Four KPIs for the assessment of biofouling effect on ship performance

Abstract

Biofouling accumulation on hull and propeller is one of the principal contributors to a ship's service performance losses. Ship Performance Monitoring Systems (SPMSs) are widely regarded as the primary means of monitoring the service performance decay of ships. The effect of fouling can be assessed by observing the change over time of parameters commonly termed Key Performance Indicators (KPI). Common KPIs are power increase and speed loss. These KPIs are, however, not enough to provide a clear perspective of the hydrodynamic vessel performance.This paper introduces three new KPIs in support of the common power increase KPI. These three KPIs need the propeller characteristics (e.g. open water curves) to be known, and one of them is based on the measurement of thrust. The method used to calculate them is described. The derivation of the reference performance baselines is demonstrated in applying this methodology to Newcastle University's Research Vessel “The Princess Royal”. The concurrent analysis of all four KPIs is finally shown to provide more robust and detailed information regarding the source of the performance losses and their entity when compared to the real fouling state of this vessel.