82 by 3.3 ft (3 m by 1 m), weighs up to 354 lb (160.5 kg) in air, and has shown endurances of up to six months in testing of its prototypes (with a focus on the lifespan of its solar cells and electric thrusters). Its PV panels nominally supply up to 400 W over a bus voltage of 5-28 V, while its battery stores sufficient energy for about 575 nautical miles without solar. Its motor provides a top speed of 5 knots. Up to 110 lb (50 kg) of payload can be installed onboard, as can an optional generator for those seeking the extra redundancy, power or energy of a hybrid powertrain. “In addition to our defence users, we have some customers who are very interested in mapping applications for Lightfish, as well as marine scientific uses like water-condition monitoring, as well as monitoring and prediction of harmful algal blooms,” Kerwin adds. Solar power is rapidly becoming a universal sight among monohull USVs as an apt use of the real estate atop their decks for efficient and clean energy; PV cells serving as either a primary or redundant energy source. The larger the USV, the more real estate available for powering onboard payloads and computers sustainably, and for autonomously recharging batteries without returning to port. One notable new unveiling is Demcon Unmanned System’s new DUS V5750, the Dutch company’s newest USV class, at a length of 7 m. In addition, in integrating photovoltaics into its redundant powertrain, the vessel is engineered with a dynamic positioning system, featuring a new weathervane control mode, which enables the USV to serve in real-time inspection of subsea cables as they are laid down for offshore wind farms. Typically, a crewed survey vessel will follow the cable-laying ship for such inspection, but will become highly unstable and potentially hazardous in challenging weather conditions. In addition to an electric USV being far less expensive and polluting than a large, diesel-powered boat, the 5750’s environment-dependent control mode points its nose in the optimal direction of wind, current and waves to minimise resistance. It can then follow the cable-laying ship while angled laterally, thereby optimising its power resistance and stability while sailing behind the cable-laying crew. Further north in Europe, Danish offshore wind-farm producer Ørsted’s Hugin USV is, much like the ACUA H-USV, intended as a stable, multi-sensor survey platform, though especially for deep investigation of data that is critical to early-phase development activities prior to new wind farms being built. These include wind conditions, seabed hydrography, biological and ecological parameters, and further specifics of the local area. The Hugin USV integrates five solar panels as standard across its fibreglassconstructed hull (two on its front deck, one at port and starboard, and one at the rear). It can also equip two small wind turbines to further supply clean onboard power, as well as added redundancy for the hybrid-electric powertrain. June/July 2024 | Uncrewed Systems Technology Ørsted’s Hugin USV is designed for stability in surveying wind conditions, seabed hydrography and other critical factors to offshore wind-farm development (Image courtesy of Ørsted) The V5750’s weathervane dynamic positioning control mode points the nose in the optimal direction of wind, current and waves Demcon’s new DUS 5750 is designed to follow cable-laying ships for stable inspections of the work their crews carry out (Image courtesy of Demcon)
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