An analysis of ship escort and convoy operations in ice conditions

Winter navigation is a complex but common operation in the Northern Baltic Sea areas. In Finnish waters, the safety of the wintertime maritime transportation system is managed through the Finnish–Swedish winter navigation system. This system results in different operational modes of ship navigation, with vessels either navigating independently or under icebreaker assistance. A recent risk analysis indicates that during icebreaker assistance, convoys operations are among the most hazardous, with convoy collisions the most important risk events. While the accident likelihood per exposure time is rather low, accidents occur almost every winter. Even though these typically lead to less serious consequences, accidents leading to ship loss and oil pollution have occurred and may occur in the future. One aspect of ship convoy navigation in ice conditions is the distance kept between the icebreaker and the ships in the convoy, a form of the well-known ship domain concept. While operational experience naturally is a valuable source of information for decision making about the distance of navigation in convoys, systematic analyses are lacking. The aim of this paper is to investigate selected operational aspects of convoy navigation in ice conditions in the Finnish waters of the Gulf of Finland, based on data of the Automatic Identification System and sea ice hindcast data. Focus is on obtaining qualitative and quantitative knowledge concerning distances between vessels in escort and convoy operations and the respective transit speeds, conditional to ice conditions. Such empirical knowledge can support operational decision making, contributing to wintertime maritime safety.Peer reviewe

Uncertainty in maritime risk analysis: Extended case study on chemical tanker collisions

Uncertainty is inherent to risk analysis. Therefore, it is extremely important to properly address the issue of uncertainty. In the field of risk analysis for maritime transportation systems, the effect of uncertainty is rarely discussed or quantified. For this reason, this article discusses a case study dealing with risk analysis for a chemical spill in the Gulf of Finland and analyses the related uncertainties by adopting a systematic framework. Risk is assessed in terms of the expected spill frequency and spill volumes caused by collisions between ships and chemical tankers in the Gulf of Finland. This is done by applying a collision consequence with a novel approach-to-collision-speed linkage model and Gulf of Finland-specific causation factors, which are based on reanalysing accident data. This article also presents a metamodel for assessing collision probability with initial vessel speeds for any given scenario where a chemical tanker is about to be struck by another vessel. Even when conducting a risk analysis using state-of-the-art methods, there is still a medium-high degree of uncertainty in the model presented in this article, which only becomes apparent when conducting a systematic uncertainty assessment analysis. However, an uncertainty assessment is an important part of quantitative maritime risk analysis. For this purpose, a qualitative framework for uncertainty assessment analysis is introduced for general use in the field of maritime risk analysis.</p

Species and habitats in danger : estimating the relative risk posed by oil spills in the northern Baltic Sea

Large-scale oil spills can have adverse effects on biodiversity in coastal areas where maritime oil transportation is intense. In this article we conducted a spatial risk assessment to study the risk that potential tanker accidents pose to threatened habitat types and species living in the northern Baltic Sea, which has witnessed a rapid increase in maritime oil transportation within the past two decades. We applied a probabilistic method, which combines three components: a Bayesian network describing tanker accidents and uncertainties related to them, probabilistic maps showing the movement of oil, and a database of threatened species and habitats in the area. The results suggest that spatial risk posed by oil spills varies across the area, and does not correspond, for example, to the frequency of accidents in a given area. The relative risk is highest for seashore meadows, which is important to take into account when managing these habitats. Our analysis underlines the importance of a thorough risk assessment, which is not only based solely on one or two specific factors such as accident probabilities or the trajectories of spilled oil but also contains as broad a view of the consequences as possible. We believe that the probabilistic methodology applied in the study will be of high interest to people who have to cope with uncertainties typical for environmental risk assessment and management.Peer reviewe

Exploring the context of maritime SAR missions using visual data mining techniques

The environmental conditions in the Gulf of Finland vary significantly in different locations. In addition, the gulf is a busy and important area for waterway traffic and international trade throughout the year. In summer, the area is ideal for recreational activities such as boating and other water-related activities. Water accidents occur due to different factors and under varying weather conditions. This paper introduces a visual data mining analysis applied to Search and Rescue (SAR) missions related to recreational boating. Starting from a SAR operations database, an integrated database was constructed by adding weather and wave data. The aim was to compare the different mission types as well as the activity of different SAR organisations during challenging wind and wave conditions. The investigation was performed using visual analysis techniques. The densest areas of challenging wind and wave conditions were found in the western and eastern parts of the gulf. Other investigated parameters were travelled distances and occurrence of the incidents during different times of day. A more detailed analysis was conducted for one dataset

