2025 Volume 10 Issue 2 Pages 83-91
The Kanmon Passage poses navigational challenges for ships because of its severe conditions, such as long and bending channels, narrow channel widths, and strong currents. Despite the implementation of various measures, ship collisions continue to occur in these waters. To understand the current traffic conditions, this study investigated ship collision accidents and estimated the number of ship encounters, En, for three types of encounters, head-on, overtaking, and crossing encounters, in each segment of the passage divided into small areas. The results indicate that a high percentage of overtaking collisions occur in the Hayatomo Seto Fairway of the Kanmon Passage and that overtaking encounters are particularly frequent around the fairway. Based on these results, this study further analyzed ship congestion in the Hayatomo Seto Fairway to confirm the mechanisms underlying collisions and encounters. The traffic speed index (TSI) was employed to analyze the degree of ship congestion. In addition, correlations between the indices were calculated to examine each relationship. The results demonstrate that each index has distinct characteristics and can be used to assess potential collision risk and congestion situations.
