Propulsion System Integration (PSI) refers to a set of methods and procedures that are deployed to effectively integrate the functioning of the Propulsion Machinery into the Hull structure with out any untoward vibrations, noises (SBN, ABN and URN) and to make the controllability and operation of the vessel and the overall functioning of the vessel smoother. PSI activities start early in the design life cycle of a vessel and continue till the vessel becomes operational. The activities include preparation of Concept design, model testing, engine and gearbox SOTRs, selection of prime movers and gearbox and other auxiliary machineries, Propeller and rudder design, vibroacoustic studies, structural design of the ship etc.