On a risk perspective for maritime domain

In the maritime domain, the risk is evaluated within the framework of Formal Safety Assessment (FSA), introduced by International Maritime Organization in 2002. Although the FSA has become internationally recognized and recommended method, the definition, which is adopted there, to describe the risk, seems to be too narrow to reflect properly 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 the special attention to maritime transportation systems (MTS). This perspective considers risk as a set encompassing the following: the set of plausible scenarios leading to an accident, the likelihoods of the unwanted events within the scenarios and the consequences of the events. These elements are conditional upon the available knowledge about the analyzed system, and understanding of the system behaviour, therefore these two are inherent parts of risk analysis, and need to be included in the risk description

Model oceny ryzyka statków do przewozu ropy naftowej

The paper presents a model for risk analysis regarding marine traffic, with the emphasis on two types of the most common marine accidents which are: collision and grounding. The focus is on oil tankers as these pose the highest environmental risk. A case study in selected areas of Gulf of Finland in ice free conditions is presented. The model utilizes a well-founded formula for risk calculation, which combines the probability of an unwanted event with its consequences. Thus the model is regarded a block type model, consisting of blocks for the probability of collision and grounding estimation respectively as well as blocks for consequences of an accident modelling. Probability of vessbl colliding is assessed by means of a Minimum Distance To Collision (MDTC) based model. The model defines in anovel way the collision zone, using mathematical ship motion model and recognizes traffic flow as a non homogeneous process. The presented calculations address waterways crossing between Helsinki and Tallinn, where dense cross traffic during certain hours is observed. For assessment of, a grounding probability, a new approach is proposed, which utilizes a newly developed model, where spatial interactions between objects in different locations are recognized. A, ship at a seaway and navigational obstructions may be perceived as interacting objects and their repulsion may be modelled by a sort of deterministic formulation. Risk due to tankers running aground addresses an approach fairway to an oil terminal in Skoldvik, near Helsinki. [...]W artykule przedstawiono model oceny ryzyka w transporcie morskim, w aspekcie kolizji statków oraz wejść na mieliznę. W modelu przyjęto jeden typ statków, tankowce do przewozu ropy naftowej, z uwagi na fakt, iż w przypadku wystąpienia kolizji lub kontaktu z dnem statek ten może stanowić bardzo poważne zagrożenie dla środowiska. W pracy przedstawiono dwa nowatorskie podejścia do modelowania prawdopodobieństwa wystąpienia powyższych wypadków. Model do oceny prawdopodobieństwa kolizji statków definiuje w nowy sposób strefę kolizji, w oparciu o właściwości manewrowe statku oraz jego hydrodynamikę. Intensywność ruchu morskiego na analizowanym akwenie modelowana jest w oparciu o proces niestacjonarny, w przeciwieństwie do istniejących modeli. Model oceny prawdopodobieństwa wejścia na mieliznę wykorzystuje model grawitacyjny, który wyznacza bezpieczny obszar manewrowy dla danego statku i danego akwenu. W modelu tym statek i otaczające go płycizny traktowane są jako masy, wzajemnie na siebie oddziaływujące. Obydwa modele wykorzystują dane o ruchu statków zarejestrowane w systemie automatycznej identyfikacji statków (AIS). Analiza ryzyka przeprowadzona została dla dwóch wybranych akwenów w Zatoce Fińskiej. Jako konsekwencje wypadku przyjęto model kosztów, skonstruowany w oparciu o dane statystyczne z międzynarodowego funduszu IOPCF, który pokrywa koszty w związku z rozlewem olejowym na morzu

The storied lives of fronteriza bilingual maestras : constructing language and literacy ideologies in nepantla

This dissertation examines the language and literacy ideologies of in-service fronteriza bilingual education maestras utilizing a life story methodology. Drawing on an indigenous research paradigm and three theoretical frameworks that accentuate the lived experiences of fronteriza teachers—nepantla, border thinking, and raciolinguistic perspective—this study addresses how the life stories of fronteriza teachers illuminate their construction of language and literacy ideologies. Findings unsettle the mismatch between articulated and embodied language ideologies and demonstrate that the contradictions that manifest in home, school, and community language ideologies are an aspect of living in nepantla. The findings reveal that bilingual maestras’ language and literacy ideologies are influenced by their personal lived experiences, macro-hegemonic discourses, and the history of geopolitical spaces. As bilingual education becomes engrossed in neoliberal logics, implications for utilizing border thinking and anticolonial practices with in-service and pre-service teachers are discussed. In studying fronteriza bilingual teachers that inhabit a unique geopolitical space along the Texas-Mexico border, this dissertation contributes to the larger debate regarding the multiplicity of embodied and articulated language ideologies in bilingual settings.Curriculum and Instructio