Int. J. Powertrains, Vol. 9, No. 4, 2020 289 Copyright © 2020 Inderscience Enterprises Ltd. Marine powertrain simulation for design and operational performance evaluation Aboozar Gholami Department of Mechanical Engineering, Islamic Azad University, Ayatollah Amoli Branch, Amol, Iran Email: ahlam.gholami@yahoo.com Seyed Ali Jazayeri* Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran, Iran Email: sajazayeri@hotmail.com *Corresponding author Qadir Esmaili Faculty of Engineering, Amol University of Special Modern Technologies, Amol, Iran Email: q.esmaili@ausmt.ac.ir Abstract: This research investigates the performance of a propulsion system and the emissions parameters of a merchant ship by using the consequences derived via a modular ship simulation model that is executed in MATLAB/ Simulink. In the model, numerous components of the drive system such as engine, shafting framework, propeller, and vessel are shown by separated blocks whereas proper interfaces and connections are utilised to swap the desired factors between the blocks. Therefore, the created model can be used to explore the steady state and transient behaviour of the ship propulsion system and investigate the engine/propeller/shafting framework and vessel connections. Using this model the performance parameters of a ship in normal speed and slow steaming were calculated and investigated. In addition, the ship’s powertrain system was investigated using distributed-lumped parameter model. The shear stress analysis of the propeller shaft was performed using a distributed-lumped model and compared in two normal speed and slow steaming modes. Due to the model’s modular structure, its components can be modified and extended to be used in future new technologies and fuel evaluation as a part of the ship designing process. Keywords: ship propulsion system; performance and emissions; distributed-lumped parameter model; shear stress; Simulink; simulation.