Admiral E Motion hybrid Quinta Essentia is unlikely to be confused with any other yachts moored along the French and Italian rivieras. Not only does the 180-foot (55-meter) superyacht have eye-catching exterior styling that singles her out from the crowd, but she is truly a standout beneath her striking burgundy and white livery.
The starting point for the project was her Russian owner’s previous Heesen of the same name and length overall, launched in 2011. A competitive sailor who races in the Melges 32 class, he mostly used the semi-displacement yacht as a mothership during regattas. The problem was that her powerful 5,766-horsepower MTU engines were not ideal for keeping station on the start line or following a sailboat race: noisy engines that produce clouds of diesel fumes at low revs is not the best way to make friends among sailors.
The owner approached broker-turned-designer-and-builder Sergey Dobroserdov of Nakhimov Yachts in Monaco to devise a more “regatta-friendly” yacht with additional interior and exterior space for post-race partying. Dobroserdov Design was brought in for the exterior styling, Vripack in Holland for the naval architecture, Michela Reverberi in Italy for the interior design and British consultant Rob Williamson—who had captained the Heesen Quinta Essentia— as the owner’s project manager. The result is an all-aluminum displacement yacht with dynamic exterior design, efficient propulsion and ample connection to the sea. The Italian Sea Group in Carrara, Italy, built the yacht under the Admiral brand.
“Our key objectives were comfort in terms of noise and vibration, combined with efficiency, flexibility and reliability,” Williamson says. “After examining the options, we realized that hybrid propulsion was the way to go.”
The new is fitted with relatively small 1,400-horsepower MAN engines coupled to an Auxilia DC electric motor installed on each drive shaft between the main engine and gearbox. Powered by two variable-speed generators, the e-motors can drive the yacht without the main engines, or can serve as shaft generators with the gensets switched off. Battery banks were considered, but rejected on account of their limited energy output and the extra weight and space they require.
The e-motors provide near-silent maneuvering in and out of port—or on the regatta course—and low-emission cruising at 9 knots (an electric Voith bow thruster and electric CMC stabilizers further reduce noise and vibration). For faster cruising up to a top speed of
16.5 knots, the main engines take over, while the e-motors can service the hotel loads. In diesel-electric mode using the e-motors, the yacht has an impressive range of around 6,000 nautical miles.
In addition to the quiet propulsion system, double- and tripleglazed windows throughout with flush glass on the outside of the portholes further reduce noise levels. A heat-reflective film applied to the glass increases the efficiency of the air-conditioning system, which means lower air speeds from the fan coils and less noise. At anchor in the owner’s stateroom and guest staterooms, for example, the noise level is 41 decibels—about what it would be inside a library.
“Basically, the yacht ticks all the right boxes,” Williamson says. “You can come in and out of a harbor with much less noise and bluster, and the yacht is definitely more fuel efficient than conventional propulsion when cruising at low speed with the electric motors.”
Vripack optimized the hull form by doing resistance, propulsion and seakeeping trials in the towing tank, and by using proprietary computational fluid dynamics software. Because of the owner’s plan to use his yacht at inshore regattas, the draft had to be relatively shallow. The lightweight aluminum hull reduced the draft and wave profile, and lowered resistance to maximize speed in hybrid mode. But the relatively high superstructure and full-height glass raised the metacentric height (center of gravity), which is critical in stability calculations, so Vripack introduced a wide aft body and bilge keels that work with the stabilizer fins to dampen roll.
“We really put the model to the test in conditions the yacht is unlikely to encounter in a real-life scenario,” says Aleksandr
somewhat ironic that Quinta Essentia is unlikely to be used for her intended purpose. At the time of writing, the yacht was for sale, but the hybrid concept has produced a spin-off: an Admiral E Motion 52 currently in build. With exterior styling again by Dobroserdov Design, its propulsion system consists of four main engines and two DC electric motors that can be combined to reach a higher maximum speed of 23 knots.