Machinery maintenance programs based on vibration trend monitoring have been successfully used in several applications. In essence, these programs rely on the interpretation of changing machinery vibration patterns to diagnose developing defects and subsequently define a relative condition index. This information, along with other operating parameters and constraints, is then used to draw up meaningful maintenance schedules.This paper, after a brief review of the vibration monitoring programs in use by the Sea Element of the Canadian Armed Forces, discusses the operational problems that arise in the definition of a vibration health monitoring program for a 750 kW gas turbine generator. It describes in detail the rationale for selecting the location of points where measurements should be made and lists the mechanical components which influence the vibration pattern at each station.The effect of local resonances and limitations of instrumentation used are identified for a portable octave band measurement system utilizing a magnet attached accelerometer. Finally, the inaccessibility of monitoring stations within the acoustic enclosure to periodic measurements is examined and two possible solutions are proposed.