Fig.7 TTC (ship & land) results without collision avoidance maneuvers
As shown in Fig. 9, skill improvement is determined from the risk reduction ratio for the TTC produced by each student for each scenario, which is calculated by taking time integration by second for TTC in Fig. 7 as a standard value.
TTC was not detected for one student in any of the experiments but the other 3 students produced TTC at the 1 st or 2nd time. However, every student henceforth has eliminated the risk of collision and stranding from the process of collision avoidance manoeuvres.
Therefore, a numerical index using TTC is considered to be an effective evaluation index or yardstick to objectively determine the quantitative risks of collision and grounding, and the process of overcoming risks when the experiment is executed using a ship handling simulator.
Fig.8 TTC (ship & land) results of three students on scenario 3
Student A's 1st time on scenario 3
Student B's 1st time on scenario 3
Student C's 2st time on scenario 3
Fig.9 Risk Reduction ratio
In this paper, we focus on such implementation phases of collision avoidance as timing, method and result of collision avoidance manoeuvres. A new approach is attempted to evaluate skill improvement from the standpoint of objective evaluations of risk exclusion behind the process of collision avoidance manoeuvres, adding to evaluations of ship handling difficulty.
The judgment of skill in a collision avoidance maneuver is from (1) timely action, (2) suitable operation, and (3) satisfactory result. The following evaluation measures are introduced: the initial TCPA for timely action, heading angles altered for appropriate operation, and Environmental Stress Value (ES value) and Time to Collision (TTC) for a satisfactory result.
Taking collision avoidance manoeuvres in a narrow channel as examples, 60 experiments with 4 students using a ship handling simulator were carried out systematically, and the effectiveness of the indices was discussed.
As a result, it was again confirmed that both judgment by TCPA used so far, and judgment by ES value proposed before were effective. In particular, newly introduced TTC as a judgment index was found to be effective for evaluating skill improvement of collision avoidance manoeuvres in terms of safety.
 Kinzo INOUE: Evaluation Method of Ship Handling Difficulties for Navigation in Restricted and Congested Waterways, The Journal of Royal Institute of Navigation, Vol.53, No.1, ppl67-180, January 2000.
 Kinzo INOUE: Rating the Quality of Ports and Harbours from the Viewpoint of Ship Handling Difficulty, Proceedings of 12th International Harbour Congress, pp.203-214, September 1999.
 Kinzo INOUE and Asako OHNO : Quantitatively Evaluating Method of the Achievement Process of Simulator Training, The Journal of Japan Institute of Navigation, Vol.99, pp. 171-180, September 1998.
 Kinzo INOUE: Concept of Potential Area of Water as an Index of Risk Assessment of Ship Handling, The Journal of Royal Institute of Navigation. Vol.43, No 1, pp1-7, January 1990.
 Kinzo INOUE, Wataru SERA and Kenji MASUDA : Evaluation of Ship Handling Safety Based on the Concept of PAW, The Journal of Japan Institute of Navigation, Vol.99, pp.163-171, September 1998.
Name: Kinzo INOUE
Chronology of Education:
1964-1968: Kobe University of Mercantile Marine, (Bachelor of Maritime Science)
1976-1978: Graduate School of Kobe University of Mercantile Marine, (Master of Maritime Science)
1985: Doctor of Engineering, University of Kyoto
Chronology of Experience:
1968-1975: Deck officer of seagoing vessels, NYK Line
1975-1981: Associate Professor in Toyama National College of Maritime Technology
1981-1990: Associate Professor in Kobe University of Mercantile Marine
1990-present: Professor in Kobe University of Mercantile Marine
2000-2002: Vice president in Kobe University of Mercantile Marine
Major Research Field:
Marine Traffic Engineering
Theory of Ship Handling
Maritime Safety Management