You might be used to take-offs and landings, but soon you might need to get ready to “float, foil, and fly.”
These are the three phases of a journey aboard a seaglider, a new type of fully electric boat-plane hybrid that could revolutionize coastal transportation, according to its maker, Rhode Island-based startup REGENT.
Like a boat, a seaglider initially floats. As it picks up speed, it transitions to foiling—gliding over the water using wing-like hydrofoils. Finally, it takes off to fly up to 30 feet above the water, leveraging a principle called “ground effect” for a smooth ride with reduced drag compared to traditional flights.
“We’re going to put humans on board a full-scale, 15,000-pound prototype later this year,” says Billy Thalheimer, co-founder and CEO of REGENT. The first seagliders will carry up to 12 passengers and have a range of about 180 miles, competing directly with small ferries and seaplanes.
Seaglider Sales and Manufacturing
REGENT has already sold more than 600 seagliders, totaling over $9 billion. While manufacturing will start in North America, REGENT has signed a deal with Abu Dhabi’s government to build a second plant in the UAE, serving clients in Europe and Asia. Seagliders will soon connect Abu Dhabi to Dubai and other island communities currently underserved by existing services.
Ground Effect and Historical Context
The “ground effect” principle isn’t new; it was extensively tested by the Soviet Union in the 1960s with “ekranoplans,” large planes designed to fly at low altitudes over water, ice, or land. The most famous example is the “Caspian Sea Monster.”
“Technically, everything that flies leverages the ground effect during take-off and landing,” explains Thalheimer. “When you’re coming in on a bumpy approach and the plane sort of floats before landing—that’s ground effect. Wouldn’t it be great to spend the entire flight in that calm state over the runway?”
Modern Advancements and Challenges
To create a viable ground-effect vessel, REGENT had to overcome several issues. Seagliders are better at handling waves than vintage ekranoplans. “These things were skipping off the sea surface, making them uncomfortable and bumpy at best, inoperable at worst. We solved this with hydrofoils,” Thalheimer says, noting that full-scale seagliders can tolerate waves up to five feet high.
Another challenge was maneuverability in harbors. Unlike ekranoplans, which lacked waterborne steering mechanisms, seagliders use hydrofoils and operate in three modes: floating, foiling, and flying. “The foiling mode allows us to navigate harbors safely before transitioning to flying in open water,” Thalheimer explains.
Safety was another concern. Old ground-effect vehicles required constant pilot control, but modern seagliders use advanced flight control sensors and software systems to handle flying. “The captain now only manages boat controls: left and right, fast and slow,” Thalheimer says. “It’s a highly automated system still controlled by a human captain.”
Testing and Future Plans
In summer 2022, REGENT tested a quarter-scale prototype of its seaglider, a remotely operated version weighing 400 pounds with an 18-foot wingspan. The full-scale commercial vehicle, named Viceroy, will have a wingspan of 65 feet and fly 20 to 30 feet above the sea.
Early adopters of seagliders include Surf Air Mobility, which plans to use them to connect islands in Hawaii and along the Miami coastline, Brittany Ferries for routes across the English Channel, and other operators in the Mediterranean, Japan, and New Zealand.
In Abu Dhabi, seagliders will support tourism and alleviate public transport bottlenecks, increasing connections to more distant emirates and underserved island communities.
Expanding Capacity
REGENT plans to introduce an even larger seaglider, Monarch, capable of carrying up to 100 passengers by the end of the decade. However, improvements in battery technology are necessary to achieve its projected range of 300 to 500 miles.
Industry Perspective
Darren Biddlecombe, head of data at aviation consultancy AviationValues, notes that REGENT’s plan is technologically feasible but faces regulatory and commercial barriers. “Turning its order book into actual deliveries will depend on attracting and retaining necessary capital and expertise,” he says.
A new, convenient, and environmentally friendly form of travel looks promising, but REGENT’s success hinges on producing and supporting seagliders reliably and cost-effectively. “If REGENT can navigate these challenges, they may well have a shot,” Biddlecombe concludes.