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A sensor instrumentation and an automated process are proposed for sea-ice field analysis using ship mounted machine vision cameras with the help of inertial and satellite positioning sensors. The proposed process enables automated acquisition of sea-ice concentration, floes size and distribution. The process contains pre-processing steps such as sensor calibration, distortion removal, orthorectification of image data, and data extraction steps such as sea-ice floe clustering, detection, and analysis. In addition, we improve the state of the art of floe clustering and detection, by using an enhanced version of the k-means algorithm and the blue colour channel for increased contrast in ice detection. Comparing to manual visual observations, the proposed method gives significantly more detailed and frequent data about the size and distribution of individual floes. Through our initial experiments in pack ice conditions, the proposed system has proved to be able to segment most of the individual floes and estimate their size and area.

Funding Information: The work is supported by SIMREC project. The South-East Finland-Russia CBC 2014-2020 programme is the main contributor. Publisher Copyright: © 2021 Elsevier Ltd To ensure the risk level associated with continuously increasing maritime traffic through particularly sensitive sea areas remains at acceptable level, a periodic risk assessment needs to be carried out by the relevant authorities. As a part of such assessment, allowing for proactive countermeasures to mitigate risk, the frequency of accidents is estimated along with the assessment of geographical locations where the accidents are most likely to happen. To this end scientific literature offers a number of approaches, however only a few solutions are recognized by the maritime authorities and applied world-wide. One of such approach is a evidence-based, semi-dynamic, network-based model called IWRAP Mk2. Despite its advantages, the tool lacks the verification procedure of the model development process that governs the reliability of the results. This ultimately may undermine the reliability of the obtained results. This shortcoming seems to be quite common in the field of maritime risk assessment, as revealed by the recent analysis of the risk assessment method and tools. Therefore, this article attempts to close this knowledge gap by providing a novel framework for ship-ship collision probability estimation and identification of the collision-prone locations, encompassing novel verification procedure suitable for network-based maritime risk models such as IWRAP Mk2 tool. As a results this new, wider modeling framework offers more reliable, evidence-based estimates of the probability of ship-ship collision and identifies more accurately the collision-prone locations in a given sea area. To demonstrate the usability of the framework a case study is performed, with the use of 10 months of ship traffic data recorded in the heavily trafficked and enclosed sea area of the Gulf of Finland during ice-free season with the special attention paid to the oil tankers. The updated framework delivers the annual probability of ship-ship collision, where at least one ship is an oil tanker, which is higher by 16% compared to the results obtained from regular IWRAP Mk2 software, that lacks verification procedure. Also the framework identifies the most collision-prone locations in the Gulf of Finland, which are located in the eastern part of the Gulf, explaining over 60% of the total collisions in the whole GoF, for ice-free seasons.

The Baltic Sea is a unique and sensitive brackish-water ecosystem vulnerable to damage from shipping activities. Despite high levels of maritime safety in the area, there is a continued risk of oil spills and associated harmful environmental impacts. Achieving common situational awareness between oil spill response decision makers and other actors, such as merchant vessel and Vessel Traffic Service center operators, is an important step to minimizing detrimental effects. This paper presents the Next-Generation Smart Response Web (NG-SRW), a web-based application to aid decision making concerning oil spill response. This tool aims to provide, dynamically and interactively, relevant information on oil spills. By integrating the analysis and visualization of dynamic spill features with the sensitivity of environmental elements and value of human uses, the benefits of potential response actions can be compared, helping to develop an appropriate response strategy. The oil spill process simulation enables the response authorities to judge better the complexity and dynamic behavior of the systems and processes behind the potential environmental impact assessment and thereby better control the oil combat action.

The increased activity in the Arctic involves hazards such as a harsh environment, especially the ice cover and cold temperature, remoteness and lack of infrastructure, and lack of information about bathymetry, among others [...]

openaire: EC/H2020/730888/EU//RESET Safety assurance of autonomous ships is one of the major long-term challenges faced by the maritime world. Applying systemic hazard analysis methods at this early stage will guide the design and operation of safe autonomous ships. This paper proposes an initial hierarchical ship systems structure that could be the basis for a systemic hazard analysis of autonomous ship systems and operations. The approach is based on the systems theory and the principle of hierarchy and has been developed via the combination of models used in past research projects and requirements of the STCW convention. For enabling the operation of autonomous ships, the ship crew functions are either replaced by ship technical systems or assigned to the Shore-Based Control Centre (SCC).

