Resumen
An extensive series of towing tests using flat plates covered with artificial barnacles were carried out at the Kelvin Hydrodynamics Laboratory (KHL) at the University of Strathclyde. The tests were designed to examine the effect of the coverage percentage of barnacles on the resistance and effective power of ships, over a range of Reynolds numbers. This paper presents the added resistances due to calcareous fouling in terms of the added frictional resistance coefficient for a surface coverage of fouling of up to 20%, over different speeds (Reynolds numbers). The drag coefficients and roughness function values of each surface were evaluated. Roughness effects of the given fouling conditions on the frictional resistances of an LNG tanker were then predicted for different ship speeds using an in-house code which was developed based on the similarity law analysis of Granville (1958). Added resistance diagrams were then plotted using these predictions. Finally, powering penalties of the LNG tanker were predicted using the generated diagrams.