Ice blockage tests with a podded propulsor - Effect of recess

Propeller ice interaction is a complex phenomenon, which relies on innovative and complex experimental research in dedicated ice tank facilities. Whilst ice tanks model the contact forces with good agreement, the possible effect of the cavitation on the hydrodynamic propulsor loading is often assumed due to the inability to scale atmospheric pressure during these experiments. This paper reports on tests performed in the Emerson Cavitation Tunnel (ECT) examining effect of performance of an ice class propulsor operating in an ice cavity (or recess), a typical phase of bollard pull manoeuvres of podded icebreakers. The findings reported herein are part of a PhD study into the phenomenon and represent the early analysis of the findings. Further analysis is ongoing to better understand the phenomena.