AURORA BOREALIS, POLAR RESEARCH DRILLING VESSEL: PROPULSION STATION KEEPING IN SOLID DRIFT ICE

摘要

This paper discusses the propulsion and stationkeeping aspects in the design and development of the AURORA BOREALIS (AB), a dynamically-positioned Polar Research and (Scientific) Drill Vessel for the European Polar Research Icebreaker Consortium (ERICON). The design of the vessel was contracted with Waertsilae Ship Design Germany (WSDG) under the project management of Alfred Wegener Institute for Polar and Marine Research (AWI). The AB is a heavy icebreaker of the highest ice class. She is powered to break continuously in more than 2.5 m of multi-year ice and is able to manage ridges up to 15 m. The ship is designed to perform research tasks including scientific drilling year-round in the Arctic and Antarctic without any support vessels. The key issue in the performance specification of the vessel is the mandatory requirement of performing stationkeeping operations in drifting solid ice of more than 2.0 m thickness during drilling and other research tasks. This paper presents and discusses some of the design challenges and problems, as well as the test results and design solutions. It includes selected results of the ice tests for stationkeeping in drifting solid ice of up to 2.0-meter thickness, i.e., icebreaking in a practically stationary mode, which were carried out in two ice tanks in Helsinki and Hamburg. For the various propulsion tasks - transit at 16 knots, icebreaking, and stationkeeping in ice - a propulsion system is installed totaling 108,000 kW. The selected propulsion arrangements is described and several alternate propulsion concepts are discussed. Conclusions: A great amount of propulsive power is required to implement the tasks of stationkeeping and icebreaking applying conventional ice breaking techniques, i.e., providing icebreaking forces through propulsors. As an alternative, the breaking of ice in stationary mode of the vessel by means of induced motions on the vessel was investigated. Based on the results of the AB design effort, we conclude that stationkeeping operation in solid drift ice is feasible. Currently, several leading oil companies are conducting research regarding exploration in Arctic waters. The presented results are of significant importance for all projects dealing with stationkeeping of offshore vessels in ice. The results are a valuable addition to the database of knowledge regarding Arctic vessels in general and, in particular, stationkeeping in ice.