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The risks of ship besetting under ice pressure are examined. Hindcasts of ice dynamics examine the conditions that led to the besetting of two vessels in the Gulf of St. Lawrence on 9 March 2005. The analysis examines the distributions of potentially significant variables such as pressure (mean normal stress), ridge thickness and strain rates. A cr...
Citations
... Iceberg disasters are mainly concentrated in the ocean areas off Antarctic coast, surrounding Greenland and northeastern Canada. Sea ice disasters focus on coastal and offshore areas of Arctic countries, especially in the Arctic shipping routes (Kubat et al. 2012(Kubat et al. , 2015. Coastal freeze-thaw erosion mainly occurs on the northern coast of Russia, Alaska, and Canada. ...
... The presence of sea ice (especially floating ice) in northern regions has significant economic, environmental, and social implications (Kubat et al. 2012(Kubat et al. , 2015. Sea ice is the main load of offshore and shore-based facilities and ships in ice-prone areas, threatening the safe operation of these facilities and ships. ...
... For example, in 2007, strong southwesterly winds, ocean currents, irregular shorelines, massive shoals, further drift of floating ice, and intrusion of multiyear ice caused damage to severe pressure buildup along the east coast of Newfoundland and Labrador in April and May. As a result, a large number of fishing vessels were trapped in the pressure ice field (Kubat et al. 2012(Kubat et al. , 2015. In 2010, in the southern Bohai Bay in China, a ship loaded with 1,000 t of fuel oil was squeezed by floating ice and the cabin was flooded. ...
... Second, they include no or limited information on the occurrence of pressured ice, which might significantly increase a ship's resistance and the amount of ice loading acting on its hull. As per Kubat et al. (2012) and Turnbull et al (2019), the occurrence of pressured ice depends on multiple factors, including the speed and direction of the prevailing wind and sea currents, as well as on the presence of shorelines acting as geographical boundaries. Third, they include no information on physical and mechanical ice properties, which as per Timco and Weeks (2010) are needed for detailed ice load calculations. ...
Arctic shipping is growing driven by a demand for natural resources, climate change, and technological development, among other factors. While this provides many benefits for society, it also entails risks for people, the environment, and property. The purpose of this article is to assist ship designers, operators, owners, and other stakeholders in managing those risks by defining a comprehensive approach to scenario-based risk management for Arctic waters. The approach covers both the management of short-term operational risks, as well as of risks related to a ship’s long-term extreme (design) ice loads and structural response. For operational risk management, a further developed version of the established Polar Operational Limitations Assessment Risk Indexing System (POLARIS) method is defined. In contrast to the established method, the further developed version considers the consequences of potential accidental events. For managing risks related to a ship’s long-term extreme ice loads and structural response, guidelines are provided for the application of existing methods of assessing ice loads, including analytical, numerical, and semi-empirical methods. In addition, to support the design of ice class ship structures, a new approach based on closed-form expressions is defined that can be used in the conceptual design phase to determine preliminary scantlings of primary hull structural members (e.g., transverse web frames).
... Second, they include no or limited information on the occurrence of pressured ice, which might significantly increase a ship's resistance and the amount of ice loading acting on its hull. As per Kubat et al. (2012) and Turnbull et al (2019), the occurrence of pressured ice depends on multiple factors, including the speed and direction of the prevailing wind and sea currents, as well as on the presence of shorelines acting as geographical boundaries. Third, they include no information on physical and mechanical ice properties, which as per Timco and Weeks (2010) are needed for detailed ice load calculations. ...
While society benefits from Arctic shipping, it is necessary to recognize that ship operations in Arctic waters pose significant risks to people, the environment, and property. To support the management of those risks, this article presents a comprehensive approach addressing both short-term operational risks, as well as risks related to long-term extreme ice loads. For the management of short-term operational risks, an extended version of the Polar Operational Limit Assessment Risk Indexing System (POLARIS) considering the magnitude of the consequences of potential adverse events is proposed. For the management of risks related to long-term extreme ice loads, guidelines are provided for using existing analytical, numerical, and semi-empirical methods. In addition, to support the design of ice class ship structures, the article proposes a novel approach that can be used in the conceptual design phase for the determination of preliminary scantlings for primary hull structural members.
