ClassNK issues AiP for Liquified CO₂ carrier design with Wind-Assisted Propulsion System

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 during the Sea Japan 2026 event held this week.

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 (render pictured, courtesy MOL) 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.