Maritime activity in the Arctic is on the increase, driven by multiple factors including the development of Arctic natural resources, climate change, regulatory changes, improved technology and operations, national and international policies, infrastructure developments, fuel prices, and the global economy. This article aims to identify and analyze such change drivers and to discuss how these might influence the future of three specific segments of Arctic shipping: destination-Arctic shipping (operation between Arctic and non-Arctic locations), trans-Arctic shipping (operation between non-Arctic locations through Arctic waters), and Arctic cruising. The study finds that each considered segment of Arctic shipping is subject to a unique set of significant change drivers.

Substantial progress has been made in the last decades to computationally model the structural response of marine structures subjected to collision and grounding accidents. The finite element method stands out as the most reliable and robust technique within other tools for this purpose. However, there are still some complex physical aspects arduous to be modeled numerically. This work presents an experimental technique to reproduce the mechanical response and collapse mode of marine structures subjected to collision and grounding events by using miniature models built by additive manufacturing. This experimental technique relies on structural scaling and thickness distortion formulations. A raking test on a large-scale ship bottom was replicated in a 1:30 reduced scale to validate this technique. The miniature ship bottom structure was additively manufactured from stainless steel 316L considering all structural details. Flat dog-bone samples with different thicknesses were also built in the same way for mechanical characterization of the material via tensile tests and microscopy analysis of material fractures. Tensile tests showed a good consistency in stress-strain curves with a small, but noteworthy, influence of plate thickness and a large dispersion in rupture elongations. The fractured sections revealed various void formations around non-sintered metal powder. In spite of that, the structural response obtained from miniature test showed a good correspondence with the large-scale reference test when both are brought to the same dimensional scale.

Full-scale measurements on polar research vessels present an opportunity to advance the state-of-the-art in ship design through high-quality long-term measurements of environmental conditions and s...

Overload response of the stiffening frames in ship side structure due to ice loading is an important design consideration for ships operating in ice infested waters. By overload, we mean loads that are larger than assumed by the rules. Therefore, the response of ice strengthened grillage frames is investigated under a range of idealized rectangular pressure patches and by assuming different boundary conditions for the structural units. A flat, representative grillage of an ice-strengthened ship is considered and analysed using non-linear Finite Element Method. The response of the grillage frames is compared with the isolated frame response. Two frame types are considered: flatbars and L-frames. Finite element simulations revealed that patch length has strong effect on the frame deformation mode. The key characteristic that differentiates the response under shorter and longer patches is the longitudinal membrane stretching of the shell plating. Longer patches tend to suppress this deformation mode that leads to similar frame behaviour observed in isolated frame analysis. It is further shown that overload capacity of grillage frames reduces with increasing patch length to levels observed in isolated frame analysis. Analysis of plastic strain development in the frames and plating revealed that plastic strain localized faster in frames, but shell plating is more sensitive to patch height variations. This renders frames more susceptible to fracture than plating. Finally, the local failure mechanisms of the L-frames tend to diminish the load sharing capability and so negatively affects the overload behaviour.

openaire: EC/H2020/814753-2/EU//FLARE This paper presents a big data analytics method for the evaluation of ship-ship collision risk in real operational conditions. The approach makes use of big data from Automatic Identification System (AIS) and nowcast data corresponding to time-dependent traffic situations and hydro-meteorological conditions respectively. An Avoidance Behavior-based Collision Detection Model (ABCD-M) is introduced to identify potential collision scenarios and Collision Risk Indices (CRIs) are quantified when evasive actions are taken for each detected collision scenario in various voyages. The method is applied on Ro-Pax ships operating over 13 months of the ice-free period in the Gulf of Finland. Results indicate that collision risk estimates may be extremely diverse among voyages, and in 97.5% of potential collision scenarios the evasive actions are triggered only when risk is at 45% or more of its maximum value. The overall CRI for ships operating over the given area tends to be lower for adverse hydro-meteorological conditions. It is therefore concluded that the proposed method may assist with the (1) identification of critical scenarios in various voyages not currently accounted for by existing accident databases, (2) definition of commonly agreed risk criteria to set off alarms, (3) the estimation of risk profile over the life cycle of fleet operations.

