Usuki Shipyard Co. delivered the first chemical tanker in the world to use a combination of duplex stainless steel (DSS) and stainless clad steel in the construction of its cargo tanks to Oita-based Hiro Naviera on 15 November 2014. The application of the duplex steels in the vessel’s cargo tanks was made possible as a result of an expansive joint research program involving steel manufacturers, leading technical universities and ship designers, as well as ClassNK, which supported the project as part of its Joint R&D for Industry Program.
The 12,500MT chemical tanker Sunrise Hope, owned by Hiro Naviera, will be operated by Nippon Marine Co. The eco-ship design vessel is equipped with 14 cargo tanks, all of which employ duplex stainless steel technology. Construction of the vessel was carried out in accordance with ClassNK’s Guidelines on Welding of Duplex Stainless Steels, which were released in January 2014, marking the first time the Guidelines have been used in the construction of an actual vessel. Although duplex stainless steel technology has been used previously in shipbuilding internationally, this marks the first time in the world that a combination of both duplex and stainless clad steels have been used in the construction of a chemical tanker’s cargo tanks. It is also the first time that duplex stainless steels have been used in a Japanese shipyard, while the lean duplex stainless steel, which contains lower nickel compared to duplex stainless steel, have been used in some cases.
