Abstract

By outlining a few COLREG rules and studying the links between these rules and rule 17, we have theoretically analysed the recommendation made by Captain Cockcroft & Lameijer in their book "A Guide to the Collision Avoidance Rules". This recommends that the stand on vessel wishing to manoeuvre should do so before the distance separating it from the other vessel falls below 12 lengths. After analysing the rules theoretically, we set up scenarios that we simulated on the Polaris simulator. The aim was to see whether this recommendation would still be applicable in 2023, given the size of today's ships. The notion of 12 ship lengths as the minimum distance for the stand on vessel to manoeuvre is analysed in various purely theoretical situations and then in a practical way on the simulator.
Thanks to this research, we understand the reason for this recommendation of 12 preferred ship lengths and can clearly make the link with ship testing manoeuvres and in particular the emergency stop manoeuvre.