In case of a “serial hybrid drive” the diesel generator supplies the electric motor directly. The electric motor is the main propulsion of the boat. In case of a “parallel hybrid drive” the electric motor is parallel switched to the drive shaft of the diesel drive engine. This means that the electric motor “works” as a generator when the boat is running with its diesel engine. When the diesel engine is turned off the vessel can be driven with the electric motor only. As, generally, the output of the diesel engine and the output of the electric motor are very different it is important to choose a suitable reduction and clutch. Please contact us. We will be glad to assist you.