Seawolf X is something a little different, which is just how Captain Sean Rysenbry likes it.
Catamarans have rarely been considered the beauty queens of the fleet — but a revolution is underway. Shipyards are rethinking the formula, and Seawolf X is leading the charge. Her sweeping curves might be reminiscent of a concept car, but this is no mere prototype; it’s a fully realized supercat brought to life by Italian shipyard Rossinavi and delivered in 2024.
At the helm is Kiwi Captain Sean Rysenbry, whose career has been shaped by the pursuit of something a little less ordinary. One of his previous commands was a single-screw, Ferrari-red explorer yacht that took him from the icy fjords of the Baltics to the winding rivers of the Garonne and Guadalquivir. So when he saw the plans for the 140-foot Seawolf X, there was little hesitation. “A friend at JMS Yachting said, ‘There’s this crazy project,’” he says. “I took one look at it and said, ‘Yes, yes, please. I’ll take it.’”
Not only is this Captain Sean’s first command of a catamaran, but it’s also his first at the helm of a hybrid-electric vessel. Its propulsion system is made up of two 360kW generators that supply power to 250kW electric motors, and 14 tons of batteries with 1.5 megawatts of capacity. This allows Seawolf X to cruise silently and emission-free for extended periods. By comparison,the 274-foot Savannah, which has an additional 1,750GT of volume, has just one megawatt of battery storage. This extra power enables Seawolf X to cover up to 80 percent of a transatlantic crossing on battery power alone.
Adding to its capabilities are 1,670 square feet of solar panels, carefully positioned on every sun-facing surface. These panels continually feed energy into the batteries, enabling the yacht to remain at anchor for several days or cruise for a full day without engaging the generators. “If we’re gliding between islands, we can leave, find a spot, stay at anchor all day and come back without starting a single piece of machinery,” Sean explains.
Effective load management is essential to maximizing Seawolf X’s efficiency. Thanks to the catamaran design, its inherent stability eliminates the need for energy-intensive stabilizers, saving an estimated 360kW of energy daily. This level of efficiency is supported by an advanced AI system that meticulously monitors power consumption, identifies inefficiencies, redirects energy and analyzes usage trends. “It tells me what it’s using now, what it’s used historically and with the AI, it’s analyzing the trends and feeding us back the data,” Sean says.
The system also provides tailored operational modes such as “Hibernation,” “Eco Cross,” and “Eco Guest.” For instance, “Eco Guest” mode automatically adjusts environmental controls by lowering blinds in sunlit cabins, turning off lights and deactivating A/C in unoccupied areas, ensuring seamless energy conservation in everyday operations. The system maintains continuous communication with the crew, advising on how to adopt lower-impact behaviors and promoting conscious cruising. The owner also added a unique touch: an efficiency game that tracks cabin power usage, with prizes for the most energy-efficient guests. “He’s trying to teach his kids that small changes make a difference,” Sean says.
The concept of redirecting energy to where its most needed extends to how Captain Sean runs his crew, operating on a foundation of shared responsibility. “Everybody mucks in. If there’s somebody who has more load, we all take on more to balance it. The captain is in there doing the dishes, the chef’s out there scrubbing teak,” he says. “Everyone helps everyone else out, and it has made us a strong team.”
Having joined the vessel six months before its completion, Sean was able to build his crew with intention, blending diverse experiences to create balance. “I’m stepping up from smaller boats, so I [hired] a chief mate who is stepping down from larger boats. She brings that big boat experience, and I bring the experience from smaller boats, which is much more personal and team-involved,” he says. “What I didn’t want to bring down from the bigger boats was this departmental thing.”
For the interior, the owner went out on a limb, enlisting New York studio Meyer Davis, a design firm better known for hotels and private residences than superyachts. The unconventional choice resulted in an interior that prioritizes warmth and livability over opulence, with organic shapes, natural textures and recycled wool rugs. “The yacht feels homely,” Sean says.
The main salon takes full advantage of the 45-foot beam, with the formal dining table positioned longitudinally to one side and sofas to the other. A 750-square-foot owner’s cabin is forward and four guest cabins are found below. The propulsion system frees up significant interior space. “Because we don’t have the main engines and we have these quite small drives, we don’t need a lot of space for them,” Sean says. “We’ve saved a lot of extra space to give to the guest cabins, which are forward, and that’s why they’re so spacious.”
On Seawolf X, every square foot of space and every megawatt of energy is carefully considered. And every effort — whether from man or machine — is directed toward ensuring everything runs smoothly and efficiently.