On board the 42.8-metre Rossinavi yacht Seawolf X

“Honestly, I’m building a lot of yachts with diesel-electric, and the reduction in consumption isn’t that much,” says Rossi. “Maybe four, five per cent.” He wanted something more dramatic (50 per cent became the ambition) and he realised the multihull platform was the only way to give a yacht eco credentials with real weight.

In the end, the yacht ends up burning closer to 20,000 litres of fuel on a transatlantic voyage, which is still an impressive saving. The stability afforded by the two hulls allowed the yard to slash the stabilisation system altogether, meaning a reduction in both fuel (because of the reduced drag) and electric consumption. Rossi estimates a saving of 360 kilowatts per day just from cutting the stabilisation alone.

All the exterior elements had to be carefully considered to make sure they wouldn’t compromise the yacht’s streamlined silhouette

The other big benefit of the sub-500GT cat was ample area for solar panels (covering 150 square metres total) and plenty of space for storing batteries. When the yacht is in hibernation mode, the yard has proposed an innovative solution: “giving back” energy to power shoreside residences, essentially making the yacht the most expensive battery bank money can buy.

Christened Seawolf X, the 42.8-metre was delivered in 2024 to an exterior design by Fulvio de Simoni, with interiors by Meyer Davis, a newcomer to superyachting. The New York-based design firm was brought into the project early on, when the shipyard and the studio were introduced by their shared publicist during Miami’s Art Basel.

Meyer Davis is best known for its work on hotels and private residences including the Ritz Carlton and Mandarin Oriental. However, most of the project’s inspiration came from Meyer Davis’s work on 1 Hotel South Beach in Miami, which was designed to be calm, casual and underpinned by an eco focus.

“Our projects are based around the luxury of sustainability,” says Will Meyer, one half of the studio. “The owner has a great vision about sustainability and how he wants to live. There’s this cool energy that came from us designing our first yacht and [the client] building their first yacht and Rossinavi creating this new platform.”

The exterior of Seawolf X, meanwhile, is arresting. It’s stealthy, sharp and reminds me of a spider. “Certainly, [a spider] wasn’t the intention, but I can share your impression,” says Enrico Lotti of Fulvio de Simoni Yacht Design. Supercars were the original inspiration behind the lines, and the vision was translated into a high hull and low superstructure, with a bowsprit that calls to mind the front wing of a Formula One car.

“The smooth surfaces and steering positioned on a mezzanine deck [reduces] the overall height of the ship [and] led us to design a very sleek line,” says Lotti. “In fact, there’s almost no discontinuity between the hull and the superstructure.”

All of the exterior elements had to be carefully considered to make sure they wouldn’t compromise the yacht’s streamlined silhouette. The sundeck is entirely covered, giving the illusion of being more compact than it really is, and comprises a sizeable bar and seating area.

But for my money, the best al fresco living area is on the bow, where there’s a recessed lounge concealed under a flat disc that rises up electronically under the support of four pillars. I mistake it for a touch- and-go helipad at first, but it’s just a cover for two crescents of sofas sitting alongside coffee tables and a spa pool. A 100-inch projector screen drops down to transform the seating nook into a cinema.

There’s a second spa pool at the stern, something which is “unheard of ” on yachts of this size, according to Vanessa Buck of Cecil Wright, the yacht’s charter manager. The other chief selling point on the charter market is the APA, which is whittled down to just 20 per cent because of the reduced fuel consumption (APA typically sits at 30 to 40 per cent for yachts of this size). But aside from the money-saving benefits, Buck says more and more charter clients are becoming interested in eco-focused boats for the sake of the planet.

“I’ve had brokers approach me saying they wouldn’t have normally gone for a catamaran, but they’re really keen on an eco-friendly yacht,” she says. Seawolf X also features Rossinavi’s newly developed AI system, which is designed to predict future consumption, provide recommendations for fuel-saving initiatives and make helpful tweaks around the yacht. “It detects when guests are not in a cabin, and it switches off the air conditioning and the lights,” says Buck.

If your hobby is yacht-spotting, I bet Rossinavi trips you up. The young yard has so much variety in its fleet, there is no signature style. It’s true that some of its best-known boats have low profiles, slicked-back superstructures and plumb bows; but at the other end of the spectrum, you have muscular explorers like the scarlet-hulled 59-metre Akula and graceful classics like 39-metre Taransay. And now, a cat. Not quite a frog, not quite a spider, but a stealthy, silent, eco-minded wolf on the water.

First published in the February 2025 issue of BOAT International. Get this magazine sent straight to your door, or subscribe and never miss an issue.