... Kubat [14] obtained significant risk factors that result in ice pressure by distributing a questionnaire to captains who operated ships through Canadian waters. Based on the surveyed results, Kubat [15] further developed besetment criteria in terms of ice pressure and ridge height by examining two separate ship besetment events in the Gulf of St. Lawrence in March 2005. Subsequently, this criterion was applied to analyse the besetment events in Frobisher Bay during the 2012 shipping season [16], the Gulf of St. Lawrence and the Strait of Belle Isle during the winters of 2013 and 2014 [17], and Beaufort Sea [18]. ...
To facilitate shipping in ice and to meet the increasing requirements of icebreaker services, convoy operations are the most effective alternative. However, convoy operations are among the most dangerous operations as they can result in ship-ship collisions and/or ship besetting in ice. To safeguard the assisted ships and improve the efficiency of convoy operations, predicting the besetment event is a paramount proactive measure. In this study, a Bayesian Network model is developed to predict the probability of ship besetting in ice in a convoy operation along the Northern Sea Route (NSR). The model focuses on the first-assisted ship and is based on expert elicitation. Correspondingly, four scenarios that may result in the first assisted ship besetting in ice have been identified. Further, the applicability of the model is evaluated through 12 scenarios derived from the real NSR voyage of ‘TIAN YOU’ assisted by the icebreaker ‘VAYGACH’ in August 2018. The results of the model evaluation and validity studies indicate that the developed model is feasible and can adequately predict the besetment event of the first assisted ship in convoy operations. The most important factors contributing to besetting in ice were found to be ice concentration, distance between icebreaker and ship, and navigation experience.
... The first category takes a data-driven approach. Kubat et al. (2012; analyzed the correlation between occurrences of ship besetting with ice forecast data, while Montewka et al. (2015) focused on establishing a probabilistic model based on ship and environmental data to predict ship performance in dynamic ice. Similä and Lensu (2018) and Lensu and Goerlandt (2019) used various data to estimate ship speed in varying ice conditions but lack a specific focus on dynamic ice. ...
... The data-driven approach requires sufficient and highresolution data in order to obtain an applicable prediction for a specified ship. For example, the investigation by Kubat et al. (2012; only targeted one ship. Therefore, there is considerable uncertainty about the performance of another vessel even in the same conditions. ...
Ships navigating in ice inevitably encounter different ice conditions. Dynamic ice typically presents severe conditions when it is moving perpendicular towards the parallel midship section, which can lead to ships getting stuck in ice. This can cause delays for ships or even damage to the ship hull. However, there currently is no model to assess ship operability in this dynamic ice. This paper aims to develop a method to assess operability of ships in dynamic ice conditions, which can be used for ship routing to avoid ship stuck. The method is especially useful for emergency response planning purposes, e.g. for marine pollution preparedness and response planning, where an understanding of the operability of response vessels in dynamic ice conditions currently is lacking. First, a transit model is introduced for both independent navigation and escort operations, considering the additional ice resistance by dynamic ice. Then, a ship operability index is proposed based on the modelling of ship's performance. Case studies of independent navigation and escort operations in realistic dynamic ice conditions are investigated to compare with the simulated results. Reasonable agreement is obtained, indicating that the proposed method can be used for ship operability assessment in dynamic ice.
... In addition to a ship's ice-going capability, numerous external factors may contribute to the probability of a ship becoming beset in ice, including the prevailing ice thickness and concentration, the occurrence of pressured ice conditions, and the degree of ice ridging (e.g. ridge thickness or height, ridge density) (Kubat, et al., 2012). The ice conditions (e.g. ...
... Previous studies on ship ice besetting events have mainly been related to ship operations in the Baltic Sea and the Canadian Arctic. Kubat et al. (2012) studied two separate ship ice besetting events in the Canadian Arctic to identify and specify critical besetting criteria, among others. One of the besetting events involved a general cargo ship, the other involved a tanker. ...
... The outcome of their analysis suggests that the primary cause of the two studied besetting events was the presence of large ice floes (the majority of the floes present during the besetting events were greater than 6 km in diameter) in combination with the presence of wind and sea currents. Although the studies by Kubat et al. (2012) and Turnbull et al. ...
