision: 120 million DKK
Information from other sources, Appendix 15 Accident costs in Norwegian waters,
indicates lower values than those shown above. Furthermore, it is noted that these
costs relates to accidents for a wide range of areas and ship types. It is considered
that Øresund differs from the average conditions – especially concerning groundings
due to the fact that the bottom in Øresund is mainly sand bottom which makes the
consequences of grounding significantly smaller.
In the consequence model, relations between ship type, speed etc. is established
such that different damage states are obtained. On basis of the distribution functions
in Figure 9-2 and the special conditions related to Øresund, the relations given in
Table 9-1 are used in the analysis for property costs.
129
Damage state
Very small
Small
Medium
Large
Very large
Collision cost
[DKK]
120 000
1 200 000
12 000 000
120 000 000
4 800 000 000
Grounding cost
[DKK]
0
2 760 000
276 000 000
22 080 000 000
0
Table 9-1 Cost distributions for property costs.
It is noted that each of the damage states in the model is obtained with a given
probability depending on the input parameters. Thus, the damage state ‘medium’
does not necessarily reflect the mean value.
9.2.3
The cost related to clearing and clean-up (environmental damage) is estimated
based on information given in Safedor, ref. [6], where an economical cost of 12 700
US$ per spilled ton of oil due to an accident is proposed. Information from accidents
shows economical costs ranging from 15 000 DKK pr. tonne to 55 000 DKK pr.
tonne.
The value proposed in Safedor, ref. [6] of 12 700 US$ pr. tonne has been used in the
present analysis.
The spillage volumes if accidents occur have a large variation. In ref. [14], an average volume of 400 ton spilled oil per accident is used, and in various accident registrations in Øresund spillage volumes of between 1000 and 6000 ton are registered,
i.e. the Fu Shang Hai and the Baltic Carrier accidents. On this basis, the relations
given in Table 9-2 are applied.
Oil spill
[tonne]
Very small
Small
Medium
Large
Very large
500
1000
5000
10 000
25 000
Cost
[DKK]
19 050 000
38 100 000
76 200 000
762 000 000
1 905 000 000
Table 9-2 Spillage volumes and corresponding costs
The probability of being in different states is modelled in the Bayesian networks
given in Appendix 13 Bayesian network for frequency models and 14 Bayesian network for consequence models.
130
10.
Presentation of results from risk analysis (FSA step 2)
Based on the frequency and consequence calculations, the risk related to various
locations and scenarios can be found. The locations and scenarios, where the models
are applied, are selected on basis of the input given at the hazard identification
workshop, the preliminary risk ranking (see section 7.4) together with outcomes of
the data analysis and are summarised in the following section.
10.1
Locations and scenarios
The locations in Øresund where a significant contribution to the risk of collisions and
groundings is expected are included in the risk analysis. The selection of these locations is based on the identified hazards from the hazard identification workshop supported by a data analysis of the traffic patterns at the location (see section 5.9) and
a detailed review of the registered accidents. For the identified hazards, the initial
risk ranking have been considered such that all hazard having medium or high risk
levels have been taken into account in the risk analysis. Hence, hazards with a low
risk level has only been considered to if these hazard are related to hazards with
higher risk levels.
Bearing this in mind, the critical locations have been selected and grouped into 5
overall locations in Øresund as listed below.
•
•
•
•
•
Drogden
Flintrännan
Entrance to port of Copenhagen,
Ven
At each of these locations, a number of scenarios have been identified and models as
described in chapter 8 and 9 are established in order to calculate frequencies and
consequences of accidents at the given locations.
Hence, the scenarios and locations given in Table 10-1 are selected for the detailed
risk analysis.
131
Scenario
Location
Collisions at crossing routes (Drogden/Flintrännan)
Drogden
Collisions of ships in northern direction passing Drogden
Lighthouse at both sides
Collisions during ship passings or overtakings in Drogden
Groundings outside Kongedybet
Groundings outside Drogden channel
Groundings at Quartus Grund
Groundings at Peberholm
Collisions at crossing routes (Kongedybet and Drogden)
Collisions at crossing routes (Kronløbet and Hollænderdybet)
Port of Copenhagen
Groundings at Lous Flak
Groundings at Middelpult in Kongedybet
Collisions during ship passings or overtakings in Flintrännan
Flintrännan
Collisions with the protective islands at the bridge piers in
Flintrännan
Groundings at Stengrund between Pinhättan and Landskrona
Ven East
Groundings at Väster Flacket off of Landskrona
Collisions during ship passings or overtakings at Ven East
Groundings at Swedish coast at Ven East
Collisions during ship passings or overtakings at Ven West
Ven West
Collisions at crossing routes at Helsingør/Helsingborg
Helsingør/Helsingborg
Grounding north of Helsingborg
Table 10-1 Scenarios and locations used in the risk analysis
132
It is noted that the locations and scenarios listed above are selected on basis of the
identified scenarios at the workshop and a review of registered accidents. Hence, the
risk analysis does not cover all potential scenarios and locations, but only the most
significant.
For this reason, it is expected that the total frequencies for collisions and groundings
underestimates the total frequencies. However, it is judged that the underestimation
is at a tolerable level.
Grounding and collision risk results
The results of the risk analysis are in the following presented for
•
•
Groundings
Ship-ship collision
Results related to the two accident types are given separately for each of the locations and are given in terms of yearly frequencies (accidents pr. year) and in terms
of economical risk (MDKK pr. year).
It shall be noted, that ship-obstacle collisions in Flintrännan from collisions with the
bridge piers are interpreted as groundings due to the fact, that the protective islands
constructed around the piers closest to the navigation route will prevent from actual
collisions and transform potential accident into groundings. In Figure 10-1 is shown
the overall frequency of groundings and collisions at the different locations in Øresund.
1.4
Frequency [per year]
10.2
1.2
Collision
Grounding
1.30
1.30
1.07
1.0
0.8
0.6
0.63
0.58
0.4
0.12
0.2
0.030.03
0.000.00
Flintrännan
Port of
Copenhagen
0.0
Drogden
Ven
Figure 10-1 Grounding and collision frequencies in various locations in Øresund.
133
It is seen from Figure 10-1 that the grounding frequencies in general are higher than
the collision frequencies. Furthermore, the areas where grounding most frequently
are expected to occur is in Drogden, north of Helsingborg and around Ven.
The groundings at Helsingør-Helsingborg are grounding occurring for northbound
ships after the bend on the route.
