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

Sammanfattning: The purpose of this thesis is to contribute to the understanding of social and technical aspects of the work of Vessel Traffic Service (VTS) operators. VTS operators monitor maritime traffic in order to promote safety in narrow waters and around major ports. The task of the VTS operator is to support and direct ships that sail through the monitored area, primarily making the navigating officer of each ship aware of the current traffic situation, local weather and geographical conditions. When performing this task, it is crucial that the VTS operator builds a mental model of the situation in the monitored area. To understand this process, we need to explore what type of information VTS operators use as well as when, why and how they use available information. We also need to understand what factors affect the work of VTS operators and the influences of these factors on the work process. Applied Cognitive Task Analysis (ACTA) was used to study how VTS operators work with anomaly detection and pattern recognition from a holistic perspective. In addition, a midfidelity simulation was used as a knowledge eliciting tool to explore the work situation of VTS operators. The combination of methods was assessed using Hoffman’s (1987) method evaluation criteria. The results indicate that VTS operators build their mental models by combining their experiences, previous nautical experience, local area knowledge and information from technical support systems. In particular, voice communication was identified as an important source of information for creating these mental models and factors behind non-technical miscommunication were investigated, since the latter may lead to negative effects on navigational safety. As for the miscommunication, the results indicate that regulation and technical systems are not sufficient to combat miscommunication within VTS systems. For doing this, it is also necessary to consider social aspects.