The maritime sector plays a crucial role in the global economy. With over 80 percent of the world’s trade by volume transported by sea, the maritime industry plays a critical role in the all more globalised world. However, the complexity of the maritime environment presents numerous challenges, including safety, energy efficiency, navigation, and operational efficiency. In this context, co-simulation is a promising tool for enabling predictive and proactive decision-making during large construction projects when building ships and during operation. Co-simulation provides a more modular way of executing simulations than traditional all-in one simulations. This is crucial for the maritime industry, as the expertise behind a complete ship is so diverse that no single entity has a deep understanding of it all. With co-simulation, we can split the simulation into smaller pieces which are then finally connected together into one complete simulation. Therefore, the construction of the simulation can be easily distributed over several groups with the appropriate expertise. The potential benefits of co-simulation are many. By offering the ability to simulate real-world maritime scenarios with a high degree of fidelity, co-simulation allows for risk mitigation, optimisation of operational procedures, increased safety, improved energy efficiency, and better planning and decision-making. In this thesis, a co-simulation of a battery sub-system onboard a ferry has been implemented based on actual operational collected data. Further, a module to represent electrical car chargers has been implemented to gain an understanding of how the extra energy requirements such a system would impose on the ferry would affect the battery sub-system. This thesis demonstrates a use case for co-simulation within the maritime industry to gain insight into how an unknown component might integrate with an already existing ferry during the planning phase. The results display the potential co-simulation can play when experimenting with new technologies in the maritime industry, accelerating the positive impact technological innovation will have on the industry.