OHT orders innovative heavy lift crane vessel

OHT is pleased to announce the signing of a contract with China Merchants Heavy Industry (CMHI) in Jiangsu, China, for the construction of a 48,000 dwt semi-submersible offshore windfarm foundation installation vessel, with options to extend the program with up to three vessels. The first vessel will be ready for project deployment from early 2021. The design has been developed by OHT in close cooperation with Ulstein Design & Solutions BV, Liebherr and DNV GL. The vessel will fly the flag of the Norwegian International Ship Register.

The new additions to the existing fleet of five semi-submersible heavy transportation vessels will enable the company to take on full Transport & Installation (T&I) scope for foundations for offshore windfarms.

 “We have one overriding goal with this initiative; to bring down the cost of building offshore windfarms. Our existing fleet already represents the most efficient way of transporting offshore windfarm foundations over long distances. Combining this with the patent pending ULSTEIN Alfa Lift installation vessel design, we expect to set a new benchmark in cost per foundation installed. We look very much forward to working closely with the industry to achieve our ambitious targets”, said Torgeir E. Ramstad, CEO for OHT.

Alfa Lift is a unique T&I vessel design that includes several innovative solutions to ensure superior efficiency when installing foundations for offshore windfarms. The vessel combines unprecedented cargo carrying capacity with a 3,000 t crane and the ability to submerge offshore. Liebherr will deliver the crane which has been designed to be particularly robust with respect to motions and dynamics, enabling the crane to lift loads up to its maximum capacity in challenging offshore conditions. The vessel has a total length of 216.3 m, and a breadth of 56 m. Total usable deck area exceeds 10,000 m2. Up to 10 x 1,500 t ultra-large jacket foundations or 11 x 2,000 t XXL monopiles together with transition pieces and mission equipment can be loaded on to the decks, transported to the wind farm, and installed – all with the same vessel.

The Company’s high focus on HSE is reflected in the design. The vessel’s main deck is fully mechanized with skidding tracks, which are used to move foundations during loadout and installation. A trolley picks up each foundation and brings it to within reach of the crane. No crew is present on the main deck during these operations. The integrated motion compensated pile gripper allows installation of monopiles in DP mode, making time-consuming mooring operations unnecessary.

The vessel has been ordered with the latest engine technology. It is designed with battery hybrid propulsion, it has an exhaust gas scrubber and is Tier III compliant, all in order to protect the environment. To enhance sea state limitations and reduce weather downtime, Alfa Lift has the capability to submerge offshore during the installation operation.

All the above-mentioned features combined makes the vessel an important contributor to lowering the cost of energy from offshore windfarms.

Due to the versatile nature of the design, the vessel may also serve other secondary markets within heavy transportation, installation and decommissioning. For instance, the beam has been set to enable the vessel to carry topside structures weighing more than 30,000 t and still fit into the slot of the world’s largest installation vessel, Pioneering Spirit. As it can submerge the main deck below the sea surface, the vessel is particularly well suited to perform lifts of suction bucket jackets, mono buckets and subsea structures where lifting through the splash zone is critical.

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