Chinese Shipyard Cosco Shipping to Build Four New Offshore Construction Vessels for Sea1 Offshore

Four new offshore construction vessels (OCVs) to be built by Chinese shipyard Cosco Shipping for Norwegian offshore services provider Sea1 Offshore are set to sport Kongsberg Maritime comprehensive equipment packages.

Sea1 Offshore, previously known as Siem Offshore, placed the order for the first two offshore energy support vessels (OESVs) with Cosco Shipping in November 2024, revealing at the time that negotiations were ongoing for the delivery of more vessels.

This March, the company signed a new contract with the Chinese shipyard for the construction of two additional vessels, set for delivery in the second half of 2027.

Kongsberg Maritime’s equipment package includes K-Pos dynamic positioning systems, integrated control and navigation systems, battery hybrid DC electrical systems, as well as all main propulsion and thruster units.

The company shall also collaborate with Sea1 Offshore on a study to accurately assess emissions reductions achieved with the equipment.

According to Kongsberg, the battery-hybrid DC power and propulsion system allows for single-engine usage for most of the vessels’ operational time, and the high-capacity shore connection, battery system, and energy control system allow for zero-emission operation during port stays and loading procedures.

“Our integrated systems will enhance vessel efficiency and significantly reduce emissions,” said Ottar Ristesund, VP Sales Offshore at Kongsberg Maritime. “We are collaborating with Sea1 on an in-depth benchmark study to assess emission reductions of the many individual measures incorporated into the design and our deliverables. This insight may increase the awareness of the efficiency potential of operations as well as provide insight into future vessel designs.”

The OESVs will be 120 meters long, with a cargo deck of 1,400 square meters, and each will feature a 250-ton deck crane and provide accommodation for up to 120 personnel. Based on the ST-245 design by Skipsteknisk, they will be capable of serving both the oil & gas sector and the renewable energy market.