The groundings in Drogden related to ships grounding at Quartus Grund and also
groundings east and west of the channel – in many cases due to the transverse current in the southern part of Drogden – is the most likely cause of groundings in this
area.
The groundings round Ven relates mainly to groundings southeast of Ven towards
the Swedish coast.
The most dominating contributions to the collision frequencies arise from the crossing ship traffic in Helsingør/Helsingborg and from collisions during ship passages in
Drogden. The reason for having large collision frequencies at these locations is a
combination of the large traffic volumes which yields a large number of yearly passages and the difficult navigational conditions that are present at these locations.
In Drogden – specifically in the southern part – a transverse current may shift the
ship location to bring them close to passing ships and thus increase the risk of collisions.
Around Ven a large percentage of the ship traffic is separated since most southbound
ships goes west of Ven and most northbound ships goes east of Ven. However, a
small ratio of the ship traffic goes the other way round Ven – either because of regulations or due to draught requirements when heading towards the port of Malmö. For
these reasons, collisions between north- and southbound ships may cause collisions.
The main contribution comes from the eastern side of Ven, where the navigational
conditions are more complicated than on the west side of Ven.
In general, the high contributions to the frequencies are related to areas with high
traffic volumes and difficult navigational conditions as seen for the crossing traffic at
Helsingør-Helsingborg and for the ship passages in the narrow southern part of the
Drogden channel.
For both groundings and collisions there is good coincidence with calculated and registered accident frequencies for the relative distribution on the various locations. The
registered accident frequencies are slightly higher than the calculated (in particular
for groundings) and is mainly due to the fact that not all possible scenarios at all
locations have been included in the analysis, but only the scenarios considered to
give a significant contribution or scenarios that have been identified as being of a
special character.
134
The registered accident frequencies as shown in Table 6-2 is based on a counting of
all registered accidents in Øresund in the period 2000 to 2005. Reviewing these accident registrations shows that a number of registrations are outside the areas considered in the analysis. In Table 10-2 is shown the calculated frequencies together with
the frequencies based on the accident registrations presented in section 6.2 and frequencies based on the number of accidents within the considered areas.
Accident type
Calculated
annual
frequency
Registered annual frequency
(2000-2005)
From section 6.2
From considered areas
Collisions
1.36
2.2
1.33
Groundings
3.70
8.8
5.16
Table 10-2 Calculated and registered yearly accident frequencies
An overview of all contributions to the total collision and grounding frequencies are
shown in Table 10-3 in ranked order such that the most dominating contributions are
on top of the list.
Description
Frequency
[pr. year]
Grounding at HH (bend)
1.298
Grounding at Peberholm (bend)
0.785
Grounding at Ven east (bend)
0.710
Crossing at Helsingør-Helsingborg
0.629
Passages in Drogden
0.503
Grounding at Väster Flacket (too far out)
0.356
Grounding in northern Drogden
0.343
Grounding at Quartusgrund (bend)
0.101
Passages at Ven east
0.092
Crossing at Drogden lighthouse
0.059
Grounding at Quartusgrund (too far out)
0.053
Grounding at Øresund Bridge (too far out)
0.031
Passages at Ven west
0.031
Passages in Flintrännan
0.029
Crossing at Drogden-Kongedybet
0.018
Grounding in exit from Kongedybet (Sundby Hage)
0.014
Grounding at Stengrund
0.003
Grounding at Middelgrund
0.003
Crossing at Drogden-Flintrännan
0.002
Crossing at buoy 21
0.001
Table 10-3 Ranked list of accident frequencies for considered scenarios
135
Expected annual accident costs
By combining the accident frequencies with the consequences given an accident – in
terms of fatality, property and environmental costs – the annual expected costs from
collisions and groundings are calculated. The overall results divided into the different
locations are shown in Figure 10-2.
14.0
12.0
Risk [MDKK pr. year]
10.3
Collision risk
Grounding risk
11.75
11.01
10.0
8.0
6.0
4.0
3.98
3.26
4.00
1.70
2.0
0.46
0.08
0.0
Drogden
Ven
Flintrännan
0.020.01
Port of
Copenhagen
Figure 10-2 Annual expected accident costs [MDKK/year]
The costs are determined on basis of the accident frequencies and on basis of the
consequence given an accident. Hence, ship types and number of passengers on
board the ship has large influence on the calculated costs. The largest expected costs
is seen in the Helsingør/Helsingborg area, and the total for the entire Øresund is
summing up to approximately 36 million DKK pr. year. This number includes costs
related to fatalities, property and environment.
It is noted, that even though the grounding frequencies dominates the total accident
frequencies, the most significant contributions to the risk originates from collision
scenarios. This is due to the fact that the costs related to groundings in Øresund are
relatively small due to bottom being mainly sand in Øresund.
A list of the individual contributions to the total annual accident costs are given in
Table 10-4.
136
Scenario
Risk
[DKK/year]
11,754,302
Passages in Drogden
9,595,504
Grounding at HH (bend)
4,004,438
2,419,664
Grounding at Ven east (bend)
2,190,583
1,140,543
Grounding at Väster Flacket (too far out)
1,059,532
Grounding in northern Drogden
1,023,972
Crossing at Drogden lighthouse
994,101
Passages at Ven west
556,377
460,372
Crossing at Drogden-Kongedybet
381,840
340,142
Grounding at Quartusgrund (too far out)
160,628
Grounding at Øresund Bridge (too far out)
77,976
Grounding in exit from Kongedybet (Sundby Hage)
39,358
Crossing at Drogden-Flintrännan
36,585
Crossing at buoy 21
23,170
12,125
10,732
Grounding at Lous Flak
125
Table 10-4 Ranked list of risk contributions
On top of the list is seen accidents related to high collision frequencies but also with
a potential of many fatalities due to the presence of passenger ships. An overview of
all contributions to the total risk is given in Table 10-5.
