Shin-Nippon Kaiyosha (SNK), a progressive NYK Group company operating under the slogan “Challenge to the future” spoke with the Japan P&I Club, the insurer behind the world's first commercial ammonia-fuelled tugboat, Sakigake, to discuss the development and safe operation of this groundbreaking vessel.

A Project Led by Industry Experts

The ammonia-fuelled tugboat Sakigake was completed in August 2024, evolving from the hull of Japan's first LNG-fuelled tugboat — a vessel SNK had operated for eight years since its maiden voyage in 2015. Following a rigorous 10-month conversion process that included substantial modifications and engine replacement, Sakigake was transformed to operate on ammonia fuel.

Developing a commercial ammonia-fuelled vessel represents a pioneering achievement on a global scale. For SNK, already recognised as an innovator in LNG-fuelled vessel operations, this project presented a unique set of challenges. Ammonia fuel differs markedly from LNG in terms of toxicity, flame retardancy, and corrosiveness. Ensuring the vessel’s operational feasibility while balancing safety with commercial viability was a significant hurdle.

The project was a collaborative effort involving SNK's parent company, NYK Line (NYK), alongside key partners such as IHI Power Systems Co., Ltd., Nippon Kaiji Kyokai (ClassNK), and Keihin Dock Co., Ltd. Within this collaboration, SNK played a pivotal role by providing expertise during the design phase, supervising construction, developing bunkering operations, and training crew members. These efforts were bolstered by the extensive experience SNK gained from eight years of operating an LNG-fuelled tugboat.

Ms. Asae Yagino, manager of the Planning Department at SNK, explained, "Given the number of people involved, we held regular weekly online meetings, supplemented by close face-to-face communication, to ensure thorough information-sharing."

With each participant being an expert in their respective field, there was a dynamic exchange of ideas, all focused on one common goal — safety, which facilitated the smooth progress of the project.

"Safety was our top priority, and everyone was aligned on the optimal solution. We approached the project with professionalism and a positive attitude, which ensured the project progressed seamlessly," added Mr. Akiyuki Ishida, deputy general manager of SNK’s Technical Department.

The knowledge gained from operating the LNG-fuelled tugboat was particularly valuable in the engine development. Close collaboration allowed the manufacturer to combine its equipment expertise with SNK’s operational expertise in gas systems, thereby enhancing the overall quality and reliability of the final product.

Relentless Pursuit of Safety — Understanding Risk and Responding Appropriately

Given ammonia’s toxicity to humans, ensuring crew safety remained paramount. To meet this challenge, SNK worked diligently to train onshore and offshore crews even before the vessel’s launch. These initiatives included health and safety training in collaboration with an ammonia manufacturer, experimental sessions to study ammonia’s physical properties using a group company's laboratory, and safety briefings led by the shipowner, NYK. Guided by the principle "Understand the risk and respond appropriately," these training efforts continue regularly even after the vessel’s launch.

Mr. Yasuhiro Asada, senior manager of the Marine Department at SNK, explained, "Ammonia is a dangerous substance, but it can be handled safely with the right knowledge. Through training, we aim to ensure that the crew can perform their duties with peace of mind."

In terms of hardware, Sakigake adopted different safety measures distinct from those of the original LNG-fuelled vessel from which it was converted. Recognising the risks associated with ammonia, the engine room is designed as a no-entry zone while the engine operates. Should a crew member mistakenly attempt to access it, the vessel is designed to automatically switch the fuel supply from ammonia to diesel fuel. In addition, because ammonia dissolves easily in water, a control system has been installed to spray fresh water to absorb any leaked ammonia in emergencies. Other numerous safety measures include segmenting the vessel into three distinct zones — restricted, conditional, and safe — with each requiring specific protective equipment for crew members. Crew must also carry portable gas detectors and protective masks at all times, and are trained on their proper use before boarding.

