ABSTRACT: Vibration and acoustic radiation characteristics of a finite cylindrical shell with a floating raft are investigated in this paper. A FEM/BEM model is established for the complex dynamic system composed of machineries, floating raft, and the shell, with which three projects, i.e., one cabin, three cabins, and whole submarine, are considered for the prediction of the underwater sound level. Discussions are presented for the influences of three different projects on the shell’s surface vibration velocity and the far-field acoustic radiation, which indicate that below the resonance frequency for the first bending mode of the submarine cabin, it’s improper to simulate the dynamic characteristics of a whole submarine with one cabin model, and above this frequency, it’s acceptable for using a cabin model to predict the shell surface velocity of a whole submarine.