As a wave rolls towards a coastline, the sea floor rises until a critical point is reached which is where the water is too shallow to support the wave shape and it breaks, forming white water that sweeps into the shore. The surf zone is popular with water sports enthusiasts and casual beachgoers alike. The combination of people and powerful waves, though, creates a ripe environment for rescue work.
Lately, great strides have been made in using UAVs in a surf rescue role. These remotely piloted aircraft have become mainstream for land-based missions, where their role is to locate casualties. In the surf, however, the challenge is to do something to help the victims reach the shore. Crewed helicopters, on the other hand, have been involved in surf rescue work for decades. While the equipment involved may be the same as for working in offshore waters, the techniques are different due to the action of the breaking waves and their effects on the victim.
Ian T. Gaernter, Primary Instructor / Hoist System Operator for Priority1AirRescue, commented: “In my experience, surf rescue is very unique because of its proximity to the shore. Generally, by the time a helicopter crew receives the call launches the aircraft and gets on scene, the person in distress has been rescued by another asset (i.e. lifeguards, bystanders or watercraft, drones and drop floats). But, on the rare occasions that a helicopter does arrive prior to other rescue personnel, then that helicopter has a very technical rescue on their hands.”
Crew co-ordination skills
One organisation that specifically trains for helicopter surf rescues is the US Coast Guard (USCG). Lt John (JJ) Briggs is the MH-65 (Dolphin helicopter) senior instructor pilot at the USCG Advanced Helicopter Rescue School, which teaches surf rescue at Cape Disappointment near Astoria, Oregon. He commented: “We utilise the Pacific Northwest’s predictably poor weather and high swells as a training ground where students are placed in difficult situations with specially trained instructors to refine their skills in a high-risk environment.”
To lower the swimmer to the water in large seas or waves, the pilots maintain a steady hover at a fixed altitude and let the waves pass under the aircraft. The flight mechanic, who operates the rescue hoist, conns (directs the movement of the helicopter) by giving the pilots directional commands. The pilots and flight mechanic work in concert to position the helicopter and rescue swimmer into a pre-briefed location. All while the survivor is being dynamically moved by the sea.”
Waters offshore often present consistent, predictable swell patterns, but working within the surf line the rescuer has to expect large, erratic movements of the survivor, said Briggs. He added: “If we are working in the surf with large breakers close to shore or rocks, we may change tactics to remove the swimmer and survivor quickly from immediate danger. We teach crews to recognise the different types of breaking waves and how to work in them to complete hoists. They use experience and judgement coupled with knowledge of wave hydraulics to create their plan of attack.”
First, explained Briggs, the crew estimates the swell height, speed, type of wave and its associated dangers and chooses an appropriate hoisting altitude, usually between 25 and 55 ft above the highest wave peak. The extraction method used will then depend on the survivor’s condition, he said: “If the survivor is ambulatory, a basket may be lowered to them. If a rescue swimmer is deployed to assist the survivor, they can free fall (jump out) and swim to the person or be lowered using the rescue hoist. To lower the swimmer to the water in large seas or waves, the pilots maintain a steady hover at a fixed altitude and let the waves pass under the aircraft. The flight mechanic, who operates the rescue hoist, conns (directs the movement of the helicopter) by giving the pilots directional commands. The pilots and flight mechanic work in concert to position the helicopter and rescue swimmer into a pre-briefed location. All while the survivor is being dynamically moved by the sea.”
When the rescue swimmer is lowered by the cable, they can choose to disconnect and swim to the survivor, explained Briggs, and use hand signals to request a rescue device appropriate to the survivor’s condition. Alternatively, the swimmer can opt for a ‘direct deployment’ and remain attached to the hoist cable, using a strop to secure the survivor to the hoist hook. In more urgent situations, however, the swimmer can simply physically grip the survivor as the flight mechanic lifts them both out of the water. Briggs explained: “In fast-moving large waves, normally found within the surf line, survivors are often tired and are being continually trounced by waves. As this is a highly dangerous scenario, the crew may elect to direct deploy the rescue swimmer into the surf with the intention of a physical-grip pick-up to immediately reduce the likelihood of the survivor drowning or hitting rocks.” The two pilots and flight mechanic attempt to anticipate the movements of the survivor, which can be radical in high surf, to place the swimmer at a position to grab the survivor, said Briggs. He added: “Depending on the time between waves, usually between five to 18 seconds, the swimmer must decide to either secure the person with the quick strop or simply grab hold of them and lift them to safety.”
Ian T. Gaernter said: “Due to the tendency to get dragged, swamped and or injured by the crashing seas, the hoist operator will pay out slack in the hoist cable to ensure the rescue swimmer can move freely. Once the swimmer is in contact with the survivor the hoist operator will conn the aircraft over the top of the swimmer and survivor to safely remove them from the water, all the while pilots are calling out and timing waves, ideally they will pull them free of the water, from the trough of a wave prior to the next one crashing into them.”
Briggs noted that if the sea state is relatively calm outside of the surf, one option is to lift the swimmer and survivor a few feet above the tops of the waves as the helicopter repositions to a safer location. They would then be lowered back into the water outside of the surf line, allowing the swimmer to use a more secure method of completing the hoist, he said. In extremely rough seas, the safest option can be to complete the physical-grip pick-up by hoisting them into the cabin.
In extreme conditions, the helicopter crew could need to ‘chase’ the survivor as they’re pushed by the waves. In the kind of conditions seen in competitive surfing, for example, the crew would typically position overhead and chase the surfer as each wave pushes them under and away, said Briggs: “During the chase, the rescue swimmer will be lowered within an arm’s length to grasp the surfer. If there is little time between swells both will likely be struck by crashing waves. The helicopter will remain in chase, and once the swimmer is ready for pick-up, the aircrew will time the extraction between crashing waves.”
