64 Insight | USVs Search and rescue Edinburgh-based Zelim is developing its Guardian USV to be the first uncrewed system capable of rescuing human casualties fromwater – including in dangerous high sea states. It will offer the flexibility of both crewed and uncrewed operation modes though, with both a remote and onboard helm. There are several reasons why fully uncrewed rescuing of souls at sea is desirable. Rescue crewmembers are often killed in the line of duty, particularly during the launch and recovery of their fast rescue craft. Also, the physical act of hauling casualties from the sea can injure the victim or the rescuers, the rescuers themselves can fall overboard, or they can end up suffering from PTSD, particularly in cases where casualties have already died. SamMayall, CEO and founder of Zelim, was previously a career mariner with experience of these issues, so in 2017 he conceived an uncrewed fast rescue craft. At the time, there was scepticism that casualties could be safely lifted from the water by a totally uncrewed boat. “In 2020 though, Sam had met with myself and others, and we built a fullscale prototype of the Guardian in the summer of that year,” recounts Doug Lothian, CTO of Zelim. “That was 6.5 m long and based on a Royal Marines Rigid Raider. It had our Swift casualty recovery conveyor mechanismmounted in the front, and we demonstrated that it could lift a casualty from the water, albeit with a rescue crew operating on board.” By December 2020, Zelim had developed the Guardian’s remote systems, upgraded its engines, hydraulics and electronics, and subsequently performed what it believes to be the world’s first uncrewed recovery of an incapacitated casualty. Interested partners and supporters of the project includeOcean Infinity, Chartwell Marine, InnovateUK and theOffshoreWind Growth Partnership, which represents the UK’s offshorewind farm industry. Working with these groups has provided advice and funding for the design, development and fabrication of the next Guardian prototype, whichwill be anOEMvessel rather than a modified Rigid Raider. “There are more than 150 electronic components in the Guardian that need to be fully tested and integrated to support its self-righting capability, including things like closing and reopening ventilation for the diesel engines – fuel power is necessary because of regulations on minimum endurance for rescue craft,” Lothian says. “Many self-righting vessels will close those inlets automatically but not reopen automatically, so features like that had to be made from a blank sheet. “By this July we’ll be testing that vessel on the water, and through the winter weather later in the year we’ll be able to put it through its paces. That will culminate in a validation trial with Northstar Shipping and Seacroft Marine Consultants.” The Guardian is a high-speed planing craft with a frontal deep vee to cut through water, and appropriate buoyancy in the superstructure as well as ballast below to enable self-righting. Also, its GZ curve (the angle at which a vessel will roll over and self-right) has been calculated to work across different sea states. A rescue conveyor called the Swift also provides a stabilising effect when deployed at the front of the Guardian. Its belt consists of a soft, gripping material that handles and orients casualties without causing or exacerbating injuries. As a final measure, an inflating bag on the craft will expand to push it back upright. Meanwhile, AI survey and recognition of casualties is enabled by SARBox, the company’s proprietary and sensor-agnostic computer vision solution. “We use Sea Machines’ SM300 as our onboard autonomy and control suite,” Lothian adds. “The big draw there was how closely they’ve sought to understand our vehicle and purpose. “Instead of just delivering what we want, they delivered what we need. They made technical recommendations, corrections and fine-tuning to their offerings in order to make the Guardian smarter and more successful.” Future developments include hybridelectric powertrains (or even fully electric, given ongoing advances in marine batteries and e-thrusters) to decarbonise the Guardian without falling short of minimum endurance regulations. June/July 2023 | Uncrewed Systems Technology The L3Harris ASView control software continues to be updated for a range of defence industry USVs (Courtesy of L3Harris)
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