A 45,061-kilometre, non-stop lap of the planet by sea, the Vendee Globe is the longest race in the world and may well be the toughest, too. On top of the sheer distance covered, the race must be sailed solo, meaning competitors face three solitary months at sea, racing 24/7 and surviving on little more than dried meals and snatched bouts of sketchy sleep. Since the first race in 1989 - the race runs every four years and starts on November 10 this year - 108 sailors have risen to the challenge; yet, only 39 have ever made it to the finish line. Three have lost their lives trying to get there.
It is not your average race, and unsurprisingly, the sailors who dare to take it on are far from average too. With the physical and mental resilience of polar explorers and high-altitude mountaineers, these sailors are allied with a heavy dose of skill, grit and stamina.
Alex Thomson of Britain is one of those sailors this year. The 37-year-old is sailing from the southern coast of the UK across to the start-line in Les Sables d'Olonne, northern France, and invited The National on board for a test run.
Arriving at Portsmouth marina and clapping eyes on the £3 million (Dh17.6m), custom-built craft where we would be spending the next 724-watery-kilometreswas an experience in itself. Purposeful like a jet fighter and pared to the bone like a Formula One car, it was a mesmerising study in carbon fibre. Once on board, a quick tour reinforced the impression that the purpose of this boat was to go as fast as possible, for as long as possible.
The boat itself is a key part of Thomson's motivation for the challenge ahead.
"Someone like me could never afford a boat like this," he says, grinning. "Racing this boat, I'm like a kid in a toy shop. Even better, I was part of the design process. This boat has been customised for me. I've got the best job in the world."
There's no doubt that having your own £3m bespoke yacht is quite a perk, but it is one Thomson earns every time he hits the water, because the living conditions aboard are as spartan as they come.
There are no bunks - on the rare occasions when he can sleep during the race, Thomson will crash on a single, thin, foam mat. There is no kitchen, there is no toilet. There is no insulation inside either, meaning the wafer-thin carbon-fibre hull will not only shed heat faster than an Eskimo in an ice bath when temperatures fall, it will also amplify every slap and ripple of the water, making the aural experience inside similar to being in a massive drum rather than a sailing boat.
These conditions would be punishing enough for three months on a calm lake, but where Thomson and his fellow racers are headed, nature will be pushing them harder. Although the law of averages dictates that some days will be calm, there will be many more where they will face the full force of the elements, often well beyond the reach of rescue should anything go terminally amiss.
Having started the last two Vendee Globes in 2004 and 2008 (on both occasions he was eventually forced out of the race because of damages to the boat), Thomson is well aware both of what lies ahead and also the deeper reserves he'll need to find in himself to keep going.
"The first couple of days are always the hardest, the race is just so daunting. But gradually it starts to feels much more natural - I'm always amazed at how quickly the body can adapt. People generally think a lot less of their own abilities than is actually achievable, but the body is an amazing thing."
He's under no illusions about just how hard the event is going to push him, either.
"The toughest thing with this race is the relentlessness, there is no break. Sailing double-handed, you can always sleep in shifts, safe in the knowledge there's someone upstairs saving your life. But sailing single-handed, you never really sleep properly."
According to Shaun Biddulph, Thomson's trainer, it is not the extremity of the conditions that will keep Thomson awake, it is the noise around him.
"Alex is conditioned to tough extremes and knows he can sleep in the boat with just that small mattress. The most important thing isn't the bed, but the sounds on the boat - as long as they're normal he'll sleep, but at the slightest unusual noise which could mean imminent danger, he'll be ready to go."
Coping with this permanent knife-edge situation is a major task, Biddulph admits.
"He has to be able to fall asleep really quickly, and to stay hydrated and fuelled at all times while sailing non-stop. Managing this for three months is an immense balancing act."
As Thomson himself puts it: "Once the race is on, I'm the doctor, the maintenance man, the trimmer, the navigator, the meteorologist, the cook, all of these things". Because of this, his preparation for the race involves a lot more than just gym work and time on the boat.
"You have to break down every task that's needed and prioritise. Spending 10 hours each week training is good, but maybe I should spend some of that time working on meteorology instead, and so on."
Back on board, Portsmouth is now fast receding behind us as the open waters of the English Channel beckon.The boat's giant sails, each stretched bowstring tight, fill with steady wind and bring the sleek craft to life. A long wake, more like that of a speedboat than a sailboat, trails behind us and a quick glance at the instruments on deck show that we were now cruising at 15 knots - just under half of this boat's top speed - and already almost three times the pace a regular sailing boat could achieve in the same conditions.
At the helm, Thomson looks like a man in his element. Relaxed, calm and constantly checking the sails, he makes continual minor adjustments to coax every last ounce of speed from the wind around us.
After getting used to the wild pitch of the vessel, which seems to have permanently canted to one side with one sill of the cockpit pointing to the sky and the other virtually below the water level, I start to get a feel for what this boat could do and an inkling of why Thomson does it.
Yet, as day turns to night and conditions become more challenging, I am treated to an unforgettable insight into what will be Thomson's world for the next three months. And while I can still understand why he does it, I have no idea how he does it.
For starters, there is the rocking and constant wallowing, all of it exaggerated by the relentless need for speed and topped with regular take-offs as the boat leaps over large waves before slapping back into the water. Like the wake, this motionis normally the preserve of speedboats, not sailing boats.
Then there is the matter of sailing at night. With the comfort of the horizon removed and all depth perception lost to the enveloping blackness, the speed is amplified hugely and the experience becomes far more like being on a roller coaster, only this roller coaster never stops or so much as slows for a second.
As the hours roll by and Thomson merrily trims sails up above and barrels down below to spend long periods in front of his bank of navigational equipment checking our course throughout, I go steadily greener before the inevitable happens - I say goodbye to my breakfast, lunch and dinner. Hoping sleep will save me, I stagger into the dank, dark, low cavern below before flopping into a sleeping bag wedged between two enormous kit bags.
The noise is phenomenal: howling wind, the never-ending rush of the sea just millimetres from my head through the sleek hull, and the myriad creaks, groans and rattles of a racing yacht at full tilt. The fact that I was simultaneously being tossed around like clothes in a tumble dryer wasn't helping either.
Yet, somehow, I sleep for a few short hours before staggering back to the deck with a huge headache, where Thomson, as relaxed and in his element as ever, is calmly going about the job of getting us to France as the first fingers of dawn begin to creep across the sky.
With the reappearance of the sun and the sight of the Brittany coast, I know I am at least going to survive this madcap voyage. But survival was all it would be. Staggering from the boat, 30 hours after first climbing aboard, I am exhausted and feel like I have been running marathons all night. And I'm battered - I feel like I have been in the ring with Rocky.
How Thomson copes with this for months at a time I have no idea. I take my hat off to him.
To follow this year's Vendee Globe visit www.vendeeglobe.org
To follow Thomson directly, visit www.alexthomsonracing.com