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83 Sea Machines/MSRC oil-spill skimmer | In operation you’d just have a flow switch in the collection tank, so that when it gets to a certain level it activates a pump,” he adds. “That transfers the oil via a hose over to the barge, and once the oil level falls to a suitable level it would switch off and the skimming can start again. “We have different technological approaches and adaptations we could try, which is important because every spill is different. Wave levels, weather, local restrictions, navigability of waters, spill size, oil types, all these and more come into play. The best approach and tools for the job therefore depend on a lot of external factors and functions that you have to be able to manage.” For added situational awareness of the skimming operation, electro- optical cameras are installed atop the pilot house. These point down at the skimmer belt to enable the operator to continuously check that the system is working and not affected or blocked by floating debris. Also, the holding tank has fluid level sensors installed to detect the level of collected oil, while the associated monitoring system gives alerts when fullness levels of 50% and 80% are reached. The exact purity of the oil being collected in the holding tank – that is, how free from seawater it is – will vary according to factors such as water temperature, oil viscosity and how long the oil has been sitting in the water before a skimming operation begins. After being collected, it is typically transferred to the party responsible for the spill, so that it can then be re-used or recycled. Decontamination When the job is done, the skimmer boat is moved back to the launching ramp, where the MSRC performs what it calls a “gross de-con”. This is to ensure there is no oil or other toxic matter left on the hull or between its components that could harm the health of its personnel or drip onto the road behind the trailer as the boat is driven away from the site. Initially the boat, now mounted on its trailer and with plastic sheeting underneath, is sprayed down with water and detergent. “We then go to a special decontamination site, where the boat and equipment are dismantled and thoroughly cleaned, because we use them for training when we’re between spills,” Swift says. “So we make sure it’s completely oil-free down to every nut and bolt.” After cleaning all the parts, the USV is reassembled, and each part is inspected to see where repairs or replacements might be needed before reinstalling them. Once all the parts are approved and re-integrated, consumables such as fuel and lubricant are replenished, and the vessel can once again be used for training or deployed for oil spill response when the MSRC’s next call comes in. The future As mentioned, until now the onboard skimmer belt assembly has been remotely operated in the trials, but Venetiou says it is more than possible for the belt’s systems to be autonomously activated and deactivated at the desired waypoints. That would be enabled through the SM300 GCS’s mission planning software before a launch, pending the MSRC’s continued trials and growing confidence in the safety of its new unmanned systems. For such future operations, Swift and the MSRC envision the fully autonomous skimmer’s performance being monitored from a remote location within line of sight. “We also have a lot of r&d projects that stand to enhance the use-case for autonomy in oil spill response, such as sensor payloads and towfish for detecting and classifying the spilled oil types and quantities before skimming, computer vision for accurate sense & avoid, and situational awareness,” Bourque says. Unmanned Systems Technology | October/November 2020 Kvichak Rapid Response Skimmer Aluminium hull Gasoline- and diesel-powered Length: 9.5 m Draft: 0.94 m Fluid storage capacity: 3816 litres Some key suppliers Autonomy hardware, software and integration: Sea Machines GCS: Sea Machines Control systems integration: Navtronics Vessel chassis: Kvichak Marine Oil-skimming equipment: Marco Outboard thrusters: Yamaha GNSS receiver: Hemisphere GNSS antennas: Hemisphere IMU: Hemisphere Maritime radars: Furuno Data links: Peplink Digital control systems for throttle and steering: SeaStar Specifications The SM300 onboard cabinet houses a Siemens S7 processor and an industrial Linux computer for controlling sensors, machinery, payloads and other systems