This work presents a revision of the structural similarity technique developed for the experimental modeling of marine structures subjected to collision, grounding or similar catastrophic events via miniature models with drastic scale reduction. This revision involved basically the inclusion of combined collapse modes to predict the mechanical behavior of structural members and the redefinition of the flow stress range. The revised technique was validated through numerical simulations of the miniature modeling of nine large-scale marine structures’ experiments found in literature and here presented in the form of nine study cases. Each study case evaluates the accumulated effects of scale reduction, thickness distortion and material distortion in the miniature model as part of the similarity technique. In general, a reasonable-to-good correspondence was observed between the force and absorbed energy responses obtained from reference large-scale structures and their miniature models once brought to the same dimensional scale. Discrepancies between structural responses were quantified by evaluating the normalized root mean square error. By these means, most of the study cases presented errors below 12.5% in terms of force response and below 4.5% in terms of absorbed energy response. On the other hand, lower agreement was encountered when reproducing experiments strongly ruled by progressive buckling or crack initiation/propagation together with severe reduction scales. In these cases, better results are achieved when implementing a more accurate material failure model or by moderating the reduction scale.

Structures used in Arctic regions must comply with ice-induced loading without failure, asset loss, or loss of life. Current structural design regulations, particularly for ships, rely primarily on...

This article investigates how the-organization of the shipbuilding process influences production efficiency-by creating a model of the shipbuilding process utilizing a Bayesian network. In this model, the variables are determined by factors having an impact on production efficiency. Causal dependencies between these variables create the network. Three different configurations of organization are included, namely, line organization, project organization, and a hybrid organization. All model probabilities for reaching the targeted production efficiency are elicited from experts. Based on the results, project organization has the highest probability of achieving the desired efficiency. The higher probability is mainly because, in project organization, clear responsibilities lead to target-oriented problem solving and decision making. The model demonstrates that organization has impact on production efficiency. The model can also be used for further developing the cruise shipbuilding process.

A method for estimating ship's resistance caused by sea ice ridge keels is revised and used as a part of a method for predicting performance of ships in ridged ice conditions. The resistance method is based on a continuum plasticity model of ridge rubble and is simple to compute. The performance prediction method combines deterministic simulations of ship motion with probabilistic modelling of ridged ice fields. Performance estimates given by the model are distribution of attainable mean speeds for given ice conditions and probability of the ship being able to operate independently. A comprehensive sensitivity analysis was performed to gain insight into the model and identify possible problematic parameters. The sensitivity analysis covered both the ice conditions and modelling assumptions. Two data-sets were used to test the simulation method. One set included the depth profile of sea ice, machinery data and the speed of a ship operating in ridged ice. The resistance method was able to predict the mean speed over 3km well. The second data-set consisted of a history of ship's speeds and positions from AIS data and ice conditions estimated by a numerical ice model HELMI, developed in the Finnish Meteorological Institute. Observed mean speeds were mostly well within the distributions of mean speeds simulated by the transit simulation model. Predictions of independent operation were also promising.

To achieve increasing emission requirements, the cruise ship industry is working to develop higher efficiency ships. Cruise ships are different from other ship types in their relatively higher consumption of electrical power, steam and hot water. Several novel high-efficiency system concepts are possible for on-board electrical power generation and other utility services, each with differing impacts and first costs. Low-emission concepts novel to the cruise ship industry include combinations of exhaust gas heat recovery, heat pumps, steam turbines and organic Rankine cycles (ORCs). Yet, evaluation of these concepts is difficult given the different operating modes of cruises, and overall efficiency is dependent on the dynamic operational sequences. In this paper, we compare alternative energy efficiency concepts for cruise ships through simulation studies of the ship operations when equipped with different novel power generation systems. We find that the dual pressure steam systems and ORC offer the greatest potential for energy efficiency improvements in the cruise ship industry. We also find that relatively conventional technologies enable cruise ships to comply with planned upcoming higher ship energy efficiency requirements.

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.

According to International Maritime Organization (IMO), the Baltic Sea Area has some of the densest maritime traffic in the world. The Baltic Sea was designated a Particularly Sensitive Sea Area (PSSA) at IMO Marine Environment Protection Committee's 53 rd session in July 2005. The Mandatory Ship Reporting System in the Gulf of Finland Traffic Area (GOFREP) was established by IMO in 2003 and has been in operation since 2004. The objective of this study in progress is 1) to outline the hierarchical structure of the maritime navigation safety management system from European to ship onboard level and 2) to apply the Systems-Theoretic Process Analysis (STPA) to identify system level hazards and potentially unsafe ship speed and maneuvering control actions with respect to IMO Collision Regulations (COLREGs) Rules on ship safe speed, ship safe separation distances and the Traffic Separation Schemes requirements with the aim of evaluating the effective hazard control options to enable efficient updating of ship level situational awareness and the enforcement of safety constraints in real time.

