VESSEL CONVERSION | Shenghang Yongle – Gas carrier rebuilt for ammonia bunkering and supply duties
Chinese operator Jiangsu Andefu Energy Development has converted the liquefied gas carrier Shenghang Yongle (盛航永乐) and configured her to carry liquid ammonia as well as deliver it as marine fuel via ship-to-ship (STS) bunkering.
China Classification Society (CCS) has awarded the vessel a class certificate for ammonia-fuel bunkering, the first such certificate issued to an operational vessel. On October 13, Shenghang Yongle delivered 1,000 tonnes of green ammonia to the Belgian-flagged, 210,000DWT Mineral Europa at Xiushan East Anchorage in Zhoushan, an operation CCS and the China Maritime Safety Administration described as the first commercial ship-to-ship bunkering of green ammonia.
Andefu, which operates the ship, led the conversion and certification process. Swedish naval architecture firm FKAB Marine Design, the original designer, prepared the conversion's technical drawings alongside Gloryholder, a cargo handling supplier.
FKAB announced the completed conversion in September, describing the ship as the world's first operational ammonia bunkering vessel.
Certified for international operation
Shenghang Yongle is owned and managed by Nanjing Shenghang Shipping and was built by China Merchants Jinling Dingheng Shipbuilding, with the owner listing April 15, 2024 as her completion date. She entered commercial service carrying liquid ammonia in August 2024.
The vessel is a liquefied gas carrier designed for semi-refrigerated and semi-pressurised service, with a cargo capacity of 5,546.8 cubic metres (1.22 million gallons). She has an LOA of 99.9 metres (328 feet), a moulded beam of 19 metres (62 feet), a deadweight of 4,626, and a gross tonnage of 6,524. The ship is registered in Nanjing and is designed for unrestricted navigation in domestic and international trade.
Cargo is carried in two independent cylindrical Type C tanks with a design pressure of 5 bar, a minimum design temperature of -48°C, and a maximum cargo density of 0.68 t/m³.
The owner stated that the tanks are built from 13MnNi6-3 low-temperature carbon-manganese steel with external insulation. Temperature management is handled by oil-free cargo refrigeration compressors and two low-temperature reliquefaction systems.
Bunkering setup complementing existing ammonia transport fitout
According to the owner, the original carrier can load low-temperature ammonia, propylene, propane and butadiene, as well as LPG, butadiene and VCM at ambient temperature. The owner also said the ship was designed to meet EEDI Phase III requirements ahead of its application date.
The design carries Liquefied Gas Carrier Type 2G, Type C Independent Tank and Ice Class B notations. The hull uses FKAB's patented bow, which was optimised through CFD for wave and calm-water performance within the design's principal dimension constraints.
Manoeuvring is assisted by a high-lift rudder and a bow thruster.
FKAB said the existing ammonia-compatible containment and cargo handling systems formed the technical basis for the conversion and could meet further requirements for transferring ammonia as fuel via STS.
Andefu said the four main areas of work in the project were adapting and upgrading the bunkering system, preparing operating procedures, conducting risk assessments, and putting safety and emergency-response measures in place.
Through repeated drawing reviews, onboard surveys and safety verification with CCS, the project addressed ammonia's toxicity, material compatibility, operation at low temperatures, leak detection and control of risks during STS transfer.
Shenghang Yongle will remain on time charter to Andefu, which took delivery of the ship under a one-year charter on August 26, 2024.
Shenghang shareholders approved a renewal in August 2025 that extends the charter through December 31, 2034, with monthly hire made up of a capital component plus actual vessel operating and management expenses.
