Sea1's first methanol-ready offshore energy support vessel fitted with offshore crane and helideck

Sea1 Offshore's first of four 120-meter-long offshore energy support vessels (OESVs) being built in China has been fitted with an offshore crane and helicopter deck, with delivery expected in January.

Norwegian offshore services provider Sea1 Offshore placed the order for the first two OESVs with Cosco Shipping in November 2024, revealing at the time that negotiations were ongoing for the delivery of more vessels. The contract for the construction of two additional vessels was announced in March 2025.

The construction of the first vessel, named Sea1 Diamond, began in September 2025, with the second, named Sea1 Citrine, following in December.

Sea1 Diamond, launched at the yard in July, is currently undergoing outfitting and commissioning at the COSCO Nantong Shipyard, with the offshore crane and helicopter deck installed, as Sea1 Offshore reported on November 3.

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