Is it a ship? Is it a plane?

No, it's an all-electric, wing-in-ground-effect vehicle (WIG), according to Brittany Ferries.

The French shipowner said its new cross-Channel design will travel at up to 180 mph (290 km/h) — six times faster than conventional ferries.

This will mean a crossing from Portsmouth to Cherbourg in 40 minutes.

In effect a sea glider, the WIG operates like a hydrofoil and a hovercraft, flies like a plane and offers all the comfort and convenience of a ferry, the company claims.

The concept, with a battery-powered range of 180 miles, is under development in the US through Boston start-up REGENT (Regional Electric Ground Effect Nautical Transport).

Brittany Ferries has signed a letter of intent under which sea gliders with a 50 to 150-passenger capacity could sail between Britain and France by 2028.

REGENT expects the first commercial passengers to travel on smaller electric craft by 2025.

The WIGs will work by harnessing a concept well known to pilots, ground effect.

This is the cushion created by high-pressure air trapped between wings and the ground or water while flying at low altitude.

"Seagliders are therefore akin to a hovercraft with wings, rather than a skirt," the shipowner said.

Rising on foils before take-off

Following departure from port, the craft will rise on foils, insulating passengers from wave discomfort.

In open waters, the WIG will take off, riding the air cushion a few metres above the sea all the way to its destination.

Wing-mounted propellers provide the thrust to take to the air at low speeds, and electric motors regulate air flow over wings while riding the air cushion.

"It’s a highly efficient mode of transport, capable of moving significant loads over long distances at high speed," Brittany added.

Next-generation sensor suites will detect and automatically avoid other vessels, the owner said.

Brittany has already invested in two new LNG-fuelled ropaxes for delivery in 2022 and 2023 as it seeks to bring down its emissions.

"Seaglider is an attractive and exciting concept and we look forward to working with REGENT in the months and years to come,” said Frederic Pouget, ports and operations director at Brittany Ferries.

"We hope this may help bring commercial success in the years that follow. Who knows, this could be the birth of ferries that fly across the Channel."

REGENT is working on several different sizes of passenger-carrying sea gliders, all of which operate on the same principle.

The companies realise many technological, practical and regulatory milestones lie ahead. However, both say that caution should not stand in the way of the design.

Several hybrid vessels, using batteries and diesel, are already plying their trade around the UK, including between the Isle of Wight and Portsmouth in southern England and off the west coast of Scotland.