This paper presents the results and discussion of an extensive set of tests of a hybrid generation system (gas-electric), to feed the electric motors which propel a small or medium vessel. Primarily, the hybrid electric system includes An otto cycle combustion engine, an electric generator and electric induction motors. The diesel engine represents the central part in regards to the propulsion task [1][2]. Thus, it provides the energy required by the electrical system, also supports load variations at low speed or cruising speed. Furthermore, it feeds other critical loads such as lights, electronic navigation systems, ancillary systems and other comfort loads within the hotel facilities. Presently, many technical challenges associated with the design of hybrid-electric propulsion systems are under discussion. Regarding technical limitations, the loading level and perhaps even more important is to deal with the complexity of the hybrid systems. Concerning to technical limitations, we can, therefore, highlight the following issues; the pilot excitation control, the performance of crash-stop manoeuvre and lastly the protection and control task.