INFLUENCE OF MODELING FULL SCALE BASED MANAGED ICE CONDITIONS IN DP ICE MODEL TESTS

摘要

Recently there have been significant steps taken regarding the development of ice model testing capabilities for dynamic positioning (DP) operations in ice. Such developments have stemmed from the knowledge gained through involvement in real life DP operations in ice, namely the subsea construction operation with the CSO Constructor in the Sakhalin offshore in 1999, and the Arctic Coring Expedition with the icebreaker Vidar Viking near the North Pole in 2004. Lessons learned from these operations have lead to the conclusion that ice model testing for DP vessels in ice may require the need for a new approach to modeling ice conditions in order to achieve results that would start to approach real life experience. Two big steps have been taken that attempt to narrow the gap between model scale results and full scale expectations. First, a novel approach of starting to model ice such that the ice more closely resembles managed ice conditions that a DP vessel would be expected to operate in full scale was developed and applied in actual ice model tests. This will be the focus of this paper. Second, an actual DP system was installed on a model and tested in an ice model basin, to achieve a realistic level of behaviour of the model to match the real life operation as close as possible. Additional information on this topic can be found in Hals and Efraimsson (2011). These two developments constitute a major advancement in the development of dynamic positioning vessels and their DP systems in ice, and provide an approach to evaluate their operational capabilities.