Ship operation in brash ice: results of investigations

The paper gives a review of the studies concerned with operation of vessels in brash ice. Recently, the ice conditions have received an ever increasing attention of the researchers related to the fact that shipping in the Arctic regions and freezing seas, as well as in inland waterways has been scaled up. One of the important fields of brash ice studies is specifics of sailing under these conditions and primarily determination of the ship ice resistance. The paper shows that theoretical methods combined with physical modeling in ice basins are used for determination of the ship ice resistance under brash ice conditions. The paper traces the evolution of theoretical models utilized for calculations. It is mentioned that the models are mainly based on loose material mechanics. A rapidly developing computer modeling of ship motion in brash ice based on discrete element method is considered. Physical modeling techniques used for modeling brash ice in ice basin are described, and challenges of experimental investigations are discussed. It is pointed out that experimental studies in ice basin can provide valuable data not only about ship ice resistance but also about the mechanisms giving rise to ice channels filled with brash ice. The paper describes the methods for studying operation of ship propellers in brash ice conditions. It is concluded that further research into brash ice is needed.