Observations from Jonathan Volanthe, "one of the British cave divers who helped rescue 12 schoolboys from a flooded cave in Thailand in 2018 " [who] says cave diving carries risks fundamentally different from open-water diving"

"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.

#3 | POSTED BY DONNERBOY

Sums up my own experience. I dove for years, spent ages as an air hog before finally settling down and only then getting into that magical glide through alien space. Where keeping alert, knowing and properly using your gear/gauges, being aware of depth/air supply/time considerations, and particularly knowing your physical and knowledge limitations in a situation where you simply cannot b.s. your way out are paramount. Our son became a dive master and worked through all sorts of certifications. He drew the line at large wrecks and caves. Both activities are in every possible way well beyond the zone of experience of those of us who have engaged in recreational diving. He's a brave guy, a first responder, and he got the distinct impression that when it came to cave diving it wasn't a question of whether you would die on a cave, just a matter of when,