Japan’s Penta-Ocean Construction has signed a shipbuilding contract with Seatrium covering the construction of what it says will be the world’s largest heavy lift vessel. To be used for the installation of offshore wind turbine monopile foundations, it will feature a fully revolving 5,000-tonne crane and the Ulstein U-stern.
The customised ULSTEIN HX118 design will feature a 5,000-ton Huisman main crane and the ULSTEIN U-STERN™, which enables the installation of increasingly larger monopile foundations.
Following feasibility and concept studies in 2023, Penta-Ocean Construction selected Ulstein for the project. Ulstein proposed the HX118 with the U-STERN™, a design that builds on Ulstein’s successful track record of crane vessels. The chosen design offers a well-balanced combination of a flush work deck, lifting capacity, accommodation and DP capability and will be the largest X-BOW® vessel to date.
The HX118 design is 215m long and 56m wide. The longest X-BOW vessel so far is the Island Venture (160m), and the vessel with the widest beam is the Fortitude (32m).
The U-STERN™, developed by Ulstein, features longitudinal storage and upending of monopiles along the ship’s centreline. This innovation enables the installation of longer monopiles without overhanging the ship’s sides and allows the vessel to face the waves during the installation, minimising ship motions and fuel consumption.