137
Frequency
[accidents
per year]
Fatalities
Property
Environment
[DKK/year]
[DKK/year]
Description
[DKK/year]
Crossing at Drogden
0.059
4,262
91,290
898,549
lighthouse
Crossing at Drogden0.002
205
9,188
27,193
Flintrännan
Crossing at DrogdenKongedybet
0.018
1,912
91,551
288,377
0.629
76,394
3,256,565
8,421,344
Crossing at buoy 21
0.001
114
4,590
18,466
Passages in Drogden
0.503
43,021
1,009,217
8,543,265
0.029
2,937
84,858
372,578
0.092
7,716
198,750
934,077
Passages at Ven
west
0.031
2,279
62,232
491,866
Grounding at HH
(bend)
1.298
763
1,114,847
2,888,827
0.101
55
80,368
259,719
Grounding at Quartusgrund (too far
0.053
170
41,432
119,025
out)
Grounding at Väster
Flacket (too far out)
0.356
201
293,242
766,090
Grounding at Øresund Bridge (too far
out)
0.031
17
25,369
52,590
0.003
2
2,973
9,150
0.003
2
2,470
8,259
Grounding at Lous
0.000
0
31
93
Flak
Grounding in exit
from Kongedybet
0.014
8
11,724
27,626
(Sundby Hage)
Grounding in
northern Drogden
0.343
188
275,178
748,605
0.785
1,852
2,724,754
6,431,270
Grounding at Ven
east (bend)
0.710
1,677
2,466,790
5,822,393
Table 10-5 Risk contributions for fatalities, property and environment
It is seen from Table 10-5 that the risk contributions related to property and environment are dominating. Only at Helsingør/Helsingborg and in Drogden is seen large
fatality costs – mainly due to the high passenger ship traffic in these areas.
138
From the Bayesian network calculations it can furthermore be seen, that if an accident gives a large number of fatalities there is high probabilities that a passenger
ship is involved. Similar, if large environmental damage is seen, there is large probability that tankers are involved in the damage, and there is furthermore increased
probability that single hull ships are involved.
10.4
Sensitivity analysis
In the present section, the sensitivity of the main results for the most significant
scenarios is investigated for changing the following basic input parameters:
•
•
•
•
Increase in total ship traffic volume of 20% according to a situation in 2015
(2% increase pr. year)
Removal of all leisure boats
Double number of leisure boats
Changes of human failure rates (ratio of +/- 10)
The sensitivity analysis is carried out for
•
•
•
Collision scenario at Helsingør/Helsingborg
Passage collision scenario in Drogden
Grounding scenario at Drogden/Kongedybet.
As an indicator for the change in risk, the changes in the frequencies for the various
sensitivity analyses are given in Table 10-6.
Frequency [pr. year]
Base
case
0.63
Increase
in ship
traffic
0.89
Removal
of leisure
boats
0.59
Double
number of
leisure boats
0.70
Human failure
uncertainty
Passages in Drogden
0.51
0.74
0.49
0.51
0.49 - 0.76
Grounding in Kongedybet/Drogden
0.34
0.41
-
-
0.034 - 3.43
0.63 - 0.66
Table 10-6 Sensitivity analysis for collision and grounding frequencies
It is seen that the frequency of collisions in both Drogden and Helsingør-Helsingborg
increases with increasing ship traffic volume such that an increase in ship traffic of
20% yields an increase in collision frequency of more than 40%. For the same traffic
volume increase the grounding frequency is increased by 20%.
Furthermore, it is seen that the leisure boats in Drogden and Helsingør-Helsingborg
do not contribute significantly to the collision risk at these locations. This is in Drogden due to the fact that the leisure boats will tend to keep away from this dense
trafficked area and are - in case they appear in Drogden - located in the outer regions of the channel. At Helsingør-Helsingborg the number of leisure boats is small
compared to the number of ferries, and thus removing the leisure boats or doubling
the number of leisure boats does not change the collision frequency much. In the
grounding scenarios leisure boats were not considered in the base case scenario, and
139
thus the sensitivity analyses concerning leisure boats are not relevant for a grounding scenario.
Finally, it is seen that by assuming that the human failure rates are 10 times smaller
and 10 times larger, respectively, the collision frequency varies onlye slightly at
Helsingør-Helsingborg, whereas in Drogden they vary between 96% and 150% of
the base case collision frequency. The reason for the relative small decrease in frequency when the human failure rate is 10 times smaller is that when the failure rate
becomes very small, other failure types and conditions will dominate the collision
frequency.
In the grounding scenario it is seen that by varying the human failure rate by a factor of 10 the frequency also varies by a factor of 10. This is due to the fact that in a
grounding scenario the primary reason for avoiding a grounding is by not committing
a human failure.
140
11.
Cost-benefit models (FSA step 4)
As described in chapter 3 the cost benefit model includes
•
•
The costs related to implement a measure
The benefit from reducing the risk when the measure is implemented
The following sections show the details in this modelling.
11.1
Description of cost-benefit model
The principle in a cost-benefit analysis is to evaluate cost against achieved benefit.
For the risk analysis of the navigational safety in Øresund, this implies that cost of a
given risk reducing measure is evaluated against the safety benefits that will be
achieved by the risk reducing measure.
The IMO-guideline, ref. [1], gives the following description for use of methods to
apply in cost benefit analyses:
There are several indices which express cost effectiveness in relation to safety
of life such as Gross Cost of Averting a Fatality (Gross CAF) and Net Cost of
Averting a Fatality (Net CAF) as described in appendix 7.
Other indices based on damage to and affect on property and environment may
be used for a cost benefit assessment relating to such matters.
Comparisons of cost effectiveness for RCOs may be made by calculating such
indices.
In the present risk analysis the cost-benefit criterion used is as defined by the Danish Ministry of Transport for Social-economical evaluation, ref. [11]. This cost-benefit
criterion is in agreement with Swedish recommendations as well, ref. [34].
141
The cost-benefit criterion herein is defined as the ratio between the net benefit of
implementing a given measures and the net costs related to establish and operate
the measure. The criterion is shown below.
NPV
T
C Net, t
∑ (1 + r)
t =1
t
where
C Net, t
is the net-cost for the society in year t
T
r
NPV
is the considered period of time
is the interest rate
is the Net Present Value defined as
T
NPV =
Bt − Ct
∑ (1 + r)
t =1
t
where
Bt
is the benefit for the society in year t
Ct
is the cost for the society in year t
In general the Ministry of Transport, ref. [12], prescribes an interest rate of 6%.
Further, the considered time period for the present analysis is 25 years.
In ref. [12] it is noted that the considered period of time may be lower depending on
the life time of the risk reducing measure. As an example a period of 25 years were
used for signalling systems in ref. [13].
In the present situation, where there will be no income due to the implementation of
a risk reduction measure, the net-cost for the society, CNet,t will equal the cost of the
society, Ct. If it furthermore is assumed that the investment is made in year 1, the
cost in year 1, C1, equals the investment cost, and Ct for year 2, 3, .., T, equals the
operation and maintenance cost in these years.
