Interest in ship hybridization has increased as a result of policies to combat climate change and boost energy independence. However, designing and optimizing hybrid propulsion systems is a challenging task. The availability of numerous power, propulsion, and energy system topologies with different energy storage and conversion technologies presents a significant challenge. In this paper, the optimum sizing of various components and systems in a CTV is thoroughly investigated. The appropriate sizing of a maritime vessel depends on energy management and control, making optimization and retrofitting a complex problem. Thus, this paper develops a method to select a power, propulsion, and energy system architecture and optimize the power and energy ratings of the components. The operational profile and various system structures make up the system's input. The technique provides optimized system architecture and contains the data required for vessel retrofitting. Optimization criteria include cost, fuel volume, propulsion system rating, and other sustainability factors. The proposed approach incorporates the price of fuel and electricity as an uncertainty element. As a result, the developed strategy can assist ship owners in deciding whether and when to retrofit their vessels as well as the optimum design for doing so at the chosen moment. In addition, it takes into account the effects of the GHG emission reduction measures, which can lead to a more practical solution.