The prototypes of unmanned merchant vessels are expected to come into service within the coming years. The main line of argument supporting their introduction pertains to the increase in navigational safety, which is expected to be achieved by reducing the frequency of human-related accidents on board ships, by removing the crews. On the other hand, the response of unmanned ship to potential accidents is still uncertain. With enthusiasm on one side and apprehension on the other, the literature lacks an objective study on the effect of unmanned ships on safety of maritime transportation. This paper constitutes an attempt to bridge the aforementioned gap by applying a framework based on what-if analysis to a hundred maritime accident reports. The aim of the analysis is to assess whether the accident would have happened if the ship had been unmanned, and once the accident had happened - would its consequences have been different. The results obtained reveal that the occurrence of navigational accidents (e.g. collision, grounding) can be expected to decrease with the development of unmanned ship. However the extent of consequences resulting particularly from non-navigational accidents (e.g. fire, ship loss due to structural failure) can be expected to be much larger for the unmanned ships when compared to the conventional ones.

In the last few years, additive manufacture techniques — also known as 3d printing — are gaining more applications in the maritime sector including the production of functional large ship components in compliance with demanded operational and quality standards. By contrast, 3d printing miniature models of marine structures with the aim to reproduce structural responses brings along a higher degree of complexity. On the one hand, miniature thin-walled structures entails different manufacturing challenges when compared with large-size ship components. On the other hand, modeling structural events that comprise extreme reduction scales (around 1:100), material deformation and fracture at high loading rates, among other aspects, require purpose-designed scaling laws to handle all these effects adequately. The aim of this work is to present a wide panorama in the development of miniature 3d printed marine structures aiming to model experimentally ship collision and grounding events in reduced scale. Some preliminary experimental tests in miniature marine structures are also presented.

This paper investigates the influence of the strain rate and element size on the fracture of steel plates presented in marine structures undergoing grounding when modeled by the finite element method. Three different experimental tests (tensile, tearing and perforation tests), performed at different velocities, are used in the study. These tests are conceived to cover diverse rupture modes related mainly to crack initiation and propagation. Plastic strain- and stress state-based failure criteria were calibrated from these experiments. Sensitivity to strain rate and mesh size were also evaluated. A ship grounding event was reproduced experimentally in 1:100 reduced scale. This experiment was FE modeled to evaluate the performance of the aforementioned failure criteria. The results verified the significant influence of the strain rate and stress state on the failure strain. In addition, it is shown that the sole use of tensile tests is not enough to properly characterize the material failure observed in the structural collapse mode of the miniature ship bottom structure. This collapse is shown to be a combination of stretching and tearing of structural members.

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.

Groundings are among the most common and serious maritime accidents. The shape of the sea bottom is one of the important factors that determine the extent of grounding damage on ships, including loss of watertightness. This paper presents a four-step methodology for mathematically analyzing sea bottom shapes, where individual peaks are identified and isolated from larger datasets. To these individual peaks mathematical models are fitted and the goodness of the fit is evaluated. The aim is to develop mathematical rock models that can be used in grounding damage analysis. The method is applied to bottom topography data from the two busiest tanker harbors in Finland. As potential mathematical rock models common assumptions found in literature as well as new suggestions are used. It was observed that rocks vary in shape and size locally as well as between different geographical areas. This highlights the need to have rock models that are flexible enough to model a wide range of sizes and shapes so that the local conditions can be taken into account. This includes modeling asymmetrical shapes, which is not taken into account in the current models. The analysis results suggest using a binormal function to describe the bottom shape: This model gives overall better goodness-of-fit test results than the cone and polynomial models. In the data the binormal model can model well the also the bottom shapes where the polynomial and conical models had a good fit in statistical terms. Although the paper discusses data from the Gulf of Finland, the framework for analyzing bottom shapes is expected to be applicable to other sea areas as well. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Groundings are among the most common and destructive maritime accidents. Sea bottom shape influences greatly what kind of damage the ship structure suffers and whether this leads to loss of water tightness. Sormunen et al. [21] presented and statistically compared rock models used in grounding damage analysis with detailed bottom shape data from two Finnish harbour fairways. The results were promising in terms of statistical fit especially for the binormal rock model, which also showed a wide range of flexibility in representing different types of sea bottom shapes. However, this measure does not explicitly tell if the model rock in grounding damage analysis results in similar damage size as real rocks cause. To test this, this paper develops a framework for studying, testing and evaluating rock models in terms of resulting grounding damage. FEM is used to analyse and compare grounding damage of rock models to the actual rock using otherwise identical grounding scenarios. Analysis is performed for four different real rocks with each rock being modelled with four different analytical rock models as well. The results show that rock models with good statistical fit did not necessarily result in similar grounding energy compared to results using the real rock. Differences in energy are caused especially by the rougher surface of the real rocks. For the similarity in rock area and the damaged ship structure element volume the results are much better, especially for the binormal model. As such another criteria for evaluating rock models for grounding damage analysis is needed. The results show that the damaged material volume is strongly linearly dependent on the rock area- and volume metrics. A similar linear dependency exists between the damaged volume and the energy dissipated in grounding. Knowledge of these relationships can be used towards estimating grounding damage of ships in future investigations, but rock surface unevenness should be evaluated as well.

