This work aims to propose a new powertrain for the ferry 'ELIO' operating in the Strait of Messina. Based on the operating data kindly provided by Caronte&Tourist, the authors suggest an alternative propulsion system with methanol fueled HT-PEM fuel cells and batteries, supported by multilevel converters feeding the electric propulsion motors. The power plant is sized through an optimization process considering fuel cell power levels, battery pack capacity and battery current. The detailed modeling of the multilevel converters allows for accurate evaluation of losses on both converters and electric propulsion motors. Eventually an evaluation of the overall efficiency of the system and the reduction of emissions is presented.