Such manoeuvres require precision movements and expert timing by all crew members, said Briggs. Hoisting into high seas and surf is a triad of teamwork between the pilots, flight mechanic, and rescue swimmer, he said with very small margins for error, adding: “We strive to constantly refine our skills and hone our craft though training.”
While the USCG continues to train for working in the surf, some helicopter rescue providers are seeing demand drop. One civilian organisation contacted for this article said that although they used to conduct helicopter surf rescues in the past, this would be a very rare mission for them these days, due to ‘improvements in surf life-saving technique over the years.’ Among such improvements, of course, has been the development of UAVs able to drop rescue devices to swimmers in need.
A number of organisations around the world have been working on the problem of how to adapt drones to be effective in surf rescues. Highlighting the limited usefulness of off-the-shelf, camera-equipped UAVs in this scenario, Ulf Bogdawa, Director/CEO of SkyDrones Tecnologia Aviônica, Brazil, put it this way: “It is fairly easy to find the victims, but you cannot do anything besides filming the drowning.”
In 2018, SkyDrones became one of the first organisations to save a life in the surf using a UAV. In February last year, one of its customised DJIs flew to the aid of a kite surfer in trouble off São Paulo, Brazil. The remotely piloted machine dropped a Restube flotation device for him to cling to until a rescue boat could reach him and bring him to shore.
While that might sound a simple mission, it was only possible due to the work that SkyDrones has done to make this possible. One element was to source a flotation device small and light enough not to affect the UAV’s handling (especially important with smaller drones, which Bogdawa noted are cheaper and can be safer). For this reason, SkyDrones chose to work with Restube, whose flotation devices pack small, but instantly inflate when they hit the water.
A second key ingredient was the software. Bogdawa commented that a drawback of the typical drone is that it’s not easy to get the co-ordinates of the victim’s location to share with other rescuers: “Apps (like DJI Go) only have a dot on the map, but no co-ordinates to send the help to.” Therefore, SkyDrones worked on a custom app that takes some of the burden of flying off the pilot so they can concentrate on saving lives. He explained: “We developed a system that can be used with [a DJI] Phantom 4, Inspire 1 and 2. Other platforms can be developed at request. The app has very few things to do for a rescue operation. You have an ‘asking for help’ icon. When you press it, the drone takes off. Then you have the option to fly to the victim by hand or to use the assisted ‘tap to fly’ to go to the victim.” After reaching the victim, a lifebuoy icon can be tapped to release the Restube. Bogdawa continued: “At the moment you drop the Restube, an SMS is sent automatically to pre-programmed receivers (usually first responders by boat) with the victim’s GPS co-ordinates in order to make rescue faster.” There are even algorithms in the SkyDrones app that help the Restube to fall close to the victim by compensating for wind strength and direction.
The São Paulo rescue perhaps came on the heels of a mission to save two fatigued swimmers who were being washed out to sea off Lennox Head, New South Wales (NSW), Australia. Hailed as a world first, that tasking involved one of the NSW ‘Little Ripper’ drones being operated by the Australian Lifeguard Service in what started as a training flight. In this example, a flotation device was dropped to help the swimmers make their way to shore, where they were met by lifeguards who had rushed to the scene on an ATV.
The bigger picture
It’s worth bearing in mind that helicopters and drones form just part of the wider mix of SAR assets, ranging from beach-based rescue swimmers to jet skis and life boats. What’s most suitable in a given region will depend on the factors such as the local environment and available budgets, and will likely change as technology develops. However, given the different benefits offered by UAVs and crewed helicopters, both would seem to have an assured future in that mix.
“We are receiving more and more requests to lead drone projects to carry out rescue and emergency response trials and achieving increasing levels of success as the technology and capabilities improve.”
It’s likely that for the foreseeable future, there will be a role for helicopters in plucking people from danger, especially where they are unconscious or risk being washed onto rocks, both of which are scenarios in which drones would be of little benefit. However, where swimmers just need help to reach shore or await rescue, float-dropping drones could soon be the go-to option, thanks not least to lower costs, ease of pilot training and the ability to station and launch the aircraft right on the beach. As well as the examples listed above, there were other drone-assisted rescues in 2018 in inland and coastal waters around the world. And the use of drones for water rescue is spreading. Just this past July, Ocean Shores Police Department in Washington State, US, revealed plans to buy 12 UAVs specifically for surf rescue.
Speaking on the future role of drones, Kelvin Morton, Managing Director and Airboss at DroneAdvantage and Surf Life Saving NSW UAV Project Manager, commented: “We are receiving more and more requests to lead drone projects to carry out rescue and emergency response trials and achieving increasing levels of success as the technology and capabilities improve.”
It’s also significant that with drones, personnel can effect a rescue without putting themselves in harm’s way. Morton commented: “This is a very compelling motivator when leaders of SAR organisations are facing the daily challenge of having to ask rescuers to perform rescues – and seeking ways to reduce the risk to their people.”
Looking further forward, one possible avenue for research could be the integration of artificial intelligence into the SAR framework. Bogdawa of SkyDrones said he sees a future where more complex systems will operate together: “While a bigger (maybe solar powered) UAV makes flights over beaches, finding a rescue situation (using AI), this info is sent to one of the automatic and persistent ground stations who will deploy a SARtube drone.”
If that sounds far-fetched, note that Bogdawa has already seen interest in developing such a system. It may be that for surf extractions, technology use in air rescue is only just getting started. Ian T. Gaernter said: “I feel like the role of helicopters being used in this manner has always been extremely limited … and as rescue personnel I would say we all welcome advancements in technology that save lives.”