Undoubtedly, the main advantage of the additive manufacture technology is to allow building miniature structural parts with a large degree of complexity such as to replicate structural details of real-scale marine structures. This work presents a new technique for reproducing the structural response of large-scale thin-walled metallic structures when subjected to crushing loadings by using scaled-down additive manufactured models. This technique couples scaling laws for strain rate sensitive materials and a thickness distortion technique based on the structural collapse mode. In order to validate this coupled technique, the structural response of a large-scale crushing test of a web girder structure was experimentally replicated by using a 1/40 scale reduction model. The results and conclusions summarize the prospects and limitations of additive manufacturing of miniature complex marine structures for structural purposes and crashworthiness verification.

For the evaluation of ship performance in ice and ice loads on the ship hull, numerical simulation methods have been increasingly developed in recent years. In these models, the shapes of ice cusps broken from the intact ice sheet are idealized as either part of a circle or a triangle. Effects arising from the geometry of the loading area are neglected or idealized. Since the proper definition of the geometry of ice cusps is one of the key factors in numerical models, this paper introduces a new icebreaking pattern based on theoretical deviation. The finite difference method is adopted to approximate the deflection field of the wedge plate. This model takes a large set of factors as input while consuming little computation time. The outcome provides some new features compared to previous models. The results are validated using full-scale measurements of ice cusps around a ship hull, based on stereo camera recording and image processing. The validation shows that the derived method is appropriate in predicting realistic icebreaking patterns. Hence, it is plausible that its implementation in numerical models for ship performance in level ice will lead to improved prediction of the ship performance and ice loads on the hull.

Ship collisions are rare occurrences with a potential to cause significant human, monetary and/or environmental loss. One element in preventing collision accidents is the presence of a collision alert system (CAS), providing warnings to ship crews and/or personnel in Vessel Traffic Services of the collision risk in a real-time operational environment. In risk research, there is a recent focus on foundational issues related to risk concepts, perspectives and methods for describing risk, with calls for work addressing these risk-theoretical issues in application areas. Despite several proposed applications for CAS, no frameworks covering these risk-theoretic issues have been presented. Hence, the purpose of this paper is twofold. First, a framework for maritime risk-informed CAS (RICAS) is presented, including a risk-conceptual basis, a systematic description of the risk perspective and a discussion on the intended use of the risk model. A theoretical framework for the operationalization of the construct “ship collision risk” is presented, and a method for measuring this construct is introduced. Second, the framework is applied to a case-study concerning open sea navigation. An evaluation of the proposed RICAS in comparison with earlier proposed CAS methods indicates an improved performance over these.

International audience; This paper presents study of 115 grounding accident reports from the Safety Investigation Authority of Finland and Marine Accident Investigation Branch of the UK, as well as 163 near-miss grounding reports from ForeSea and Finnpilot incident databases. The objective was to find the type of knowledge that can be extracted from such sources and discuss the usability of accident and incident reports for evidence-based risk modeling. A new version of Human Factors Analysis and Classification System (HFACS) is introduced as a framework to review the accident reports. The new positive taxonomy as Safety Factors, which are based on high level positive functions that are prerequisite for safe transport operations, is used for reviewing the incident reports. Accident reports are shown as a reliable source of evidence to extract the most significant contributing factors in the events. Mandatory incident reports are considered useful for understanding the effective barriers as risk control measures. Voluntary incident reports, though, are seen as not very reliable in their current form to be used for evidence-based risk modeling.

