Complex technical objects such as ship power plant are the source of many hazards to their operators. Identification and elimination of these hazards on the finished objects is very labor-intensive task and involves significant financial outlays. Therefore, it would be advisable to carry out these activities much earlier – at the design stage. However, this entails to some difficulties. Depending on the design phase the designer has a limited amount of information from which the operator’s safety can be assessed. Additionally, this information is associated with considerable uncertainty. These difficulties can be overcome by using subjective estimates of persons having practical knowledge in the field of our interest – the experts. Such knowledge can be formulated most easily in linguistic categories, that is fuzzy logic language. In the paper the basis of construction of ship power plant operator risk assessment system at the design stage are presented. This system was based on a fuzzy inference mechanism. For this purpose linguistic variables are defined. Based on these variables, fuzzy risk assessment would be carried out. Variables were related to each other within the fuzzy rule base. Fuzzy inference in the system is based on the Mamdani model. Use of this system will enable the identification of hazards for the operators of ship power plant and will indicate the necessary corrective actions
