In this paper, we have analyzed the propulsion performance of KVLCC2 in presence of waves. Different factors affecting the propulsion performance have been studied. Analysis of the extent of change in wake quality and its effect on the cavitation of propeller has been presented. Effect of wake change alone was separately calculated to analyze its importance in the design process, as wake data in waves is usually not available. It was observed that wake change itself does not significantly affect the amount of cavitation hence; cavitation margin should be considered only to handle increased load and relative stern motion.