Analysis of AFRAMAX Tankers accidents

1
Analysis of AFRAMAX Tankers accidents

• International workshop
• on marine oil pollution control
• June 9, 2006 Athens Greece

Professor A. Papanikolaou, Ship Design
Laboratory, NTUA, GREECE
2
Introduction

• The scope of presented research is the
  identification of basic events leading to major
  tanker casualties and the investigation of
  factors related to consequences such as the
  degree of incidents severity, event location and
  ship operating condition at the time of incident,
  loss of watertight integrity, weather impact,
  loss of life/injury and oil spill occurrence.
• A rational database of AFRAMAX tankers was set up
  in the framework of the EU funded project POPC
  (Pollution Prevention and Control, 2004-2007) to
  enable the full exploitation of available raw
  accident data of INTERTANKO, mainly compiled by
  Lloyds Marine Information Service (LMIS).

3
Methodology of work (1)

• Source of data
• Raw accident records were made available by
  INTERTANKO
• Since the POPC project has used the AFRAMAX size
  tankers to demonstrate the applicability of the
  developed risk based methodology, the present
  analysis focused mainly on records pertaining to
  AFRAMAX tankers (DWT size segment 80,000
  119,999).
• In addition to the size constraint, only the
  basic AFRAMAX subtypes were investigated, namely
  Oil Tankers, Crude Tankers, Shuttle Tankers,
  Product Carriers and Chemical/Oil Tankers.
• Out of 16554 raw data accident records pertaining
  to all sizes and types of tankers, 1294 accident
  records of AFRAMAX ships were herein finally
  extracted and post-processed, covering the period
  1978 to early 2004.

4
Methodology of work (2)

• The initially selected records were imported into
  a purposely developed new database.
• This database was further enhanced to enable the
  post-processing textual information contained in
  the raw data records, namely its easy retrieve
  and systematic analysis. The registered
  information was filed in a way enabling the
  population of the Risk Contribution Fault Trees
  (FTs) and Event Trees (ETs) developed by the
  POPC project.
• The process of populating the POPC database was
  carried out by a team of experts of WP2. Each
  partner organisation undertook the task of
  studying the raw data textual information of each
  record and entering the relevant information into
  the database in the specified format. The
  initially filed information was reviewed twice by
  other experts before finalising each record.

5
POPC Database
6
Review of Results

• Since the main scope of POPC project is to
  evaluate accidents that led directly to ships
  loss of watertight integrity (LOWI), the analysis
  of data was focused on the six major POPC
  accident categories, leading to LOWI, namely
• Non-Accidental Structural Failure
• Collision
• Contact
• Grounding
• Fire
• Explosion accidents

• Below Figure presents the overall accident rate
  per shipyear pertaining to all six major accident
  categories. The straight lines represent the
  average rates for the particular reference period.

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Rates and pollution
Although the frequency of accidents occurrence
has been significantly reduced especially in the
post-90 period, the frequency of accidents that
caused pollution is about the same for the
post-90 period.
High Spilled Tonne Rate is met in 1980, 1993 and
2002. This is not related to the relatively high
number of occurred accidents but to one casualty
per mentioned year with catastrophic
environmental consequences, namely IRENES
SERENADE (80,000 t - 1980), BRAER (88,214 t -
1993) and PRESTIGE (77,000 t - 2002).
8
Oil Spill Quantity

• The highest number of accidents causing
  environmental pollution arises from
  Non-Accidental Structural Failure.
• However, when the oil spill quantity is
  considered, Grounding Explosion accidents gave
  the largest oil pollution quantities.
• The severity of the Explosion accidents must be
  highlighted For example, two Explosion accidents
  led to more pollution than nineteen
  Non-Accidental Structural Failures.

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Hull Type versus Oil Spills

• Post-90 period
• Significant increase of the pollution index
  (spilt tonnes/shipyear) for the SH-non-SBT/PL
  ships.
• Increase of index also for the DS ships.
• Significant reduction of the index for the DB and
  the SH-SBT-PL ships in the post-90s period.
• DH and SH-SBT/PL indices comparable in the
  post-90 period

10
Accident rates of Double Hull and Non-Double Hull

• The below figure presents the collision, contact
  and grounding (i.e. navigational) accident rates
  for all hull types, and also separately for the
  DH and non-DH configurations.
• For these accident categories, no consistent
  statistical difference in the accident rates of
  the different hull configurations is expected,
  because the frequency of navigational accidents
  cannot rationally be affected by the hull
  configuration.

