Development of estimation system of ice resistance with surface information of hull form

At the initial stage of an ice breaking ship design, a reliable empirical estimation of ice resistance is important to determine the power of the ship. In this study, a prediction method with three dimensional surface information of the ship is presented. The idea is from the existing empirical formula where two-dimensional approach is prevailed. This paper modifies the definition of the hull form with three-dimensional surface information to increase the accuracy. A clearing plane, vector d, the curl between vector p and vector n is adopted. Vector p is the curl between normal vector n at the design load water line and vector i of the ship in the forward direction. A tangential angle is extracted from the vector d and applied to the empirical method. Piece size of broken ice is assumed to be same as the hull form grid and taken in calculation of the clearing force of ice. In the estimation system, a graphical user interface is adopted for easy handling of the relevant data files. Comparison between model test and calculation is provided to validate the system and it is found that the difference is 15% maximum for a hull with a twin-podded system.