The Uncertainty and Uncoordination of Mariners' Behaviour in Collision Avoidance at Sea

Abstract

It is well known that many collisions occur because one ship turns right whilst the other turns left when in close proximity to one another. Little is known as to why this occurs and, although some simulation models have been established using entropy theory, the problem remains unsolved.In this paper, an assessment model for uncertainty is reviewed briefly. The concepts of uncertainty and uncoordination of mariners' behaviour in collision avoidance are discussed. A simulation model in conjunction with a DCPA (distance to the closest point of approach) decision-making model using fuzzy programming is introduced to discuss coordination.

Maritime Traffic Situations in Bornholmsgat

“…The average course alteration of avoiding manoeuvers has earlier been found to be 20° (Zhao et al, 1996) and 18° (Chauvin & Lardjane, 2008) in crossing situations, in this study the average course alteration was 8° in head-on situations, 16° in crossing situations and 7° in overtaking situations. In all studies the average course of alteration is well below the recommended alteration of at least 30° (Cockcroft & Lameijer, 2012).…”

“…An avoiding manoeuver should be made in ample time. Zhao et al (1996) measured an action point at an average time to CPA (TCPA) of 10 minutes, and Chauvin and Lardjane (2008) measured an average action point at 3.5 M. In this study the average distance between vessels when an avoiding manoeuver was commenced was 7.2 M in head-on situations, 5.7 M in crossing situations and 3.22 M in overtaking situations.…”

“…The passing distance between vessels is a key parameter for safe maritime traffic. In this study the average passing distance in head-on situations was 1.01 M, in crossing situations 1.03 M, and in overtaking situations 0.79 M, this could be compared to Zhao et al (1996) with an average passing distance of 1 M, Belcher (2007) measured 0.58 M in crossing situations and 0.44 M in overtaking situations in the Dover Strait. The reason Belcher (2007) measured a smaller value could be that he only looked at situations with a passing distance of less than 0.8 M.…”

“…The behaviour of maritime officers in traffic situations have been studied in different situations. Zhao, Price, Wilson, and Tan (1996) used cadets on board to gather information from 1053 different traffic situations. Their result was an average of 0.2 nautical miles (M) in original distance to the closest point of approach (CPA), an average actual passing distance of 1 M, an average course alteration of avoiding manoeuver of 20° at an average time to CPA (TCPA) of 10 minutes.…”

“…This means that the officer of the stand-on vessel need to trust the officer of the give-way vessel and wait for an avoiding manoeuver. The COLREGs do not provide detailed information on when and how an avoiding manoeuver should be performed, leading to uncertainties sometimes (Belcher, 2007;Zhao, Price, Wilson, & Tan, 1995). Habberley and Taylor (1989) found that officers initiated the avoiding manoeuver by measuring the distance to the target ship or the time to collision (TCPA).…”