A report published by the Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping (MMMCZCS) on a joint study project on maritime decarbonisation involving TSUNEISHI SHIPBUILDING examines the feasibility of retrofitting existing KAMSARMAX bulk carriers for methanol dual-fuel operation.

■ Retrofit of an 82,000 DWT bulk carrier for methanol dual-fuel capability
zerocarbonshipping.com/files/retrofit-of-an-82-000-dwt-bulk-carrier-for-methanol-dual-fuel-capability.pdf

This project, led by MMMCZCS, evaluates the technical and economic feasibility of retrofitting conventionally fuelled bulk carriers for methanol dual-fuel operation. As the maritime industry advances towards carbon neutrality by 2050, decarbonising the existing fleet has become an increasingly important challenge, highlighting the need for practical greenhouse gas (GHG) reduction measures not only through newbuildings but also through vessel retrofits.
The study was conducted using TSUNEISHI SHIPBUILDING’s flagship KAMSARMAX as the reference design and examined the engineering requirements for converting an existing bulk carrier fired by heavy fuel oil into a methanol dual-fuelled vessel. Medium-sized bulk carriers (60,000–99,000 DWT), including KAMSARMAX vessels, account for approximately 28% of the global bulk carrier fleet and were responsible for around 63 million tonnes of GHG emissions in 2018.
The study comprehensively examined key aspects of the conversion, including methanol fuel tank arrangement, fuel supply systems, impacts on hull structure and stability, hazard identification (HAZID), retrofit methodology and economic viability. Particular attention was given to optimising fuel tank arrangements while minimising any impact on cargo-carrying capacity, as methanol requires larger storage volumes due to its lower energy density compared with conventional marine fuels.
The design concept has also received Approval in Principle (AiP) from ClassNK, confirming the technical feasibility of the proposed design and its alignment with applicable safety requirements.
According to the report, the retrofit is estimated to take approximately 75 days, while conversion costs are projected to be equivalent to approximately 25–30% of the cost of a conventionally fuelled newbuilding. The study also explores opportunities to reduce dry-dock and off-hire periods by modularising and prefabricating retrofit work offline wherever possible.
TSUNEISHI SHIPBUILDING is committed to providing practical decarbonisation solutions for fleets worldwide, including the widely operated KAMSARMAX series, through both the development of next-generation newbuildings and retrofits for existing vessels. The company will continue to contribute to the realisation of carbon neutrality across the maritime industry by advancing alternative fuel technologies and environmental solutions that deliver value throughout the entire vessel lifecycle.
For further details, please refer to the report published by the Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping.

Related Information
■ Retrofit of an 82,000 DWT bulk carrier for methanol dual-fuel capability
https://www.zerocarbonshipping.com/publications/retrofit-of-an-82000-dwt-bulk-carrier-for-methanol-dual-fuel-capability

■ TSUNEISHI SHIPBUILDING Has Received the AiP from ClassNK for the Design of the Methanol Dual-Fuel Vessel for the Converted Existing Heavy Oil Vessels
https://www.tsuneishi.co.jp/english/news/p554/