Uncrewed Systems Technology 044 l Xer Technolgies X12 and X8 l Lidar sensors l Stan UGV l USVs insight l AUVSI Xponential 2022 l Cobra Aero A99H l Accession Class USV l Connectors I Oceanology International 2022

59 to fit the tight physical clearances needed to survey the California Aqueduct. Since then, the company has built USVs that are smaller and more convenient, with its latest project initially aimed at developing a backpack- transportable craft. The idea behind it was that land surveyors and engineers would be able to carry such a vehicle with relative ease to hard-to-reach lakes, rivers, streams and small water bodies. “Once we started testing the system, however, we actually found it to be extremely manoeuvrable and fast due to its small surface contact with the water and its integrated echo sounder transducer in the hull,” says CEO John Tamplin. “In fact, unlike our current HyDrone catamaran USV, there was no pole or transducer dragging in the water, enabling the system to work well in high- flow situations on rivers and streams.” With these advantages, Seafloor has continued developing the new platform, unveiling it as the TriDrone USV in March this year and offering it as a solution for inspecting water resources, riverine mapping, topographic surveys, reconnaissance applications and indeed any marine application where conventional transportation and launching are impossible. The TriDrone is 121.92 cm long and measures 86.36 cm wide when deployed; this width decreases to 32.5 cm when folded for transportation. It weighs 10 kg and can carry up to 11 kg of payload mass, on a hull built largely from UV- resistant HDPE and assembled about a frame of 15% fibreglass-filled Nylon. The easy foldability was a primary development target. Tamplin says, “We wanted a unit that could be folded for quick and easy transport, and put to work without the need to re-assemble the unit every time it’s used. Simply unfold the outriggers, attach the servo-controlled thruster via the quick release, and you’re ready to go. “This required quite a bit of design, testing and prototyping to get the final product we have now, while also making sure it was tough enough to handle transport and use in harsh environments.” The USV’s electronics are largely enclosed in stainless steel to ensure sufficient ruggedness for transport. Once deployed at its mission location, the TriDrone’s trimaran design enables high manoeuvrability and stable traversing over fast-flowing streams and rivers, primarily through its minimised water-hull contact. “And since the transducer is integrated into the hull it adds little if anything to the overall drag through the water,” Tamplin adds. “Plus the removeable, servo-controlled single thruster design enables the unit to turn and manoeuvre quickly and sharply in confined areas or to avoid objects.” USVs | Insight Uncrewed Systems Technology | June/July 2022 The TriDrone was first conceived as a foldable solution that could be easily transported to remote streams and rivers (Courtesy of Seafloor Systems) The TriDrone’s trimaran shape was found during testing to enable very high manoeuvrability, a key benefit in river mapping and inspection (Courtesy of Seafloor Systems)