Model tests of a submerged turret loading concept in level ice, broken ice and pressure ridges

Autor: Ø. Kanestrøm, Sveinung Løset, T. Pytte
Rok vydání: 1998
Předmět:
Zdroj: Cold Regions Science and Technology. 27:57-73
ISSN: 0165-232X
DOI: 10.1016/s0165-232x(97)00024-4
Popis: A recently developed Submerged Turret Loading concept (STL) for loading oil offshore is in use on several oil fields in the North Sea. A number of model-scale tests with the STL have been performed in the Hamburgische Schiffbau-Versuchsanstalt GmbH (HSVA) ice tank in Hamburg. The modelled ship had a conventional icebreaking bow and a length between perpendiculars of 235 m. The testing was performed at a scale of 1 : 36. The purpose of the tests was to study the feasibility of the STL concept in level ice, broken ice, and pressure ridges. The present paper describes the testing and results from the different tests. In level ice, 1.5 m full-scale ice thickness, 720 kPa flexural ice strength and 0.75 m/s speed, the average total force was 5868 kN with an average line tension in the front line of 2600 kN. The corresponding maximum loads were 8929 kN and 3507 kN. The mean value of the force peaks was 7285 kN and the standard deviation 932 kN. The measured forces (scaled) in level ice were therefore within the capacity of the present STL mooring system. Depending on the ridge consolidation, pressure ridges of the order produced for the present tests, may cause forces that exceed the capacity of the STL system. In broken ice, the average total forces did not exceed 2500 kN and the single mooring line loads were not above 1200 kN.
Databáze: OpenAIRE
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