Sea1 Offshore has launched the Sea1 Diamond, the first vessel in a series of four offshore energy support vessels under construction at COSCO Shipping.
The float-out marks a key milestone in Sea1 Offshore's newbuild program, with the company describing the vessel as the start of a new chapter for its fleet.
Sea1 Diamond is the first of four offshore energy support vessels ordered from the Chinese shipyard. The initial two vessels were contracted in November 2024, followed by two additional units in March 2025 as Sea1 expanded the program.
Based on the ST-245 design, the vessels are intended to support both offshore oil and gas and renewable energy operations. They are being built as methanol-ready vessels, with generators capable of operating on 100% biofuel, and will incorporate battery systems and other fuel-efficiency technologies.
The vessels will measure 120 meters in length, feature a 1,400-square-metre cargo deck, accommodation for 120 personnel, an ROV hangar, moonpool and a 250-tonne crane. Deliveries of the four vessels are scheduled between the third and fourth quarters of 2027.