22 April 2026 – ClassNK has issued an Approval in Principle (AiP) for a Liquified CO₂ carrier installing the ‘Wind Challenger,’ a hard sail wind propulsion system. The ship is jointly developed by Mitsui O.S.K. Lines, Ltd. (MOL) and Samsung Heavy Industries Co., Ltd. (SHI). The AiP confirms the feasibility of the ship’s design from the perspective of applicable rules and safety requirements. A certificate handover ceremony was held at Sea Japan 2026.
As a solution for responding to the environmental regulations and fuel cost reduction, the implementation of wind-assisted propulsion systems (WAPS) has been progressing. When such systems are installed on board ships, they are expected to be effective in reducing CO₂ emissions, etc., by taking advantage of wind power. To support the safe implementation of these technologies, ClassNK published the “Guidelines for Wind-Assisted Propulsion Systems for Ships” as a standard for wind-assisted propulsion systems and ships equipped with these systems.
ClassNK carried out a review of the conceptual design of the ship based on its ‘Rules and Guidance for the Survey and Construction of Steel Ships’, ‘Guidelines for Wind-Assisted Propulsion Systems for Ships (Edition 2.2)’. In addition, ClassNK participated in the risk assessment through HAZID from a regulatory and technical perspective to examine the combined risks arising from the ship’s unique design elements —such as the fore accommodation, liquefied CO₂ cargo, and multiple units of the Wind Challenger— and validated the results of the assessment. Upon confirming the results and that the prescribed requirements had been met, ClassNK issued AiP.
Mr. Yoshihiko Sugimoto, Executive Officer, MOL
Dr. Youngkyu Ahn, Executive Vice President, SHI
Mr. Masaki Matsunaga, Executive Vice President, ClassNK
ClassNK will continually strive to contribute to advanced decarbonization initiatives through safety assessments and more.
Related press release:
ClassNK issues world’s first approval in principle (AiP) for LNG carrier installed with Wind-Assisted Propulsion System – For “Wind Challenger”-installed LNG carrier jointly developed by MOL and Hanwha Ocean –https://www.classnk.or.jp/hp/en/hp_pressrelease.aspx?id=11882&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.
