Optimizing reliability, maintainability and cost for shipboard systems

At present, shipboard system reliability is maintained by periodically refurbishing systems at considerable cost per ship. This paper recognizes the need for periodically refurbishing shipboard systems to sustain high reliability, and recommends a Weibull-based analytical procedure for adjusting refurbish interval, and thereby optimizing shipboard system reliability, maintainability and cost, Cosby & Johnson[1]. The analytical techniques offered in this paper exploits the multi-distribution capability of the Weibull distribution, Johnson[2] to analyze actual shipboard system performance data and from these data, determine the actual reliability of the shipboard system, the maintenance cost to sustain that reliability, and the cost associated with the maintenance efforts. To improve existing procedures for on-board equipment maintenance and logistics support, the Navy developed its Maintenance and Material Management System (3-M System) during the 1960s, DiStefano[3]. Although the 3-M System provides a maintenance history on all ship system equipment; e.g., main propulsion, electrical generation and distribution and auxiliary machinery, the potential of this database for maintenance cost savings and spare parts allocation have not been exploited to its full potential. The Weibull-based technique that is being proposed for analyzing the 3-M System database is capable of establishing cost effective refurbish intervals, providing the number of shipboard system failures to be expected over refurbish intervals as well as the associated maintenance cost to affect repairs of failed shipboard systems that occur within refurbish intervals.