Top Page > Press Release 2025 > MOL Wins AiP for Designs of Cable Jointing/Burial Vessels

MOL Wins AiP for Designs of Cable Jointing/Burial Vessels

December 24, 2025

TOKYO-Mitsui O.S.K. Lines, Ltd. (MOL; President & CEO: Takeshi Hashimoto) today announced that it has obtained approval in principle (AiP) (Note 1) from Nippon Kaiji Kyokai (ClassNK) (President & CEO: Hayato Suga, Headquarters: Chiyoda-ku, Tokyo) for the basic design of specialized vessels to joint and bury subsea power cables(Note 2).

CG rendering of a cable jointing vessel
CG rendering of a cable burial vessel

Power transmission lines must be reinforced to deliver electricity from wind power generation sites, such as those in Hokkaido, to distant major consumption centers. Long-distance subsea DC transmission is regarded as a promising solution for efficiently transmitting large volumes of power, and it is considered effective not only for power grid development but also for offshore wind power generation. MOL is working with Sumitomo Electric Industries, Ltd., Furukawa Electric Co., Ltd., and Nippon Yusen Kabushiki Kaisha (NYK Line) to develop fundamental technologies-including a new type of cable-laying vessel-as part of a project subsidized by the Japanese government's New Energy and Industrial Technology Development Organization (NEDO) (Note 3).

One of MOL's roles in this project is to develop technologies for cable jointing and burial vessels, and acquisition of AiP from ClassNK represents a major milestone.

The MOL Group identifies offshore wind power as a key business segment in its "BLUE ACTION 2035" management plan. By developing vessels for subsea power cables, the group aims to contribute to the expansion of renewable energy and the realization of a decarbonized society.

(Note 1) AiP indicates that drawings for a product at the early design stage have been reviewed in consideration of regulatory requirements and approved as meeting technical and safety standards.

AiP certificate for cable jointing vessel
AiP certificate for cable burial vessel

(Note 2) [About cable jointing and cable burial vessels]
Both are designated in this project. Transmission cables laid on the seafloor cover long distances. Therefore, support vessels are needed to joint the cables that will be laid multiple times at sea; these are called jointing vessels. In addition, the cables are buried in the seabed to keep them from being damaged by vessel anchors, fishing nets, and so on. This process is mainly carried out using remotely operated vehicles (ROVs), and the work vessel that serves as the mother ship for the ROVs and is responsible for placing the ROVs on the seafloor and retrieving it is called a cable burial vessel.

(Note 3) For details, please refer to the following press release.
NEDO Selects MOL for "Research and development of a multi-purpose and multi-terminal hIGH voltage direct current Transmission system" (RIGHT Project) - Boosting Renewable Energy through New Technology for Cable Laying Support Vessels -

MOL Group 5 Sustainability Issues
MOL Group identifies "Sustainability Issues" (Materiality) as our key issues for sustainable growth with society through realization of the Group Vision.
We anticipate this initiative to contribute especially to the realization of "Environment -Conservation for Marine and global environment-" and "Innovation -Innovation for development in marine technology-."