Abstract

Stationkeeping in ice-covered waters has become a large area of interest forresearch and development in light of heightened interest in Arctic oil and gasexploration. The performance of Dynamic Positioning (DP) control systems forstationkeeping purposes in ice conditions is a difficult challenge fornumerical modeling assessment. Given that full-scale validation data for DP inice operations is often scarce, physical modeling of stationkeeping in iceoffers the best method for assessing the performance of dynamically positionedvessels in these conditions. A series of model tests carried out at theNational Research Council of Canada's Ice Tank facility in August and Septemberof 2011 attempted to observe the effects of various managed ice conditions(i.e. ice floes which have been broken into manageable pieces by an icebreaker) on DP performance. Results from these tests are discussed. Ofparticular interest in this study is the observation of non-linear effects ofvarying ice conditions on DP performance. The use of machine vision-based dataproducts as potential estimators of ice loading is discussed. It is concludedthat simple statistical observations of these conditions will be unable tofully characterize the effects of various ice parameters on performance, andthat investigation into more advanced data products available from machinevision systems may be able to aide in characterizing these effects as well asin the development of models capable of predicting ice loads.

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