The benefit of a given risk reducing measure is estimated based on the results of the
risk model, by summarising the reduced/change in cost (benefit) over the defined
hazards and events, see Figure 11-1.
142
Risk in relation to:
Hazard
Event
- collision
- grounding
- etc.
Cost in relation to:
Human safety
Human safety
Property
Property
Environment
Environment
Near Miss
Total Cost
Figure 11-1 Link between risk model and cost-benefit model.
In a situation with unlimited funds any risk reducing measure with a positive NPV
should be implemented. As this is normally not the case risk reducing measures are
evaluated based on the cost-benefit criterion. By implementing the project with the
highest cost-benefit, the society achieves most value for money.
It should be noted that the cost benefit analyses are made for the risk reducing
measures one by one. If it at a later stage is decided to implement a particular risk
reducing measure the cost-benefit of the remaining measures will change.
It should further be noted that the cost benefit does not quantify all effects. In line
with the recommendation in ref. [11] a list of these effects are given below:
•
•
•
•
•
•
•
Effect of barriers
Landscape and urban quality
Recreational areas
Nature and wildlife
Relation to existing physical planning
Cross border effects
Integration
Keeping the above list of not quantified effects in mind, risk reducing measures with
minor negative NPV may still be recommendable. The influence on the cost benefit
ranking of the considered risk reducing measures due to the uncertainty from omitted contributions is not quantified in the present analysis. Based on the cost-benefit
model and the above considerations a ranked list of measures is established and
forms the basis for recommendations to the decision makers.
143
Since the recommendations are based on economical reasoning, there may be local
or global political restrictions that prevent some of the proposed measures to be implemented. This issue is not discussed in the present report.
11.2
Assessment of basic cost-benefit parameters
The basic cost parameters include accident costs as described in Chapter 9 and the
costs of implementing a risk reducing measure. These costs consist of direct costs for
implementation and operational costs during the lifetime of the measure considered.
As mentioned, the lifetime is in all cases taken as 25 years and the interest rate is
taken as 6%.
The actions that must be taken to implement the measure consists of physical
changes to the routes – excavations, new markings, change of location of existing
marking etc. Standard costs in terms of installation costs and costs for operation and
maintenance (O&M costs) for these components/activities are given in Table 11-1.
Component
Unit price
[DKK]
-
O&M costs pr. year
[DKK]
15,000
Light buoys
-
70,000
Racons (yearly cost based on
5 year lifetime)
-
112,350
Investigation and application
for IMO-approval
Investigation and application
for smaller activities
Ship rent pr. hour
200,000
-
25,000-50,000
-
6,033
-
Day marks
Table 11-1 Standard costs for various components/activities in order to implement risk reducing measures
Based on the unit costs in Table 11-1 and information from the authorities of the
likely layout of changed navigation routes and additional markings, a list of costs to
implement the identified risk reducing measures are given. This includes:
•
•
•
•
•
A description of the measure
A description of actions taken to implement the measure
The installation costs
The operation and maintenance costs
The changes to the calculation models in order to account for the implementation of the measure
The list is shown in Table 11-2. It is noted that only overall descriptions are given for
all risk reducing measures in terms of regulation changes and changes to existing
markings or introduction of new markings.
144
Hence, it is not the purpose of the present study to make proposals to the detailed
design of any risk reducing measure. This is expected to be carried out in a later
stage.
145
No.
Description
Actions
Cost
[DKK]
O&M Costs
pr. year
[DKK]
1
Traffic Separation Scheme (TSS)
between Drogden and Flinten.
Northbound ships use Flinterännan
and southbound ships use Drogden.
Investigations and application for IMO-approval, ref.
[33]. It is considered that
the existing marking and
two additional light buoys
will apply also for the new
situation
200,000
140,000
2
Fixed beacons in Drogden instead of
floating beacons
Not included in analysis.
The data analysis of ship
traffic in Drogden and in
Flinterännan indicates no
difference in the use of
fixed or floationg beacons
with respect to ship locations in the route.
-
-
3
Traffic regulation in Drogden
Same scenario as no. 4
(see below).
Changes to written procedures and guidelines, ref.
[33]. No additional markings are expected.
-
4
Convoy sailing in Drogden. No considerations to waiting areas south
and north of the convoy sailing zone
are included.
Corrections to calculation
models
Removal of collision scenarios in
Change in traffic volumes in Drogden and Flinten. Traffic around Ven
is unchanged.
Change in distribution function for
grounding scenarios in Drogden
and Flintrännan (mean located in
midpoint of channel, standard deviation unchanged)
Change in distribution function
(mean value moves towards channel limit 1/3 -> ¼). This reduces
passage collisions. For grounding
scenarios, the probability of staying to far out shall be reduced.
However, no changes are seen
from the data analysis. No effect.
-
200,000
Large reduction in passage collision
frequencies in Drogden (only
front/back collisions)
grounding in southern Drogden
146
No.
5
Description
Actions
Introduction of VTS in Øresund. It is
assumed that the entire Øresund is
covered by the VTS-system.
Installation and operation
of a VTS-station includes:
VTS should comprise at least an
information service and may also
include others, such as a navigational assistance service or a traffic
organization service, or both, defined as follows:
1.
2.
3.
An information service is a service to ensure that essential information becomes available in time
for on-board navigational decisionmaking.
A navigational assistance service is a service to assist on-board
navigational decision-making, and
to monitor its effects.
Cost
[DKK]
O&M Costs
pr. year
[DKK]
25,600,000
8,800,000
Installation costs:
Material investments, ca.
17 MDKK
Consulting, app. 1 MDKK
In house salary: app. 4,6
MDKK
Travel costs. app. 0,5
MDKK
Meetings etc. 0,5 MDKK
Education app. 2,0 MDKK
models
Reduction in human failure as implemented in networks. The risk
reduction is calculated for the
three numbered descriptions. The
calculations covers a situation,
where VTS covers the entire Øresund, hence no investigation of a
partly implementation have been
made.
For option 1 (Information service)
the risk reduction is only related to
changes in the behaviour of the
navigator and hence to the
changes in the human failure
rates.
Operation
Staff (14 operators + 2
team leaders) app. 7,6
MDKK
Buildings: app. 1,2 MDKK
For option 2 there is, besides
changes to human failure rates,
also changes to the ability to manoeuvre correctly and to the space
to potential meeting ships.
A traffic organization service is
a service to prevent the development of dangerous maritime traffic
situations and to provide for the
safe and efficient movement of vessel traffic within the VTS area.