VK: T20404 For safe and efficient exploitation of ice-covered waters, knowledge about ship performance in ice is crucial. The literature describes numerical and semi-empirical models that characterize ship speed in ice. These however often fail to account for the joint effect of the ice conditions on ship's speed. Moreover, they omit the effect of ice compression. The latter, when combined with the presence of ridges, can significantly limit the capabilities of an ice-strengthened ship, and potentially bring her to a halt, even if the actual ice conditions are within the design range for the given ship. This paper introduces two probabilistic, data-driven models that predict a ship's speed and the situations where a ship is likely to get stuck in ice based on the joint effect of ice features such as the thickness and concentration of level ice, ice ridges, rafted ice, moreover ice compression is considered. To develop the models, two full-scale datasets were utilized. First, the dataset about the performance of a selected ship in ice is acquired from the automatic identification system. Second, the dataset containing numerical description of the ice field is obtained from a numerical ice model HELMI, developed in the Finnish Meteorological Institute. The collected datasets describe a single and unassisted trip of an ice-strengthened bulk carrier between two Finnish ports in the presence of challenging ice conditions, which varied in time and space. The relations between ship performance and the ice conditions were established using Bayesian networks and selected learning algorithms. The obtained results show good prediction power of the models. This means, on average 80% for predicting the ship's speed within specified bins, and above 90% for predicting cases where a ship may get stuck in ice.

Various methods have been proposed to analyse safety and risk of maritime transportation, through modelling techniques and empirical studies, focusing on ship–ship collision. However, an efficient method for screening traffic data for the near miss collisions is lacking. Therefore the contribution of this paper is two-fold. First, it proposes a novel method detecting possible near miss ship–ship collisions from AIS data. Second, it discusses how such near miss data can be used to gain further insight in safety of maritime transportation. The developed Vessel Conflict Ranking Operator (VCRO) considers the following factors affecting the complexity of an encounter between two ships: the distance between the two ships, the relative speed of the ships, and the difference between the headings of the ships. The model content and structure are based on expert judgment, whereas the parameterisation is based on AIS data points of a reference encounter situation dataset. The developed model has been applied to the traffic data from the Northern Baltic Sea. The obtained results and the model validity tests suggest the model being adequate for ranking encounters, and for prioritising the encounters to subject to further expert scrutiny.

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 40 cm 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.

Under an increasing maritime transport in the Baltic Sea, and especially in the Gulf of Finland, the possibility of environmental harm and accidents due to shipping pressure is growing. To counteract increasing risks, adequate measures for accident prevention and mitigation of environmental consequences are critically important. The Gulf of Finland Mandatory Ship Reporting System (GOFREP) is a the complex socio-technical maritime transport safety management system that has been in efficient operation since 2004 and it is open to further improvement and development. However, environmental safety is not explicitly covered by the GOFREP so far. According to our working hypothesis, the Systems Theoretic Accident Models and Processes (STAMP) can be extended beyond the area of socio-technical system safety into realm of complex eco-socio-technical systems safety. This paper attempts to demonstrate the conceptual potential of STAMP based on adaptive management of the Maritime Spatial Planning processes and integrated safety management of eco-socio-technical maritime transport system.

The importance of including knowledge about human behaviour into the safety design for passenger ships has increasingly been taken into account. The interaction between passengers and the passenger ship is critical for human behaviour in terms of passengers' perceptions of the environment. The way people perceive the environment and the various features of the environment has been studied quite extensively in design research, but little research has been done on the specific issues that shape people's perceptions, such as safety. This paper discusses how people perceive safety within the context of passenger ships. Having conducted user studies in authentic environments, this paper identifies five safety perception themes. The results indicate that passengers perceive safety via the architecture of the passenger ship, the life-saving appliances, communication, emotions and other people. The outcomes were compared with the SOLAS regulations. The article contributes to safety research on passenger ship design, where human perceptions and reactions to the surrounding environment significantly affect behaviour and should be studied in parallel with technical progress.

