Abstract: The provision of precise radio navigation systems in United States harbors and waterways will ultimately permit safe, all weather pilotage of vessels in restricted waters, using handheld or bridge mounted electronic navigation displays. The safety of such operations is integrally dependent upon radio signal/noise characteristics, system filtering and aiding methods, and the human engineered design of information displays. Quantification of these relationships is required to provide the system engineer with standards for overall design. This paper describes the first of three experiments to parametrically address the above issues. The experiment was conducted on a real-time simulator that replicates the hydrodynamic response characteristics of a 30,000 dwt tanker in a narrow channel. Various radio aids to navigation display concepts, which are representative of high, medium, and low implementation costs in today's technology, were evaluated. The presentation of information on each display was varied to determine which format contributed most significantly to improved pilotage performance, when performance is defined to be vessel-track variability over a number of sequential experiments. The experiment concluded with recommendations for elimination of some formats, modification of others, and inclusion of two additional ones in a subsequent more stringent simulator evaluation. Measures of performance and detailed design recommendations are discussed.