These two companies have adopted different approaches to hybrid operation with Hamilton offering the hybrid package as an addition to their standard water jets while the Doen unit has the electric motor incorporated into the water jet itself.
The Hamilton approach puts the company more in the position of a facilitator and they can offer their involvement in three different ways, one as the supplier of the water jet where the designer takes on the responsibility for incorporating the components into the system. The second is a sort of halfway house where the responsibility for the integration is shared and the third is where Hamilton takes over full responsibility for the entire propulsion system.
Hamilton pictures a system where the addition of the electric power is by means of an electric motor where the main engine drive shaft from the gearbox forms the centre of the electric motor so no clutches or separate drives are involved. They have designed a new control head for the system that allows it to operate automatically to match the load or where the operator can select the drive components as required.
In the Doen system the main drive from the diesel engine is maintained as in a conventional installation with the electric motor incorporated as an integral part of the water jet.Their waterjets can now be supplied with an integrated Power-Take-In (P.T.I.) feature that allows a forward facing input coupling for the connection of an electric motor with a continuous rating of up to 150kW.
Within the P.T.I. device there is provision for changing the relative input/output ratio that enables the best match to be made between the power characteristics of the electric motor to the particular waterjet and engine system. This ensures that the optimal performance and efficiency is obtained when operating under both diesel engine and electric motor.
Doen claims that this innovative approach eliminates the need for any expensive hybrid-ready marine transmissions or special in-series transmission products between engine and gearbox, and provides a simple and cost effective device allowing a variety of possible modes of operations.
To support the Hybrid-Ready waterjet package, Doen’s ECS400 control platform is readily able to interface to the electric motor, the electric power management system and the diesel engine; ensuring that the distribution of power to the water jet is managed seamlessly.
