Post-Panamax Bulk Carrier Rides Air Bubble Blanket to Reduce Emissions

Photo credit: MHI
Mv Harvest Frost. Photo credit: MHI

Mitsubishi Heavy Industries has announced the delivery of the first of three post-panamax bulk carriers to achieve energy efficient operations through the use of an air bubble lubrication system.

Illustration shows the air bubbles produced by the MALS system. Illustration credit: MHI
Illustration shows the air bubbles produced by the MALS system. Illustration credit: MHI

The recently delivered bulk carrier, MV Harvest Frost, is the first vessel of its size to use MHI’s proprietary Mitsubishi Air Lubrication System (MALS), which reduces the drag between the vessel hull and seawater by blowing air bubbles produced at the vessel bottom. MHI says that use of the system has been proven to help Harvest Frost achieve a 27% reduction in CO2 emissions compared to conventional bulk carriers, exceeding the target figure of 25%.

Harvest Frost was delivered to the U.S. company ADM Harvest Shipping, part of the Archer Daniels Midland Company, following its completion at MHI licensing partner Oshima Shipbuilding Co., Ltd.’s shipyard in Nagasaki, Japan. The vessel was constructed with MHI providing the conceptual design and various green technologies, including the MALS.

The MALS system uses special blowers to blow air from the vessel’s bottom, producing small air bubbles that cover the bottom of the hull like an “air-carpet,” reducing friction between the hull and seawater during navigation. The system was developed by MHI with support from ClassNK, and has already been adopted in module carriers, ferries and other ships constructed by MHI, the company says.

Harvest Frost also features a new bow shape designed to reduce resistance, while shallow draught facilities help the MALS achieve its target energy savings. For propulsion, an innovative system is adopted that effectively converts the main engine power into propulsion power by positioning fins forward of the propellers and placing special grooves in the propeller boss cap, according to MHI.

ClassNK says that it has completed the EEDI appraisal of the vessel, making it the first EEDI (Energy Efficiency Design Index) certification for a vessel fitted with the MALS system.

Delivery of two other ships in the series is scheduled for completion by mid-2015. The carriers measure 237 meters in length, 40m in width, and 12.5m in designed draught: deadweight tonnage (DWT) is approximately 95,000 tons.