No distinguishing between option 2
and 3 are performed.
147
No.
6
Description
Actions
Removal of Drogden lighthouse
7
outside existing markers in Drogden
– applying for north and
southbound traffic.
8
Move buoy 16, the buoy in the
southern part of Drogden.
Cost
[DKK]
O&M Costs
pr. year
[DKK]
Removal of existing lighthouse and installation of
new light house, ref. [33].
28,000,000
200,000
Removal of existing lighthouse and no installation
of new light house (this is
analysed due to the fact
that the risk calculations
do not take the effect of a
new light house into account).
Marking of additional lanes
in shallow water areas
outside the existing Drogden channel.
Application for minor
changes to written procedures and guidelines, ref.
[33].
14 daymarks located with
7 east and 7 west of the
Drogden channel at same
latitude positions, ref.
[33].
2 hours installation works,
ref. [33].
10,000,000
-200,000
50.000
210,000
12,066
models
No crossing collisions
grounding in southern Drogden.
Additional calculations for risk reduction are carried out without
taking additional cost for a new
light house into account.
Change in distribution function and
number of ships in Drogden;
draught linked to normal and uniform distribution: draught < 5 m
leads to large reduction in appearance within channel limits)
Included in 9
148
No.
9
10
11
12
13
14
Description
Actions
Funnel shaped entrance to Drogden
by new buoy marking
It is estimated that 2 additional light buoys shall be
installed at the southern
entrance.
Weather service (maybe coupled to
VTS)
Emergency anchoring
Skilled personnel (loosing manoeuvring ability)
Engine and software backup (loosing manoeuvring ability)
ECDIS
Furthermore, a removal of
Quartus Grund must be
carried out in order not to
increase the risk of
groundings. It is estimated
the the cost of removal is
40% of the cost to remove
Staffans Banke (see 28)
Not included in analysis
Included in frequency of
avoiding an accident
Included in estimation of
human failure rates
Included in assessment of
falire of steering and propulsion machinery
Cost
[DKK]
O&M Costs
pr. year
[DKK]
43,200,000
140,000
-
-
Not quantifiable
-
-
Included in frequency models
-
-
-
-
-
-
Not quantifiable
149
models
Reduction in grounding frequencies
in the southern part of Drogden.
Removal of Drogden Lighthouse is
not accounted for in this scenario.
It is assumed that Quartus Grund
is removed.
No.
Description
Actions
15
Free pilot service
16
Excavation of Drogden to make it
twice as wide
Included by assuming larger rates of ships with pilot
in frequency models. The
price for having free pilot
service is estimated by
Farvandsvæsenet on basis
of the present price and
duration for pilotages and
the assumed ratio of passage times through Øresund and amount to approximately 390 MDKK,
ref. [33].
The excavation costs are
estimated based on information given in ref. [5]
and [14].
Cost
[DKK]
O&M Costs
pr. year
[DKK]
-
390,000,000
The ratio of non-pilot ships will
decrease with a factor 0.2.
Furthermore, when pilots are present at the ship bridge, the human
failure rate is redundant, i.e. it is
related to failures of two persons
(pilot and navigator) at the same
time.
400,000,000
-
Change of distribution function for
passage collisions and for groundings such that channel width is
twice as large. Better space for
manouvrering is accounted for as
input to the frequency models.
50,000
-
Reduction in passage collision frequencies (reduction like in 4)
No expected O&M cost due
to lime stone conditions
models
17
changes to written procedures, rules and guidelines, ref. [33].
18
Pilots participating at the VTS station
Equip pilots with mobile AIS
-
-
Not quantifiable
-
-
Not quantifiable
-
-
Reduction in grounding frequency
19
20
150
No.
Description
Actions
21
One fixed buoy (instead of floating)
22
Improve marking of Trekroner
lighthouse
23
24
25
26
27
28
29
Cost
[DKK]
O&M Costs
pr. year
[DKK]
-
-
Not quantifiable
Additional lighthouse
installed
500,000
-
Reduction in grunding frequency in
Kongedybet – shift in distribution
for the ship location
Marking of route for ships with large
draught in passage guide
Application for changes to
written procedures, rules
and guidelines, ref. [33].
100,000
-
Not quantifiable
Renaming of buoy at entrance of
Port of Copenhagen (buoy 21)
Information campaign for leisure
boats
Improved control of leisure boats
and their sailing
Restricted areas for leisure boats
-
-
Not quantifiable
100,000
-
Not quantifiable
-
-
Not quantifiable
-
-
Not quantifiable
Excavation costs are estimated to 135 MSEK, ref.
[33].
3
-
Reduction in grounding frequencies.
50,000
571,500
Excavation at Staffans Banke in
order to reduce the risk of grounding.
Traffic separation scheme (TSS) at
Staffans Banke
108,000,000
Installation of 8 light buoys
and 1 racon, ref. [33].
3
Exchange rate: 1 SEK = 0.8 DKK
151
models
Reduction of collision frequencies
for ship passages east of Ven.
No.
30
31
32
33
Description
Actions
Swedish coast guard should guide
leisure boats away from Ven
Guidance from VTS about sailing
around Ven
Traffic separation scheme (TSS)
around Ven. It is assumed that
north bound ships takes the route
east of Ven and that southbound
ships takes the route west of Ven.
Deep-water route on east side of
Ven
Cost
[DKK]
O&M Costs
pr. year
[DKK]
-
-
Not quantifiable
-
-
Not quantifiable
800,000
303,000
Change in traffic volumes.
Reduction of collision frequencies
200,000
280,000
See above
Investigation and application for changes to written
procedures, rules and
guidelines for IMO approval, , ref. [33]
of 4 light buoys and 2
racons, ref. [33].
Investigation and application for changes to written
procedures, rules and
guidelines for IMO approval, , ref. [33]
models
of 4 light buoys, ref. [33].
The measure is not analysed separately, but is
considered a part of the
TSS around Ven.
34
Shorten traffic separation zone at
Helsingør-Helsingborg (see below)
See below
152
No.
Description
Actions
Cost
[DKK]
O&M Costs
pr. year
[DKK]
35
25,000
12,066
36
Marking in passage guide that
southbound ship with large draught
tend to go west of W5
Forbidden to fish in traffic separation
More attention from coast guard
toward fishing vessels in the lane
Introduction of fines for fishing in
the lane
Mid channel marking on north west
side of Ven
Installation costs taken as
app. 2 hours to move the
existing marker W4
-
-
Not quantifiable
-
-
Not quantifiable
-
-
Not quantifiable
-
-
Not quantifiable
25,000
140,000
-
-
25,000
30,000
37
38
39
40
41
Marking of ferry routes in charts
42
Improvement of marking at Gräsrännan
(This measure is included in number
43 below)
of 2 light buoys, ref. [33].
