In late March, Ant Williams is going to take a deep breath then disappear under the Arctic ice, heading straight down without an air tank for three minutes of hopefully record-setting torture.
It’s warmer in than out. In the fjord off Norway’s north coast, the air temperature should be about minus 25 degrees, while the sea should be a balmy 0.2 degrees.
After just one kick of his huge mono-flipper, it will be pitch black.
After a couple more kicks, the pressure will make him sink, dropping into the black Arctic sea at around a metre per second.
By 30 metres down, the water will feel like an icy bear hug.
Past 50 metres, his lungs will physically be unable to shrink any further, with all the air squeezed out.
All the air will be forced into his head to equalise pressure in his ears.
“The sensation is one of being crushed,” says 46-year-old Williams from coastal Torquay, Victoria.
“You have to tuck in your chin to protect your throat, and you’re going away from help.”
Williams has been freediving for 17 years and his body has adapted. But this sport is much less a physical game than a mental one, a struggle to force your body through something it desperately wants not to happen.
Divers try to cultivate a state of meditative calm, a Zen-like place of no extraneous thought.
I’ve been on dives where my brain has outright said to me, I’m dying right now.
At 70 metres, Williams’ target depth for the record-setting dive (in warmer waters he’s been down to 100 metres), he will be getting contractions in his throat and diaphragm and an overpowering urge to breathe.
And then comes the hard bit.
Turning around – a job in itself, working out which way is up suspended in these dark depths – he must fight his way uphill searching for that small cut circle in the metre-thick ice, while his brain rapidly succumbs to narcosis.
“I’ve been on dives where my brain has outright said to me, ‘I’m dying right now, I’m dying’,” says Williams. Other times, instead of panic he has fought euphoria, a deadly, delusional temptation to stretch out the dive because it was going so, so well.
And then, finally, a round window in the green glowing ice, edged in gold.
In April 2015, Konstantin Novikov of Russia set the current world record for a depth dive under ice. At the geographic north pole, he dove down 65 metres, breaking the previous record of 51 metres.
Freediving is a regular sport in Russia. Deaths are also regular.
They cut holes in the ice with chainsaws and snowmobiles yank the ice free of the dive hole.
Williams says he was a “musically inclined” kid whose passion for sport was never matched by ability.
He considered bullfighting and cliff gliding but settled on freediving because of the movie The Big Blue.
But after a time in sports psychology at age 30 he realised that what he was teaching “had all come out of a textbook and I’d never lived any of it”.
He considered bullfighting and cliff gliding but settled on freediving because of the Luc Besson movie The Big Blue.
He found that “if you are mentally tough, if you can put up with a whole lot of discomfort and wrap your head around some of the fear, you can actually do pretty bloody well”.
“I decided just to be really resilient and sit in the discomfort of that sport … My technique and skill have come a long way but number one is mental tenacity.”
And after a career in which he’s become one of freediving’s top-10 achievers, he decided that “freediving shouldn’t be about just going a metre deeper every year, it should be about going to the fringes of your sport”.
“So I decided to come up with an idea that would test me in a new way.”
It also tests his equipment – past 70 metres, divers usually fill their masks with salt water to stop them imploding but in this temperature it would risk freezing his eyeballs so he’s found a new type of goggle that deflates around his eyes.
But Williams says doesn’t have any doubt he’ll beat the record.
I ask him the biggest risk. He considers, and discards, the real but rare chance of a blackout or heart attack under the water.
The greatest risk, he thinks, is a chainsaw accident while they’re cutting a hole in the ice.
Nick Miller is Europe correspondent for The Sydney Morning Herald and The Age