This study was conducted to analyse the changes in trim and heeling using Zig-zag test, at T/S SAE DONG BACK was used to examine the manoeuvrability according to the trim and heeling changes of the vessels. Regarding the Zig-zag test to observe the trim changes at the port and with starboard rudder angles of 10° and 20° at 0.30m, and 0.52m, the overshoot angle of starboard was 18% bigger than that of the port at the rudder angle of 10°, and the course changing ability was better than the turning ability at the rudder angle of 10°. The size of the turning circle, final diameter was 4-5% and the required time was 2-7% larger than the port at the trim of 0.52m and 0.30m. External forces and superstructures that are larger than those of general ships showed characteristics that affect turning performance. When the Zig-zag test was used to compare the heeling changes, the overshoot angle of the starboard was 12°-14° larger than that of the port at 0° with no heeling compared to the 3° heeling. As a result, the Turning ability of the vessel was satisfactory. Furthermore, the second overshoot angle at 3° heeling was 6° larger; thus, the port veering showed a better rudder effect than the starboard veering. Hence, the turning ability decreased and the course-changing ability increased as the trim change in the vessel increased. Regarding the values of the turning ability index, K′, and the course changing ability, T′, according to the Trim increased when the rudder angle was used on The larger the trim, the lower the turning ability and the higher the course change ability, and when the burp is low, the turning ability is good, but the course change ability is somewhat decreased.