Not relevant - already
implemented
of 2 day marks, ref. [33].
153
models
Change in distance to observe
Distributions for location changes
Allready implemented
Reduction in human failure rates/
awareness
No.
Description
Actions
Cost
[DKK]
O&M Costs
pr. year
[DKK]
43
Improved marking of Väster Flacket
by buoy
25,000
70,000
44
Removal of wreck on west side of
Ven
-
-
45
compulsory (see section 4.5.4)
of 1 light buoy, ref. [33].
Not relevant – the wreck is
preserved and must not be
moved
Education of 6 new pilots
and price per extra pilotage (see section 5.4.1),
ref. [33].
600,000
5,021,720
Table 11-2 Installation and O&M costs for various risk reducing measures.
154
models
Reduction in human failure rates/
awareness
Not relevant
Changes to the frequency models
such that ship types and classes
according to the recommendations
all have pilots on board.
12.
Cost-benefit evaluations (FSA step 4)
In the present chapter, the results from the cost benefit-analysis are shown. The
results are given in terms of
•
Changes in total risk from implementation of risk reducing measures
•
Calculated values of the cost-benefit criterion for all proposed risk reducing
measures
•
A ranked list of risk reducing measures according the value of the costbenefit criterion
On basis of the ranked list, recommendations for which measures that should be
implemented are given.
12.1
Total risk changes from implementation of risk reducing measures
On basis of the risk reducing measures applicable for a cost benefit analysis; the
changes in risk are calculated. It is noted that the change in risk are given for the
identified and capitalized risk reducing measures. Thus, it is not a complete list of
risk reducing measures. It is however judged to include by far the most significant
risk reducing measures.
The resulting risk changes for each risk reducing measure are shown in Table 12-1
below.
ID
Description
1
4
5
5
6
6
7
9
15
16
17
20
22
32
35
43
45
Traffic separation scheme between Drogden and Flintrännan
Introduction of VTS (information service)
Introduction of VTS (navigational assistance service)
Removal of Drogden lighthouse (incl. installation of new lighthouse)
Removal of Drogden lighthouse (excl. installation of new lighthouse)
Ships with smaller draught sailing outside markers in Drogden
Free pilot service
Improved marking of Väster Flacket by buoy
IMO pilot recommendations made compulsory
Risk change
[DKK/year]
11,585,276
10,048,326
1,213,606
23,442,476
1,334,244
1,334,244
6,823,575
244,857
10,836,307
7,487,671
479,775
1,073
22,933
4,018,325
9,400,763
474,092
2,109,045
Table 12-1 Changes in risk from implementation of risk reduction
155
It is seen that there is large variation in the risk change. Different factors have influence on the degree of change in risk, i.e.
•
The effectiveness of the risk reducing measure
•
The extend of the measure (does it apply for part of the area or the entire
area)
It is noted that the change in risk not determines whether or not the measure should
be implemented. This decision relies on the value of the cost-benefit criterion presented in the next section.
12.2
Calculated values of the cost-benefit criterion
On basis of the calculated annual risk savings from implementing a risk reducing
measure and on basis of the costs related to the implementation, the cost benefit
criterion is found. Calculated values of the criterion are shown in Table 12-2.
ID
Description
Cost-benefit criterion
NPV
T
C Net, t
∑ (1 + r)
t =1
1
4
5
5
6
6
7
9
15
16
17
20
22
32
35
43
45
Removal of Drogden lighthouse (incl. installation of new
lighthouse)
Removal of Drogden lighthouse (excl. installation of new
lighthouse)
Ships with smaller draught sailing outside markers in
Drogden
Free pilot service
t
23.02
679.79
-0.88
1.33
-0.41
1.41
33.43
-0.93
-0.97
-0.75
129.02
-0.42
-0.38
7.33
721.00
6.11
-0.55
Table 12-2 Cost-benefit criterion for the risk reducing measures
156
From the list above it is seen that the criterion value ranges from values below zero
to values up to approximately 700. Ideally, if the value is positive, the effectiveness
of the risk reducing measure is so good that the measure should be implemented.
There may be other reasons –political, environmental, international regulations etc.
– for not implementing an efficient measure or for implementing an inefficient measure. Any such reasons are not considered in the present report.
12.3
Ranked list of risk reducing measures
In the present section, ranked lists of measures for the effectiveness of a risk reducing measure are shown. The lists are ranked according to the NPV-value and according to the cost-benefit criterion. By ranking according to the NPV, an absolute value
for how much money it is possible to earn on implementation of a given risk reducing
measure is given, but it does not consider the quantified risk taken by implementing
the considered measure. The list is shown in Table 12-3.
ID
Description
5
1
4
35
7
Removal of Drogden lighthouse (excl. installation of new
lighthouse)
Removal of Drogden lighthouse (incl. installation of new
lighthouse)
Free pilot service
32
6
17
43
20
22
6
45
9
5
16
15
NPV [DKK]
171,330,935
141,934,326
128,262,657
120,006,861
84,694,625
45,203,298
9,990,144
6,085,967
5,208,104
-9,866
-178,533
-11,726,972
-33,062,326
-39,282,216
-112,828,628
-281,640,931
-4,479,060,001
Table 12-3 Cost-benefit ranked list of risk reducing measures according to
NPV-values.
It is seen that according to NPV, the most effective measures are introduction of VTS
(navigational assistance service. It is furthermore seen that VTS (information service) is not a cost-efficient measure. This is due to the fact that only for VTS (navigational assistance), is it possible to make active changes to the ongoing ship traffic
and thus decrease the risk. For VTS (information service) only passive changes (the
157
psychological effect of being registered) make changes to the accident frequencies.
In Figure 12-1 is given a graphical presentation of the ranked NPV-values.
200
100
Free pilot service
as wide
compulsory
buoy
-300
-200
-100
assistance service)
NPV [million DKK]
0
-400
-500
Except for VTS, nearly all other cost efficient measures are low-cost measures to
implement, i.e. measures of regulatory character with no or only small initial and
operational costs. It is noted, that some of these measures will delay the ship traffic.
The costs related to these delays are not quantified, but it is considered that the
costs may be even very large if taken into account and will then in turn make the
measures much less cost beneficial.
