Current submarines use aging Inertial Navigation Systems (INS) that have demanding maintenance needs. A tool that can mine information from Trouble Failure Reports (TFR) and Field Engineer Information Management System (FEIMS), and can use smart prognostics and machine learning algorithms to optimize maintenance, will be very useful. IAI and its collaborator, Boeing Corporation, Integrated Shipboard Systems (ISS) propose to develop the Adaptive Prognostics Tool (APT) to support field engineers (FE) in troubleshooting the critical submarine navigation system, the Electrostatically Supported Gyro Navigator (ESGN) Stable Platform and Housing (SP&H). IAI’s APT will adhere to Naval Open Architecture guidelines and improve maintenance efficiency, by presenting troubleshooting recommendations based on historical data of faults and available resources. APT is a self-learning, adaptive software tool primarily designed for FEs to quickly diagnose and provide repair recommendations. APT will keep track of all sensor inputs to develop a probability metric of future failure within a patrol period, so the FE can perform preventative maintenance, when in port. APT will consist of advanced Prognostics and Machine Learning Algorithms that will be part of Submarine Knowledge Base (SKB) and a more general fleet wide Global Knowledge Base (GKB). User-Centered Design (UCD) process will be used to develop a Human Machine Interface for APT. APT will increase mission readiness while at the same time reducing Total Ownership Costs (TOC). A relevant and useful tool will be developed using IAI's expertise in sensor technology, networks, diagnostics, Human Factors, software development and training, and Boeing Corporation, Integrated Shipboard Systems (ISS)'s hands-on expertise in servicing ESGN systems in the fleet.