<p>As regulations on ship internal combustion engines are strengthened worldwide and the need for eco-friendly propulsion technology is required, research and development of electric propulsion systems is actively underway. The electric ship propulsion system, which replaces the ship’s internal combustion engine, is undergoing a lot of research by various researchers and has advantages such as low noise, rapid braking, and excellent turning performance. However, the design technology of the electric propulsion system is classified as security, and the disclosure of information is restricted, and the performance of the propulsion is unpredictable due to lack of maritime navigation data, and the verification of the design technology is restricted. Propulsion system design technology, which is the main technology of ships, must be reasonably designed by applying engineering theory, and it is necessary to verify the appropriateness of design technology in sea navigation experiments. In this paper, we apply the theory of ship resistance estimation in marine engineering to calculate the capacity of electric propulsion systems and propose a design methodology for electric propulsion systems that can achieve propulsion efficiency of about 65% or more. And a prototype was manufactured and installed on a ship, and the stability, speed, and propulsion performance of the propulsion system were confirmed through sea navigation experiments.</p>