Day 2 Mon, July 21, 2008最新文献

{"title":"Ice Load Prediction Formulas for Icebreaking Cargo Vessels","authors":"Kyungsik Choi, Seong-Yeob Jeong, Jong-Ho Nam","doi":"10.5957/icetech-2008-162","DOIUrl":"https://doi.org/10.5957/icetech-2008-162","url":null,"abstract":"The ice load prediction for the icebreaking cargo vessels is discussed. Ice load includes the global ice loads and local ice pressures on the hull of the icebreaking vessels. The extreme ice loads are expected from large ice features and these loads are most likely to be concentrated at the bow area of a ship. The available ice load data from model tests and also from full-scale sea trials are collected and analyzed in the same format according to various ship-ice interaction processes. The ice load prediction formulas are compared with the measured data. Based on collected test data, semi-empirical ice load prediction formulas are recommended for large sized icebreaking cargo vessels.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114789402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"February 13, 2007 Limit Driving Force Event on the Confederation Bridge","authors":"D. Tripathi, Noorma Shrestha, T. Brown","doi":"10.5957/icetech-2008-143","DOIUrl":"https://doi.org/10.5957/icetech-2008-143","url":null,"abstract":"On February 13, 2007, the Confederation Bridge piers experienced a sustained ice jam leading to a limit-driving force event. The objective of this paper is to analyze this limit force event and explain the processes involved.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132788135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protection Barrier for Shallow Arctic Waters","authors":"O. Gudmestad, A. Gürtner, Ada Rpetto Llamazares","doi":"10.5957/icetech-2008-117","DOIUrl":"https://doi.org/10.5957/icetech-2008-117","url":null,"abstract":"Hydrocarbon discoveries in the shallow waters of the Northern Caspian Sea have caused intensive drilling activities to be carried out to explore the potentials. Experience with mobile drilling units in the seasonally ice infested waters hitherto originates from the drilling campaigns of the Sunkar drilling barge at Kashagan and Kalamkas.\u0000 However, with increased drilling activities upcoming, innovative drilling concepts are desirable due to the objective of maintaining drilling operations (of production wells) also during the ice period with the use of conventional non-ice-resistant drilling platforms. The employment of external Shoulder Ice Barriers (SIBs) to protect a conventional jack-up drilling rig from the hazards of drifting ice in shallow water is discussed. Model tests on the SIB were performed in the large ice tank of the Hamburg Ship Model Basin (HSVA) during July 2007. These tests were performed to investigate the conceptual design under ice impact. The characteristic shoulder sections' inclination was varied to investigate the shoulder’s contribution towards stabilizing broken ice and to prevent ice from over-riding. Ice up-riding onto the barrier contributes towards increased vertical forces. The global vertical forces showed to be higher than the global horizontal forces, and in particular when ice grounding was observed. Even under extreme rubble heights of up to 9.4 m (full scale), ice overtopping the structure was effectively prevented. The SIB showed the potential to be utilized as ice protection structure for future shallow water developments.\u0000 Finally, the stability on the sea bottom was investigated. The conclusion being that the concept will perform well on average to strong soils but needs to have a larger foot print area in very soft soils condition.\u0000 This paper thus documents, on a feasibility level, the concept of ice protection in shallow water by means of the SIB. This paper presents a summary study of the design and verification work performed with regard to the feasibility of an innovative design.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126146774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Icebreaking Ore Carrier Project for Baffinland Iron Mines Corporation","authors":"G. Wilkman, Matti Arpiainen, Riku Kiili, T. Mattsson, R. Cooper, John T. Stubbs","doi":"10.5957/icetech-2008-112","DOIUrl":"https://doi.org/10.5957/icetech-2008-112","url":null,"abstract":"Baffinland Iron Mines Corporation is planning to utilize the iron deposits on the northern Baffin Island (Canada). The iron ore was discovered in the beginning of 1960ies. The mine is 100-142km from the sea shore (Milne Inlet or Steensby Inlet). The sea area from Milne Inlet and Steensby Inlet to North Atlantic is most of the year ice covered. Open water period may be only three months, from July to October.\u0000 The operation is planned to be year-round.