VESSEL MAIN PROPULSION ENGINE PERFORMANCE EVALUATION

In general, the performance of a ship in service is different from that obtained on shipyard sea trial. Apart from any differences due to loading conditions, and for which due correction should be made, these differences arise principally from the weather, fouling and surface deterioration of the hull and propeller. The influence of the weather, both in terms of wind and sea conditions, is an extremely important factor in ship performance analysis. Consequently, the weather effects needs to be taken into account if a realistic evaluation is to be made. The primary role of the ship service analysis is a standard of performance data, under varying operational and environmental conditions. The resulting information, derived from this data, becomes the basis for operational and chartering decision. In addition, the part for the data records is to enable the analysis of trends of either the hull or machinery, from which the identification of potential failure scenarios and maintenance decisions can be derived. The traditional method of data collection is the deck and engine room log records, and this is the most commonly used method today. In terms of data processing and capabilities, this method of data collection is far from ultimate, since involves significant data distortion risk. Instrumentation errors are always a potential source of concern in performance analysis methods. Such errors are generally in the form of instrument drift or gross distortion of the reading. However, these can generally be detected by the use of trend analysis techniques. The procedure for the evaluation o