Enersea delivers cable installation system for DEME’s Viking Neptun

Enersea has designed a modular next-level cable installation system (CIS) for DEME’s DP3 multipurpose installation vessel Viking Neptun.

Enersea’s scope consisted of concept and detailed design along with fabrication, mobilization and site support.

According to the company, the complete project was carried out in less than one year, comprising a.o. the assessment of DEME’s requirements, discussing possible solutions, finite element analyses, detailed calculations, fabrication support in Poland, and engineering support during mobilization.

“DEME acquired the Viking Neptun in 2022 and now the vessel is already equipped with a high tech and flexible CIS,” said Philip Scheers, Business Unit Director at DEME. “Quite an achievement as these processes normally take about three years’ time. The vessel already had a turntable capacity of 4,500 tonnes of cables below deck but we wanted to add another 8,000 tonnes on deck to support the growing offshore wind market even better.”

Enersea also delivered the design of the CIS for DEME’s DP3 multipurpose vessel Living Stone.

“Compared to the Living Stone, the Viking Neptun has become even more versatile as the vessel can also install offshore mooring systems, and carry out other subsea work and is equipped with a 100 tonnes and 400 tonnes crane,” Scheers noted.

Viking Neptun has already started its first cable laying missions on an offshore wind farm in North Sea.

Enersea said that the design requirements DEME set for the Viking Neptun led to a very innovative design. The company’s Project Engineer Tim de Rooij explains that as a first requirement, the vessel cranes needed to install all parts of the CIS itself and with a minimal number of lifts.

To achieve this, the team split the system up in eight skids weighing 20 to 100 tonnes. All skids contain the required pieces of equipment like tensioners, winches and the required hydraulic and electrical power supplies. Overall, this minimizes the number of lifts to mobilize or demobilize the system.

A second requirement was to remove the CIS in a short time. To fulfill this, the connection to the ship was redesigned by Enersea. For the new CIS a bolted connection was designed. At strategic strongpoints on the vessel deck, thick connection plates were welded to join the skids to the deck. As the skids are already equipped with integrated hydraulic and electric power supplies, only a minimum amount of connections need to be dismounted for demobilization of the CIS, De Rooij said.