The paper suggests a new method of collision avoidance stemming from the concept of the polygonal target ship domain. Since the last century, we have witnessed the current typical ship domains classified and described. In this proposition, firstly, the domain is a geometrical manner which is used in both analytical and statistical method, resulting in the signification of practical application and simulation. Secondly, such domain will be applied to target ship under the combination of two separated parts: “Blocking area” and “Action area” in order to define the area where the ship must keep outside and how the actions to avoid collision can be generated. Thirdly, the concept has suggested the number of mathematical models for different approaching encounters, including head-on, overtaking and crossing situation. Finally, the parameters of turning circle of the ship can be proposed in determining the size of the domain. Statistical evidences indicate that this method reflects a crew’s real habit and psychological in maneuvering. As the result, simple domain is shaped like imagination of sailors, but more accurate in calculating boundary. It promises an effective solution for automatic collision avoidance method. The next researches of this paper have achieved positive results in finding shortest route for avoiding collision. Moreover, while using statistical methods, classical researches face a serious problem in a wide application with different areas, this concept can make up a beneficial solution for the popular application. The numerous ship domains which are in previous researches will be carried out to compare and point out the simplification and effectiveness of the new method in practice.

The studies on automatic ship collision avoidance system, which have been carried out in the last 10 years, are facing on new situation due to newly developed high technology such as computer and other information system. It was almost impossible to make it used in real navigation field 3-4 years ago because of the absence of any tool to give other ship's information, however recently developed technology suggests new possibility. This study is carried out to develop the automatic ship collision avoidance support system which considers ship's manoeuvrability into it's collision avoidance algorithm. One of the important part in ship collision avoidance system is collision decision module which can calculate collision risk with other ships and act properly to avoid the situation. Many of previous researches are using present ship's dynamic data such as present speed, position and course to calculate collision risk. However when a ship commences avoidance action, the real situation is quite different with one that has been estimated by the ship's initial data due to the ship's manoeuvring characteristic. Therefore it is better to take into account ship's manoeuvring characteristic from the stage of collision decision in ship collision avoidance system. In this study, these effects are included in the developed system. The proposed system are verified its usefulness in numerical simulation environments.

In this paper, a 3m-class free running model ship will be introduced with its manoeuvring performance experiments. The results of turning circle test and zig-zag test will be explained. The developed system are equipped with GPS, main control computer, wireless LAN, IMU (Inertial Measurement Unit), self-propulsion propeller and driving rudder. Its motion can be controlled by RC (Radio Control) and wireless LAN from land based center. Automatic navigation is also available by pre-programmed algorithm. The trajectory of navigation can be acquired by GPS and it provides us with important data for ship's motion control experiments. The results of manoeuvring performance experiment have shown that the developed free running model ship can be used to verify the test of turning circle and zig-zag. For next step, other experimental researches such as ship collision avoidance system and automatic berthing can be considered in the future.

This paper deals with effect of wind forces and moment acting on the training ship SAE NURI. The results of drift angle and counter rudder angle due to wind effect are calculated by using the static equilibrium method especially with nonlinear mathematical expression, and then the critical wind velocity is found out. The given results can be applied directly to T/S SAE NURI in handling under the wind condition and used for merchant ships as a referential tool.