Unmanned Systems Technology 025 | iXblue DriX I Maintenance I UGVs I IDEX 2019 I Planck Aero Shearwater I Sky Power hybrid system I Delph Dynamics RH4 I GCSs I StreetDrone Twizy I Oceanology Americas 2019

75 Delft Dynamics RH4 | In operation to haul it along with the attached 30 mm diameter floating line, as they would normally. As Smoor explains, “The 30 mm line is best for ship-handling, so it will slowly be hauled on deck and tied to the correct chock by the deck crew, who will then give the sign that the tugboat and the ship are connected.” Rath adds, “Getting the line in safely is a capability that requires real focus to develop. It’s a harsh and windy environment, you’re very high up, and the ship might be moving. A transponder beacon in the base station helps the UAV return to its launch and recovery point. Given the disruptions the ship could cause to the GNSS receiver and magnetometer, as well as the fact that the tug may have moved since the UAV’s launch, programming the RH4 to return to a specific GNSS coordinate would not work. Post-flight procedures After returning to its base station, the RH4 might need to be rigged up to another heaving line, in case another flight is needed. Another visual check is conducted during this process. “One flight will often be enough though, because once the container ship is lined up with the harbour, the tugboat can just push it from behind, rather than pulling it from the bow,” Smoor notes. The crew might choose at this point to wash the UAV with fresh water, including the motors (closed as they are), to remove any salt and further prevent corrosion. The UAV could also be charged inside the base station, although given the short flight time this will not always be immediately necessary. The future At time of writing, Kotug had recently gained a patent for this line transfer method. “We hope to start full operational testing of it in a couple of months, but we first need to prove which line attachment method works best, and how to get special dispensation to fly over water at short notice,” Smoor says. The UAV might also be engineered further. “We may integrate a tether cable between the base station and the craft in the future, to supply power without batteries taking up weight, and to enable consistent comms amid the ship’s disruptions,” Rath explains. Smoor adds, “Fitting a tether could also help with flight approvals in the future, as it physically geofences the UAV within the length of the umbilical – although airports don’t accept that in their safety policies yet.” Rotor guards might be installed, given the possibility of the UAV bumping into a ship’s hull and chocks, and damaging the propellers and motors. This might also help during landing, to prevent damage to the RH4 as it nears the tugboat’s mast, wheelhouse and other potential obstacles. “In addition to tug-to-freighter connections, this technology could also be used for shipwrecks, coastal salvages and search-and-rescue operations, where a line needs to be transported to people on deck or on the water,” Smoor comments. “The video feed from the EO camera can also be used to help the tugboat crew observe the other sides of the freighter as it pushes it towards the quayside.” This collaboration between Kotug and Delft Dynamics clearly has the potential to improve tugboat operations and the safety of harbour workers the world over. Unmanned Systems Technology | April/May 2019 Kotug can keep its tugboats to the side of incoming ships (top) and at a safe distance, rather than directly in front of or behind them (below), as in the past