Transformation of Vessel Performance System into Fault-tolerant Syste - Example of Fault Detection on Speed Log

In this paper fault diagnosis as the first step of system transformation into a fault-tolerant system has been presented. Fault diagnosis means that the existence of faults has to be detected and the faults have to be isolated. As an example, fault detection on the speed log (measurement of speed through the water) and GPS corrected speed (calculated speed through the water by combining the vectors of speed over ground and sea current) has been presented. Furthermore, the influence of hull fouling on the results has been discussed. In order to achieve the final goal, i.e. transformation of the system into a fault-tolerant system, the system must be redesigned. System re-design implies that the system has to be adapted to the faulty situation so that the overall system continues to satisfy its goal. The results of the fault detection from one VLCCs (Very Large Crude Carrier) and one SUEZMAX tanker, with clean and with fouled hull will be shown.