Dutch subsea services and vessel operator N-Sea has contracted compatriot shipyard Neptune Marine for the construction of a methanol-retained multipurpose cable maintenance vessel to strengthen its fleet capacity.
The vessel is under construction in Poland and will transfer to The Netherlands in Q4 2025 for fitting and commissioning in Q2 2026.
The new built DP2 vessel, ‘Altera’ will be dual fuel (methanol) prepared, equipped with a 25t offshore knuckle boom crane, mooring system and can accommodate up to 99 people.
The deck spread has been designed and procured by N-Sea, considering valuable lessons learned by the N-Sea team over the last 15 years, in cable repair and installation on Offshore Wind and Interconnector projects. The 4,500t carousel, 15t tensioner, quadrant handling system and shutes have been designed to handle cables with minimum bending radius till 5mtr. Installation of the deck spread will start in Q1 2026 by the N-Sea mobilisation team in The Netherlands, managed from the new offshore supply base and logistic centre in IJmuiden.
Due to the combination of its mooring system, DP2 capabilities and beaching capacities, the vessel will be able to operate year round in both very shallow and deep water conditions, on interconnector, export and inter-array cable projects.
N-Sea is a leading integrated subsea solutions provider specializing in Survey, UXO Identification & Disposal, IRM & Construction, and Subsea Cable Repair & Installation. The company delivers end-to-end solutions for subsea infrastructure and assets, catering to the needs of clients across the international offshore energy sector while prioritizing a safe and efficient working environment.
By minimizing complex interfaces, leveraging strong project management, and maintaining a client-centric approach, N-Sea creates significant value for its partners. With decades of industry expertise, the privately owned Dutch company operates across the EMEA region, employing over 500 professionals and achieving a revenue of €200 million in 2024.