Maritime transportation is a major source of global greenhouse gas emissions, creating an urgent need for effective decarbonization solutions compatible with onboard operational and spatial constraints. Ship-based post-combustion carbon capture and storage (CCS) systems represent a promising pathway to significantly reduce CO2 emissions from marine diesel engines. The purpose of this study is to evaluate the thermodynamic performance and energy requirements of a monoethanolamine (MEA)-based post-combustion CCS system specifically designed for maritime applications. A comprehensive parametric thermodynamic model was developed to investigate the influence of key operating parameters, including absorber and stripper stage numbers, solvent-to-CO2 ratio, absorber inlet temperature, CO2 loading, and stripper temperature, on CO2 capture efficiency and system energy consumption. The model was applied under different engine load conditions representative of real ship operation, and waste heat recovery from exhaust gases was integrated to supply the stripper reboiler. The results indicate that CO2 capture efficiencies of up to 99% can be achieved at absorber temperatures of 40-42 degrees C with a CO2 loading of approximately 0.35 and a solvent-to-CO2 mass ratio above five. An optimal stripper temperature of about 109 degrees C was identified, balancing effective CO2 separation and energy demand. The findings were validated through consistent thermodynamic trends and energy balance analyses, providing practical guidance for the design and integration of shipboard CCS systems.