A coupled kinematics model for icebreaker escort operations in ice-covered waters

In northern sea areas such as the Baltic Sea and the Arctic, especially in winter conditions, the presence of sea ice frequently necessitates icebreaker assistance operations for vessels navigating in these areas. Icebreaker escort operations are important for ensuring the safety of navigation in these harsh environments. While these operations reduce the overall system risk, studies have shown that specific navigational risks are associated also with escort operations, necessitating appropriate training and operational support for ship crew engaged in these. In this paper, the icebreaker escort operations are investigated, and a ship-following model is proposed, drawing on similarities with the car following phenomenon. This ship-following model accounts for the necessity of keeping an appropriate safety distance to avoid collision, as well as for the effects of sea ice on the operation. Its main intended use is for implementation in maritime simulators, providing a realistic environment of operational conditions for training ship crews. As a first approximation, the model accounts for the ice condition by the average ice thickness, while the safety speed constraint is relative to the vessel's ability of navigating in ice. The model parameters are calibrated using empirical data of icebreaker escort operations. Case studies are executed, showing good agreement between the simulation model and real-world operational conditions.