A comparison of two definitions of ship domain for analysing near ship–ship collisions

Paper in proceeding, 2020

This paper compares two definitions of ship domain (SD) for analysing near ship–ship collisions in order to assess the risk of such events. One of the SDs follows Fujii’s definition, which is based on a ship’s dimensions, whereas the other was calculated with data from the Automatic Information System (AIS) in selected traffic locations. Case study simulations of traffic situations at three ship crossing locations were conducted using a Vessel Conflict Ranking Operator model, the results of which were examined according to the two definitions and their suitability for analysing near ship–ship collisions. The SD defined according with AIS data identified more cases with low angles of intersection as near-misses than the SD based on Fujii, which identified more situations with larger angles and higher speeds. IWRAP calculations are presented for the three locations to illustrate the probability of ship–ship collisions.