Risk Analysis of Sea Traffic in the Area around Bornholm, 2008. - VTT

Risk Analysis for Sea Traffic in the Area around Bornholm
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In both accident modes, the same parameters determine the grounding probability:
• ground depth and vessel draught
• location of vessel and ground
• distribution of the vessel course (i.e. the weight of the different arrows in
Figure 12)
In addition, missed-turn groundings depend on
• the distance between turning point and ground
• the frequency, at which bridge personnel checks ship position and course
Appendix B provides a more detailed description.
4.6.4 Grounding consequences
The consequence model for groundings is based on a previous project /COWI
2007/. The model provides an estimate for the spillage of cargo (oil tankers)
and of bunker oil (all ship types) based on a statistical approach.
Furthermore, some relations describing the probability and extent of ship damage
as well as the expected number of lives lost were needed for the risk assessment.
These modelling aspects are further explained in Appendix B.
4.7 Direct cost model
Accident costs occur with some uncertainty, because accidents are uncertain.
Therefore they are referred to expected costs. Expected costs are opposed to
direct costs, i.e. costs that will occur with certainty.
In the case of traffic re-routing, such direct costs (or benefits) arise mainly because
of the difference in route lengths, leading to different sailing durations
between point A and point B. Among others, this affects
• fuel consumption costs
• capital costs for owning and running the ship
• external costs, i.e. damage due to ship engine exhaust fumes
Appendix C quantifies these factors in DKK per kilometre for a number of ship
types and sizes. The numbers are based on ship trading data from /Clarksons
2007/ and environmental data from /Transportmin/.
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