\u0000 The amount of iron ore to be transported in the beginning of the production in 2014 is c. 18 million tonnes/year. The ore carriers are to be operated independently without icebreaker assistance. The ore carriers are assumed to operate at full draught both in loaded and ballast condition when operating in ice. The ship size was selected to be of main dimensions as a Dunkirkmax/Capesize vessel. There are two basic ore carrier alternative designs; The first alternative is conventional icebreaking vessel, which mainly operates by breaking ice with the bow. The second alternative is the so called Double Acting Ship (DAS). In the DAS concept the vessel is designed to operate bow first most of the time, in open water and in light ice conditions, but in severe ice conditions running astern. This paper describes the design process of the vessels including the basic requirements, operational conditions, transit simulations, model tests and the vessel designs.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"09 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127223114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural Breaker Drillship/FPSO Concept for Ice Offshore","authors":"A. Keinonen, E. H. Martin","doi":"10.5957/icetech-2008-126","DOIUrl":"https://doi.org/10.5957/icetech-2008-126","url":null,"abstract":"A new type of drillship and floating production platform concept has been has been a developed by the author. This is based on lessons learned from azimuth thruster icebreakers and lessons of station keeping with dynamically positioned and moored vessels in real life operations. The new concept, called Natural Breaker, is based on the concept that the ice does not need to be broken by the hull of the drillship/platform but can be broken using the wake of azimuth thrusters. Some of the key lessons from use of the azimuth thrusters support the fact that the wake of the thrusters can be more efficient breaking the ice than the hull of the vessel. Furthermore the azimuth thruster wake clears ice efficiently including dismantling keels of first year ice ridges. The resulting concept contains a combination of several thrusters and can be further enhanced by using a turret mooring system. The capability of self ice management thus introduced, can result in a reduction in the need of external ice management system in support of such drillship/platform.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116746726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iceberg Design Load Methodology","authors":"Paul Stuckey, F. Ralph, I. Jordaan","doi":"10.5957/icetech-2008-103","DOIUrl":"https://doi.org/10.5957/icetech-2008-103","url":null,"abstract":"An iceberg design load methodology has been developed to address the risk of icebergs to offshore structures. The methodology is probabilistic, accounts for the range of iceberg shapes, sizes and strengths, and environmental conditions. The model is applicable to both fixed structures such as a gravity based structure or a jackup, as well as floating structures such as a semi-submersible or a FPSO. This paper will focus on recent improvements made to key models within the methodology. A probabilistic iceberg drift speed model has been developed, which takes into account the inherent randomness in the observed data. With an expanded set of iceberg profiles, covering a wider range of iceberg shapes and sizes, the area-penetration and iceberg eccentricity models have been enhanced. In addition a new contact depth model has been implemented.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130151634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Construction of Icebreakers for Operation in the Barents Sea","authors":"C. Tan","doi":"10.5957/icetech-2008-104","DOIUrl":"https://doi.org/10.5957/icetech-2008-104","url":null,"abstract":"Recent major oil finds in the Russia Arctic region have led to a marked increase in exploration and production activities. Russian Government and Russian oil companies have invested heavily to make year–round export of oil and gas from the Barents and Pechora Seas a reality. Lukoil, in particular, is developing the Varandey terminal. Lukoil has ordered one dedicated icebreaker and one icebreaking standby/supply ship from Keppel Singmarine.\u0000 The icebreaker is capable of operating independently in the ice conditions. Built to RMRS LL7 notation, its main function is to perform ice channeling for tankers within the terminal area, assist in tanker maneuvering, mooring and loading. The icebreaking standby/supply ship is built for year–round operation within the area of the offshore oil terminal in the Barents and Pechora Seas. Built to RMRS LU7 notation, its main function is to provide limited ice escort services at the terminal area in the event that the icebreaker becomes unavailable. Operating ambient air temperatures are in the range +30°C to – 40°C. Both ships are built to “Clean Design” standards. The paper describes some of the challenges faced by the Builder during the design and construction of the vessels.