The waters between the UK and France are set to see an exciting new addition to their current ferries. French shipping company Brittany Ferries has announced a plan to introduce an all-electric high-speed seaglider by 2028. This will fly at 180 miles per hour just above the surface.

Introducing a 'seaglider'

Brittany Ferries announced on June 15th that it has signed a letter of intent to purchase new seagliders, currently under development in the US. These new concept aircraft will glide over the sea at just a few meters altitude. Brittany Ferries explains the concept:

"Seagliders combine the convenience of passenger ferries with the comfort of hydrofoils, the aerodynamic efficiency of hovercraft and the speed of aircraft."

The seaglider will have a capacity of between 100 and 150 passengers and will be able to operate from existing ports. It will be battery-powered, with a range of up to 180 miles (290 kilometers). And it will fly at speeds of up to 180 miles per hour (290 kilometers per hour). Brittany Ferries says the crossing from Portsmouth to Cherbourg could take just 40 minutes, compared to three hours on a high-speed ferry (and around nine hours overnight).

Brittany Ferries seaglider
The seaglider will be much faster than current ferries. Photo: Brittany Ferries

Low-altitude high-speed flying

The new aircraft works using the principle of 'ground effect.' This refers to the reduced drag and increased lift generated by a fixed-wing aircraft close to a surface. Air pressure on the wing's lower surface is increased close to the water (or ground), improving the aircraft's lift to drag ratio. Obstructed wingtip vortices also reduce drag.

The result is a lower angle of attack needed to produce lift and less thrust. Hovercraft work using the same ground-effect principle, with a skirt rather than wings.

This will allow the seaglider to achieve high-speed flight but with less power than a traditional aircraft. When leaving and entering the port, it will move on foils, which will provide stability in open water. It will then take off at low speed and use the 'air cushion' to cruise across the sea - at all times just a few meters above the surface.

Brittany Ferries seaglider
The aircraft will fly just over the surface of the sea. Photo: Brittany Ferries

Built in the US

The concept of sea gliders has been experimented with for some time, but they have not yet been commercially developed. The Soviet Union developed one during the Cold War - known as the Caspian Sea Monster.

KM Ekranoplan, aka Caspian Monster
The Caspian Sea Monster could fit five crew members and had the capacity for 50 people. Photo: Getty Images

The Brittany Ferries craft will be manufactured by Boston-based startup REGENT (Regional Electric Ground Effect Nautical Transport). It hopes to be the first company to develop a commercial sea glider.

REGENT expects the aircraft to be operational by 2025, and Brittany Ferries hopes to have them in service by 2028. Billy Thalheimer, co-founder, and CEO of REGENT explained the importance of the deal, saying,

"REGENT is excited to partner with Brittany Ferries to bring the future of maritime transportation to market.  Brittany Ferries offers world-class operational experience which will help REGENT ensure that our seagliders will be the most convenient and comfortable form of cross-Channel travel."

Brittany Ferries seaglider
REGENT also plans different-sized aircraft - and later, increased ranges. Photo: Brittany Ferries

Zero-emission future

The appeal of the seaglider is not just its high-speed channel-crossing ability. It promises zero-emission operation - an area of growing interest to all transportation companies. This is achieved with electric-powered engines and onboard batteries. Current battery technology will limit the initial range to 180 miles (290 kilometers), but REGENT expects this to increase to 500 miles (805 kilometers) with next-generation batteries.

Brittany Ferries, and other operators, have already committed to LNG (liquefied natural gas) ships (Brittany Ferries expects two of these in 2022 and 2023). Smaller, electric craft will be an impressive next step.

A cross-channel seaglider in an exciting introduction. There are many other possibilities and routes such an aircraft could operate, especially as the technology improves. Feel free to discuss this further in the comments.