DYNAMICS OF CONTINUOUS-MODE ICEBREAKING BY A POLAR-CLASS ICEBREAKER HULL

Results of an experimentally-based study aimed at determining the relationships between resistance, icebreaking pattern and hull motions for a POLAR-Class hull during continuous-mode icebreaking of monolithic ice sheets are presented. The study involved two sets of experiments conducted with a 1:48-scale model hull towed at a range of steady speeds through sheets of urea ice grown on an ice tank. For one set, the hull was free to pitch, heave and undergo limited roll. For the other set, a fixed hull was used. It was found that the free hull experienced larger values of mean resistance than did the fixed hull. The difference is attributed to the influences of hull motions. A relationship is shown between dominant cycles of resistance experienced by the hull, its pitch and heave motions, and the icebreaking pattern that it created.