Application of a System Reliability Assessment for the Increasing of the Availability Performance

In the present study we assessed the reliability performance of a Coast Guard Patrol Vessel; in particular we have concentrated our efforts on the engine propulsion system. Our goal was to perform a deep failure analysis, aiming at giving information useful to implement a proper diagnostic system. The first step was to define the system structure, followed by the identification of all the possible mission profiles assumed by the equipments. For each operational profile we determined the relative RBD diagram and then defined the operation performance. We assessed the parameters of the above models, basing on the analysis of many data collected from the propulsion system’s manufacturer, from the scientific literature and from reliability databases. The evaluation was carried out by an FMEA/FMECA analysis of a single engine, that is an useful methodology to highlight the failure modes, and to take the following step of assessing the suitable diagnostic system and its best threshold limits. One of the most important matters of this work is the mission profile definition because each different operation of the ship is distinguished by different performance requirements. Thus the diagnostic system to be studied, should optimize the overall system availability.