Dimitrios I. Stavrou

Studying the marine accidents of the Aegean Sea: critical review, analysis and results

ABSTRACT This paper aims at discovering characteristics, aspects and statistical patterns of recorded maritime accidents within specific zones of the Aegean Sea. A focused database with 10 years’ accidents data has been studied on the special characteristics of the ships that had been involved. Based on this database, the paper presents results derived by statistical analysis that are able to provide valuable information about the accidents under examination in terms of type, size and other parameters of the involved ships. Two models are developed and implemented to establish a risk perspective view of maritime transport within the Aegean Sea; a stochastic Poisson function is used to determine the probability of accident occurrence for each one of the three sea zones of study. Next, a fault-like approach is explored as the basis for an alternative way of studying marine safety; in this context, a seismic-driven model is applied for the calculation of the probability of accident occurrence. To do so, the concept of energy release is used so as to develop a novel modelling approach for maritime accidents. Both models present in a systematic way the hazardous profile of maritime transport in the Aegean. The paper concludes with valuable insights.

A novel approach in risk evaluation for ship-to-ship (STS) transfer of cargo using process failure mode and effects analysis (PFMEA)

The ship-to-ship transfer (STS) of oil and oil products plays currently an important role on a worldwide scale. Usually, it refers to the transfer of cargo between seagoing ships positioned alongside each other. Although the procedure of STS transfer has become a day-to-day practice, it remains a difficult operation, which deserves special consideration. To reduce the adverse effect of a potential accident on humans as well as on the environment, a risk assessment is necessary to be done to evaluate the hazards that derive from such a difficult procedure. To this end, the process failure mode and effect analysis (PFMEA), which is under the umbrella of the traditional failure mode and effect analysis, is properly modified and applied to assess the hazards of a typical STS transfer procedure. PFMEA is based on the risk priority number with regard to each risk related to the procedure of interest by multiplying the numerical values of the severity, occurrence and detection indices. Although PFMEA is currently applied mainly to manufacturing processes, the aim of the paper was to implement this methodology to STS transfer of petroleum products. According to the study of PFMEA implementation, the petroleum cargo is the product similar to the product in a manufacturing procedure; hence, the different phases of the STS procedure are similar to the production line of the manufactured product. Moreover, proposals to eliminate the disadvantages of the implementation of PFMEA by a qualitative manner (using linguistic terms) are proposed. The objective target of this effort is to assess and evaluate the effectiveness of implementing the PFMEA in a maritime activity and therefore to address the advantages and disadvantages of such an approach.

Risk assessment of ship-to-ship transfer operations based on stochastic criteria evaluation and intervally scaled importance weights

Ship-to-ship (STS) transfer of cargo operations suffers inherently from risks that can compromise the success of such operations, leading to an accident with adverse effects on human lives and the environment. A feasible way to tackle the risks of STS transfers is through the use of multicriteria decision aid (MCDA) methodologies. This paper aims to develop an MCDA model to evaluate risks of an STS transfer based on the outranking relation concept. The proposed methodology uses confidence indices to compare alternative risk scenarios on stochastic risk criteria evaluation. To do so, a team of experts evaluate the scenarios regarding three risk factors; the likelihood of a scenario to occur, the severity of the scenario and the ability to detect the risk on time. Next, fuzzy domination relation is applied to complete the ranking of the risks. Finally, robustness analysis is performed to control the models stability.

Robust Evaluation of Risks in Ship-to-Ship Transfer Operations: Application of the STOCHASTIC UTA Multicriteria Decision Support Method

Decision making in the maritime environment is a complex and difficult task. The stochastic nature of maritime operations, in combination with the complicated and often hostile sea setting, composes a scene where obvious solutions are not always the best choice. The assessment and evaluation of risks often lays on the exploitation of the experts’ knowledge. However, this approach may suffer from uncertainty, stemming from potential biases inherent to the opinions of the experts. The aim of this chapter is to evaluate the risks of a ship-to-ship transfer of cargo operations, proposing a challenging approach to address the aforementioned uncertainty, by utilizing a sophisticated and targeted multi-criteria decision aid (MCDA) framework. The STOCHASTIC Utility Additives (UTA) method, adopting the philosophy of aggregation–disaggregation, is applied, coupled with a robustness control procedure. This methodological framework helped in the examination, management and reduction of uncertainty, and in the eventual attainment of robust and reliable evaluation results.

Locating Ship-to-Ship (STS) Transfer Operations via Multi-Criteria Decision Analysis (MCDA): A Case Study

Nowadays Ship-to-Ship (STS) transfer has become common practice. However, it remains a complex and difficult procedure, with risk assessment essential for both vessels and location selection. A variety of risk assessment techniques are thus commonly applied in order to evaluate the factors affecting STS transfers. This paper proposes a novel approach to the risk assessment of different locations for STS transfer operations, using the ELECTRE methodology borrowed from the Multi Criteria Decision Aid (MCDA) discipline. The proposed MCDA methodology is properly developed and thoroughly analysed with the aim of supporting operators in choosing the best alternative STS location. To this end, a case study is presented with which to testify the effectiveness and verify the strength of the suggested approach. In particular, four different locations within the Mediterranean Sea, which represent the set of alternative actions, are evaluated according to four different groups of criteria, with a view to selecting the most appropriate location at which to conduct the transfer operations. Different operational, economic, environmental and safety-security criteria regarding each location are assessed and evaluated by a team of three experts designated by the stakeholders (decision makers) of a shipping company. In addition, a robustness analysis is performed in order to control the stability of the model results. The objective is to develop an MCDA model with which to select the most appropriate location according to its operational eligibility.

Risk evaluation of ship-to-ship transfer of cargo operations by applying PFMEA and FIS

The ship-to-ship (STS) transfer of cargo operations are increasingly safe procedures, nevertheless they remain difficult and complex operations. The adverse effects of a potential accident demands a detailed and thorough work on risk and safety analysis for the transfer operations. In the light of the above, the Process Failure Mode and Effects Analysis (PFMEA) which is a branch of the traditional Failure Mode an d Effects Analysis (FMEA), is applied in combination with a Fuzzy Inference System (FIS) methodology to evaluate different risk scenarios of STS transfer of cargo operations. Although PFMEA is currently applied mainly to manufacturing processes, the aim of the paper is to implement this methodology to the ship-to-ship transfer of cargo. A significant advantage of the PFMEA is the analytical review of the STS operations. Nevertheless, serious drawbacks such as the fact that different combinations of the three implemented risk constituents may lead to the same Risk Priority Number (RPN) or the determination of the relative importance among the three risk factors of the PFMEA namely the likelihood of occurrence (O), the severity of a failure (S), and the ability to detect the potential failure (D), make the PFMEA weak and ineffective. To deal with the aforementioned weaknesses a fuzzy inference system (FIS) based on Mamdanis methodology, is applied as a remedy. The objective of this paper is to assess and evaluate different hazardous scenarios in an STS transfer operation implementing the PFMEA in combination with a FIS. To do so, a team of experts with relative experience with respect to STS transfer operations evaluated certain hazardous scenarios that have derived by the study of several guidelines and recommendations regarding these operations. The paper concludes with interesting insights emerged by the aforementioned tasks.