Due to the restricted areas, Sakigake is equipped with more than ten 360-degree cameras, which allow constant monitoring throughout vessel operations, compared to about five fixed cameras on a typical vessel.

"We have anticipated worst-case scenarios and pursued safety from every angle. Our mission is to create an environment where crews can perform their duties with complete peace of mind," explained Mr. Ishida.

Bringing Operational Knowledge into Design — Ensuring Safety and Commercial Viability

The Sakigake crew are all seasoned professionals with experience operating an LNG-fuelled vessel — expertise that has played a key role in ensuring the safe operation of ammonia-fuelled vessel.

Ms. Yagino commented, "We’ve applied our LNG-fuelled vessel experience to ammonia-fuelled operations, but ammonia’s distinct properties necessitate acquiring new skills and knowledge. Our crew is continually learning and gaining valuable hands-on experience."

The expertise of crew members with LNG-fuelled vessel experience also influenced the design of Sakigake. By incorporating insights from on-site staff, the project team aimed to create a safer and more efficient vessel.

"Input from on-site staff with onboard experience was incredibly valuable. We’re continuing to work closely with the crew to make the vessel even better," added Mr. Ishida.

The World's First Ammonia Bunkering

Building on the knowledge gained from operating the LNG-fuelled tug, Sakigake is now pioneering ammonia fuel bunkering. The "truck-to-ship method" uses a dedicated hose to connect a tank lorry on land directly to the vessel. This marked the world's first instance of supplying ammonia fuel to a commercially operated vessel using this method.

Ms. Yagino explains, "Implementing ammonia bunkering through the truck-to-ship method was a global first, presenting numerous challenges. We successfully achieved this milestone by collaborating with relevant organisations and implementing comprehensive safety measures."

The successful execution of ammonia bunkering is expected to bolster the development of an ammonia fuel supply chain, contributing significantly to the overarching goal of zero emissions.

Taking on the Challenge of Next-Generation Fuels — A Project in Motion

SNK believes that the safe operation of Japan's first LNG-fuelled tugboat over eight years played a pivotal role in the broader adoption of LNG-fuelled vessels. Likewise, by successfully operating an ammonia-fuelled vessel, SNK aims to enhance the credibility of ammonia as a marine fuel and help establish it as a next-generation fuel of choice.

"Ammonia is expected to be used as fuel for thermal power plants and as a hydrogen carrier. We foresee demand growing in Japan and internationally, making it essential to develop an ammonia value chain with a low environmental impact," commented Ms. Yagino.

To further capitalise on Sakigake’s success and advance the broader utilisation of ammonia-fuelled vessels, NYK has formed a consortium with partner companies to complete an oceangoing ammonia-fuelled ammonia carrier by the end of fiscal year 2026. The vessel will incorporate the same engine as the one used on Sakigake (repurposing it as an auxiliary generator), and the experience gained from this project will be fully applied.

NYK has set a goal of "net zero emissions by 2050," and SNK, as a part of the NYK Group, is actively exploring not only ammonia fuel but also other next-generation fuels to meet this goal. Tugboats, unlike large vessels, experience large engine load fluctuations, making it necessary to experiment with a variety of alternatives, including biofuels and synthetic fuels, in addition to ammonia. The ongoing efforts with LNG and ammonia are also helping to raise employee awareness of decarbonisation.

The success of the ammonia-fuelled tugboat Sakigake is a testament to the unwavering dedication and passion of countless individuals. The project is an evolving challenge, and SNK remains committed to advancing next-generation fuels and contributing to a sustainable future, truly embodying its motto: "Challenge to the future"

Conclusion

This interview provided the Japan P&I Club with a valuable opportunity to hear directly from those at the forefront of maritime innovation in the transition toward decarbonisation.

We remain committed to listening to the evolving needs of our members as they navigate new challenges. In support of their safe operations, we will continue to offer tailored insurance services designed to address even the most demanding scenarios.

We extend our sincere gratitude to SNK for generously sharing their experience and insights.