In order to describe the safe ship trajectory, the movement of a ship returning by her rudder in deep water was described. Still, the safe ship trajectory may prove little inefficient to evaluate the ship properties. Therefore, in order to precisely calculate a ship dynamic properties we used parameters of the transfer function or the advance time tw [19].
The model of safe ship trajectory can be represented by the state equation [2]:
                                    f (X, U) ® XxU                                  (1)