Summary of Working Paper No. 155-1999

Simulation Study Work Package 6 “Simulation of Ship Transit through Ice”

By Matthey Patey and Kaj Riska, Helsinki University of Technology, Ship Laboratory, Espoo, Finland.

Helsinki University of Technology’s Ship Laboratory has developed a computer program for transit simulation along the Northern Sea Route as well as any other ice covered navigation route. The program is capable of predicting the average speed and propulsion energy consumed for any ship and a variety of ice conditions on the basis of certain ship parameters (e.g. length between perpendiculars, beam, propeller diameter, etc.) and quantities describing the ice cover (e.g. level ice thickness, ridge density, etc.). The basis for the calculations is the determination of the vessel speed by equating net thrust available to total ice resistance. The program can simulate navigation of a ship in a navigation channel, in level ice, in ridged ice and in a floe ice field. For the ridged ice and floe ice fields probability distributions are used to model the spacing and size of floes and ridges. This results in statistically distributed vessel speeds for the same set of parameters used to describe these two fields. Verification of the routine was performed using the limited data available about ship performance in level ice, floe ice and one ridged ice case.

The program was used to investigate the effect of variations in ice conditions on the average speed of the vessel. Level ice thickness, mean channel ice depth, ridge sail height and density and floe size and coverage were the studied parameters describing the ice conditions. For this sensitivity analysis a SA-15 series ship was used.