DNV GL: wind ships ahead.

The physical principle is the same one humans have used on sailing boats since eons ago: the wind hits the leading edge of the sail and splits into two flows which are redirected and travel at different speeds towards the trailing edge, causing a pressure difference that simultaneously pulls and pushes the sail and the craft forward.

What has changed is the efficiency. Advanced science has doubled the amount of propulsion power per square metre of sail surface, says Marc Van Peteghem, naval architect and co-founder of VPLP Design. Together with...