Five men are crowded into the hull of a small wooden boat, squeezed into a space little bigger than a queen-sized bed. A sixth member of the crew keeps watch above as the wind and waves buffet the craft, swell breaking across it. Dressed in old-fashioned wool and cotton clothing ill-suited to the conditions, the men are soaking wet and freezing.
They are in the Southern Ocean, 320km from Elephant Island, a mountainous mass of ice and rock between South Georgia and the tip of the Antarctic Peninsula. They have no electricity, no modern navigation equipment. To eat, there is dried meat, biscuits and pemmican, made principally of lard. In a few days time, they hope to land on South Georgia and traverse its icy, mountainous interior. For the climb, they have nails pushed through the soles of their boots in place of crampons.
The 1916 Antarctic journey of Ernest Shackleton is remembered as one of the great stories of survival. Intending to traverse the Antarctic continent, Shackleton's ship was destroyed by ice, leaving him stranded with his crew on the remote and inhospitable Elephant Island. With little chance of rescue if they stayed put, he and five men sailed a lifeboat the 800 nautical miles (1481km) to South Georgia before crossing the mountainous interior with makeshift climbing equipment to reach a whaling station and summon help.
This scene could well come from the pages of South, Shackleton's classic account of the journey, but it is in fact from a documentary following the (ultimately successful) attempt by British-Australian adventurer Tim Jarvis and his team to retrace Shackleton's voyage, recreating the original equipment and conditions as authentically as possible.
"I suppose, in polar terms, this one was always the big one," Jarvis says of the expedition. "Edmund Hillary described this as the greatest survival journey of all time, so I always thought, wouldn't it be fantastic to attempt this thing."
Invited by Shackleton's granddaughter Alexandra to recreate the voyage and buoyed by his success in recreating Sir Douglas Mawson's failed 1912 trek across Antarctica in 2007, Jarvis embarked on four years of preparation. The extensive process involved "everything from rebuilding the boat from scratch through to selecting the team, doing the risk assessment, getting the partners".
"To do it as he did was absolutely critical," Jarvis explains. "I have been in a number of ships from South Georgia to Elephant Island before - modern ships - and if you're in a 110m ship with stabilisers and ice strengthening and radar it's a manageable trip. If you go in a 23-foot (7m) wooden rowboat with no buoyancy and no stabilisers and no means of avoiding capsizing, no communications and no lights, it's a totally different story. It makes something that's already difficult really challenging."
This thirst for a challenge is a driving force for the 46-year-old, who has lived in Australia since 1997 and is now based in Adelaide. A veteran of numerous Antarctic and Arctic adventures, he has also completed expeditions closer to home, including the first unsupported crossing of the Great Victoria Desert (Australia's largest) in 2001.
Having developed a taste for adventure during an outdoorsy childhood spent largely in South-East Asia, Jarvis undertook his first expedition in his twenties to Arctic Norway, motivated by a desire to find a purer form of personal challenge than that found, for example, on the sporting field.
"I've always been fascinated with personally challenging myself and you can do that when you go to the outdoors more so than sport," says the former rugby player. "Sport, you're up against human opposition, you can psych them out, you can play mind games, your 8-0 home record makes the opposition feel concerned when they come and play you at home. Antarctica, mountains, deserts, oceans don't care about your CV. You're either good enough to do the job each time you step up to the plate or not."
Describing himself as a "very simple, outcome-focused sort of person", Jarvis' willingness to challenge himself also translates into work as an environmental scientist, a career which grew out of his love for the outdoors and which he sees as being "inextricably intertwined" with his expeditions.
"I spent a long time studying to try and convince politicians and corporates to try and do the right thing (in terms of the environment)," Jarvis says. "How much do people really listen when you go in through the front door with that kind of message? Sometimes. But you can go in with an adventure story with some good corporate messaging and you can pitch your environmental message and you can get some real traction, so you use it as a vehicle to try and effect some kind of environmental change."
Though he is in demand as a corporate speaker, Jarvis is focused on action rather than advocacy in his environmental work, much of which relates to climate change. Spending time in polar regions has given him a keen appreciation of the effects of global warming and he thinks it has made the land-based portion of the Shackleton expedition more dangerous than it was in 1916.
"There are 160 mapped glaciers on South Georgia - the place is just one big, glaciated, angular, mountainous island sticking out of the ocean - and 97 per cent of them are in retreat, that's (according to) the British Antarctic Survey and they've been studying that place for 50, 60 years. The effect is that more of the crevasses are open and dangerous and waiting for you. It does make that crossing a lot more difficult."
Given the dangers of these expeditions - Jarvis says while preparing for the Shackleton journey his team produced a spreadsheet of 171 things that could go wrong - the obvious question is: why?
"It is about self-exploration, really," he says. "It started off as a physical challenge and it's become much more than that. The irony is that you have to go to really remote places to discover who you are.
"There's no money, there's no societal structure, there's not even vapour trails in the sky from aircraft. And so you strip back all the noise we're used to living with and you replace that with really memorable, significant emotional experiences, sometimes with other people, sometimes on my own. It's about survival and the honour of doing it for someone else and the honour of not doing it for the money and the opportunity to explore things that are just outside the normal constructs we have.
"I think actually those motives have not changed that much over time. If you look at the first guys that tried to reach the North Pole, the North Pole is just a piece of ice at 90 degrees north floating in the sea. There were no tribes to conquer, there were no minerals to extract, there was no land to stick a flag in or anything - it's about the personal exploration of trying to do it."
These motivations help keep him going when the going gets tough on an expedition.
"You don't really fear dying, you fear failing," Jarvis says. "Dying obviously would be a ridiculous thing to happen but the chances are it would happen through something unforseen that would just happen - you'd get hit in the head by the boom coming across and you'd get knocked overboard and that's it.
"But failing through not being good enough - falling short at some level in terms of either your physical or your mental resolve to complete the thing - that's something that's far more difficult to come to terms with. Part of the desire to keep going is one of the original reasons you go.
"If they're about testing yourself, finding out more about who you are, it's a very powerful motivator."
Admitting he finds everyday life "a bit dull", Jarvis says adventuring has become a cornerstone of his identity, citing Aristotle's maxim that "we are what we repeatedly do".
"I've spent so much time doing this that you feel that's more you than back here (at home) and it draws you to want to keep going back."
Despite this, he acknowledges that the birth of his two sons in recent years has given him pause for thought.
"It has made a difference. For a start, regardless of whether you're risking life and limb, and what that would mean for not being there to see them grow up or be there for them, you just don't want to be away for extended periods because there's so much developmental stuff that happens.
"In the 2 1/2 months I was away (for the Shackleton expedition), I came back and both my boys had already really made huge leaps. You just don't want to miss that."
Having said that, his next adventure is in the works. Although obliged to be secretive at this early stage, Jarvis does say he'll be heading somewhere "around the equatorial bit of the Earth, not the poles".
"It has a real climate change advocacy and action component to it and it involves mountaineering."
But on one point he is quite definite: "It won't involve a small boat, I can tell you that."
The book Shackleton's Epic: Recreating the World's Greatest Journey of Survival, by Tim Jarvis, is out now (ABC Books, $45).