Interaction of Ships Under Traffic Within Navigable Ice Channel

At intensive winter navigation, the ships should separate under movement on opposite courses or make overtaking of slowly moving cargo vessels in the water areas covered with ice. Side force and yawing moment that appear on ship hull under these maneuvers are different from items on the water area without ice cover. Therefore, it is necessary to allow them at navigation and for training on simulators. At carrying of these maneuvers in the free from ice water area, the distortion of the structure of flow in changeable space between hulls of vessels produces the side force and yawing moment. In ice conditions, the ice floes between hulls and outside are the major factors defining values and direction of side force and yawing moment. Ice loads on the ship hull exceed considerably the loads caused by water flow around hull. Experiments in the ice basin performed early have shown that besides increase of side force and yawing moment modules the variation of their action directions occurs during the separation of ships. Paper contains the analytical approach to the solution of stated problem, namely, parameterization of ice effect on vessel hull at interaction with opposite or overtaken ship. The base assumption for mathematical model development is the variation of ice floes concentration around hull because of space within ice channel decrease, when other vessel hull moves along modeled vessel. Results of computations, namely, character of variation of side force and yawing moment during passage along overtaken ship and dependence of the peak values of side force, ice resistance and yawing moment on beam distance between vessels and thickness of ice are presented in paper.