This thesis develops a time-domain integrated modeling approach for design of hybrid-electric marine propulsion systems that enables co-simulation of powertrain dynamics along with ship hydrodynamics. This work illustrates the model-based design and analysis methodology by performing a case study for an EV conversion of a short-cross ferry using the BC Ferries’ M.V. Klitsa. A data acquisition study was performed to establish the typical mission cycle of the ship for its crossing route between Brentwood Bay and Mill Bay, across the Saanich Inlet near Victoria, BC Canada. The data provided by the data acquisition study serves as the primary means of validation for the model’s ability to accurately predict powertrain loads over the vessel’s standard crossing. This functionality enables model-based powertrain and propulsion system design optimization through simulation to intelligently deploy hybrid-electric propulsion architectures. The ship dynamics model is developed using a Newton-Euler approach which incorporates hydrodynamic coefficient data produced by potential flow solvers. The radiation forces resulting from vessel motion are fit to continuous time-domain transfer functions for computational efficiency. The ship resistance drag matrix is parameterized using results from uRANS CFD studies that span the operating range of the vessel. A model of the existing well-mounted azimuthing propeller is developed to predict thrust production and mechanical torque for pseudo-second quadrant operation to represent all operating conditions seen in real operation. The propeller model is parameterized from the results of a series of uRANS CFD on the propeller geometry. A full battery-electric powertrain model is produced to study the accuracy of the model in predicting the drivetrain loads, as well as assessing the technological feasibility of an EV conversion for this particular vessel. A dual-polarization equivalent circuit model is created for a large-scale LTO battery pack. An average value model with MTPA control and dynamics loss model is developed for a commercially available electric drive system. Power loss models were developed for required converter topologies for computational efficiency. The model results for load prediction are compared to data acquired, and results indicate that the approach is effective for enabling the study of various powertrain architecture alternatives. / Graduate