What makes a yacht diesel-electric?
Diesel-electric means that the yacht is moved by electric motors, which turn the propellers through a gearbox.
This type of yacht has a set of diesel generators that supply energy to electric motors. The technology is not new, trade ships have had this type of power plant for almost a hundred years. First used in 1903 to move the triple-screw Russian tanker Vandal on the Volga River and the Caspian Sea, the diesel-electric drive is now used in the most advanced cruise ships and thousands of other commercial vessels.
The main benefits of a yacht with diesel-electric are:
- Less noise and vibrations: Noise and vibration are more easily suppressed than in a conventional direct engine-to-propeller drive. With no need to provide a mechanical power-transfer connection to the hull, the generator mounts can be chosen for optimum vibration isolation. If desired, the generator can be enclosed in a sound shield, giving excellent noise attenuation without the need to insulate an entire compartment. Vibration and noise from propellers are reduced with accurate control of the corresponding position of the blades on one prop with those on the other prop. This method is standard on many multiengine aircraft and is called prop phasing.
- The flexibility of the layout-design freedom: The generators and the electric motors can be placed apart, only connected by the electric cables. The electric motors can be located to the stern of the yacht, while the generator room can be located in the bow section.
In a diesel-electric system, the generator can be mounted virtually anywhere in the hull and whatever orientation is required to achieve optimum use of space. With no need to provide a mechanical power-transfer connection to the hull, the engine mounts can be chosen for optimum vibration isolation. The small size of the prop-drive motor and gearbox makes it possible to place the props at the most advantageous position on the hull.
- Slow-speed manoeuvrability: Electric motors provide unrestricted minimum prop speeds with 100 % torque available to provide immediate power response at all times. Prop synchronization is automatic and extremely precise.
- Fuel efficiency: Depending on the positioning of the engine, power loss due to exhaust backpressure may be less than what can be achieved in a conventional installation. The option of drawing the vessel's AC house power from the propulsion system when underway, eliminating the need to run the vessel's genset, can improve fuel efficiency. Overall, the fuel economy of the diesel-electric drive will be close to or as good as what can be achieved using a direct-drive system.
- Zero emissions: With the support of rechargeable batteries, the yacht can travel in full electric zero-emissions mode for a few hours.
One of the largest diesel-electric luxury yachts is a 107 m mega yacht Benetti Luminosity delivered in 2021. Other leading shipyards-Abeking & Rasmussen, Feadship, Lürssen and Rossinavi, to name a few, have diesel-electric yachts in their portfolios.
Do not hesitate to contact a Romeo United Yachts specialist for details of any diesel-electric yacht.