VESSEL REVIEW | Challenger – Norwegian joint venture to deploy unmanned craft for inspection and exploration duties
Spanish shipbuilder Gondan has handed over a new unmanned surface vehicle (USV) ordered by USV AS, a joint venture formed by Norwegian companies DeepOcean, Solstad Offshore, and Østensjø Rederi.
Challenger was designed by Norwegian naval architecture firm Salt Ship Design for operation in Norwegian waters, where it will be used for ocean exploration, seabed mapping, and inspection, maintenance and repair (IMR) of offshore structures.
The craft is able to deploy offshore and conduct subsea operations independently, or serve as a supplement to larger subsea vessels to expand the scope of their IMR activities. Instead of mobilising large vessels for every offshore task, operators can deploy the USV and its onboard remotely operated vehicle (ROV) for parts of the subsea installation, survey, or IMR scope.
DeepOcean said that by reducing the need for repeated transits of larger vessels, the USV will offer significant cost savings.
Capable of ROV deployment
The USV measures 24 by 7.5 metres (79 by 25 feet) and can be remotely controlled from a shore operations centre supplied by semi-autonomous maritime services provider Remota. Maritime Robotics meanwhile supplied the system that enables autoremote control and navigation for the USV.
The craft will be equipped with an onboard sensor system that will allow efficient underwater inspection work to be carried out using a fully electric, ROV capable of operating at depths of 1,500 metres (4,900 feet). The USV is equipped with tools that will allow it to perform a wide variety of tasks such as laying of underwater cables.
To facilitate efficient subsea inspection work, the ROV has been outfitted with the same software as DeepOcean’s autonomous inspection drone. This will allow the ROV to perform pre-programmed inspections of subsea assets.
This is made possible by DeepOcean’s proprietary digital twin platform, through which a model of the ROV is controlled. In seabed areas with low visibility, for example, the ROV operator can instead control the ROV in the digital twin.
The ROV can perform subsea maintenance and repair work including light lifting operations, as it is equipped with powerful thrusters and has a through-frame lifting capacity.
The ROV can open hatches on subsea templates, conduct repair work, use torque tools on subsea equipment, or run cleaning tools and conduct leak measurement work. It can also connect and disconnect flying leads, perform general commissioning support on subsea equipment, and provide touchdown support for cable-laying operations.
During operations, both the USV vessel crew and ROV operators will be co-located in the same remote operating centre at Killingøy near Haugesund. Although the USV will primarily be remotely controlled from shore, it will have autonomous features to ensure safety and integrity of the spread. The craft can even be operated in severe weather conditions.
A hybrid diesel-electric propulsion system that includes a Seam battery pack will enable the USV to stay out at sea for up to 30 days without charging or refuelling. Gondan said this will ensure that the craft can generate approximately 90 per cent fewer CO2 emissions compared to a conventional offshore vessel when conducting subsea IMR operations.
Even the ROV launch and recovery system (LARS) has been designed to maximise operational windows and ensure safe equipment handling in harsh environments.
Launch and recovery of the ROV will be conducted over the stern of the USV. When launching, the ROV will simply be pushed into the water, while the USV moves forward. When recovering, the ROV will be pulled in like a trawl, while the USV moves forward.
Laid out for greater safety
The USV is equipped with a gyrostabiliser that reduces vessel movements during launch and recovery operations. The combination of the LARS and the USV’s other features will allow DeepOcean to launch and recover the onboard ROV in significant wave heights.
The USV is also equipped with a wheelhouse and is certified for having four crewmembers on board for operations within 20 nautical miles off the Norwegian coastline. DeepOcean said this is a solution to be employed during inshore testing of the USV, the LARS, the remote operating technology, and future new technologies.
Challenger will undergo additional testing and subsequent maritime authority approval for fully remote operations before commencing an IMR charter agreement with DeepOcean. The USV’s development included contributions from Aker BP, which initially operated the craft in collaboration with DeepOcean and its JV partners.
DeepOcean has also been in dialogue with other Norwegian Continental Shelf operators regarding utilising the USV for demonstration projects. Vår Energi is among the participants in a project to demonstrate the USV’s operability and capabilities in 2025.
