The thrill of discovery has led Dr Craig Challen of Vetwest Animal Hospital in Clarkson, WA, to become one of Australia’s leading technical cave divers
“Cave diving is one of the few pursuits that offers the opportunity to go somewhere and discover things nobody has seen before. Once you’ve experienced it, the thrill of discovery never leaves you. It’s hard to explain the excitement I feel when I see a hole in the ground with outflowing water—I have to know where that water comes from and where it goes.
“I belong to an informal group of cave divers called the Wet Mules. There are about six of us who have dived together for the past 15 years. During an expedition, we are often on site camping for a couple of weeks. You want to share that experience with like-minded people you trust and with whom you can have a good time.
“Cocklebiddy Cave is located on the Nullarbor Plain and, at one stage, was the longest known underwater cave in the world. We went there in 2008 and managed to extend the exploration of the cave by another 120 metres. That was pretty exciting—it was the first big thing on my resumé.
“We have also had multiple expeditions to the Pearse Resurgence in New Zealand. It’s the deepest dive in Australasia and in 2012, I set a depth record of 220 metres. Not that I went out to break any records—it was simply a matter of wanting to explore a world-class site and making the most of it.
“A dive of that depth takes 17 hours and is only possible with the use of rebreathers. Of that 17 hours, half an hour was spent at the bottom followed by 16-and-a-half hours of decompression. There was a lot of time to think about life.
“The next big thing for us is China. There are a lot of caves to be explored and cave diving is not a well developed activity in that country. One of our team has been over to reconnoitre and we are all going over soon to have a look and bag some sites.
“When I’m going for a dive, it doesn’t have to be a big site. Often you can dive in caves that have been well explored and find another little passage off to the side. That can be just as exciting as the really big expeditions. My favourite dive is always the one I’ve just completed.”