Ships operating in ice-infested Arctic waters are exposed to a range of ship-ice interaction related hazards. One of the most dangerous of these is the possibility of a ship becoming beset in ice, meaning that a ship is surrounded by ice preventing it from maneuvering under its own power. Such a besetting event may not only result in severe operational disruption, but also expose a ship to severe ice loading or cause it to drift towards shallow water. This may cause significant structural damage to a ship and potentially jeopardize its safety. To support safe and sustainable Arctic shipping operations, this article presents a probabilistic approach to assess the probability of a ship becoming beset in ice. To this end, the proposed approach combines different types of data, including Automatic Identification System (AIS) data, satellite ice data, as well as data on real-life ship besetting events. Based on this data, using a hierarchical Bayesian model, the proposed approach calculates the probability of a besetting event as a function of the Polar Ship Category of a ship, sea area, and the distance travelled in the prevailing ice concentration. The utility of the proposed approach, e.g. in supporting spatiotemporal risk assessments of Arctic shipping activities as well as Arctic voyage planning, is demonstrated through a case study in which the approach is applied to ships operating in the Northern Sea Route (NSR) area. The outcomes of the case study indicate that the probability of besetting is strongly dependent on the Polar Ship Category of a ship and that the probability increases significantly with higher ice concentrations. The sea area, on the other hand, does not appear to significantly affect the probability of besetting.
... 冰山灾害主要集中在南极沿岸海 域、格陵兰周边区域、加拿大东北部. 海冰灾害则主 要集中在环北极国家沿岸和近海地带, 以及中国环渤 海区域 [15] . [16] . ...
The cryosphere is the part of the earth's surface where the temperature is always below freezing. Since the 1970s, the frequency of rapid cryospheric change events has been increasing along with the significant rise of global temperature. This has or will lead to a series of cryospheric disasters with extreme damage. Disaster-formation mechanism, disasterreceptors, and environmental reactions to different types of disasters in the cryosphere have different spatial distribution patterns. The cryosphere can be divided into three major categories: Continental cryosphere, marine cryosphere, and aerial cryosphere. These depend mainly on its geographical distribution, dynamics, and thermodynamic conditions. Based on the results of past research, the present study systematically expounds the formation mechanism classification, spatial and temporal scales, and spatial differentiation of cryospheric disasters and reveals the comprehensive impact of global cryospheric disasters at high-risk areas and their trend. The results show the following. (1) Continental cryospheric disasters (e.g., avalanches, glacial lake outburst floods, freezing and thawing disasters, and glacier/snow flood/debris flow) are concentrated mainly in the Qinghai-Tibet Plateau, Siberia, Peruvian Andes, and northern North America and have already caused considerable risk to personal safety and damage to infrastructure. (2) Marine cryospheric disasters (sea ice disasters, coastal freeze-thaw erosion, and rises in sea level) occur mainly along coastal areas of the Arctic and the lowlying areas and island countries of the world. These disasters mainly affect navigation safety and ports, coastal/offshore facilities, and homeland security. (3) Aerial cryospheric disasters, especially snowstorms and rain and snow freezing disasters take place in the northeastern United States, Europe, East Asia, and China, mainly affecting transportation, aviation, and agriculture. Although the frequency of the cryospheric disaster is low, the scope and impact are very large. Cryospheric change, risk of cryospheric disaster, and the management thereof are closely related. It is urgently necessary to strengthen the understanding and assessment of the cryosphere change and its impact on the socio-economic system and integrated risk analysis. Specifically, we must adjust economic and social activities in areas at high risk of global cryospheric disasters and develop strategies for prevention and mitigation of cryospheric disasters and so reduce risk and improve resilience and sustainability.
... The Gulf of St. Lawrence accounts for the majority of reported cases of ship besetting and damage in Canadian waterways, as identified in the database of ship besetting events presented by Kubat et al. (2012). This increased frequency of besetting events is largely due to the high volume of vessel traffic in the region. ...
... Within the vicinity of the Berge Atlantic, ice pressure varies from the coastline to the location of the vessel, with a maximum value of 4 kN/m. Kubat et al. (2012) ice pressure of 4 kN/m is relatively low. Note that pressure is quantified as force per unit length as it is more indicative of the forces that act on a ship, rather than force per unit area which would require accounting for ice thickness. ...
A detailed account of the besetting and break-out of the MV Berge Atlantic in the Gulf of St. Lawrence in 2014 is presented. Field observations indicate that besetting occurred with the absence of significant ice pressure, and may have been triggered by ice ridging. An ice dynamics model was used to reproduce the evolution of ice conditions in the vicinity of the beset vessel. The results show that appropriate initialization of ridge distribution is needed for accurate evaluation of the risk of besetting.