Autonomous and remote controlled technologies in shipping are becoming a reality with the rapid advances in communication technology, sensor systems, and navigational decision-making software. The emergence of the new autonomous technologies brings along modified and new risks and potential hazards, as well as needs for changes in predicting and controlling the risks to ensure safe operation. In this paper, we present a safety qualification process using a goal based safety case approach that we have specified and applied to facilitate qualification of an autonomous ship prototype for a series of proof-of-concept demonstration trials at sea. As a case example, the goal-based methodology is applied on the situational awareness system of a proposed autonomous vessel prototype.

Due to the complexity of the ice-structure interaction, the knowledge about the ice-induced loads on a ship hull has been gained from full-scale measurements. As the instrumentation of the hull for the measurements is expensive, the extension is concerned at the planning phase. However, a narrow instrumentation can cause an error in the measurements, as the response of the adjacent frames with respect to the observed frame is not known. Thus, this paper studies the differences between loads measured from one or several frames on board S.A. Agulhas II. The difference results from the ability of the structure to transport loading internally. The results show that when the loads affect only an individual frame, the instrumentations give similar results. However, the difference increases with the load length and the loading that is determined can be 15% higher for one frame instrumentation for a structure similar to the aft shoulder of S.A. Agulhas II. Furthermore, the difference in the mean value and standard deviation of the measurement time histories can be up to 10%. The study presents a new efficient method to obtain a rough estimate of the possible difference in the measured results between extensive and narrow instrumentation.

Navigation in ice covered waters is a challenging and hazardous activity, threatening the ship herself and the environment. Proper evaluation of the attainable ship speed in ice prior to setting off the journey is essential to mitigate the risk of besetting in ice which may cause further damages. The majority of the existing models evaluating ship speed in ice are physics-driven requiring detailed, not always accessible, input data, thus featuring high uncertainty. In this paper we propose an event-oriented model, reflecting the ice features under which an event of interest occurs (a given speed interval or a significant speed drop). To this end we utilize a large set of full-scale data and Bayesian learning algorithm to organize the data into a probabilistic model linking the ice conditions with the ship speed. Conditional probabilities are derived from the detailed dataset obtained in the course of full-scale tests of S.A. Agulhas II (ice class PC 5) carried out in the Baltic Sea in 2012. A set of parameters related to ice conditions; rudder and engine settings are recorded with the use of on board instruments. Ice thickness is measured with the use of electromagnetic device. Various types of ice navigation are performed i.e. steaming straight through the level and ridged ice as well as in ice channel. The model yields the probability of a certain speed under given ice conditions, and has application potential in risk assessment of besetting in ice or route finding problem. This approach could be developed further e.g. by incorporating other types of maneuvers.

A number of authors have discussed reliability and validity of quantitative risk analysis (QRA). These concepts address respectively whether a QRA provides the same risk picture when the analysis is repeated and whether the analysis addresses the right concept. While it has been argued that QRA is not in general reliable, there is little evidence supporting this claim available in the scientific literature. In light of this, this paper studies the reliability of QRA through a case study of ship–ship collision risk. It is found that probability- and indicator based risk perspectives do not necessarily provide a reliable risk picture, neither in terms of numerical accuracy of the risk metrics, nor in terms of rank order of risk metrics in various parts of the system. The results of the case study indicate a low inter-methodological reliability for the selected methods, raising concerns about their validity. This is discussed applying criteria concerning validity of risk analysis and in terms of the validity of the proposed encounter detection mechanisms. Significant uncertainty is found regarding this encounter definition in the selected methods, implying a need for more focus on this important aspect of maritime traffic risk analysis.

When considering the implementation of a novel risk-control option, the estimation of its possible effects often relies on expert elicitation. This article presents an expert-knowledge–based preliminary assessment of how the deployment of Enhanced Navigation Support Information navigation service would affect the ship collisions and groundings in the Gulf of Finland. Experts probabilistically assess the service’s direct effects on various factors, which are then utilized in collision and grounding probability Bayesian network models. The results indicate that implementing the Enhanced Navigation Support Information service could decrease the number of accidents. However, a comparison of the model outcomes to the experts’ qualitative opinions reveals some discrepancies, which suggest that the elicitation procedure or the applied models might require further improvement. Nevertheless, with the proposed Bayesian approach, the model can be updated and uncertainties in the estimates reduced after more evidences are available later from longer and wider use of the service.

VK: T20404 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 riskframework 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.

