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Collaborating Authors
Oldford, Dan
Ice Class IA or Ice Class PC7 for Arctic Operations
Oldford, Dan (ABS HETC) | Moakler, Ed (ABS HETC) | Bond, James (ABS Ottawa)
ABSTRACT Additional strengthening of vessels intended to operate in ice range from very light scantling increases to accommodate minor interaction with ice up to the creation of very significant icebreaking structures. These structures are measured by an Ice Class notation assigned by the vessel's Classification Society. The two main rule sets used in the marine industry are the International Association of Classification Societies (IACS) Polar Class rules and the Finnish Swedish Ice Class Rules (FSICR). The two lowest Polar Classes overlap with the two highest FSICR Ice Classes, and at this ice strengthening level, there continues to be a tendency to select the FSICR over the Polar Class for ships intended for summer / autumn service in Polar waters. This paper explores the structural scantling differences between these ice classes. INTRODUCTION In 2007, the International Association of Classification Societies (IACS) published the Polar Class Rules (IACS 2007). The rules were adopted by all IACS members as the rules for high ice class ships intended to operate in Polar ice conditions. The Finnish and Swedish Administrations jointly develop, maintain, and publish the Finnish-Swedish Ice Class Rules (FSICR) (Traficom 2021). Nearly all IACS members have duplicated the FSICR within their own rule sets (Traficom 2017). The two highest FSICR ice classes, IA-Super and IA, are notionally comparable to the two lowest Polar Classes, PC6 and PC7 (ABS 2023b). The FSICRs are intended for vessels operating in the Baltic Sea during winter, sailing in first year ice while being escorted by an icebreaker (Traficom 2019). The Polar Class rules are based on vessels operating independently and with ice impacts from much harder multiyear ice (ABS 2023b). It is noted that first year ice in the Baltic Sea may be stronger than first year ice in Polar waters due to lower brine concentrations, however Baltic Sea ice is weaker and lighter than multi-year ice in Polar waters. This stronger ice is the design point for polar classed ships whereas vessels designed for the Baltic are intended to encounter first year Baltic ice. Most ice classed vessels observed operating in the Arctic (where multiyear ice is present) have a FSICR ice class (PAME 2022) even though the intent behind the FSICR is for operations in Baltic Sea first year ice. It is postulated that due to the low number of Polar Class ships in comparison to the FSICR ice class ships, there is a lack of detailed understanding of the subtleties and differences between PC6 / IA Super and PC7 / IA scantlings.
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Floating production systems (0.66)
- Data Science & Engineering Analytics > Information Management and Systems > Artificial intelligence (0.54)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Platform design (0.48)
Abstract For decades the Northwest Passage (NWP) has been a formidable challenge for the shipping and maritime industries. Arctic community resupply and export of Arctic resources by ship has been seen as the viable in the summer season. Changing ice conditions and the new ability to process high volumes of data in real time has allowed the quantification of risk and determination of the required ship strengthening to a specific ice class notation for seasonal and year-round export planning. The International Maritime Organization (IMO) has provided a methodology to assess the risk of operating a ship in a specific ice regime, as seen from the bridge, or as reported in an ice chart. An ice regime, from a navigation standpoint, is the ice that the ship will likely encounter and defines several important factors including the ice-concentration, thickness, age, state of decay, and roughness. The authors have developed methods to convert ice charts into maps using the IMO POLARIS risk assessment methodology. By processing decades of ice charts, the trends of changing ice and the variation in ship access through the NWP was determined. Focusing on critical resource development locations, routes and the ships needed for seasonal and year-round export have been developed. This paper provides an examination of the viability of various routes through the NWP for a series of ships of different ice class using the IMO POLARIS methodology. The results are presented in terms of the most recent 5-year averaged ice condition. The 5-year averaged ice conditions are compared to a 10-year dataset to highlight and contrast past and current ice conditions. Risk maps for recent individual years are also presented to illustrate year on year variability of ice conditions. Observations are drawn from the plots to summarize the necessary ice class for year-round NWP transit, and also ship traffic for specific locations (eg. Alaska North Slope LNG shipment to Asia with a 5-month (September to January) shipping window). This paper provides the answer to "What ice class ship is needed to operate in specific locations the Arctic at different times of the year.?"
- North America > Canada (1.00)
- North America > United States > Alaska > North Slope Borough (0.35)
- Transportation > Marine (1.00)
- Transportation > Freight & Logistics Services > Shipping (1.00)
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Midstream (1.00)
The Canadian Parliament approved the Arctic Waters Pollution Prevention Act in 1970 to assert Canadaโs jurisdiction to regulate all shipping in zones up to 100 nautical miles off its Arctic coasts. Control measures and clarity were added in 1985 when the Arctic Shipping Pollution Prevention Regulations were enacted and shipping control zones were created. The Canadian Arctic is divided into 16 zones, where Zone 1 is generally considered to have the most demanding conditions, and Zone 16 the least. Access to each zone was established for specified ship ice class, based on historical data related to the probable ice conditions at different times of the year. The system is based on the premise that nature follows a consistent pattern. In the decades since the zone / date system (Z/DS) of access was created the sea ice has changed in spatial (areas and volume) extent and temporal extent, as have the reasons for taking a ship to a specific location. The Z/DS continues to be used for basic route planning, estimating ice conditions, and can be used for preliminary ice class selection without offering needed accuracy. A study was undertaken to postulate a revised Z/DS that can be applied to the International Association of Classification Society (IACS) Polar Classes (PC) and Finnish-Swedish (Baltic Ice Class) ships. To guide the change ice data for the years 2006 through 2020 was used while considering destinations and proposed safe shipping corridors. Using the IMO Polar Operation Limit Assessment Risk Indexing System (POLARIS) and its resulting Risk Index Outcomes (RIOs) new zone boundaries were developed that incorporated common shipping routes and destinations. In addition, the boundaries for the new zones follow line of latitude and longitude so seafarers can easily determine when they are entering or leaving a zone. A zone was considered โopenโ when there was no negative RIOโs inside its boundaries. In accordance with IMO POLARIS methodology a negative RIO indicates elevated risk operations. This paper details the process used to create an initial updated Z/DS that has 26 zones, encompassing the Canadian Arctic, the Alaskan portion of the Beaufort Sea, the Labrador Coast and the Gulf of St Lawrence. The new 26 zones are shown on maps and entry and exit dates are tabulated. With further validation this process can be expanded to any waters where sea ice data exists.