... Otherwise, a ship can get stuck in ice, suffer ice damage of various levels of severity, or get grounded with drifting ice pack. [3][4][5][6][7][8][9][10][11] To plan ship route in ice, two elements are indispensable: reliable ice information and the knowledge about the effect of ice cover on ship speed. [12][13][14][15][16][17] The former is obtained from ice charts or numerical ice models, whereas the latter comes from the ship transit models, which can be roughly divided into two main groups: engineering type and datadriven. ...
... 31 The data-driven models do not look into the physics of the icebreaking process, but tend to reflect the ice features under which an event of interest occurs, for example, ship proceeding with certain speed or a ship getting stuck in ice. 7,9,32,33 They are based to large extend on experience 32 or learned from the observable data. 9,33 With this type of model, one can evaluate performance of a ship. ...
Practical knowledge about the performance of a ship while navigating in ice is crucial for the selection of safe and efficient route for a ship. Existing route finding tools estimate ship performance in ice adopting numerous approaches, ranging from model tests and engineering models to experts-based guidelines. Therein ship performance is usually understood as attainable ship speed or the average speed in given ice conditions; rarely the probability of besetting in ice is taken into account. Those models despite being fairly accurate in the theory share the same shortcoming in practice. The latter encompasses three main issues: (1) inaccurate information about prevailing ice conditions, (2) presence of ice conditions that goes beyond the scope of the models, and (3) the effect of operational patterns and traffic organization on the performance of an individual ship. To approach those issues, we propose a hybrid model of ship performance in ice-covered waters. The hybrid model combines two other sub-models: engineering and data-driven. The former determines ship speed and besetting probability in ridged ice field with ice concentration close to 100%. The latter sub-model provides information on ship’s speed in the actual ice conditions, where the speed is affected also by operational restrictions and icebreaker assistance. It is based on an extensive dataset combining ship data from automatic identification system and ice data from ice charts and ice forecast models. The presented hybrid model is valid for a specific ship type, which is ice going bulk carrier (IA Super ice class), operating within the Northern Baltic Sea winter navigation system. The obtained results reveal that the hybrid model in principle is capable of providing reliable information about the performance of a ship in a wide range of conditions accounting for environmental variability and existing operational conditions. The model is suitable for the purpose of safe route planning in ice for a single ship or group of similar ships, accounting for the economy and safety of a voyage.
... In the Canadian context, several aspects of this issue have been considered, including surveying Captains' perspectives on how ship safety and performance can be improved in pressured ice regions (Kubat and Sudom, 2008), developing models for assessing ice pressure effects at small scales (e.g. Sayed and Kubat, 2011), compiling a database of vessel besetting and developing tools to aid in forecasting pressured ice (Kubat et al., 2012). Probabilistic models of ice jamming have also been developed to aid in assessing the likelihood of ice-related disruptions to offshore supply vessel traffic servicing oil platforms on the Grand Banks (Turnbull et al., 2014). ...
The aim of this paper is to examine experiences from Eastern Canada to summarize and present information which may help operators, planners, researchers, and policy-makers in the marine transportation sector identify potential short-term and long-term strategies for improving services and making more effective decisions regarding ways to minimize the impact of ice-related disruptions to ferry service in ice prone regions of the world. In this study, emphasis has been placed on examining the impacts of ice-related disruptions in ferry service on public stakeholders, since this end-user perspective provides important insights into consequences and associated mitigation strategies. The methodology employed includes a high-level examination of regional ferry services, followed by an identification and selection of specific routes, completion of a survey of publically reported disruption events for these routes and compiling information about reported stakeholder consequences associated with ice-related disruptions. Three representative ferry routes have been considered to assess issues relating to resilience in urban versus rural regions, the availability of alternatives and changes with time, as well as potential strategies that may be taken to help address the most pressing issues are discussed. The main impacts most frequently reported as consequences of ice-related disruptions for these routes are: (1) Reduced access to medical care; (2) Decreased food security; (3) Disruptions for workers and commercial transport; and (4) Inconvenience, frustration and cost to travelers. Most commonly identified preventative strategies for addressing these issues include: (1) New ferries with increased ice capabilities; (2) Increased icebreaker support and ice forecasting capabilities; (3) Infrastructure upgrades, including consideration of alternative ports; and (4) Use of alternative modes of transport (e.g. alternate routes, airplanes, or fixed links). Identified mitigation strategies for reducing the impact of these disruptions include: (1) Increased communication services; (2) Government programs to improve community preparedness and resilience; and (3) Government programs (e.g. subsidies) to assist those affected by disruptions.
