Parameterization of the Propeller Thrust for Modelling Ship Braking within Ice Channel behind Icebreaker

Abstract

Cargo ship sailing within the ice channel that assisting icebreaker tracks in the compact ice cover is the usual practice of the navigation for the difficult ice conditions in the freezing seas and in the Arctic water areas. When the icebreaker or an ahead vessel stops before the insuperable ice obstacle or because the engine trouble, the danger of an emergency appears, namely, the collision with the icebreaker or the ahead ship, if the interval between them is not sufficient for the effective braking and stop. The paper presents the equation that describes the ship braking process within an ice channel and includes the thrust of the propeller that works under the reverse regime. The specific of this regime is following: the ship continues the motion “forward» and the propeller rotates “backward”. Analytical method for description of the ship propeller work on the reverse regime is absent because the detached flow on its blades. The paper describes the developed empirical method of this regime parameterization on the base of the serial models of propellers testing. The outcomes of this investigation will be applied for the ship braking process simulation and the safe interval between the ship and the icebreaker evaluation in what follows.