ClassNK has published a revised edition of its Guidelines for Ships Using Alternative Fuels, updating safety requirements for vessels using methanol, ethanol and hydrogen and incorporating new interim guidance on hydrogen, Hellenic Shipping News Worldwide reported on 18 August 2026.
The document, issued as Edition 3.1, revises safety requirements for ships using methanol and ethanol and makes specific amendments for hydrogen-powered vessels in Part D. Hellenic Shipping News said the Part D revision incorporates the International Maritime organisation’s Interim Guidelines for the Safety of Ships Using Hydrogen as Fuel, MSC.1/Circ.1701, issued this year.
The bulletin makes clear the edition is intended to bring the class society’s guidance into closer alignment with the IMO’s recent interim recommendations on hydrogen safety. Hellenic Shipping News also reported that the revised edition introduces additional provisions beyond the IMO text, although the summary did not enumerate those measures.
ClassNK’s update covers three fuel types named in the report: methanol, ethanol and hydrogen. Edition 3.1 is described as a targeted revision focused on the safety regime for ships employing those fuels rather than a wholesale rewrite of previous guidance.
The timing of the revision follows the promulgation by the IMO earlier this year of MSC.1/Circ.1701, which provides interim safety guidance for hydrogen as a ship fuel. Hellenic Shipping News noted the circular has been incorporated into ClassNK’s Part D as part of Edition 3.1.
Industry readers will find the revised edition significant because it draws an explicit connection between an IMO interim circular and a leading classification society’s technical guidance. Hellenic Shipping News’ report frames the move as an update to safety requirements for the named fuels rather than an expansion to other alternative fuels.
Regulatory alignment with IMO guidance
By incorporating MSC.1/Circ.1701 into Part D, the revised Guidelines for Ships Using Alternative Fuels (Edition 3.1) signal an effort to standardise expectations for hydrogen-fuelled vessels. Hellenic Shipping News reported that the circular issued by the IMO this year is reflected in the text.
The report states that, beyond adopting the interim circular, Edition 3.1 introduces further provisions; the summary provided did not detail those additional elements. Operators and technical teams will thus need to consult the full text of ClassNK’s Edition 3.1 to identify the precise changes.
Scope limited to methanol, ethanol and hydrogen
Hellenic Shipping News’ summary emphasises that the revision focuses on methanol, ethanol and hydrogen. Edition 3.1 is presented as a safety-focused update for ships using those fuels, with Part D dedicated to hydrogen-fuelled vessels and the incorporation of the IMO interim guidance.
The report does not indicate further alterations to guidance for other alternative fuels, nor does it provide a list of the additional measures introduced alongside the IMO material.
The ClassNK revision reported by Hellenic Shipping News reflects a continuing process among regulatory and technical bodies to adapt safety frameworks as new marine fuel options are adopted. Readers seeking operational detail or compliance implications should refer to the full text of Edition 3.1 and the IMO circular MSC.1/Circ.1701 for the precise requirements and any newly introduced provisions. The Hellenic Shipping News item carrying this summary was published on 18 August 2026.