Search

Winter navigation is a complex but common operation in north-European sea areas. In Finnish waters, the smooth flow of maritime traffic and safety of vessel navigation during the winter period are managed through the Finnish-Swedish winter navigation system (FSWNS). This article focuses on accident risks in winter navigation operations, beginning with a brief outline of the FSWNS. The study analyses a hazard identification model of winter navigation and reviews accident data extracted from four winter periods. These are adopted as a basis for visualizing the risks in winter navigation operations. The results reveal that experts consider ship independent navigation in ice conditions the most complex navigational operation, which is confirmed by accident data analysis showing that the operation constitutes the type of navigation with the highest number of accidents reported. The severity of the accidents during winter navigation is mainly categorized as less serious. Collision is the most typical accident in ice navigation and general cargo the type of vessel most frequently involved in these accidents. Consolidated ice, ice ridges and ice thickness between 15 and 40cm represent the most common ice conditions in which accidents occur. Thus, the analysis presented in this article establishes the key elements for identifying the operation types which would benefit most from further safety engineering and safety or risk management development., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Featured Application: A risk assessment framework that supports Arctic voyage planning and real-time operational decision-making through assignment of operational criteria based on the likelihood of ice-induced damage and the potential consequences. The International Code for Ships Operating in Polar Waters (Polar Code) was adopted by the International Maritime Organization (IMO) and entered into force on 1 January 2017. It provides a comprehensive treatment of topics relevant to ships operating in Polar regions. From a design perspective, in scenarios where ice exposure and the consequences of ice-induced damage are the same, it is rational to require the same ice class and structural performance for such vessels. Design requirements for different ice class vessels are provided in the Polar Code. The Polar Operational Limit Assessment Risk Indexing System (POLARIS) methodology provided in the Polar Code offers valuable guidance regarding operational limits for ice class vessels in different ice conditions. POLARIS has been shown to well reflect structural risk, and serves as a valuable decision support tool for operations and route planning. At the same time, the current POLARIS methodology does not directly account for the potential consequences resulting from a vessel incurring ice-induced damage. While two vessels of the same ice class operating in the same ice conditions would have similar structural risk profiles, the overall risk profile of each vessel will depend on the magnitude of consequences, should an incident or accident occur. In this paper, a new framework is presented that augments the current POLARIS methodology to model consequences. It has been developed on the premise that vessels of a given class with higher potential life-safety, environmental, or socio-economic consequences should be operated more conservatively. The framework supports voyage planning and real-time operational decision making through assignment of operational criteria based on the likelihood of ice-induced damage and the potential consequences. The objective of this framework is to enhance the safety of passengers and crews and the protection of the Arctic environment and its stakeholders. The challenges associated with establishing risk perspectives and evaluating consequences for Arctic ship operations are discussed. This methodology proposes a pragmatic pathway to link ongoing scientific research with risk-based methods to help inform recommended practices and decision support tools. Example scenarios are considered to illustrate the flexibility of the methodology in accounting for varied risk profiles for different vessel types, as well as incorporating input from local communities and risk and environmental impact assessments. [ABSTRACT FROM AUTHOR]

Highlights: [•] Reliability and validity of ship–ship collision risk analysis methods investigated. [•] Focus on probability- and risk indicator perspectives. [•] Varying internal reliability and low cross-methodological reliability found. [•] Both accuracy of total system risk and rank order of subsystem risk questioned. [•] More valid definitions of the ship encounter process needed to reduce uncertainty. [ABSTRACT FROM AUTHOR]

Highlights: [•] A model evaluating oil spill cleanup-costs for the Gulf of Finland is presented. [•] Bayesian Belief Networks are used to develop the model in a probabilistic fashion. [•] The results are compared with existing models and good agreement is found. [•] The model can be applicable for cost-benefit analysis in risk framework. [Copyright &y& Elsevier]

