VESSEL REVIEW | Armada 7801 – Large unmanned motherships for Ocean Infinity’s ROV operations

US-based Ocean Infinity has taken delivery of the first two units of a planned series of eight unmanned surface vessels (USVs) built by Vard Vung Tau in Vietnam.

Sister vessels Armada 7801 and Armada 7802 will be used as launch, recovery, and support platforms for smaller unmanned craft such as autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs). The large USVs will be operated initially with small crew complements but will be completely uncrewed in future sailings. By then, control of the vessels will be executed remotely via satellite with the aid of Ocean Infinity's own operations centres in Austin, Texas, and Southampton, UK.

Each USV has an LOA of 78 metres, a beam of 15 metres, a draught of 4.8 metres, a DP2 system, and two nine- by four-metre moonpools for the deployment and recovery of embarked unmanned craft.

The propulsion systems on the USVs are diesel-electric battery hybrid arrangements though these will be modified in the future to enable them to run on ammonia as a low-emission alternative to traditional marine fuels. The current propulsion configuration can deliver a maximum speed of 14 knots and a cruising speed range of between eight and 10 knots.

Both Armada 7801 and Armada 7802 will undergo installation of their respective remote operation systems at Vard's Soviknes facilities in Norway before they commence operational sailings with Ocean Infinity. The vessels' initial lean-crewed sailings will be in support of clients in the offshore energy industry. Future operations will serve other sectors such as logistics and maritime transport, as the USVs also feature spacious open decks for the carriage of containers and other related payloads totalling 1,000 tonnes.

Design of the USVs was completed in compliance to DNV class rules.