Ship grounding accidents, being one of the major types of maritime accidents, are significant failures putting in danger maritime transportation systems. Moreover, the risks associated with those failures can be catastrophic for the system, society, and the environment. This highlights the importance of appropriate methodology for assessing and managing the associated risk. Many scholars have introduced a wide range of methods for modeling the risk, utilizing the concept of the probability and the consequence of an accident; however, those models very often employ critical assumptions on the behavior of maritime transportation systems, which may seem not to be supported by evidences. This in turn limits models' ability to mitigate the risks, as those simply remain unknown. Therefore, this article has three aims. First, it proposes a methodological framework suitable for knowledge-based risk modeling, fulfilling the recommendations given by the Formal Safety Assessment issued by the International Maritime Organization. Secondly, it thoroughly reviews and discusses all the existing risk models available in the literature developed for ship grounding risk analysis in light of the proposed risk perspective. Third, the models that are more appropriate for risk management and decision making are highlighted and the recommendations are given to future model developments.

This paper is presenting novel model-scale ice property measurements for grain size, elastic strain-modulus, compressive and tensile specimen tests. The testing and analyzing procedure is targeted to define the basic material behavior accurately to understand the material behavior for the future development of a numerical material model. Additionally, the model-scale ice thickness and the bending strength (following ITTC) are determined to classify the ice properties. The experiments consist of systematic in-situ tests to identify the model-scale ice properties in a format suitable for numerical simulations. The elastic strain-modulus is determined on the intact level ice sheet based on the load displacement relationship of the infinite plate deflection. All specimens are cut with a template to minimize dimensional variations. The specimens are loaded with a linear drive at constant speed while displacement and force are recorded. The resulting load–displacement curves indicate good repeatability. The experiments are conducted over a time of 4 h–5 h in the keeping phase , where the cooling system is adjusted to maintain the mechanical ice properties, and the obtained results do not show a dependency on the time of testing. A linear-elastic finite element model is used to reproduce the plate bending measurements for the elastic strain-modulus determination. Therewith, it is found that the actual elastic strain-modulus is 27% larger than in plain stress theory due to stresses in thickness direction. Additionally, the approximate yield strength of the model-scale ice is investigated and is found to be significantly lower than the determined maximum stresses in compression, tension and bending. Consequently, this paper contributes to a deeper understanding of the mechanics of model-scale ice, and a procedure is shown how the mechanical parameters can be determined by systematic experiments and analyses.

The bending strength of the sea ice cover is crucial in the design of ice-going vessels. Therefore, a series of in situ four-point bending tests have been performed earlier, which are now utilized to present a particle swarm optimization–based procedure to identify the material parameters needed for numerical simulations. The resulting numerical simulations are found to comply well with the experimental results in terms of force, failure time, and displacement. Therefore, it can be concluded that the presented optimization-based material parameter identification procedure can also be used in the future if similar material parameters are to be found.

Ship traffic is one of the factors that is presented in almost all of the existing grounding models, and is considered as one of the factors on the likelihood of a grounding accident. This effect in grounding accidents is mostly accepted by experts as common sense or simply by just generalizing the ship-ship collision cases to grounding accidents. There is no available research on the actual causal link between the ship traffic and grounding accident in the literature. In this paper, the authors have utilized the statistical analysis on historical grounding accident data in the Gulf of Finland between the years 1989 and 2010 and the AIS data of the same area in year 2010, as the source of ship traffic data, to investigate the possible existence of any correlation between the ship traffic and the grounding accident. The results show that for the studied area (Gulf of Finland) there is no correlation between the traffic density and the grounding accident. However, the possibility of the existence of a minor relation between the traffic distribution and grounding accident is shown by the result. This finding, however, needs further investigation for more clarification.

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.

Chemical tanker traffic constitutes a hazard for the environment; large chemical spills caused by, for example, ship–tanker collisions can have catastrophic effects in similar manner to oil spills. For this reason, it is important to have a generalized spill model for chemical tankers, so that the spill size for a given geographical area can be assessed. The spill volume can be used as an indicator of risk in the given area. Furthermore, such a model can be used to analyze the possible effects of potential risk-mitigating measures such as requiring wider double hulls for chemical tankers. In this article, a spill model is proposed, which for a given collision scenario can model the penetration, spill probability, and size caused by a ship striking a chemical tanker. This is done using finite element method, MATLAB, and statistical metamodels with ship particulars extracted mainly from automatic identification system data from the Gulf of Finland.