Wind-Assisted Propulsion (WAP)

Wind-assisted propulsion adds sails, Flettner rotors, suction wings, or towing kites to a conventionally powered ship to cut main-engine fuel burn on suitable routes, typically saving a single-digit to low-double-digit percentage of fuel depending on wind and routing. It is one of the few measures that reduces emissions of any fuel without changing the engine, and it earns a reward factor under the EEDI and EEXI. Rotor sails are the most-installed type, with growing deployment on bulkers and tankers.