22 April 2026 – ClassNK has issued an Approval in Principle (AiP) for an Ammonia–Fueled Panamax Bulk Carrier Equipped with an IMO Type B Independent Fuel Tank developed by Planning and Design Center for Greener Ships. This marks the world’s first AiP for a ship with Type B tanks installed on the exposed deck. The certification demonstrates its feasibility from regulatory and safety perspectives.
As decarbonization becomes a major challenge for the shipping industry, ammonia, which emits no CO₂ during combustion, is expected to be utilized as a zero‑carbon marine fuel. Traditionally, IMO Type C tanks* have been the mainstream choice for ammonia‑fueled ships and other alternative‑fuel ships due to their advantages in productivity and cost. Meanwhile, for the large-capacity fuel tanks required on ammonia-fueled ships, IMO Type B tanks are gaining recognition as an alternative, offering superior cargo efficiency and outfitting flexibility.
ClassNK has been involved in projects aiming for zero-emission ships using ammonia fuel in terms of safety assessment, and has issued its ‘Guidelines for Ships Using Alternative Fuels’ as a necessary standard to minimize the risks related to ammonia-fueled ships for the ships, crews, and environment by stipulating requirements for installation, controls, and safety devices. Following a review of the ship design based on the above guidelines and the relevant Rules and Guidance for the Survey and Construction of Steel Ships. Upon confirming compliance with the prescribed requirements, ClassNK issued an AiP.
Left: Mr. Yoshifumi Miyatake, Senior Executive Vice President, ClassNK
ClassNK will continually strive to contribute to advanced decarbonization initiatives through safety assessments and more.
* One of the independent tank types defined under the IGC Code, the international code for the construction and equipment of ships carrying liquefied gases such as ammonia and LNG in bulk.
Related press release:
ClassNK issues Approval in Principle (AiP) for ammonia-fueled Panamax bulk carrier developed by Planning and Design Center for Greener Ships (GSC)
https://www.classnk.or.jp/hp/en/hp_pressrelease.aspx?id=7262&layout=1
ClassNK awards approval in principle (AiP) for ammonia fuel tank (IMO Type B independent tank) for container ships developed by GSC
https://www.classnk.or.jp/hp/en/hp_pressrelease.aspx?id=10882&layout=1
Approval in Principle (AiP):
At the initial stage of designing or before the specific target ship to be implemented is decided, the design is examined based on the existing regulations such as international conventions and ship classification rules, and an Approval in Principle (AiP) is issued as proof of conformity with requirements. It also prevents rework of regulatory aspects in the post-process, shortens the examination time at the time of class registration, and can be used as a technical basis for external appeal of the design status. For more information, visit our website.
