Abstract: The authors have developed the passage planning system for small inland vessels. In this paper, algorithms, models and simulator studies on the passage planning system are discussed. The proposed passage planning system consists of following three sub systems; 1) Route planning system, 2) Maneuver planning system and 3) Real-time maneuvering information support system. Simulations of the passage planning system show that the system can generate the good passage plan automatically. Simulator studies by navigators using the real-time maneuvering information support system based on the passage planning system also shows the good tracking performance.

　

 When a large vessel enters and leaves a port, a pilotage by a pilot is provided to the vessel with a legal basis. This pilotage keeps the safety operation of the vessel and contributes the safety and effective port operation. But in Japan, almost 10 or more times as many as the number of legal piloted vessels have accessed ports. Almost all of them are small inland vessels which have no legal basis on not only pilotage but also VTS: Vessel Traffic Service and AIS: Automatic Identification System. Many marine accidents on the small inland vessels had been occurred in and around Japanese ports. From a viewpoint of safety port operation and efficient traffic management, maneuvering assistance for whole vessels, including small inland vessels, should be provided.

　

 If real-time information of an appropriate planned passage, like a pilotage, for each small inland vessel is provided to the vessel, her operator can maneuver the vessel more safely and without any delay. In order to realize this real-time maneuvering information support system based on the appropriate planned passage for a small inland vessel, the authors has tried to develop the passage planning system [3,4,5,6]. In this paper, system configuration of the passage planning system, algorithms and models, which were developed and used in the system, are introduced. Simulations and simulator studies, which were executed in order to verify the passage planning system, were also reported.

　

 The paradigm of passage planning by expert and skillful mariners are investigated by questionnaire surveys, passage planning experiments and simulator studies. Expert captains have many experiences to maneuver vessels. Pilots have not only many experiences to maneuver vessels but also much priori knowledge on the target port and area. A passage planning for a vessel in a water area should be produced based on these priori experiences and knowledge. A passage plan has to include a route plan and a maneuvering plan. The standard passage planning consists of two sub-plannings. One is route planning and the other is maneuver planning.

　

　

 A rational method to plan routes was found by investigating standard methods and guidelines on route planning. This rational route planning methods consists of following 4 steps.

　

 The No-Go Areas should be defined based on a database of topographical constraints on the target water area. Figure 2 shows an example of the defined No-Go Areas.

　

 Using the Visibility Graph method [7], a shortest path from the init to the goal through the free area except the No-Go Area should be found. Figure 3 shows an example of the found shortest path.

　

 In order to maximize the clearance between the ship and the No-Go areas, elemental Safe Waters along the shortest path should be found. Figure 4 shows an example of the chained elemental Safe Waters.

　

 In order to keep the continuity of the passages, elemental Safe Waters should be transformed into elemental passages. The route, which keeps the enough clearance to the No-Go Area like as the Voronoi diagram method [7], should be planned. Figure 5 shows an example of the chained elemental passages and the planned route.