Investigation of vessel resistance in model scale brash ice channels and comparison to full scale tests
Riikka Matala, Mikko Suominen
Abstract
The ice class-based rules and restrictions aim to ensure the safety and efficiency of the winter navigation system in the Baltic Sea. The vessel resistance prediction in a brash ice channel is a mid-term step in Finnish-Swedish Ice Class Rules ice class granting process that can be based on model scale tests. However, there are some limitations in the current model scale test guidelines. To improve the test procedures and to provide a better real-world correlation for all ship shapes, this paper explores the relationship between the brash ice properties and vessel resistance utilizing channel resistances measurements in model scale and full scale. The results indicate that the model scale results can be scattered and conservative, especially for modern, open-water-optimized bow shapes when model ice with a scaled-down strength is utilized. Model scale tests in brash ice channels with unscaled ice strength provided good correlation with full scale resistance tests and small variation in repeated tests. The results suggest that the correct modeling of ice fragment interaction would improve the prediction quality for all hull shapes.