The diving tragedy in the Maldives – which claimed the lives of four Italian divers inside an underwater cave, followed by the death of a Maldivian navy diver – has renewed warnings from experts about the risks of cave diving without proper training, planning and specialised equipment.
On Thursday, the Divers Alert Network (DAN), which coordinated the complex search and recovery operation at the Dhekunu Kandu dive site in Vaavu atoll, announced all the divers' dead bodies had been recovered.
The victims were identified as Monica Montefalcone, an ecology professor; her daughter Giorgia Sommacal; marine biologist Federico Gualtieri; researcher Muriel Oddenino; and diving instructor Gianluca Benedetti. The body of Benedetti was recovered earlier outside the cave.
Mohamed Mahudhee, a member of the Maldivian national defence force, also died in the tragedy, as a result of decompression sickness after taking part in a recovery mission.
After initial attempts by the Maldives National Defence Force, DAN deployed a specialised rescue team to the site. It included Finnish cave diving experts Sami Paakkarinen, Jenni Westerlund and Patrik Grönqvist.
Working with Maldivian authorities, the team recovered all the bodies during multiple long dives over several days, using closed-circuit rebreathers, underwater scooters and extensive backup equipment.
Investigations into the circumstances of the fatal dive by Maldivian and Italian authorities are still ongoing. But diving experts are already calling for stricter adherence to established cave-diving safety protocols.
Experts have also stressed the need for greater awareness of the many factors involved, including proper training, equipment configuration and even diver mindset.
Speaking to the Guardian, Jonathan Volanthen – one of the British cave divers who helped rescue 12 schoolboys from a flooded cave in Thailand in 2018 – says cave diving carries risks fundamentally different from open-water diving.
The vastly experienced Volanthen says cave divers cannot make a direct ascent in an emergency.
“If something goes wrong, you can’t simply head to the surface because there’s usually something that’s preventing that … Quite often in caves as well, it’s very easy to swim in somewhere and then find you stirred some silt up,” Volanthen says.
The combination of not being able to ascend to the surface and a poor-visibility exit makes it “much more difficult to get out” if a diver hits trouble, he says.
Adding depth to the equation, he says, exacerbates the dangers.
“The deeper you are, the more air you use, or the more gas, depending on what you’re breathing … Depth generally equals an increase in danger,” Volanthen says. Divers must carefully manage gas supplies to ensure a slow ascent, to reduce the risk of decompression sickness.
“Pressure [as a result of depth] creates a situation where gas dissolves into the bloodstream, and that means you have to ascend slowly,” he says.
Edd Sorenson, an American cave diving expert who has led more successful cave diving rescues than anyone else in the world, explains a common misconception about caves.
“Caves are not dark. Everybody thinks they’re dark … They’re devoid of light. Your house at night is dark … When your light goes out [in a cave], there’s nothing,” Sorenson says. “You don’t see a reflection, your eyes don’t get used to it.”
As a result, divers can lose track of all spatial awareness: “That’s why we learn to always have a continuous guide line to the surface.”
Sorenson also emphasises a philosophy known as “redundancy” in cave diving – multiple independent backups for all critical systems.
“We have a minimum of two tanks for your two regulators, we have a three-light minimum rule … If we’re going to go a long way, we’re going to have more. We have to have two computers,” he says, referring to the devices that track depth, time and ascent rate. “We have to have two writing devices, we have to have dual, redundant everything.”
He also highlights anti-silting techniques that cave divers should use, because common open-water flutter kicks in caves can quickly reduce visibility.
“If you get close to the bottom, that’s going to disrupt the sediment on the bottom … so on a flutter kick, you can instantly go from crystal clear water to zero visibility in the blink of an eye,” Sorenson explains.
Instead, cave divers use a frog kick. “Our propulsion goes horizontal or up from horizontal,” Sorenson says.
With decades of technical experience, Volanthen and Sorenson both stress the importance of training and personal limits.
“If you are trained properly by a reputable instructor and a training agency, you’ll understand the limits,” Volanthen says. “Hopefully you can make good decisions, whether that’s going into a cave or not going into a cave.”
Sorenson warns that experience can also create false confidence. Often, he says, when people reach the status of a divemaster or an instructor, “they think they know it all … However, a bad idea is a bad idea”.
“If they’re exceeding their training limit, exceeding their experience and exceeding their knowledge limits, they’re playing Russian roulette … Cave diving is a very, very safe sport with good training. It’s a very unforgiving sport without.”
Beyond technical skill and proper gear, experts say human factors and mindset are critical elements in diving decisions.
Cristina Zenato, a Bahamas-based cave diving instructor with more than 4,500 cave dives and over 80km of guide lines laid across different cave systems, cautioned against vilifying cave diving as a discipline, despite its technical complexity.
She says the underwater environment – “an alien place for us” – demands a level of respect.
“Is cave diving potentially dangerous? Absolutely. So is being two metres below the surface because we’re not aquatic animals.”
In addition to proper training, human factors and mindset are critical, Zenato says.
“You can be super hyper-trained, but I’ve sat on that water’s edge when I said ‘not today’, and then you’re in a car driving back, [wondering] did I call it right? And usually when you question yourself … you know it’s the right answer,” she says.
