This paper presents the technical study of a commercial sailboat conversion, originally manufactured with an internal combustion engine (ICE), into electrical hybrid propulsion system with fuel cell and batteries. Batteries are charged with electrical energy from grid when boat remains at port. The used hydrogen is generated with the electrolysis of water using energy provided through the on-board renewable system (eolic, photovoltaic and marine generation). In order to check the viability of conversion mathematical modelling is used. Firstly, hull hydrodynamic resistance is obtained through Free!Ship software. Then, this result is implemented into a global model which is developed under Matlab/Simulink (R) environment. Furthermore, renewable energy and power systems are developed as Simuline models and a logic controller manages them. In this study, the selection of all energy and power elements is shown. Real operation sailboat under real conditions is simulated. Finally, results obtained are compared with Spanish Navigation Normative to study a possible technical feasibility. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.