A Norwegian manufacturer of fishing boats had the need to develop new boats with hybrid propulsion, which easily changed from diesel modality to the electric one, allowing travelling in protecting marine areas, besides entering ports without impacts on the environment. The requirements were compact dimensions and high torque. We have therefore designed and developed an electromagnetic toothed clutch with an elastic joint, also customised. A normally closed safety clutch, spring applied, which allowed the motion transmission from the diesel engine to the electric motor. Electric motor that, in its turn, operated as generator to recharge batteries and to power utilities.