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"49 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122724666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Periodical Ice Loads Acting on Screw Propeller During its Interaction with Ice","authors":"M. Karulina, E. Karulin, V. A. Belyashov, I. Belov","doi":"10.5957/icetech-2008-163","DOIUrl":"https://doi.org/10.5957/icetech-2008-163","url":null,"abstract":"Periodical ice loads on blades of the screw propeller of icebreakers and ice-going ships are one of the reasons for occurrence of fatigue damages of the propulsion system structures as well as for generation of the ship hull vibration. The paper describes an approach of the Krylov Shipbuilding Research Institute, St. Petersburg, to the problem of determination the oscillation of propeller thrust and torque during interaction with ice, and spectra of these loads. A comprehensive approach to this problem includes three lines of investigations, namely, an application of a theoretical model and two types of model tests that are to be performed in the Ice Basin: tests of ice milling by screw propeller model with use of a free-water unit and towing testing of a ship model with working propulsion devices. Each of the investigations lines has its limited capacity and, at the same time, supplements general picture of the complicated process under consideration. The estimated values of periodical ice loads on the propeller may be applied to fatigue strength analysis of structures of the propulsion system or to numerical estimation of vibration characteristics of ice going ship. An example of such calculation of vibration characteristics is shown in the paper. It has indicated that the general ship hull vibration in specified ice conditions can be 3-4 times greater, if ice induced periodical loads on the propellers are taken into account. Periodical ice loads on blades of the screw propeller of icebreakers and ice-going ships are one of the reasons for occurrence of fatigue damages of the propulsion system structures as well as for generation of the ship hull vibration. The paper describes an approach of the Krylov Shipbuilding Research Institute, St. Petersburg, to the problem of determination the oscillation of propeller thrust and torque during interaction with ice, and spectra of these loads. A comprehensive approach to this problem includes three lines of investigations, namely, an application of a theoretical model and two types of model tests that are to be performed in the Ice Basin: tests of ice milling by screw propeller model with use of a free-water unit and towing testing of a ship model with working propulsion devices. Each of the investigations lines has its limited capacity and, at the same time, supplements general picture of the complicated process under consideration. The estimated values of periodical ice loads on the propeller may be applied to fatigue strength analysis of structures of the propulsion system or to numerical estimation of vibration characteristics of icegoing ship. An example of such calculation of vibration characteristics is shown in the paper. It has indicated that the general ship hull vibration in specified ice conditions can be 3-4 times greater, if ice induced periodical loads on the propellers are taken into account.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127744134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Flexural Failure Models with Extreme Events","authors":"J. S. Tibbo, T. Brown","doi":"10.5957/icetech-2008-144","DOIUrl":"https://doi.org/10.5957/icetech-2008-144","url":null,"abstract":"This paper details an assessment of three flexural failure ice models for offshore conical structures. Models assessed include the modified Croasdale model, the Ralston model and the recently developed Mayne model. Each model was used to predict global ice loads for selected events observed at the Confederation Bridge. The theoretical loads from each model were compared to the actual measured load for each event. Measured loads were determined through processing data recorded by the bridge instrumentation. The investigation included 22 ice-structure interactions which were considered extreme.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122985137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Field Program for Simulation of Station-keeping Conditions for Arctic Drilling and Production Vessels","authors":"J. Valkonen, Gus Cammaert, M. Mejlænder-Larsen","doi":"10.5957/icetech-2008-169","DOIUrl":"https://doi.org/10.5957/icetech-2008-169","url":null,"abstract":"A field program was carried out on the Norwegian Coast Guard icebreaker KV Svalbard in February 2008, in the Barents Sea. The Ice Load Monitoring project currently undertaken by DNV and joint industry partners was extended to include progress through ice at very low velocities as a simulation of station keeping conditions for a new generation of Arctic drillrigs and production vessels. Existing scaling relationships were used to relate the resistance of the Svalbard to the expected resistance of a moored vessel of defined characteristics, and for different conditions. The paper summarizes the results of the field measurements, and provides an insight into how the scaling relationships were developed, and their limitations.","PeriodicalId":262766,"journal":{"name":"Day 2 Mon, July 21, 2008","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114576064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}