The AN/SSN-6 Navigation Sensor System Interface (NAVSSI) Project is a new system being designed with two primary objectives; to serve as the central distribution computer for navigation data to shipboard combat/weapon systems and to serve as the electronic chart display and information system (ECDIS). The NAVSSI will operate the digital nautical chart (DNC) database being developed by the Defense Mapping Agency (DMA). Our goal is for the digital nautical chart to replace the paper chart as a legal means of ownship navigation plotting. This paper will introduce the project and will primarily explore the use of digital nautical charts for ownship navigation with NAVSSI.