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AFRAMAX Tankers, Frequencies by Age
12
AFRAMAX Tankers, Non-Accidental Structural
Failures

• Focusing on the Non-Accidental Structural
  Failures which occur to ships of age up to 5
  years, it can be stated that DH-ships have lower
  but non negligible rates, Figure left hand side.
• Considering Non-Accidental Structural Failures
  which occur to ships of age between 11-15 years,
  Single Hull non-SBT/PL ships presented by far the
  highest rates, while it is still too early to
  attempt drawing any conclusions on the
  performance of middle aged Double Hull tankers,
  Figure right hand side.

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Main Conclusions (1)

• Accident databases such as the one utilized by
  POPC are potentially important tools for gauging
  the safety and the environmental performance of
  the tanker industry.
• Other databases currently in use suffer from some
  serious weaknesses that greatly diminish the
  ability to utilize their data
• Firstly, although they contain a plethora of
  records of shipping casualties, the source of
  their information is often non- technical.
• The way the information is categorised, is not
  detailed. Accidents are assigned to a single
  category, such as Collision, Grounding,
  Fire/Explosion, Hull Machinery. This
  one-dimensional categorisation ignores the basic
  fact that accidents are sequences of undesirable
  events each of these having their own probability
  profile.
• Regarding the accidents of AFRAMAX fleet
• Overall tanker accidents decreased significantly
  in the post-90s period, however oil pollution
  rates remained about the same.
• From the various tanker hull design concepts
  currently operating, it appears that the Double
  Hull and the Single Hull with SBT/PL perform best
  in all accidental categories.
• The impact of ships age on tanker accidents is
  not straightforward middle aged ships appear to
  be more sensitive to Non-Accidental Structural
  failures, compared to older (!) and younger
  ships. This is clearly so with single hull ships
  and remains to be clarified for the double hull
  ships, currently too young in age to be
  conclusively assessed.

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Main Conclusions (2)

• Further studies beyond those of the POPC project
  were conducted by the Ship Design Laboratory of
  NTUA, namely addressing the SUEZMAX, VLCC and
  ULCC tanker fleets, thus practically all large
  size tankers.
• Accident rates of large tankers have been
  significantly decreased over the period
  1978-2003.
• Rates of accidents leading to pollution as well
  as rates of accidents with high degree of
  severity have been reduced as well but not to the
  same extent.
• Spilled tonne rates present a decline trend along
  the studied period for SUEZMAX and VLCC-ULCC
  tankers. Concerning AFRAMAX tankers, a slight
  increase has been found mainly due to the BRAER
  and PRESTIGE casualties in the post 90ties
  period.

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Main Conclusions (3)

• World map of oil pollution due to large tankers
  accidents over the period 1978-2003.

The analysis of geographic locations of recorded
accidents with high pollution showed that besides
the Caribbean Sea, the Southwest South European
and Southwest South African coasts were more
heavily polluted by large oil tanker accidents in
the period 1978-2003.
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References

• POPC, Pollution Prevention and Control. EU
  project, 6th Framework Programme, Contract No
  TST3-CT-2004-506193, 2004-2007,
• website www.pop-c.org
• Papanikolaou A., Eliopoulou E., Alissafaki A.,
  Aksu S., Tuzcu C., Delautre S., Mikelis N.
  2005. Critical Review of AFRAMAX Tankers
  Incidents, 3rd International Conference ENSUS
  2005, 13-15 April, Newcastle upon Tyne.
• Papanikolaou A., Eliopoulou E., Alissafaki A.,
  Aksu S., Delautre S. and Mikelis N. 2005
  Systematic Analysis and Review of AFRAMAX
  Tankers incidents. Proc. 11th International
  Association of the Mediterranean Congress IMAM
  2005 , Portugal.
• Papanikolaou A., Eliopoulou E., Mikelis N., Aksu
  S. and Delautre S. 2005 Casualty analysis of
  tankers. RINA, Proc. Learning from Marine
  Incidents III 2006, London, UK.
• Papanikolaou A., Eliopoulou E., Mikelis N.
  Impact of hull design on tanker pollution RINA,
  9th International Marine Design Conference IMDC
  2006, Ann Arbor Michigan.
• Mikelis N., Delautre S. and Eliopoulou E. Tanker
  safety record at all-time high Lloyds List, 29
  September 2005.
• Mikelis N., Papanikolaou A. and Eliopoulou E.
  Analysis uncovers tanker fleet pollution
  surprises Lloyds List, 17 February 2006.

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Analysis of AFRAMAX Tankers accidents

• International workshop
• on marine oil pollution control
• June 9, 2006 Athens Greece

Professor A. Papanikolaou, Ship Design
Laboratory, NTUA, GREECE