Work Underway to Convert NYK’s LNG Tug to First Ammonia-Fueled Vessel

ammonia-fueled tug
NYK is converting its LNG-fueled tug to operate on ammonia (NYK)

Published Oct 31, 2023 8:48 PM by The Maritime Executive

Japan’s NYK Group reports that work has begun on its project to convert the company’s pioneering tug, the LNG-fueled Sakigake to be a demonstration vessel and among the world’s leaders in the use of ammonia. It is one of several projects moving forward to introduce ammonia which is widely viewed as one of the leaders for future alternative fuels.

The project is years in the making with NYK, IHI Motor Co., and Nippon Kaiji Kyokai announcing in 2020 that they have signed a joint R&D agreement for the commercialization of an ammonia-fueled tugboat. After initial discussions, the project won the support of the Green Innovation Fund Project of Japan’s New Energy and Industrial Technology Development Organization (NEDO). The project launched in October 2021 with NYK, Japan Engine Corporation, IHI Power Systems Co., and Nihon Shipyard Co., agreeing to work together for the development of a vessel with a domestically produced ammonia-fueled engine.

The vessel selected for the project was historic even before as in 2015 the Sakigake became Japan’s first LNG-fueled vessel. The 272-ton tug, which is 122 feet in length, operated for years in Tokyo Bay by the NYK Group's Shin-Nihon Kaiyosha. The tug conducted its last bunkering in Yokohama in late July 2023 with the companies reporting they were ready to proceed with the conversion. ClassNK reviewed the designs and issued the approvals. In addition, the companies report the new engine has been tested at IHI Power Systems’ Ota Plant to confirm virtually zero emissions from the unburned ammonia and nitrous oxide (N2O).


The tug Sakigake was pulled from the water recently to begin the conversion to run on ammonia (NYK)


The tug recently arrived at the Oppama factory of Keihin Dock Co. to begin the conversion process. It calls for cutting the engine room to remove the existing LNG-fueled equipment and install the new ammonia-fueled machinery. This includes a new main engine and the fuel tanks designed for ammonia.

A-tug is scheduled for delivery in June 2024. The vessel will continue to be operated by Shin-Nihon Kaiyosha as a demonstration to verify its decarbonization effect and operational safety as an ammonia-fueled vessel.

U.S.-based Amogy is also pursuing a project to demonstrate the first ammonia-fueled tug as part of its efforts to develop the technology for the shipping industry. In March 2023, they announced the purchase of a tug built in 1957 which they planned to convert to an ammonia demonstration ship. Amogy uses an ammonia-to-power technology that feeds liquid ammonia through its cracking modules integrated into a hybrid fuel cell system, which powers the electric motors. They said they were targeting the first demonstrations late this year following on from Amogy’s previous demonstrations with an ammonia-powered drone flight, a 100kW powerpack in a tractor, and a 300 kW powerpack for an ammonia-powered semi-truck.