Sea1 orders second next-generation, methanol-ready OESV pair from Chinese shipyard

Norwegian vessel operator Sea1 Offshore, ex-Siem Offshore, has placed an order with Chinese shipyard Cosco Shipping for an additional two next-generation offshore energy support vessels (OESVs), sisters to the two ordered at the end of 2024.

Sea1 Offshore placed the order for the first two OESVs with Cosco Shipping in November 2024, revealing at the time that negotiations are ongoing for the delivery of more vessels.

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

The vessels will be based on a design and function resembling the first two units and will be equipped to serve both the oil & gas sector and the renewable energy market.

The 120-meter-long OESVs will have a cargo deck of 1,400 square meters, each will feature a 250-tonne deck crane and provide accommodations for up to 120 personnel and will be equipped with a remotely operated vehicle (ROV) hangar and a moonpool.

Based on the ST-245 design by Skipsteknisk, the vessels are methanol-ready and the generators can operate on 100% biofuel.

In terms of other news related to Sea1 vessels, a total of 11 units will transfer to Aurora Offshore as part of the companies’ collaboration. The first two vessels, anchor handling tug supply (AHTS) vessels Siem Pearl and Siem Challenger, were delivered to Aurora in January, followed by the takeover of the first high-end subsea vessel Siem Stingray.

The second of three high-end subsea vessels joined Aurora’s fleet earlier this month when the takeover of Siem Day was completed at Las Palmas.