The article proposes a method of constructing the trajectory of a ship’s turn using a control device. Mathematical modelling of the turn trajectory is performed using MS Excel in conjunction with the MATLAB environment. To construct a trajectory, a conditional centre of turn will be used, it will be guided by a control device, such as a radio buoy, or a lighthouse with pre-known coordinates. The construction of this trajectory has two features: a step course change when rotated equal to a sector step, and the accuracy of the trajectory is achieved by using the Kalman filter, simplified to the amplification factor. The bow thruster moment is calculating using the bow thruster shoulder. The angular velocity of turning depends on the linear speed, therefore, the angular velocity can be adjusted not only by changing the bow thruster mode of operation, but also by changing the linear speed of the vessel. The article provides the program code for constructing a trajectory in the MATLAB environment, which takes its initial data from MS Excel. Therefore, the work forms the basic view of autonomous bow thruster control.