Ice management enables offshore and marine activities in Arctic waters in the presence of sea ice or icebergs. The presence of ice introduces additional risks to the activities. This paper discusses the risks in the light of novel risk perspectives, emphasizing uncertainties arising from potentially weak background knowledge in ice management operations. An ice management system is defined and a generic risk picture of an ice management operation is created. Risk theory is connected to the results using discussion and a conceptual example. Ice management operations are complex socio-technical systems requiring expertise in various fields. Available data is scarce and uncertainties are high. Still, the main activities need to trust in the ice management system to operate safely. The risks in ice management operations culminate in decision making and physical ice management. These need to be better understood to manage the operational risks. [ABSTRACT FROM AUTHOR]

Most of the risk models for ship-grounding accidents do not fully utilize available evidence, since it is based on accident statistics and expert opinions. The major issue with such kinds of models is their limitation in supporting the process of risk-management with respect to grounding accidents, since they do not reflect the reality to the extent required. This paper presents an evidence-based and expert-supported approach to structure a model assessing the probability of ship-grounding accidents, to make it more suitable for risk-management purposes. The approach focuses on using evidential data of ship-grounding accidents extracted from the actual accident and incident reports as well as the judgement elicited from the experts regarding the links and probabilities not supported by the reports. The developed probabilistic model gathers, in a causal fashion, the evidential contributing factors in ship-grounding accidents. The outcome of the model is the probability of a ship-grounding accident given the prior and posterior probabilities of the contributing factors. Moreover, the uncertainties associated with the elements of the model are clearly communicated to the end-user adopting a concept of strength-of-knowledge. The model can be used to suggest proper risk-control-measures to mitigate the risk. By running uncertainty and sensitivity analyses of the model, the areas that need more research for making educated decisions are defined. The model suggests the high-level critical parameters that need proper control measures are complexity of waterways, traffic situations encountered, and off-coursed ships. The critical area that calls for more investigation is the onboard presence of a sea-pilot. [ABSTRACT FROM AUTHOR]

Abstract: In the maritime domain, risk is evaluated within the framework of the Formal Safety Assessment (FSA), introduced by the International Maritime Organization in 2002. Although the FSA has become an internationally recognized and recommended method, the definition, which is adopted there, to describe the risk, seems to be too narrow to reflect the actual content of the FSA. Therefore this article discusses methodological requirements for the risk perspective, which is appropriate for risk management in the maritime domain with special attention to maritime transportation systems. A perspective that is proposed here considers risk as a set encompassing the following: a set of plausible scenarios leading to an accident, the likelihoods of unwanted events within the scenarios, the consequences of the events and description of uncertainty. All these elements are conditional upon the available knowledge (K) about the analyzed system and understanding (N) of the system behavior. Therefore, the quality of K and the level of N of a risk model should be reflected in the uncertainty description. For this purpose we introduce a qualitative scoring system, and we show its applicability on an exemplary risk model for a RoPax ship. [Copyright &y& Elsevier]

Abstract: An important element in assessing the consequences in a tanker collision is the probability of breaching an oil cargo tank. It is well recognized that the dynamic parameters at the moment of impact significantly affect the deformation energy. Assumptions regarding dynamic parameters at the moment of impact are nevertheless little discussed in context of collision risk analysis. The available impact scenario models are analyzed using a system risk approach. Comparison of impact scenario models from literature is performed with a risk analysis algorithm emphasizing on oil tanker collisions. Monte Carlo simulation is applied in the risk analysis algorithm for each impact scenario model. Only the impact scenario module is changed while other modules of the algorithm (encounter scenario generation, determination of deformation energy and structural hull capacity) are kept the same. Analysis reveals important differences in results of risk analysis when performed with different assumptions for the impact scenario. Moreover, in the discussion inherent conceptual limitations of the impact scenario models in the system risk framework are revealed. It is concluded that using more accurate collision energy and/or structural capacity models for purposes of maritime traffic risk analysis is currently not worthwhile, as the uncertainty regarding impact scenario is overwhelming. [Copyright &y& Elsevier]

