Analysis of AFRAMAX Tankers accidents International workshop on marine oil pollution control June 9, 2006 Athens Greece Professor A. Papanikolaou, Ship.

Analysis of AFRAMAX Tankers accidents

International workshopon marine oil pollution control

June 9, 2006 Athens Greece

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

NTUA-SDL POP&C: Analysis of AFRAMAX Tanker Accidents 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 POP&C (Pollution Prevention and Control, 2004-2007) to enable the full exploitation of available raw accident data of INTERTANKO, mainly compiled by Lloyd’s Marine Information Service (LMIS).


Methodology of work (1)

Source of data Raw accident records were made available by INTERTANKO Since the POP&C 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.


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 POP&C project.

The process of populating the POP&C 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.


POP&C Database

Initial LMIS data

New Accident categories

Fault TreesInformation

for each accidentcategory

Oil spill info

Fatalities-Injuries

Location

Oper. Cond.

Envi

Outcome

Hull Info


Review of ResultsSince the main scope of POP&C project is to evaluate accidents that led directly to ship’s loss of watertight integrity (LOWI), the analysis of data was focused on the six major POP&C 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.

POP&C AFRAMAX Tankers Accident Rate per ShipyearNon-Accidental Structural Failure, Collision, Contact, Grounding, Fire, and Explosion

0.00E+00

5.00E-02

1.00E-01

1.50E-01

2.00E-01

2.50E-01

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003


Rates and pollution

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).

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.

AFRAMAX Tankers, Six accident categoriesSpilled Ton Rate per shipyear

0.00E+00

5.00E+01

1.00E+02

1.50E+02

2.00E+02

2.50E+02

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

POP&C AFRAMAX Tankers, Rates of accidents leading to pollutionNon-Accidental Structural Failure, Collision, Contact, Grounding, Fire, and Explosion

0.00E+00

2.00E-03

4.00E-03

6.00E-03

8.00E-03

1.00E-02

1.20E-02

1.40E-02

1.60E-02

1.80E-02

2.00E-02

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003


Oil Spill QuantityThe 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.

AFRAMAX Tankers, POP&C Database, Period 1978-early 2004 Total Oil Pollution Quantity

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

StructuralFailure

Collision Contact Grounding Fire Explosion

Total Oil Pollution Quantity in POP&C Database = 412,253 t


Hull Type versus Oil SpillsPost-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

DB concept

DS concept

DH concept with “L” and “U” arrangement


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.

Aframax Tankers (Collision+Contact+Grounding) Accident Rate per Shipyear

0.00E+00

2.00E-02

4.00E-02

6.00E-02

8.00E-02

1.00E-01

1.20E-01

1.40E-01

1.60E-01

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

All ships Non-DH ships DH


AFRAMAX Tankers, Frequencies by Age

AFRAMAX Tankers, Non-Accidental Structural Failures

Period 1978-2003, Accident Rates by Age

0.00E+00

5.00E-03

1.00E-02

1.50E-02

2.00E-02

2.50E-02

3.00E-02

3.50E-02

4.00E-02

4.50E-02

0 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

Age of ship at the time of incident



0.00E+005.00E-031.00E-021.50E-022.00E-022.50E-023.00E-023.50E-024.00E-024.50E-02

0 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


SH-non SBT/PL DS

SH-Non SBT/PL ships (pre-MARPOL tankers) & DS ships



0.00E+005.00E-031.00E-021.50E-022.00E-022.50E-023.00E-023.50E-024.00E-024.50E-02

0 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


SH-SBT/PL DH

SH-SBT/PL ships (MARPOL tankers) & DH ships

AFRAMAX Tankers, Accident Rates by AGE

0.00E+00

5.00E-03

1.00E-02

1.50E-02

2.00E-02

2.50E-02

3.00E-02

0-5 years 6-10 years 11-15 years 16-20 years > 20 years

Collision Contact Grounding Structural Failure Fire Explosion



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.

AFRAMAX Tankers, Non-Accidental Structural Failure

Accident Rates by Age, Period 1978-2003

0.00E+002.00E-034.00E-03

6.00E-038.00E-031.00E-021.20E-021.40E-02

1.60E-021.80E-022.00E-02

0 1 2 3 4 5


All SH-non SBT/PL SH-SBT/PL DH

AFRAMAX Tankers, Non-Accidental Structural Failure Accident Rates by Age, Period 1978-2003,

0.00E+00

5.00E-03

1.00E-02

1.50E-02

2.00E-02

2.50E-02

3.00E-02

3.50E-02

4.00E-02

4.50E-02

11 12 13 14 15


All SH-non SBT-PL SH-SBT/PL


Main Conclusions (1)Accident databases such as the one utilized by POP&C 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 ship’s 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.


Main Conclusions (2)

Further studies beyond those of the POP&C 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.

Accident Rate per Shipyear

0.00E+00

5.00E-02

1.00E-01

1.50E-01

2.00E-01

2.50E-01

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

AFRAMAX SUEZMAX VLCC & ULCC


Main Conclusions (3) World map of oil pollution due to large tankers accidents over the period

1978-2003.

Spill <7t (green) Spill: 7-700 t (yellow) Spill: 700-20000 t (red) Spill: 20000-60000t (red cycle) Spill: 60000-100000t (red triangle) Spill > 100000t (red square)

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.


References POP&C, “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, 9 th 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.

Analysis of AFRAMAX Tankers accidents

International workshopon marine oil pollution control

June 9, 2006 Athens Greece

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

Analysis of AFRAMAX Tankers accidents International workshop on marine oil pollution control June 9, 2006 Athens Greece Professor A. Papanikolaou, Ship.

Documents

aframax size tankers

analysis of data

present analysis

systematic analysis

raw data accident records

major popc accident

shuttle tankers

basic aframax subtypes