Press Release

Title:

ClassNK grants Approval in Principle (AiP) for the designs of cable jointing vessel and cable burial vessel developed by Mitsui O.S.K. Lines

24 December 2025

Tokyo - ClassNK has issued an Approval in Principle (AiP) for the designs of a cable jointing vessel and a cable burial vessel developed by Mitsui O.S.K. Lines, Ltd. The certification demonstrates its feasibility from regulatory and safety perspectives.

In Japan, the expansion of wind power generation utilizing offshore areas and surrounding islands with favorable wind conditions and relatively limited site constraints is expected as part of efforts to increase the share of renewable energy. However, regions suitable for wind power generation are often located far from major electricity demand centers, making the development and reinforcement of power transmission infrastructure a key challenge in delivering generated electricity to demand areas.
In response to this challenge, long-distance subsea DC transmission using cable jointing and burial vessels is regarded as an effective solution for achieving efficient power transmission.

ClassNK carried out a design review of the ship based on part O of its "Rules and Guidance for the Survey and Construction of Steel Ships", as well as other relevant rules. ClassNK issued AiP after it was confirmed that the prescribed requirements were met.

ClassNK will continue to contribute to the widespread adoption of offshore wind power generation by supporting new technology development and social implementation, including through safety assessments.

Image of a cable jointing vessel (left) and a cable burial vessel (right) (Courtesy of Mitsui O.S.K. Lines)

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.

For inquiries about this press release:
ClassNK Technical Solution Department
Tel: +81-3-5226-2017
E-mail: hld@classnk.jp

For media-related inquiries:
ClassNK Public Relations Team
4-7 Kioi-Cho, Chiyoda-Ku, Tokyo 102-8567 Japan
E-mail: eod@classnk.or.jp