The effect of hull biofouling on parameters characterising ship propulsion system efficiency

One of most important issues concerning technical objects is the increase of their operating performance. For a ship this performance mainly depends on the efficiency of its main propulsion system and the resistance generated during its motion on water. The overall ship resistance, in turn, mainly depends on the hull friction resistance, closely related with the presence of different types of roughness on the hull surface, including underwater part biofouling. The article analyses the effect of hull biofouling on selected parameters characterising the efficiency of the ship propulsion system with adjustable propeller. For this purpose a two-year research experiment was performed on a sailing vessel during its motor navigation phases. Based on the obtained results, three groups of characteristics were worked out for different combinations of engine rotational speed and adjustable propeller pitch settings. The obtained results have revealed that the phenomenon of underwater hull biofouling affects remarkably the parameters characterizing propulsion system efficiency. In particular, the development of the biofouling layer leads to significant reduction of the speed of navigation.