The ship control system for the U.S. Navy's newest attack submarine, Seawolf; incorporates hardware modular redundancy both in its core processing and its input/output system. This paper provides a practical experience report on the redundancy management software services developed for this system. Introductory material is presented to provide contextual information regarding the overall ship control system. An overview of the system's processing platform is presented in sufficient detail to define the problems associated with redundancy management and to describe hardware functionality which supports the software services. Policies and procedures for detection and isolation of faults are discussed as are reconfiguration responses to faults.