MODEL TESTS OF A SUBMERGED TURRET LOADING CONCEPT IN LEVEL ICE, BROKEN ICE AND PRESSURE RIDGES

Citation
S. Loset et al., MODEL TESTS OF A SUBMERGED TURRET LOADING CONCEPT IN LEVEL ICE, BROKEN ICE AND PRESSURE RIDGES, Cold regions science and technology, 27(1), 1998, pp. 57-73
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geosciences, Interdisciplinary",Engineering,"Environmental Sciences
Journal title
ISSN journal
0165-232X
Volume
27
Issue
1
Year of publication
1998
Pages
57 - 73
Database
ISI
SICI code
0165-232X(1998)27:1<57:MTOAST>2.0.ZU;2-Z
Abstract
A recently developed Submerged Turret Loading concept (STL) for loadin g oil offshore is in use on several ail fields in the North Sea. A num ber of model-scale tests with the STL have been performed in the Hambu rgische Schiffbau-Versuch-sanstalt GmbH (HSVA) ice tank in Hamburg. Th e modelled ship had a conventional icebreaking bow and a length betwee n perpendiculars of 235 m. The testing was performed at a scale of 1:3 6. The purpose of the tests was to study the feasibility of the STL co ncept 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 l ine tension in the front line of 2600 kN. The corresponding maximum lo ads were 8929 kN and 3507 kN. The mean value of the force peaks was 72 85 kN and the standard deviation 932 kN. The measured forces (scaled) in level ice were therefore within the capacity of the present STL moo ring 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 forc es did not exceed 2500 kN and the single mooring line loads were not a bove 1200 kN. (C) 1998 Elsevier Science B.V.