where, v is ship speed, v_max is maximum open water speed as defined in the figure., T_net is the net thrust(kN), T_pull is the bollard pull thrust(kN), Ke is the coefficient： 0.728 for single screw, 0.98 for twin screw, and 1.12 for triple screw. P_D is the propeller diameter(m), P_D is the ice resistance(kW), and Ri is the resistance of icebreaker in each ice condition.

　

Figure 2.6.1 Schematic of the solution for ship speed

　

Ship speed in open water

The ship speed in open water is equal to the navigation speed of input data; V_max.

　

Ship speed in channel ice

R_CH, the resistance of channel ice, is given by the equation(2.6.3).

The voyage speed is calculated by equation(2.6.1)in which R_CH is assumed to be equal to T_NET in the equation(2.6.1).

　

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