Equivalent ice thickness in ship ice transit simulations: overview of existing definitions and proposition of an improved one

Journal
Ship technology research  
Volume
67
Issue
2
Start Page
84
End Page
100
Citation
Ship Technology Research 2 (67): 84-100 (2020)
Publisher DOI
10.1080/09377255.2019.1655260
Scopus ID
2-s2.0-85071051986
Publisher
Taylor and Francis
Several definitions of equivalent ice thickness for simplification of complex ice cover are found in the literature. However, their systematic analysis is currently absent. Therefore, this paper reviews different definitions and validates them against a high-fidelity ice transit simulator, determining the most accurate one, with an average error of 16% for one analysed ship, and 10.5% for the other. Furthermore, capability of equivalent ice thickness to predict ship besetting in ice is tested, accurately predicting this event in 88% of the cases. Moreover, sensitivity analysis to the parameters not included in the traditional definitions is conducted, and it is found that only the thickness of ridge consolidated layer has significant impact. Finally, traditional concept based on equivalent ice volume is extended, and a concept of equivalent-performance ice thickness is developed, outperforming the traditional approach by reducing the average error to 4.6% for one ship, and to 3.2% for the other.
Subjects
Equivalent ice thickness
ship ice transit simulations
ship resistance in ice
DDC Class
600: Technik
More Funding Information
The financial support by the Barents 2020 project (NOR-13/0080) funded by the Norwegian Ministry of Foreign Affairs, as well as the support from the project partners, namely: ABB, CHNL, DNV GL, Hi? (now part of NTNU), Marintek (now part of SINTEF Oceans), Northenergy and NTNU, are greatly appreciated.