Hazard identification and scenario selection of ship grounding accidents
Introduction
While in service, ships rarely are subjected to accidents which include grounding, collision, contact, fire, explosion, capsizing and hull girder collapse. Such accidents may result in catastrophic consequences associated with casualties, property damage and environmental pollution. Ship grouding studied in the present paper is one of the most frequent accidents in shipping. When large tankers are involved in a grounding event with breaching one or more cargo tanks, the environmental pollution due to an oil spill becomes a great concern. Fig. 1 shows the causes of oil spills with greater than 700 tonnes in amount occurred during 1970–2015 (ITOPF, 2016). It is seen from Fig. 1 that grounding accidents take up 33%. AGCS (2014) indicates that ship grounding takes up 50% of all marine insurance claims in excess of 1 m Euro during 2009–2013. Moreover, wreck removal costs can be several times larger than that of the hull value in some cases, because rescue and salvage operations are complex and costly as environmental concerns are raised. For example, the passenger vessel “Costa Concordia”, which ran aground in 2012, significantly raised many issues to be resolved in the international marine salvage industry and caused new regulations to be set for improving safety performance in wreck removal operations (Senauth, 2013).
The International Maritime Organization (IMO, 2002) introduced a procedure for formal safety assessment (FSA) which is handy in identifying and evaluating risks to personnel, assets and the environment. The FSA procedure comprises five main steps as follows:
- •
Step 1: Hazard identification.
- •
Step 2: Risk analysis
- •
Step 3: Risk control options
- •
Step 4: Cost-benefit assessment
- •
Step 5: Decision making and recommendations
In step 1, all potential hazards leading to damages to personnel, asset and the environment are identified. The main result of this step is a list of hazards and associated scenarios which should be prioritized by identified risk level that should be the focus of a more thorough analysis in subsequent phases of the FSA. The accidental scenario identification and selection is the most vital stage of any risk assessment procedure or quantitative risk assessment and management (QRA&M), which affects all the following stages in the FSA framework.
Two available approaches can be used for the scenario identification stage; deterministic and probabilistic. In the deterministic procedure, a few scenarios are chosen by assuming a certain value for each scenario parameter where the ship might be tested under one or more unfavorable accidental scenarios with a relatively low level of occurrence probability, leading to unfavorable consequences. On the other hand, the probabilistic approach identifies the hazards probabilistically with a set of scenarios in association with the random variables affecting the consequences of the accident (Paik and Thayamballi, 2007, Samuelides et al., 2009, Youssef et al., 2016). As ship grounding is rather uncertain and probabilistic in nature, probabilistic approaches are more desirable.
Numerous studies in the literature have used the deterministic approach to choose grounding scenarios, which were implemented in model tests and numerical simulations (Glykas and Das, 2001, Haris and Amdahl, 2012, Hong and Amdahl, 2008, Hong and Amdahl, 2012, Liu et al., 2015, Paik and Seo, 2007, Yu et al., 2013, Zeng et al., 2016, Zhang and Suzuki, 2006). In contrast, a few studies have used the probabilistic approach, in which each of grounding parameters has been dealt as a random variable by formulating a distribution function. Based on statistical data collected, Brown and Amrozowicz (1996) introduced a method to define probability density distributions for grounding damage extent as a function of a simplified set of independent variables circumscribing the ship structural design. This method is initially started by formulating probability density functions (pdf's) for ship speed, depth of water and obstruction characteristics. Similar work was conducted by Lützen and Simonsen (2003) where the grounding scenarios were described by pdfs for ship draught, speed and obstruction height, and width. Moreover, such analyses have also been performed by Rawson et al. (1998) and Tikka and Chen (2001). In recent years, the studies on the structural crashworthiness and also the response of post-grounding accidents are also found in the literature (Deeb et al., 2017, Hong and Amdahl, 2008, Khan and Das, 2008, Paik, 2007a, Paik, 2007b, Samuelides, 2015, Zipfel and Lehmann, 2012).
In the light of the above discussion, this paper aims the way to select grounding scenarios using the probabilistic approaches. This method commences with collecting grounding accident database from different sources worldwide, followed by a statistical analysis which aids formulating the pdf's for the corresponding parameter of grounding. The derived probability functions are then used to select a set of grounding scenarios that can typify all possible situations. Similar approaches were applied to ship collisions (Youssef et al., 2014a, Youssef et al., 2014b).
Section snippets
Framework of the applied methodology
To choose accidental scenarios, influential parameters governing the accident are defined in Section 3. This can be done by discerning the event first through investigating a large number of historical relevant accidents. The probabilistic method presented in this study starts with gathering information about historical ship grounding accidents to erect a database with a satisfying quality and quantity. The outline of the framework developed in this study is illustrated in Fig. 2. The
Parameters affecting ship grounding mechanics
Ship grounding is defined as an accidental event where ship bottom structures are damaged. Typically, ship grounding accidents can be classified into two groups: one is an event where a ship runs on a rock pinnacle with a forward speed, and another group is a stranding situation which is similar to a collision where the bottom structures are subjected to mainly out-of-plane loads (Paik and Thayamballi, 2003). In the first group, the grounding process is distinguished by an obstruction deflects
Collation of ship grounding accident database
Two kinds of casualty databases are available: accessible by the public and privately owned databases (i.e., commercial data). One of the publicly accessible data is the national accident investigation boards (flag administrations). In this study, a ship grounding database has been amassed from more than 600 accidents investigation reports located in the web pages of about 19 national accident investigation boards, transport safety bureaus of different countries and non-governmental
Probability density distributions of random variables
The ship types involved in the collected database are regrouped into six categories, each encompasses several more specific types, as follows:
- •
All types: including all types of vessels in the database.
