ClassNK approves first ammonia-fuelled bulk carrier with deck-mounted Type B tank

Type B tanks allow higher capacity and design flexibility.

ClassNK has granted Approval in Principle (AiP) for an ammonia-fueled Panamax bulk carrier designed by the Planning and Design Center for Greener Ships.

The design is the first to feature an IMO Type B independent fuel tank installed on the exposed deck, with the AiP confirming compliance with safety and regulatory standards.

Ammonia is gaining traction as a zero-carbon marine fuel since it emits no CO₂ during combustion. Whilst IMO Type C tanks are commonly used, Type B tanks are emerging as an option for larger fuel capacity, offering improved efficiency and design flexibility.

ClassNK reviewed the vessel under its “Guidelines for Ships Using Alternative Fuels” and relevant steel ship construction rules before issuing the approval.

The AiP was awarded following a comprehensive review of the vessel design in accordance with these guidelines, as well as the Rules and Guidance for the Survey and Construction of Steel Ships. Compliance with all relevant standards was confirmed prior to certification.

The organisation said it will continue supporting decarbonization efforts through safety assessments and standards development.