Vibrational modes of a submarine hull are excited by fluctuating forces from the propeller acting in both axial and radial direction. Structural vibrations result in significant and unwanted radiated noise that can lead to discomfort for passengers and marine wildlife and detection in case of defence vessels. Aim of this book is to present some analytical tools that are used to model the structural and acoustic response of a submarine. The submarine hull is modelled as a cylindrical shell with internal bulkheads and closed by truncated conical shells, the entire structure is submerged in a heavy fluid medium. The analytical models developed in this book can also be used to examine the vibrations of other engineering structures made of coupled cylindrical-conical shells such as aircraft, missiles and autonomous underwater vehicles, where fluid-structure interaction is important. This book is addressed to naval and mechanical engineers with particular interest in submerged vessel or vibrations of coupled shells with or without the interaction with an acoustic medium.