The Entity-Relationship approach is investigated to determine its suitability for the construction of a logical database design for a tactical data system (TDS) to be used by surface ships in the U.S. Navy. Some motivation for the use of database techniques in the design of a TDS is given, and a conceptual schema design based on the Entity-Relationship approach is presented. This design includes Entity-Relationship diagrams in some detail for major entity and relationship sets for a TDS. An attempt to model behavior using Petri nets is described and several developed Petri nets are shown. It is concluded that the Entity-Relationship approach is workable for the task of building a TDS logical database design and that the resulting design is expressive and flexible. It is also argued that the simplicity of the Entity-Relationship model makes design validation by real-world domain experts easier. (Author)