Buyer's guide:

Yachts by propulsion

Motor Yachts equipped with water jets: 

Waterjets become an obvious choice to get the boat moved when equipped with big powerful engines which bring the vessel to high speed. 

Waterjets can handle the power of the most powerful engines and provide the thrust to reach speeds up to 55 knots and even more. One of the great things about waterjets is the absence of noise and vibration. When water passes through the water jet, the flow becomes linear, and a yacht will not encounter the momentum which traditional left hand or right hand rotating shafts can create. You can see water jets with twin-engine setup onboard fast luxury yachts of 80 ft/24m and bigger. Also, there are fast yachts that have triple engines with even more power on hand. Port and starboard jets are steerable, while the central engine and water jet coupled to it is playing the role of a booster.

Fast yacht manufacturers install water jets for many years: Mangusta, Pershing, AB yachts, to name a few. Jets can propel a much bigger vessel, up to 180 meters long. The largest yacht with jets is 180 m Lürssen 'Azzam' equipped with two diesel engines, two gas turbines and four water jets. Another plus point is the reduced draft of the boat fitted by a water jet what allows it to enter the most shallow areas. One may ask what the downsides of water jets are? The downside is the fuel burn rate.  Usually, vessels equipped with water jets have less autonomy than traditional shafts.

Manufacturers with a distinguished history and reliability build the most dependable water jet units - KaMeWa and MJP.
Scroll down to see yachts with water jet propulsion.

Yachts with a hybrid power plant: 

Recent years saw keen interest from yacht owners in hybrid power plants in the machine halls of luxury superyachts. As now the world goes green, future and existing owners consider hybrid yacht ownership as their contribution to saving the oceans and seas. We are proud to showcase the most comprehensive selection of the existing hybrid luxury boats and yachts available for sale and pre-order.

We explain the advantages of a hybrid yachts as Q and A:

Q: Does hybrid mean that a yacht can operate in different modes? 

A: Hybrid power can be used in different modes while moving:

Q: What is a hybrid motor yacht, and why this set-up is called a ‘hybrid’? 

A: Hybrid power on a motor yacht means that the vessel is driven by diesel engines operating together with electric motors. The advantage of hybrid power is much more comfortable navigation as the boat can run on electric motors alone, much quieter than diesel engines. That is especially useful when a yacht moves in the night when silence onboard is essential

Q: What are the components of a hybrid system? 

A: The main components of a hybrid power are a) Electric motors, b) Rechargeable batteries,с) Diesel engines and d) diesel generators

Q: Does hybrid power allow to stay at anchor without running diesel generators? 

A: Yes, as there are powerful electric batteries onboard which supply electric power to air-condition and other electric appliances so that you can stay at anchor in absolute tranquillity without a need to run diesel generators.

Q: What other advantages has a hybrid yacht over traditional diesel engines?

A: A hybrid yacht probably will have a better value than the one equipped with diesel engines. That means that a hybrid sells faster on a pre-owned market and for a higher price. 

Q: Ok, it all looks so good, so what are the downsides of this system? 

A: The disadvantage of a hybrid is more often than not, the components require more space in the engine room than a traditional set-up. Another disadvantage is an added cost. Usually, builders ask for a premium for a hybrid system.

Q: Is going hybrid becomes a trend in a modern yacht building? 

A: Yes, practically all leading shipyards have hybrid proposals in their portfolio.

One of the first builders who saw the beauty of this system was Holland Jachtbouw which introduced its silent running J-class yacht Rainbow  back in 2012.

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.