Science and Education Publishing American Journal of Mechanical Engineering 1 1 2013 04 11 Investigation of Different Methods of Noise Reduction for Submerged Marine Propellers and Their Classification 34 42 EN Mohammad A. Feizi Chekab Parviz Ghadimi Department of Marine Technology, Amirkabir University of Technology, Tehran, Iran Seyed Reza Djeddi Mehdi Soroushan AJME2013123 10.12691/ajme-1-2-3 2013 -1 20 2013 -1 09 2013 04 11 In this paper, the most prevalent methods of reducing noise from the marine propellers are surveyed and introduced. Subsequently, these methods are analyzed and classified as five different categories. This categorization is conducted from the stand points of technology and cost, the type of noise (cavitation, non-cavitation noise), the method of noise reduction (change in propeller geometry, modification of inlet flow, and confinement of the propeller), frequency of the targeted noise, and simplicity of implementation of the method of noise reduction in the existing vessels. The scientific classification performed in this article would bring about better recognition of and acquaintance with each of the mentioned methods of noise reduction, its limitations in cost and applications, which would in turn help the designers and the decision makers make the right decision under different operational circumstances.