This paper presents an efficient method to analyze noise and vibration of marine diesel engines mounted on flexible hull structure. The analysis model should in general include the hull structure, leading to lots of computational efforts. To minimize the computational efforts, in this paper, the transfer synthesis utilizing the receptance at the mounting points is proposed. The procedure is then verified by comparing the results with those from the full model calculation. The effects of flexible hull structure on the acoustic power from engine block are finally investigated. It is found that the effect of the hull is significant when the receptance of hull structure is similar to or greater than that of mount or engine block.