Abstract: A preventive maintenance strategy for key components of ships is advanced based on the delay time theory. This strategy aims at the problem of high maintenance cost and low utilization rate caused by unreasonable maintenance of key parts. It bases on periodic inspection of each component, and divides the maintenance of each component into inspection maintenance and delay maintenance according to the different characteristics of defect and failure stage. And the idea of opportunity maintenance is introduced in the delay phase, to establish an opportunistic maintenance model for the ship’s key components. According to this strategy, the opportunistic maintenance strategy of the key parts under long-term use can be obtained in four steps: Base on component failure data and inspection maintenance records. Estimate model parameters by maximum likelihood estimation. Take detection cycle and delay time as optimization variables. Take the minimum cost ratio as the optimization objective. The result of this research indicates that this strategy can more effectively reduce the cost of ship maintenance, reduce downtime for maintenance, improve the efficiency of the use of the ship, and provide a decision basis and reference for ship maintenance, than the simple test maintenance strategy and traditional preventive maintenance method.

Key words: delay time, preventive maintenance, opportunistic maintenance, inspection maintenance, maximum likelihood estimation