NYK has chartered the tug to Wing Maritime Service Corporation, another wholly owned subsidiary that operates 20 tugboats at the ports of Yokohama, Kawasaki, and Chiba and which will operate the Sakigake mainly in Yokohama and Kawasaki. It is the second environmentally-friendly tugboat to be operated by Wing Maritime which took delivery of the hybrid tug Tsubasa in March 2013.
The Sakigake is equipped with twin Niigata 6L28AHX-DF dual-fuel engines, each developing 1,618 kW. They are the prime movers for a the 360-degree steerable Niigata Z-Peller propulsion system.
The DF engines can use either of LNG and diesel oil, depending on conditions. Compared with conventional tugboats that use marine diesel oil, Sakigake emits about 30 percent less carbon dioxide, 80 percent less nitrogen oxide, and absolutely no sulfur oxide when using LNG as fuel.
NYK says that the small size of most tugboats, the limited amount of space, and the large variation in engine power make it difficult to create an LNG fueled tugboat. Keihin Dock was able to achieve the desired level of environmental performance while maintaining the same hull form and steering performance of existing tugboats. To do this, the shipbuilder made full use of its knowledge and technical strengths, and worked closely with both Niigata Power Systems and Air Water Plant & Engineering Inc. to develop equipment for supplying LNG.
LNG will be supplied by Tokyo Gas Co and delivered to the vessel from a tanker truck at a pier in Yokohama, with a successful trial fueling being carried out in July.
The project received subsidies from Japan's Ministry of Economy, Trade and Industry and the Ministry of Land, Infrastructure and Transport, which support projects promising energy-saving logistics and innovative maritime transport improvements. ClassNK also provided joint research support.
The NYK Group has already ordered the world's first LNG-fueled car carrier, in addition to an LNG supply vessel, and the group is set to participate in the LNG bunkering business.