An image from the Jason Markland documentary on rip currents shows a typical rotating eddy. He survived, but many don't. This summer is tracking to be one of the worst on record for rips: Compared with the average annual death toll from rips of 19, there have already been at least nine attributed to rips in December, according to Surf Life Saving Australia and rip expert Dr Rob Brander. Lurking every day on many of Australia's 11,000 beaches, rips draw swimmers away from the surf pounding between flags with their deceptively calm waters. Most Australians are more afraid of sharks than rips, although coastal drownings (including rips) kill an average of 100 times more people a year.

An image from the Jason Markland documentary on rip currents shows the approach of swimming parallel to the shore. A growing body of research finds rips are less predictable and harder to escape, even for strong swimmers like Muldoon, who used his first-hand experience to narrate a new documentary Rip Current Heroes. Muldoon followed traditional advice and, with his mate, swam parallel to the shore. "We swam down the beach for a while, and swam the other way. And we weren't moving whatever we did," said Muldoon, recalling that night a few years ago. An image from the Jason Markland documentary on rip currents shows how to identify a rip. He said he did everything wrong when he approached the beach. Muldoon didn't check for rips before diving in.

In the water though, he did everything right. He didn't panic, he conserved his energy, he tried swimming parallel, and was willing to change strategies when that didn't work. An image from the Jason Markland documentary on rip currents shows another type of rip. "It was lucky we were strong swimmers, and we didn't panic. We absolutely did that right," said Muldoon. Yet rips can travel twice as fast as an Olympic swimmer. An image from the Jason Markland documentary on rip currents shows how a rip can flow out and back to shore.

Muldoon and his mate were among the 4.2 million Australians who have been caught in a rip. Finally they hitched a ride to shore with the last remaining surfer. An image from the Jason Markland documentary on rip currents shows a typical boundary rip. As they discovered, no rip current escape is guaranteed, other than learning to identify and avoid a rip in the first place, says geomorphologist Dr Brander from the University of NSW. Only 30 per cent of Australians can correctly identify a rip, and about two out of three of those who say they can, cannot do so correctly. Few have the swimming skills to survive: About one in four of those who hit the surf every year can't float more than a few minutes and many can't swim 50 metres without stopping, says Surf Life Saving Australia's 2017 National Coastal Safety Report.

Tui Gallaher, 14, died at Maroubra Beach last summer. Credit:Facebook Intensive experiments on escaping rip currents, which attached GPS trackers to swimmers in a rip, found neither of the traditional escape strategies – the stay afloat or the swim parallel advice – was 100 per cent successful, said Dr Brander, the deputy head of UNSW's School of Biological, Earth and Environmental Sciences who is often known as Dr Rip. One beach could have several different types of rips nearby, which meant the optimal rip current escape strategy for one may be the "worst strategy at a nearby rip", says research by Brander and others published in Earth Science Review. Even rip experts like him have struggled. "We had situations where people who swam one way 100 per cent got out of the rip. But people who swam the other way (in the same rip) really struggled. Which way will get you out? It is like a coin toss.

"All the research shows there's no single action that you can do that will guarantee you'll get out of rips safely," Dr Brander said. "We had some of the best rip current experts in the world, and when you are in a rip, it is very difficult to know if it is going to recirculate, or take you out the back, because you are flowing very fast and you are still going to end out the back before you can swim to the side to get out of a rip," he said. That research meant swimmers needed to know the different options, he said, with the best advice to stay calm and float if possible. "There's no single thing that works. My preference is always to stay afloat, because it means you are conserving energy and thinking about the situation."

Surf Life Saving says 1281 people died on Australian beaches between 2014 to 2017. "Potentially 1281 lives may not have been lost as a result of coastal drowning if these people had been swimming at a patrolled beach, between the yellow and red flags," said Shane Daw, SLS national coastal risk and safety manager. Of the 19 people who drown in rips every year on average, about 53 per cent of these fatalities occur between December and February, and about 27 per cent in March and April. Safety experts recommend that swimmers swim only between the flags, yet only four per cent of Australian beaches are patrolled. Dr Brander, whose research is featured in Rip Current Heroes, says it is important to educate young people on the dangers and how to identify rips.

"We can't just rely on the swim between the flags message," said Dr Brander. "You don't cross the roads without looking. You shouldn't go to a beach without looking for rips," he said. If you don't know how to evaluate the safety of the beach, and your own ability, you shouldn't enter the water, he says. The documentary was produced by Jason Markland and National Geographic, and will be screened this month. It will be made available, along with educational materials, to schools free of charge to educate young people on the dangers of rips, as part of a five-year commitment by National Geographic to reduce coastal drowning deaths. A father of five, Mr Markland was prompted to make the documentary after watching beach goers swimming outside the flags near Coolangatta where he lives. About 47 per cent of drowning deaths occurred within a kilometre of a surf lifesaving club, and very often next to flags. "I saw people swimming about 200 metres outside flags. And a rip current kept returning to this section, and I kept seeing lifesavers running up the beach, and I couldn't believe what I was seeing.

Loading "So many people were choosing not to swim between the flags, and this section looked like the best. The calm water was an operating rip – so you can understand that they thought they would jump in here, but they were actually putting themselves into a rip current," he said. Rip Current Heroes will be screened again on National Geographic on Jan 8 at 8:30 am and Jan 25 at 7:30 pm eastern time.