VESSEL REVIEW | Discovery – Hybrid cable layer to support wind farm construction off Japan
Norwegian shipbuilder Vard has handed over a new hybrid cable laying and construction vessel to Japan's Toyo Construction.
Discovery was designed by Vard Design in compliance with ClassNK rules and will be operated primarily in support of customers in the Japanese offshore wind market. Her hull was built by Vard Shipyards Romania while final outfitting and commissioning were undertaken at Vard Langsten in Norway.
The vessel has an optimal hull design to suit the natural and construction conditions in Japan, allowing her to be used in both shallow and deep waters for floating offshore wind power generation and DC power transmission projects. Vard said she is able to carry out construction work at a high rate of operation in a wide range of ocean areas, which will enable her to also be deployed worldwide if needed.
Able to switch between functions for greater flexibility
The vessel can switch between cable laying mode and construction mode, providing scalability to accommodate future phases of wind farm construction such as mooring of floating turbines, cable burial and construction of HVDC submarine networks.
The tailor-made Discovery has an LOA of 150.1 metres (492.5 feet), a beam of 28 metres (92 feet), a maximum draught of seven metres (20 feet), a depth of 12.2 metres (40 feet), a gross tonnage of approximately 19,000, and accommodation for up to 90 personnel.
Vard Chairman Alberto Maestrini said that Discovery’s dimensions make her the largest purpose-built cable laying vessel to be operated in Japan.
The onboard equipment includes removable above and below deck cable carousels with a total carrying capacity of 9,000 tonnes, Huisman 400-tonne and 100-tonne active heave-compensated cranes, and a DP2 system.
A large deck area will make the vessel suitable for multi-purpose applications such as ground-based foundation work, floating offshore wind mooring work and marine resource-related projects.
Propulsion machinery and electronics configured for heavy duty use
The hybrid propulsion arrangement has a total installed power of 12,800 kW, which can deliver a service speed of 12 knots.
The setup also includes a 2MWh energy storage system and shore power connection facilities from Vard Electro, thrusters and a steering system from Brunvoll, and an energy management system. Vard said these will help result in higher energy efficiency and reductions in emissions of CO2, NOx, and SOx.
Vard Electro also supplied the vessel’s switchboards as well as the entertainment and communications systems. Vard Interiors worked on the interior spaces and installed the HVAC-R system.
Some of the other key features are a helicopter deck and a four-point mooring system. The electronics meanwhile include satellite communications equipment from Intellian.
The 90 crew and other personnel are all housed in single cabins with en suite showers and toilets.
