Future flagships
Credit: Smart Green Shipping Alliance

An evening drizzle falls on the Dutch port city of Rotterdam as dockworkers untie the moorings of Estraden and shove the 535-foot cargo ship from the industrial dock. Captain Mikko Innanen steps into the bridge, a dark room with large windows and glowing radar screens, where voices crackling over the radio in English, Dutch, and Finnish confirm that the coast is clear. Innanen takes the helm, steering the ship from the tranquil harbor into the choppy North Sea.

The main engines roar below as Estraden begins its voyage to northern England, carrying tanks of hazardous chemicals and containers of cargo. Then Innanen pushes a button.

On the ship’s deck, two 60-foot-tall tubes twirl to life, spinning like hyperactive barber’s poles. The vertical rotor sails help propel Estraden by harnessing the wind, like modern metal versions of the age-old canvas sheet. Each rotating cylinder drags air around it, forming areas of high and low pressure and producing a forward thrust — reducing some of the demand […]