- North America > Canada > Nunavut (0.28)
- North America > Canada > Newfoundland and Labrador > Labrador (0.24)
Assessing Polar Class Ship Overload and Ice Impact on Low-ice Class Vessels using a โQuasi Real Timeโ Popov/Daley Approach
Lande Andrade, Sthefano (Memorial University of Newfoundland) | Elruby, Ahmed (Memorial University of Newfoundland) | Oldford, Dan (American Bureau of Shipping) | Quinton, Bruce (Memorial University of Newfoundland)
The methodology presented in this work considers an impactโs available kinetic energy as balanced by the ice crushing energy as well as the structural deformation energy. The algorithm re-calculates the kinetic energy iteratively by subtracting the energy lost to structural deformation and ice crushing at specified time-intervals. The updated kinetic energy is then used to determine the current impact speed, which controls the indentation rate of ice on the structure. The result is a contactless ice load model which is intrinsically coupled to structural deformation. Accounting for structural deformation energy is important for overload of Polar Class ships, as well as any ice impact for non-ice class ships.
This study presents selected data from an extensive testing program on steel taken from the Kulluk that was carried out to characterize the present-day mechanical properties. The program investigated the tensile and failure behaviours as well as the fracture energies and ductile-to-brittle transition temperature of steel from two hull locations. These locations were selected based on the following criteria: exposure to seawater and temperature fluctuations, experience of high ice loads, level of plastic deformation, and steel grades. The two selected pieces were made of EH II and DHN grades. The initial results showed that the steels still meet the design requirements as per the ABS rules.
- North America > Canada > Newfoundland and Labrador (0.29)
- North America > United States > Texas > Harris County > Houston (0.16)
Risk-based Winterization on a North Atlantic-based Ferry Design
Yang, Ming (Memorial University of Newfoundland) | Khan, Faisal (Memorial University of Newfoundland / University of Tasmania) | Oldford, Dan (American Bureau of Shipping ) | Lye, Leonard (Memorial University of Newfoundland) | Sulistiyono, Heri (Memorial University of Newfoundland)
The Arctic is a recent focal point of the marine and offshore industries. Winterization is required for safe and efficient operations in these harsh cold environments. A riskbased approach to winterization was recently proposed to provide a quantitative way of determining the need for winterization and its appropriate level. To further validate and enhance this approach, it has been applied to a new ice-class passenger ferry design, which will operate in a particular area of the North Atlantic. This location is ideal for the application with low temperatures, strong wind, and high waves. To facilitate this application and eliminate some limitations of the proposed approach, this article proposes a generic framework of risk-based winterization. Results from this article validated the effectiveness and feasibility of using risk-based winterization on vessel designs.
- Energy > Oil & Gas > Upstream (1.00)
- Transportation (0.89)
Laboratory experiments were conducted by crushing a spherical indenter into cylinders of ice. These experiments were aimed at proving the force estimates produced by a program called Direct Design for Polar Ships (DDePS). DDePS is a contact-geometry specific tool based on Popov type formulations. The ice crushing experiments were performed in open air at various impact speeds using a double pendulum impact apparatus. The ice was laboratory ice with properties close to that of multi-year ice. Values of impact speed, force and penetration were measured. This paper presents the results of these laboratory experiments which were in good agreement with DDePS.
Risk-based Winterization for Vessels Operations in Arctic Environments
Yang, Ming (Memorial University of Newfoundland ) | Khan, Faisal I. (Memorial University of Newfoundland ) | Lye, Leonard (Memorial University of Newfoundland ) | Sulistiyono, Heri (Memorial University of Newfoundland ) | Dolny, John (American Bureau of Shipping ) | Oldford, Dan (American Bureau of Shipping )
Because the oil and gas industry has an increasing interest in the hydrocarbon exploration and development in the Arctic regions, it becomes important to design exploration and production facilities that suit the cold and harsh operating conditions. In addition to well-established minimum class requirements for hull strengthening, winterization should be considered as a priority measure early in the design spiral for vessels operating in the Arctic environments. The development of winterization strategies is a challenging task, which requires a robust decision support approach. This article proposes a risk-based approach for the selection of winterization technologies and determination of winterization levels or requirements on a case-by-case basis. Temperature data are collected from climatology stations located in the Arctic regions. Loading scenarios are defined by statistical analysis of the temperature data to obtain probabilistic distributions for the loadings. Risk values are calculated under different loading scenarios. Based on the risk values, appropriate winterization strategies can be determined. A case study is used to demonstrate how the proposed approach can be applied to the identification of heating requirements for gangways.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.46)
- North America > Canada > Quebec > Arctic Platform (0.97)
- North America > Canada > Nunavut > Arctic Platform (0.97)