ClassNK has published the Guidelines for Ships Using Alternative Fuels (Edition 3.0), which now encompass safety requirements for hydrogen-fueled ships along with methanol, ethanol, LPG, and ammonia. These guidelines offer guidance for designing alternative-fueled ships to enhance safety and mitigate risks associated with using alternative fuels at sea. The edition outlines specific safety requirements for installation, controls, and safety devices to safeguard ships, seafarers, and the marine environment from potential hazards. The rules incorporated in Part GF of the 'Rules and Guidance for the Survey and Construction of Steel Ships' include the IGF Code as the fundamental requirements. Part D of the guidelines, established based on insights from the IMO Subcommittee on Carriage of Cargoes and ClassNK's design reviews, introduces additional safety measures tailored to the characteristics of hydrogen fuel. These measures address critical aspects like preventing explosions due to hydrogen's ignition properties and minimizing the impact of hydrogen fuel leakage on seafarers and the environment. By expanding the scope of safety guidelines to encompass hydrogen-fueled ships, ClassNK aims to promote the adoption of cleaner and safer fuels in the maritime industry, aligning with global efforts towards environmental sustainability and maritime safety.