Estimation of shallow-water effect on icebreaker propulsion performance in ice

Abstract

Object and purpose of research. The object of this study is to investigate the shallow-water effect on icebreaker propulsion performance in ice. Materials and methods. Model test data obtained in hydrodynamic and ice basins in deep- and shallow-water conditions for an icebreaker of advanced design are handled using a new method of propulsion performance prediction for a multi-shaft icebreaker. Main results. A method for prediction of propulsion performance of a multi-shaft icebreaker in ice was developed. Data were obtained regarding shallow-water effects on propulsion performance of icebreakers and ice-going vessels operating in ice-infested polar shallow waters. Conclusion. The new method for prediction of propulsion performance in ice is enabled by introduction of a so-called “bollard pull” system of hull/propeller interaction coefficients. This method makes it possible to estimate parameters characterizing icebreaker propulsion in absence of interaction between ice cover and propellers, as well as to estimate full-scale ship ice resistance. In case of heavy interaction between icebreaker’s propellers and ice the comparison of full-scale and model data provides valuable information for better understanding of how interaction parameters influence the icebreaker performance. Estimations of icebreaker propulsion in ice under deep- and shallow-water conditions enable prediction of main parameters of ship motion so that proper measures could be taken to avoid hazardous situations.

Keywords

• icebreaker
• shallow water
• interaction coefficients
• propulsion performance in ice