• The technique using non-accident critical events as surrogate indicators to assess waterway risk has attracted much attention. • A critical review of the academic literature on non-accident critical events detected from AIS data is presented. • The analysis focuses on the definition, accident theory, measurement, model use, and validation of non-accident critical events. • Results indicate variations in conceptual basis and implementation, and a lack of extensive validation. The safe navigation of ships is of high societal concern. A promising approach for analyzing waterway risks is using non-accident critical events as surrogate indicators of collision accidents. These are typically detected in data from the Automatic Identification System (AIS). Recognizing the significant interest in this approach, this article provides a review and analysis of methods based on the detection of non-accident critical events from AIS data, which aim to provide insight into maritime waterway risk. Considering also recent calls for increased focus on foundational issues in risk research and safety science, each method in the literature is critically reviewed based on five questions: How are non-accident critical events defined? What is the accident-theoretical basis of the method? How are non-accident critical events ranked? How is the method used? To what extent has the method been validated? Based on the results, it is concluded that focus is needed to build evidence of the validity of the models' results, if these are to be effectively used for waterway risk analysis. As a prerequisite, more focus is needed on how exactly non-accident critical events are defined, and what factors are involved in the relation between their occurrence and accident involvement. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Collision accidents between icebreaker and assisted ship in ice-covered waters are investigated. • The collision risk factors are identified and classified according to HFACS-SIBCI model. • The fault tree model is proposed to analyze collision risk factors under icebreaker assistance. • Risk Control Options (RCOs) are formulated to prevent collision accident occurrence in ice-covered waters. Abstract With the global warming and a large amount of sea ice melting, the available Arctic Sea Route has greatly enhanced the value of Arctic shipping. Ship operations under icebreaker assistance have become an essential way to facilitate the safe navigation of merchant vessels sailing through the Arctic Sea Route in ice-covered waters, but they can also put the crew and the ship in danger caused by a possible collision between the assisted ship and the icebreaker. In this paper, a dedicated Human and Organizational Factors (HoFs) model of ship collision accidents between an assisted ship and an icebreaker is developed and analyzed with the aim to identify and classify collision risk factors. First, a modified model of the Human Factors Analysis and Classification System (HFACS) for collision accidents between a ship and an icebreaker in ice-covered waters is proposed, which helps to analyze ship collision reports. Then, a Fault Tree Analysis (FTA) model is utilized to analyze the fundamental collision risk factors according to the statistical analysis of accident reports and expert judgments based on the HFACS-SIBCI model. Finally, qualitative analysis is carried out to analyze collision risk factors under icebreaker assistance, where Risk Control Options (RCOs) are formulated. An important guidance for the risk control of ship collisions during icebreaker assistance in ice-covered waters is provided for lawmakers and shipping companies. [ABSTRACT FROM AUTHOR]

Abstract: Maritime accidents involving ships carrying passengers may pose a high risk with respect to human casualties. For effective risk mitigation, an insight into the process of risk escalation is needed. This requires a proactive approach when it comes to risk modelling for maritime transportation systems. Most of the existing models are based on historical data on maritime accidents, and thus they can be considered reactive instead of proactive. This paper introduces a systematic, transferable and proactive framework estimating the risk for maritime transportation systems, meeting the requirements stemming from the adopted formal definition of risk. The framework focuses on ship–ship collisions in the open sea, with a RoRo/Passenger ship (RoPax) being considered as the struck ship. First, it covers an identification of the events that follow a collision between two ships in the open sea, and, second, it evaluates the probabilities of these events, concluding by determining the severity of a collision. The risk framework is developed with the use of Bayesian Belief Networks and utilizes a set of analytical methods for the estimation of the risk model parameters. Finally, a case study is presented, in which the risk framework developed here is applied to a maritime transportation system operating in the Gulf of Finland (GoF). The results obtained are compared to the historical data and available models, in which a RoPax was involved in a collision, and good agreement with the available records is found. [Copyright &y& Elsevier]

