Investigation of model-scale brash ice properties
Riikka Matala
Abstract
A brash ice channel is a typical operation condition for ice-going commercial vessels. The Finnish-Swedish Ice Class Rules (FSICR) define the vessels ice class performance requirements particularly in a brash ice channel. The vessel performance can be verified using model tests, which are conducted according to the FSICR guidelines. However, the guidelines define mainly the channel thickness and width. This research examined, which other brash ice parameters influence the brash ice behavior around a ship hull. The study focuses on the brash ice as a material. Based on literature review of earlier research, the author focused on five central parameters: porosity, piece size and distribution, angle of repose, compressibility, and angle of internal friction. These parameters were examined in three different model brash ice types. The results show that different brash ice types have different properties covering all the five investigated parameters. This variation in brash ice properties presumably affect the behavior of brash ice mass around a moving ship hull and the vessel resistance in brash ice indicating a need for better model brash ice standardization to secure consistent channel model test results.