Nowadays specific ships are used to train students as sailors. As historical vessels are conveniently employed to this aim, the average age of these ships is usually high. In order to amortize operating and maintenance costs, the training ships' ownership (except for naval ones) is shared among multiple entities and schools. Moreover, generally these vessels are used in coastal navigation. The consequent operational profile imposes the need to rearrange the ship internal spaces according to the shipowner who will use it. Considering all these reasons, a modular design approach can be adopted in the refitting process, while reverse engineering techniques and integrated design tools should be used for the reconstruction when the original technical documentation is not available. In this context, hybrid-electric propulsion systems can be proposed as effective to enable the Zero Emission Mode, thus reducing the vessel's environmental impact during the training. By doing this, three goals are achieved to extend the ship operational life: ease of rearrangement of the internal spaces for different uses, reduction of operating/maintenance costs and eco-sustainability in coastal navigation. In this paper, after a description about modular design and hybrid electric technologies, the refitting project of the M/N "Umberto d'Ancona" is discussed. The latter is the training ship of "Tomaso di Savoia Duke of Genoa", the nautical institute in Trieste, Italy.