These massive, wing-like ‘sails’ could add wind power to cargo ships

The concept of a sailboat might conjure up thoughts of swanky sailing holidays or fearsome pirates—and some companies are hoping to bring them back into the mainstream, albeit in a modern, emissions-focused way. According to the International Maritime Organization (IMO), there are seven types of Wind Propulsion Technologies, or sails, which could potentially help the organization bring down the shipping industry’s currently massive carbon footprint.

Wired reports that a Swedish company called Oceanbird is building a sail that can fit onto existing vessels. The Wingsail 560 looks kind of like an airplane wing placed vertically like a mast on a boat, and this summer the company plans to test out a prototype on land. If all goes well, next year it could be making its oceanic debut on a 14-year-old car carrier, also known as a roll-on/roll-off or RoRo shipping container, called the Wallenius Tirranna.

This is how the sail, coming in at 40-meters high and weighing 200 metric tons, works—the sail has two parts, one of which is a flap that brings air into a more rigid, steel-cored component that allows for peak, yacht-racing inspired aerodynamics, according to Wired. Additionally, the wing is able to fold down or tilt in order to pass underneath bridges and reduce wind power in case of an approaching storm. One Oceanbird sail placed on an existing vessel is estimated to reduce fuel consumption from the main engine by up to 10 percent, saving around 675,000 liters of diesel each year, according to trade publication Offshore Energy.

But, the real excitement is the idea of a redesigned vessel built especially for the gigantic sails. According to Wired, the Oceanbird-designed, 200-meter-long car carrier Orcelle Wind could cut emissions by at least 60 percent compared to a sailless RoRo vessel. The company themselves even estimates that it could reduce emissions by “up to 90 percent if all emissions-influencing factors are aligned.” However, it will still be a few years before one of these hits the high seas.

Oceanbird isn’t the only company setting sail—according to Gavin Allwright, secretary general of the International Windship Association, by the end of the year there could be 48 or 49 wind-powered vessels on the seas. One such ship already took a voyage from Rotterdam to French Guiana in late 2022 using a hybrid propulsion of traditional engines and sails. However Allwright tells Wired “we’re still in pretty early days.”

The IMO has already set a climate goal of halving emissions between 2008 and 2050, but experts have called this goal “important, but inadequate” to keep emissions low enough for a liveable future. Currently, these goals are still not being reached, with a Climate Action Tracker assessment showing that emissions are set to grow until 2050 unless further action is taken.