Custom yachts usually begin as the germ of an idea in their owners’ minds, but they can take years to come to fruition. Such was the case with the 101-foot (31-meter) CCN Vanadis. The original concept was floated back in 2005 when a client approached Dutch designer Guido de Groot for an 88-foot (26.8-meter) motor cruiser. The design never progressed beyond the drawing board.
That was not the end of the project, however. A decade passed, and the client contacted de Groot once again: “He said he was back in the market but couldn’t find anything like the yacht we’d designed together all those years before. The overall length increased, but the basic concept and discreet styling remained virtually unchanged.”
Future-proofing his investment—aesthetically and technologically—was important to the owner. The evergreen exterior lines would never go out of fashion, but for his yacht to remain relevant in a world of climate change, he wanted a strong focus on efficiency and sustainability. With this in mind, he asked naval architect Jaron Ginton to look into both diesel-electric and hybrid propulsion.
The terms “diesel-electric” and “hybrid” tend to be used interchangeably, but there is a subtle distinction in relation to yachts. Hybrid commonly signifies a system that draws on a combination of diesel engines, electric motors and battery banks for propulsion and hotel needs, with a direct mechanical connection between the diesel engines, electric motors and propellers via the drive shafts.
In a pure diesel-electric system, on the other hand, diesel engines serve as generators to produce electricity transmitted via flexible cabling to electric motors that drive thrusters (the system may use battery banks for auxiliary propulsion and/or hotel loads). The absence of drive shafts means there is no need for a gearbox or clutch, but large frequency converters are required.
“My studies showed that given the size of the yacht, hybrid technology made more sense than pure diesel-electric propulsion,” Ginton says. “There are pros and cons associated with both systems, but the hybrid option offered more advantages in terms of simplicity, flexibility and space.”
The main challenge with any hybrid propulsion system is defining the most efficient sizing and distribution of power sources (diesel generators, shaft generators and batteries) in relation to the onboard energy needs (hotel loads, air conditioning, stabilizers, bow thruster, etc.). To best define these parameters, the CCN shipyard worked with international suppliers: Siemens for the e-motors and power management system, Schottel for the azimuthing thrusters, Xenta for the dynamic positioning system, Caterpillar for the diesel engines and generators, and Akasol for the lithium-ion batteries.
The result is the first motoryacht built in Italy to obtain Hybrid Power certification from Lloyd’s Register.
“Award-winning Vanadis opens up a new era for CCN,” CEO Diego Deprati says. “We are fully committed to developing sustainable solutions that reduce the impact of yachting on the environment, and firmly believe that hybrid propulsion is a significant step towards achieving this goal.”
The e-Prop hybrid system aboard Vanadis, now also on other CCN models, offers five propulsion modes by pairing diesel engines and e-motors with diesel generators and lithium-ion batteries to drive two azimuthing Schottel thrusters. The owner can choose, for example, to cruise at a maximum speed of 13 knots in conventional diesel mode, or at 5 knots for up to three hours or in full electric mode. Alternatively, output from the generators can be combined with power from the batteries in diesel-electric mode for extended range, or the e-motors can be used as shaft generators.
The two diesel generators developed for Vanadis use permanent magnet technology and variable-speed control for reduced fuel consumption and operational efficiency. An integrated power system manages the propulsion, power generation and battery energy via a DC switchboard. The batteries are able to handle the house loads at anchor for up to 17 consecutive hours with zero emissions and peak shaving during heavy demand without activating the diesel generators.
The thruster pods can be controlled for full dynamic positioning capability, allowing the captain to “anchor” electronically and keep the bow fixed in a direction by pressing a button. Moreover, the vessel relies on both Quick gyroscopic stabilizers and CMC electric fins. Gyros are well known for their soft and natural correctional forces at anchor, but fins are much more effective in broaching conditions. Using both systems increases zero-speed comfort and safety underway.
A final challenge the shipyard faced was defining the engine room layout. Because of the hybrid configuration and compact size of the yacht, the main engine compartment is in the stern, and the generator compartment is in the bow, resulting in better space distribution belowdecks that can be devoted to the guest and crew areas. ◊
For more information: cerricantierinavali.it
Stylish & Sophisticated
The owner of Vanadis may have requested a high-tech propulsion system, but he wanted it wrapped in a classic exterior profile and low-key interior design. Guido de Groot, known for his pure and harmonious style that often has a traditional thread running through it, executed the perfect brief for “a highly functional, comfortable, stylish and sophisticated design.”
The Dutch designer describes the interior style as a modern interpretation of Jugendstil, a Germanic style related to Art Nouveau. The main woods are bleached ash combined with walnut accents for a light and airy ambience, punctuated with commissioned and colorful works of modern art. Loose furniture the owner selected is by Wittmann, Poltrona Frau, Giorgetti, Knoll and JAB.
The dining table on main deck provides an example of how the design was customized to suit the owner’s wishes. The initial design proposed a round table in ash with walnut Canaletto accents, but the client requested something more organic and dynamic. Now, there’s a round table from Knoll with an organic-shaped stowage cabinet on one side and a gently curved bulkhead on the other.
This article originally appeared in the Spring 2020 issue of Yachts International.