Hello, is there anybody out there – just nod if you can hear me

The purpose of this thesis is to contribute to the understanding of social and technical aspectsof the work of Vessel Traffic Service (VTS) operators. VTS operators monitor maritimetraffic in order to promote safety in narrow waters and around major ports. The task of theVTS operator is to support and direct ships that sail through the monitored area, primarilymaking the navigating officer of each ship aware of the current traffic situation, local weatherand geographical conditions. When performing this task, it is crucial that the VTS operatorbuilds a mental model of the situation in the monitored area. To understand this process, weneed to explore what type of information VTS operators use as well as when, why and howthey use available information. We also need to understand what factors affect the work ofVTS operators and the influences of these factors on the work process.Applied Cognitive Task Analysis (ACTA) was used to study how VTS operators work withanomaly detection and pattern recognition from a holistic perspective. In addition, a midfidelitysimulation was used as a knowledge eliciting tool to explore the work situation ofVTS operators. The combination of methods was assessed using Hoffman’s (1987) methodevaluation criteria.The results indicate that VTS operators build their mental models by combining theirexperiences, previous nautical experience, local area knowledge and information fromtechnical support systems. In particular, voice communication was identified as an importantsource of information for creating these mental models and factors behind non-technicalmiscommunication were investigated, since the latter may lead to negative effects onnavigational safety. As for the miscommunication, the results indicate that regulation andtechnical systems are not sufficient to combat miscommunication within VTS systems. Fordoing this, it is also necessary to consider social aspects