Norwegian Vessel Operator Sea1 Offshore Orders Two More Next-Generation OESVs from Cosco Shipping

Norwegian vessel operator Sea1 Offshore, formerly known as Siem Offshore, has expanded its fleet with the recent order of two next-generation offshore energy support vessels (OESVs) from Chinese shipyard Cosco Shipping. These vessels are sister ships to the two already ordered at the end of 2024.

Sea1 Offshore initially ordered the first two OESVs from Cosco Shipping in November 2024, with plans for additional vessels in the pipeline. The company has now finalized a new contract for the construction of two more vessels, scheduled for delivery in the second half of 2027.

These 120-meter-long OESVs will feature a cargo deck of 1,400 square meters, a 250-tonne deck crane, accommodations for up to 120 personnel, and essential equipment such as a remotely operated vehicle (ROV) hangar and a moonpool. Based on the ST-245 design by Skipsteknisk, the vessels will be methanol-ready, with generators capable of running on 100% biofuel.

Furthermore, Sea1 Offshore has collaborated with Aurora Offshore, resulting in the transfer of 11 vessels between the companies. The first two anchor handling tug supply (AHTS) vessels, Siem Pearl and Siem Challenger, along with the high-end subsea vessel Siem Stingray, have already joined Aurora’s fleet. Recently, the second high-end subsea vessel, Siem Day, was successfully integrated into Aurora’s operations.