Fig.4.1, Fig.4.2 and Fig.4.3 show the results for deviated maximum lateral distance from the original course for the different ship types with function of SP12 for the case of overtaken and overtaking vessel, respectively. The lateral separation between two ships was chosen to be 0.3 to 0.7 times of L1, respectively, under the condition of b δmax = 10°. The control gain constants used in these numerical simulations are K1 = K2 = 5.0, K3 = 0.0 in h/d1 = 1.2. Ship types selected for comparison were PCC, VLCC, general cargo ship and container. The effect of wind was not taken into account. From these figures, the lateral distance between ships is necessarily required for the ship-velocity ratio of 1 .2, compared to the cases of 0.6 and 1.5 regardless of the ship types.