By ranking according to the cost benefit criterion, a relative value of the effectiveness of the risk reducing measure is given taking into account both the possibility to
have a positive outcome of implementing the measure and at the same time considering the risk. The list ranked according to the cost benefit criterion is shown in Table
12-4.
158
ID
Description
35
4
17
7
1
32
43
6
Free pilot service
5
22
6
20
45
16
5
9
15
Cost benefit
criterion
721.00
679.79
129.02
33.43
23.02
7.33
6.11
1.41
1.33
-0.38
-0.41
-0.42
-0.55
-0.75
-0.88
-0.93
-0.97
Table 12-4 Cost-benefit ranked list of risk reducing measures according to
the cost-benefit criterion.
It is seen that according to the cost-benefit criterion, the most effective measure is
moving the turn in the separation zone at Helsingør-Helsingborg. It is furthermore
seen that VTS (navigational assistance service) has a low positive cost benefit criterion and is not at the top of the ranked list according to the cost benefit criterion.
In Figure 12-2 is given a graphical presentation of the ranked risk reducing measures according to the cost benefit criterion.
159
800
Cost/benefit criterion
700
600
500
400
300
200
100
Free pilot service
ntroduction of VTS (information service)
as wide
compulsory
mprove marking of Trekroner lighthouse
assistance service)
buoy
-100
0
12.4
Cost-benefit sensitivity analysis
The cost values for the consequence cost related to fatalities, property and environment and for the costs of implementing and operating a risk reducing measure are
values assessed with some uncertainties. Hence, in order to see the robustness of
the calculated cost-benefit criteria values, a sensitivity analysis of the annual benefit
(the risk change pr. year) and of the installation and O&M costs is carried out
It is noted that the assessment of the risk is uncertain due to the uncertainty of the
input parameters. In general, it is estimated that the risk is calculated in decades
(factors of 10) and it is therefore considered reasonable to check the sensitivity for a
factor between 1 and 10. For this reason, a factor of 5 is used to increase and decrease the values of annual benefits.
Similar, the costs is estimated to be reasonable well defined and the sensitivity related to cost items is therefore investigated by applying a factor of 2 to increase and
decrease the costs.
In Table 12-5 is shown the computed cost-benefit criterion values for all annual
benefits multiplied by a factor of 5 and 1/5 along with the base case results (corresponding to Table 12-4). The results of this sensitivity analysis are illustrated in
Figure 12-3.
160
ID
Description
35
4
17
7
1
32
43
6
20
45
16
5
9
5
22
6
Cost benefit criterion
Benefit
Base
Benefit
factor 1/5
case
factor 5
143.40
721.00 3608.98
135.16
679.79 3402.96
25.00
129.02
649.11
5.89
33.43
171.15
3.80
23.02
119.12
0.67
7.33
40.66
0.42
6.11
34.55
-0.52
1.41
11.07
-0.53
-0.88
-0.88
1.33
-0.38
-0.41
10.67
2.11
1.96
-0.88
-0.42
1.91
-0.91
-0.55
-0.75
-0.88
-0.93
1.25
-0.95
-0.98
-0.99
0.27
-0.40
-0.63
Table 12-5 Ranked list of risk reducing measures according to the costbenefit criterion – sensitivity analysis of annual benefit.
3800
Benefit factor 5
3300
Base case
Benefit factor 1/5
2800
2300
1800
1300
800
Introduction of VTS (navigational assistance
service)
Traffic separation scheme between Drogden
and Flintrännan
Ships with smaller draught sailing outside
markers in Drogden
-200
300
Figure 12-3 Graphical presentation of sensitivity analysis on annual benefit.
161
Similarly, in Table 12-6 is shown the cost-benefit criterion values for all cost items
multiplied by a factor of 2 and ½ along with the base case results. This sensitivity
analysis is illustrated in Figure 12-4.
ID
Description
35
4
17
7
1
32
43
46
45
22
6
20
45
16
5
9
Cost benefit criterion
Cost facBase
Cost
tor 2
case
factor ½
360.00
721.00 1442.99
339.40
679.79 1360.58
64.01
129.02
259.05
16.21
33.43
67.86
11.01
23.02
47.05
3.17
7.33
15.67
2.56
6.11
13.22
0.21
1.41
3.83
0.17
-0.69
-0.70
1.33
-0.38
-0.41
3.67
0.24
0.19
-0.71
-0.78
-0.87
-0.94
-0.96
-0.42
-0.55
-0.75
-0.88
-0.93
0.16
-0.10
-0.49
-0.76
-0.85
Table 12-6 Ranked list of risk reducing measures according to the costbenefit criterion – sensitivity analysis of cost items.
162
1500
Cost, factor 2 down
1300
Base case
Cost, factor 2 up
1100
900
700
500
300
Excavation of Drogden to make it twice as
wide
compulsory
Introduction of VTS (navigational assistance
service)
buoy
Traffic separation scheme between Drogden
and Flintrännan
Ships with smaller draught sailing outside
markers in Drogden
-100
100
Figure 12-4 Graphical presentation of sensitivity analysis on cost items.
It is seen that most of the risk reducing measures are robust to changes in the assessment of basic cost parameters, because their cost benefit criterion remains positive when changing the annual benefit or the cost items. However, as seen in Table
12-5, two risk reducing measures were not robust to changes in model parameters.
VTS –navigational assistance - and removal of Drogden lighthouse (excluding installation of a new lighthouse) were found to be cost beneficial in the base case cost
benefit analysis, but in the sensitivity analysis of the benefit these measures were
not found to be efficient. Thus, the present analysis does not give a clear recommendation of these measures. However, further analysis of both cost and benefit of
these measures might reduce the uncertainty and prove them beneficial.
All of the other measures that were cost effective in the base case are still costeffective, in particular the low-cost measures like regulatory risk reducing measures
(convoy sailing, overtaking restrictions etc.) and simple navigation route markings,
when the annual benefit is lowered.
12.5
Control programme for follow-up and updates of results
The Bayesian network models and the associated Excel-applications for the costbenefit analysis enable the possibility of making updates and follow-up on the results. Hence, significant changes to basic input parameters or updated values of traffic volumes over time may make it interesting to check the present level of the risk
due to these changes.
163
The changes may be of different nature and may address different parameters with
influence on specific parts of the risk analysis model, e.g.:
•
•
•
•
Frequency models
Consequence models
Risk reducing measures
Cost-benefit model
Furthermore, basic changes to the assumptions for the risk modelling – changes in
infrastructure (e.g. a tunnel from Helsingør to Helsingborg), introduction of new frequently used ferry routes etc. may give significant changes to the risk results.
