ABSTRACT
The author presents here an analysis of collision accidents for clarifying the relation between ship collisions and stopping criterion. The source data of accidents are the reports of the Japan Transport Safety Board (JTSB 2017) from 2008 to 2016. Serious collision accidents of passenger ships, cargo ships, and tankers that do not include those with small boats are for the analysis. The ship speeds when recognizing the danger of collisions first and when colliding in the end, and the duration between them estimate the distances needed for the ships to stop before reaching collision points. The author normalizes the estimated distances of which initial speeds are various by converting them into those at 12 kn initial speed. He, then, assumes a stopping criterion as the distance for ships to stop at 12 kn initial speed by full astern. Considering different situations in overtaking, crossing, and facing, the analysis tells the relation between the stopping criterion and the reduction rate of ship collisions. The required engine power for improving the stopping ability to comply with the arbitrary criterion is also discussed. The study presented here from the viewpoint of stopping ability of ships excluding human factors provides an insight how the ship stopping ability with its criterion accorded contributes to prevent and decrease ship collisions.