Abstract: A number of authors have proposed probabilistic risk based ship design for ship–ship collision, conditional to the local trading area of a vessel. The probability of collision and consequences are determined based on the traffic conditions in which a vessel is expected to operate. This paper investigates the adequacy of currently available models for impact scenarios, i.e. models linking the traffic conditions to the conditions at the moment of collision. An exploratory statistical model is presented to establish such a link. A probabilistic risk based design case study is performed for a fleet of RoPax vessels trading on a specified route in the Gulf of Finland. The available impact scenario models from the literature are compared with the developed probabilistic evasive maneuvering model. The results show that the impact scenario models have a very significant influence to the calculated hull breach probabilities. No well-justified impact scenario models are presently available and also the presented probabilistic evasive maneuvering model is burdened with uncertainty. Hence, to move toward a probabilistic risk based ship design paradigm for ship–ship collision in a local trading area, more focus and research is needed to establish a credible link. [Copyright &y& Elsevier]

Following the International Code for Ships Operating in Polar Waters (Polar Code), ships operating in ice-covered polar waters must comply with an appropriate Polar Class (PC) or equivalent ice class standard. For the selection of an appropriate Polar Class, ship designers and operators are encouraged to use the Polar Operational Limit Assessment Risk Indexing System (POLARIS). A limitation of POLARIS is that it does not consider the extent to which a ship operates in various ice conditions, and thus also not the probabilistic nature of ice loading. To address this limitation, this article outlines a goal-based approach that is intended to complement POLARIS when selecting a ship's Polar Class. Following the proposed approach, the appropriateness of a ship's minimum required Polar Class as determined using POLARIS is evaluated by assessing the ship's long-term extreme ice loads, and by relating these to the design loads behind the considered Polar Class standard. To account for the probabilistic nature of ice loading, the approach calculates a ship's long-term extreme ice loads considering its intended operating profile and expected ice exposure. This is achieved by synthesising a modified version of the so-called event-maximum method, discrete-event simulations, and satellite ice data. The utility of the proposed approach is demonstrated through a case study, in which it is used as a complement to POLARIS to select an appropriate Polar Class for a double-acting ship intended for year-round independent operations along the northeast coast of Canada. • A goal-based approach complementing IMO's POLARIS methodology for selecting a suitable Polar Class for an ice-going ship. • Consideration of a ship's operating profile and the probabilistic nature of hull ice loading. • Case study regarding the design of a double-acting ice class ship for operations in Arctic waters. [ABSTRACT FROM AUTHOR]

• A framework to model a hierarchical control structure for the STPA analysis of an autonomous ship is presented. • STAMP, STPA and STECA were used as the foundation of the proposed framework. • The framework makes use of the available knowledge of current shipping operation and seafarers experience. • The resulting control structure of shipping operation includes the autonomous ship and the Shore-based Control Centre as controlled processes. • The application to the Autonomous Navigation System reveals substantial information for the safety of autonomous ships. The demand for risk and safety analysis is becoming greater due to the increased complexity of modern systems such as autonomous ships. Safety is one of the main motivations behind the efforts of multiple organizations to develop autonomous ships. The adoption of an early system-theoretic approach to safety such as System Theoretic Process Analysis (STPA) is an effective way to integrate safety in complex systems. Furthermore, many authors have urged the use of this method to analyse the risks of autonomous vessels in the development phases. Applying STPA requires a description of the system to model the hierarchical control structure and conduct the analysis. At this stage, the functional description of autonomous ships remains limited, which poses a challenge in building the hierarchical control structure. This paper proposes a framework for developing a hierarchical control structure of an autonomous ship. The framework is founded on the principles of the STPA control structure and its five main elements. It makes use of the current shipping operation system, the available information about autonomous ships and the experience of seafarers executing diverse tasks on-board conventional ships. The application of the framework showed that the information provided by the seafarers is essential in developing an initial functional description of an autonomous ship. Furthermore, the results revealed that in addition to the technical aspects of autonomous ships, introducing these vessels into the organizational control structure of current maritime operation also poses challenges that need to be addressed in the earliest design phase. [ABSTRACT FROM AUTHOR]