Longitudinal vibration of marine propulsion shafting system is a problem and the world have spent a lot of money to solve this problem. Oscillations occur at the propeller due to small variations in thrust when the propeller blades rotate through the non-uniform wake, resulting in longitudinal vibration in propulsion shafting system. Then, vibration will be transmitted to the hull through the thrust bearing. In this study propulsion shafting system modeled with decomposition of FRF’s method. Comparing between numerical solution of system in Simulink and decomposition of FRF’s method show that, the numerical solution has less 7 percent error. 
For reduce transmitted vibration to the hull we use Goodwin resonance changer (RC).An optimization method used to optimize RC’s stiffness, damping and mass coefficients. The result show that if we select appropriate coefficients the transmitted vibration can be reduced 99 percent.