- •
Tankers: including crude, product and chemical tankers as well as gas carriers.
- •
Bulk carriers: including dry bulkers and coal carriers.
- •
Cargo vessels: including general cargo and refrigerated vessels.
- •
Container vessels.
- •
Passengers: including passenger vessels, ferries and Roll-on/roll-off (Ro-Ro)
Probabilistic selection of grounding scenarios
The probability density functions determined in Section 5 are employed in a sampling process to stochastically select a limited number of grounding scenarios. In this study, the Latin hypercube sampling method (LHS) is used by implementing the selected pdfs to generate random values for each scenario parameters, with respect to the data range and variability. A Latin square is a square grid containing sample positions, if (and only if) there is only one sample in each row and each column. A
Concluding remarks and further work
Grounding accidents are a threat at the maritime sector in terms of environmental and economic impacts, despite the cautionary measures devised recently as well as the developed navigational aids onboard. In overall, this paper aims at contributing to the decrease of the grounding consequences with an advanced technology to select a set of credible scenarios which are essential within the framework of quantitative grounding risk assessment and management.
First, a database was gathered,
Acknowledgements
The second author is president of the Korea Ship and Offshore Research Institute at Pusan National University which has been a Lloyd's Register Foundation Research Centre of Excellence.
References (84)
- et al.
On the resistance of tanker bottom structures during stranding
Mar. Struct.
(2007) - et al.
Probabilistic assessment of damaged ship survivability in case of grounding: development and testing of a direct non-zonal approach
Ocean. Eng.
(2016) - et al.
A simplified grounding damage prediction method and its application in modern damage stability requirements
Mar. Struct.
(2009) - et al.
Energy conservation during grounding with rigid slopes
Ocean. Eng.
(2001) - et al.
Simplified analytical method to evaluate tanker side panels during minor collision incidents
Int. J. Impact Eng.
(2015) - et al.
On the cutting of a plate by a wedge
Int. J. Mech. Sci.
(1990) - et al.
Comparison of the crashworthiness of various bottom and side structures
Mar. Struct.
(2002) - et al.
Understanding ship-grounding events
Mar. Struct.
(2011) - et al.
Monitoring of ship damage condition during stranding
Mar. Struct.
(2011) - et al.
Advanced method for the development of an empirical model to predict time-dependent corrosion wastage
Corrosion Sci.
(2012)
A method for progressive structural crashworthiness analysis under collisions and grounding
Thin-Walled Struct.
Effect of ship structure and size on grounding and collision damage distributions
Ocean. Eng.
Ship grounding on rock—II. Validation and application
Mar. Struct.
Estimating sea bottom shapes for grounding damage calculations
Mar. Struct.
Assessment of a ship's performance in accidents
Mar. Struct.
Investigation on structural performance predictions of double-bottom tankers during shoal grounding accidents
Mar. Struct.
Statistics and damage assessment of ship grounding
Mar. Struct.
Global Claims Review 2014
Allianz Global Corporate & Specialty Safety and Shipping Review 2016
Published reports
Marine safety Investigations and Reports
Accidents Full Reports
Casualty and Reporting
Tanker environmental risk—putting the pieces together
Investigation Reports
Review of statistical data on ship accidents
Marit. Tech. Eng.
Handbook of methods of applied statistics
Clarkson Shipping Intelligence Network
A review of damage assessment models in the maritime domain
Ships Offshore Struct.
Casualty Reports
Statistical analysis of ship accidents and review of safety level
Saf. Sci.
Accident Investigation and Marine Casualties
Modeling ship transportation risk
Risk Anal.
Goal-based Damage Stability
Harmonization of Rules and Design Rational
Crushing resistance of a cruciform and its application to ship collision and grounding
Ships Offshore Struct.
Investigation Reports
A Simplified Approach to Predict the Bottom Damage in Tanker Grounding, Collision and Grounding of Ships and Offshore Structures
Plastic mechanism analysis of the resistance of ship longitudinal girders in grounding and collision
Ships Offshore Struct.
Rapid assessment of ship grounding over large contact surfaces
Ships Offshore Struct.
Interim guidelines for approval of alternative methods of design and construction of oil tankers under regulation 13F(5) of Annex I of MARPOL 73/78
Tech. Rep.
IMO MSC/Circ. 1023 MEPC/Circ. 392—Guidelines for Formal Safety Assessment (FSA) for Use in the IMO Rule-making Process
Cited by (54)
Analysing influencing factors of accidental oil spills under the IOPC Fund
2023, Regional Studies in Marine ScienceGrounding risk quantification in channel using the empirical ship domain
2023, Ocean EngineeringA content-aware corpus-based model for analysis of marine accidents
2023, Accident Analysis and PreventionAnalytical modelling of ship bottom grounding considering combined surge and heave motions
2023, Marine StructuresPhenomenological characteristics and flame radiation of dynamically evolving oil spill fires in a sealed ship engine room
2023, Ocean EngineeringCitation Excerpt :The literature review above reaches a consensus that the available studies on ship engine room fires are only based on the pool fire source in most cases, where the combustion area is unchanging throughout the experiments. In fact, in a ship engine room, the oil pipelines are easy to be damaged by external factors (collision, ship rocking, etc.) (Youssef and Paik, 2018; J. Wang et al., 2022) and internal factors (aging lines, unsafe crew behavior, etc.) (Sarıalioğlu et al., 2020), leading to the fuel leakage. When encountering with the widespread high-temperature facilities (Diaz-Secades et al., 2022), the flowing fuel will naturally form a dynamically evolving spill fire instead of a pool fire, which is full of uncertainty and danger.