96 take over in the event of failure, and if propulsion or steering should specifically suffer a fault, the USV is configured to throttle down so that position drift is minimised and the vehicle may be retrieved. “A big help is that the Mariner has dual propulsion as standard. It is built with a water jet and electric thrusters,” Moholt explains. “If our local express ferry gets its jet clogged up with something, for instance, it stops and starts drifting. If ours gets clogged, the thrusters can keep the USV in place while the operator analyses whether it’s best to drive home on the electric thrusters or stay in place and wait for human intervention, or even radio out to other boats or authorities over VHF to alert there is a USV with lost control nearby. “Top that with the six battery banks onboard the Mariner and we always had enough energy to try something else in response to the authorities’ ‘what if’ queries and scenarios.” The Norwegian authorities also required multiple redundancies to cover for cascading data-link failures, so a triple-redundant communications system is installed onboard to ensure persistent telemetry and control, including remote intervention by engineers monitoring the USV. At Trondheim Operationally, a key part of gaining permissions involves fully understanding the necessary risk analysis before commencing a day’s uncrewed sailing. Much of this was already part of Maritime Robotics’ usual practices, such as checking for decent weather, and the absence of swimmers and heavy water traffic. “Additionally, we have to make sure we have extra staff on hand in case the operator tasked with monitoring the USV becomes incapacitated,” Moholt notes. “It’s all exactly the same as good seamanship on a crewed boat. We also have to test all of the sensors, carry out maintenance inspections of the vessel’s parts, and validate that the engine fuel and oil are good to go, but if you’ve ever operated a crewed vessel or an uncrewed vessel in a reasonably professional manner, none of it should be surprising.” As of writing, the company is conducting logistics across the Trondheim Fjord in an ad hoc manner, without a fixed or minimum number of runs per day. Depending on the number of Mariner USV stock available, multiple deliveries can be carried out by an individual unit in a single day. Usually, one crew will be located in Trondheim with a VCS laptop to load and launch the Mariner. Once the risk and maintenance inspections have been completed, and the USV can be triggered to begin sailing towards Vanvikan, the crew notifies the Vanvikan control centre, whose crew is then given control of the vessel, although both continue to monitor it. October/November 2024 | Uncrewed Systems Technology The triple-redundant comms system includes maritime broadband radio, 4G and satcom, although some customers install Iridium short-burst data as a backup
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