As the old adage goes, everything old is new again. For evidence of that, you need look no farther than cargo ships, which are looking to a 5,000-year-old technology as an eco-friendly source of propulsion—the sail.
But today’s sails bear little resemblance to the papyrus or animal-skin sails used in ancient times or the billowing cotton or linen sails of 19th-century clipper ships. These are thoroughly modern, high-tech devices designed to reduce ship operators’ reliance on costly marine fuels and help curb greenhouse gas emissions—and they’re sprouting up on freight vessels around the world.
One example is the “rotor sail,” a cylindrical unit that’s mounted inside a flagpole-shaped device. When installed on a cargo ship’s deck, the sail can reduce the vessel’s fuel consumption and carbon dioxide emissions by 6% to 12%, users say. Last month, the Japanese marine freight carrier NS United Kaiun Kaisha Ltd. announced plans to install five rotor sails manufactured by Anemoi Marine Technologies Ltd. on the 1,184-foot-long iron ore carrier ship NSU Tubarao over the next year.
But the story doesn’t end with rotor sails. Companies are experimenting with other types of high-tech sails as well. For instance, the Dutch heavy-lift cargo ship Jumbo Jubileehas been outfitted with two mechanical sails known as wind-assisted ship propulsion (WASP) units in a bid to boost fuel efficiency and cut carbon. And the Dutch maritime gas carrier Anthony Veder has deployed two “VentoFoil” sails made by Econowind on its ethylene carrier Coral Patula, with plans to add two similar sails to its sister ship Coral Pearl later this year.