Table 12-7 outlines a number of parameters where changes should initiate a followup on the risk analysis results.
164
Parameter
Potential parameter changes and the effect on calculation models
The yearly traffic volume
Significant changes to the traffic volume (a change of 30-40%) will
give significant changes to the frequency calculations and may in
turn alter the need for introducing other proposed risk reducing
measures. The yearly development in ship traffic may give minor
changes to the risk results and change the ranking order of some
risk reducing measures.
Change in infrastructure
Introduction of new infrastructure (e.g. a tunnel from Helsingør to
Helsingborg). The effect from this will possibly be a removal of all
transverse ferry traffic and hence a large reduction in ship collision
frequencies.
Implementation of risk
reducing measures
By implementing some of the proposed risk reducing measures the
risk level is decreased and the overall risk level may give input to
new considerations concerning implementation of other measures or
potential changes to existing implemented measures.
Change in regulations
A change in regulations may give changes to traffic composition on
the routes and thus give changes in the frequencies or consequences.
Change in navigational markings and
route corrections
A change in navigational markings and route corrections may give
changes to traffic composition on the routes and eventually to the
ship traffic location on the routes and thus give changes in the frequencies or consequences.
Introduction of new
technology
New technology onboard the ship (instruments, machinery etc.)
may change the failure rates associated with technical or human
failures. This may lead to a general reduction in risk level and may
then change the effect of some of the proposed risk reducing measures. Furthermore, the effect of already implemented measures may
be insignificant due to these improved technical features.
New information on
cost prices
Updated information concerning cost for implementation of risk reducing measures may change the ranking of cost-beneficial measures.
Improved knowledge
of property, environmental or fatality
costs
Changes to the quantified consequence costs may in turn change
the ranking of risk reducing measures.
Table 12-7 Parameter changes calling for an update of analysis results
165
13.
The ranked list in the previous chapter of risk reducing measures with the highest
cost-benefit ratio is a starting point for the recommendations to increase the navigational safety in Øresund.
However, as stated earlier, there may be different reasons for not immediately implementing the most efficient measures, e.g.
•
•
•
•
Not all elements related to the implementation is quantifiable (imposed traffic delays etc.).
Political opinions differ from the cost-benefit ranking.
Some measures are subjected to considerations concerning the acceptance
criterion that is not comparable to the cost benefit criteria.
The sensitivity analysis results show that some measures are not robust to
changes in model parameters.
Hence, it is considered that some measures may be implemented very easily without
imposing disturbances to the traffic, whereas implementation of other measures may
lead to various degrees of traffic disturbance or have other effects to be taken into
account before deciding whether or not to implement the risk reducing measure.
Bearing this in mind, the list of recommendations is given in Table 13-1 below and
they are marked on a map of Øresund in Figure 13-1. Further development of the
details in these risk reducing measures should be carried out, and the estimated
costs confirmed.
No.
Comments
35
Move buoy W4 at HelsingørHelsingborg further north to give the
north- and southbound traffic more
time to manoeuvre before meeting the
east/west bound traffic.
This gives a large reduction in
collision frequencies. It is however noted that no collisions are
actually registered at this location
7
Mark additional lanes in Drogden outside the existing Drogden channel to be
used for smaller ships with draughts
less than 5 m.
This will give more space to the
large ships in Drogden and will
lead to a reduction in collision
frequencies
43
Improvement of the marking at the
north western area of Väster Flacket
A number of groundings have
been registered at this location,
and a better marking will lead
to improved navigational conditions
Table 13-1 List of recommended risk reducing measures.
166
35
43
7
Figure 13-1 Marking of recommended risk reducing measures.
It should be noted that detailed design of possible risk reducing measures should
result in an updating of the cost estimate and thus the cost benefit of a given measure.
Besides the measures above, a number of measures may be recommendable depending on additional clarification before implementation. These recommendations
are listed in Table 13-2 below.
167
No.
Comments
4
The convoy sailing in Drogden will lead
to a large reduction in collision frequencies. However, this will lead to delays in
passing Drogden and furthermore, no
considerations to the additional risk of
having line-up areas etc. is considered.
17
This will lead to a reduction in collision
frequencies, but will give delays for the
fast moving ships. Furthermore, the additinal risk for front-back collisions from
ships with different speeds are not taken
into account.
1
Traffic Separation Scheme in Drogden/Flintrännan
The traffic separation in Drogden/Flintrännan such that north bound
ships shall use Flintrännan and south
bound ships shall use Drogden will significantly reduce collision frequencies in
Drogden and Flintrännan. However, the
imposed additional transverse traffic
from and to the ports of Malmö and Copenhagen have not been taken into account. Furthermore, calculations on cost
from longer distances for ships in transit
and ship calling at Copenhagen and
Malmö have not been included in the
analyses.
32
Traffic Separation Scheme at Ven
The traffic separation at Ven such that
north bound ships shall go East of Ven
and south bound ships shall go West of
Ven will significantly reduce collision
frequencies at Ven. However, in order to
go to the port of Malmö, ships with large
draughts must use a deep water route
east of Ven. Grounding and collision scenarios for this route is not taken into
account.
Table 13-2 List of possible recommendations – depending on clarifications.
Furthermore, two risk reducing measures were not robust to changes in model parameters. VTS navigational assistance service and removal of Drogden lighthouse
(excluding installation of a new lighthouse) were found to be cost beneficial in the
base case cost benefit analysis, but in the sensitivity analysis of the benefit these
measures were not found to be efficient. Thus, the present analysis does not give a
clear recommendation of these measures. However, further analysis of both cost and
benefit of these measures might reduce the uncertainty and prove them beneficial.
168
It should be noted that in the analysis the risk reducing measures have been analysed one at a time, thus interaction between two or more measures have not been
taken into account, e.g. the implementation of 7 in Table 13-1 will possibly influence
the recommendations 4, 17 and 1 in Table 13-2 since they address the risk in the
same area.
Furthermore, in the analysis the principle of each measure has been evaluated, the
specific details of each measure (e.g. exact location of a buoy) have not been established at this point.
169
14.
References
[1] Guidelines for formal safety assessment (FSA) for use in the IMO rulemaking process, International Maritime Organisation, 2002
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171
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172

Navigational safety in the Sound between Denmark and Sweden

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