IN Brief:
- MAIZURU KAZENOMAI is a 95,311-deadweight-tonne coal carrier built by Oshima Shipbuilding.
- Its LNG dual-fuel main engine works with a Wind Challenger rigid sail that adjusts automatically.
- MOL forecasts up to approximately 30% lower CO₂ emissions than a conventional heavy-fuel-oil-powered vessel.
Mitsui O.S.K. Lines (MOL) has taken delivery of MAIZURU KAZENOMAI, a 95,311-deadweight-tonne coal carrier equipped with an LNG dual-fuel engine and the company’s Wind Challenger wind-assisted propulsion system. The vessel has entered service carrying coal to Kansai Electric Power’s Maizuru power station in Japan. It was built by Oshima Shipbuilding, where a naming and delivery ceremony marked completion of the project.
Built by Oshima Shipbuilding and registered in Liberia, the vessel is 234.98 metres long and 38 metres wide, with a deadweight rating of 95,311 tonnes. MOL identifies it as Japan’s first coal carrier equipped with the Wind Challenger sail and LNG dual-fuel propulsion. Kansai Electric Power’s Maizuru plant is its stated cargo destination, although MOL has not detailed its complete sailing pattern or planned annual coal volume. The ship continues to carry coal; the engineering change concerns how fuel is consumed during transportation rather than the nature of the cargo.
The Wind Challenger provides additional thrust through a rigid, wing-shaped sail. Wind sensors feed an automatic system that changes the sail’s orientation and telescopic height so the aerodynamic force can assist forward movement. The diesel-cycle main engine remains responsible for propulsion when the wind offers little benefit and for maintaining the required service speed. Retracting the sail helps limit its height and manage stability or wind loading when conditions demand it. The arrangement supplements conventional marine propulsion rather than replacing the engine with sail power.
Available wind changes throughout a voyage, and the useful thrust depends on its direction relative to the ship’s heading as well as its speed. The system is designed to work with weather routing that can select more favourable conditions where voyage constraints permit. A longer route taken solely to find wind could offset some of the fuel benefit, while weather, arrival times and port restrictions limit the choices available to a bulk carrier. MOL has not yet reported fuel-consumption data from this ship’s commercial voyages, so its practical saving remains unmeasured.
The vessel can use liquefied natural gas as its primary engine fuel. MOL expects LNG operation together with wind assistance to reduce carbon dioxide emissions by up to approximately 30% against a conventional heavy-fuel-oil-powered vessel. The company also anticipates lower nitrogen oxide and markedly lower sulphur oxide emissions. These are projected comparisons, not a measured result for MAIZURU KAZENOMAI. LNG use can produce methane emissions upstream and during operations; a comprehensive lifecycle comparison would require fuel-supply and engine data that MOL has not published for the new ship.
Wind-assisted propulsion is already operational elsewhere in MOL’s fleet. Its earlier coal carrier SHOFU MARU completed seven round-trip voyages through April 2024, and MOL reports fuel savings averaging 5% to 8% per voyage, with a maximum daily saving of 17% under the measured operating conditions. Those figures provide a practical reference for the sail technology, but they cannot be transferred directly to a different vessel with a different engine, sailing pattern and weather exposure. The new ship’s combined propulsion arrangement requires its own operational measurement.
The engineering arrangement also introduces maintenance and operating considerations. MOL identifies hydraulics used to extend and retract the sail and rotation machinery at its base as components requiring service according to operating hours. The sail surface uses glass fibre reinforced plastic to limit weight, while its telescopic structure helps manage stability and the vessel’s centre of gravity. The additional equipment must operate alongside normal bulk carrier loading, sailing and harbour procedures, with vessel safety taking precedence over opportunities for wind assistance.
A ship’s deadweight rating is not the quantity of coal carried on each trip. Freight emissions intensity depends on the actual payload, loaded and ballast distances, weather, engine operation and time spent waiting or manoeuvring at ports. The hard sail should reduce the engine power needed under favourable wind conditions, but the savings must be calculated against comparable operating conditions. No verified first-voyage fuel use, carbon intensity or methane-slip measurement has been supplied for MAIZURU KAZENOMAI, preventing a direct test of the forecast at this stage.
MOL aims to deploy 25 Wind Challenger-equipped ships by 2030 and 80 by 2035. Experience on the earlier SHOFU MARU provides evidence of the sail’s contribution, but the combination with a dual-fuel engine now needs its own operating record. On a vessel serving a coal-fired power station, the transport system can be assessed separately from the emissions associated with using its cargo. The next useful figures will be measured voyage fuel consumption, the proportion of time the sail delivers thrust and maintenance requirements during routine service.
