The crowd, half a million strong, lined the French Atlantic harbour walls in driving rain. The well-wishers were a blur of humanity, a blaze of colour, a buzz of conflicting accents and entreaties. By the time darkness fell last night, and Alex Thomson began adjusting to solitude, they were ghosts.
The British sailor faces three months with only a recurring sense of awe, dread and excitement for company. Each mile, every knot and nuance of his solo navigation in the Vendée Globe will be a journey of self-discovery.
More than 3,000 people have climbed Everest. In excess of 500 have reached outer space. Only 68 have sailed solo, non-stop, around the planet. Thomson, twice a victim of sailing's most extreme race, has yet to join them.
The Vendée Globe is France's definitive sports event, but makes a universal statement about the human condition. The 20 skippers, who include three Britons, Samantha Davies, Mike Golding and Thomson, represent nobility of spirit in a world neutered by institutional caution.
Danger is omnipresent in a uniquely attritional 26,000-mile race, which has killed three sailors in 20 years. Thomson nearly lost his life when he was rescued by Golding after the keel of his boat fell off, deep in the Southern Ocean.
Davies went to the aid of the French sailor Yann Eliès, who lived only because he instinctively grabbed a trailing rope when he was being swept overboard by a rogue wave. He crawled back to his cabin after breaking his thigh, leg and pelvis, and waited, in excruciating pain, for three days for help.
The race's folklore is punctuated by acts of heroism. Briton Pete Goss forfeited his chances of winning in 1997, when he sailed 160 miles back into a hurricane to save Raphael Dinelli, who had tethered himself to the stump of the broken mast on his sinking yacht, and was waiting to die.
Goss was my skipper when I sailed the wrong way around the world, against prevailing winds and tides. It was a formative experience. In the words of the poet Anne Stevenson, "the sea is as near as we come to another world". Surfing down waves, trailing a wake of green phosphorescence under a platinum moon, is simply surreal. The Southern Ocean, where waves, with crests up to 200 metres apart, roll unimpeded around the bottom of the world, has a terrible majesty. It has a spiritual dimension, definable moods, a distinct personality.
Anyone who feels obliged to ask the question of why these sailors put themselves in harm's way will never understand the answer. There is an element of addiction in sailing alone. No other activity threatens such prolonged physical and mental hardship, in utter isolation. Technology eases the sense of guilt of leaving loved ones – Thomson can still talk to his wife, Kate, and their 22-month old son, Oscar – but ultimately he is alone.
Thomson's boat, named after his sponsors, Hugo Boss, is the maritime equivalent of a Formula One car. It has nearly 30,000 parts, and weighs little less than eight tons. "I don't do this for the love of the sea, or the beauty of the ocean," he insists. "It's an adventure, but I do it because of the competition."
Yet just as there are few atheists in a foxhole, Thomson was keenly aware of his mortality as he waited 12 hours for rescue by Golding. The sea's defining code, that sailors respond to those in distress, cut through the clutter of personal and professional rivalries.
"Mike and I had a disagreement and hadn't spoken for weeks,"he said, "He saved my life, and then, three hours later, his mast fell down. It was a terrible thing to happen to him. We had to nurse his boat back to Cape Town, in a blizzard. We'd hated one another. We'd never sailed together. Suddenly, we were one."
It is an elemental experience. Golding admits his mantra for the next three months will be: "Sleep before you are tired. Eat before you are hungry. Change clothes before you are cold." Thomson argues: "The human mind and body is simply amazing. We can push back what we think are our limits."
Thomson will burn 7,000 calories daily in the Southern Ocean, when he will be sustained by freeze-dried, liquefied mush. His only fresh food, five packs of bacon, will be gone by the weekend. He will sleep in 20 to 40-minute bursts, on a black foam mattress which folds into a rudimentary chair, every two to four hours.
He said: "Everything slows down when you're sleep-deprived. Simple decisions seem difficult. You are not able to be rational,The key is not to end up in that state. These boats carry big loads. One mistake on deck and your hand is gone."
Thomson self-meditates, uses physical actions to alter his emotional state. In times of stress he pinches the bridge of his nose, because the pressure "reminds me of the things I value, the very best things in my life".
The boat below deck is sparse, eerie. It is a carbon-fibre sarcophagus. Noise from the hull, and rigging, stimulates the imagination. In times of stress, Thomson closes his eyes, and imagines himself "being outside the boat, looking down on it. There are no storm clouds, no rogue waves, no icebergs. It's all cool."
Ellen MacArthur, second in 2001, embraced misery as an ally. Davies, who has left a young son, Reuben, behind, insists: "I am not afraid of being afraid." Golding likens the race to three-dimensional chess.
The boats fall off waves, into troughs which have the consistency of concrete. It is a netherworld of weather "bombs", which are intense areas of low pressure, and "survival storms", in which the wind can exceed 80 knots.
Thomson admits: "There is a real understanding of the size of man in the great scheme of things. You feel scared, occasionally fearful for your life, but it puts mankind into perspective. We are a tiny cog in the wheel.
"When I lost the boat last time around, I delved into the emotions I was feeling. The biggest was sadness. The boat had become part of me. In England a boat is female, in France male. She was my friend, my livelihood. I wanted to look after her like a new-born child, and I failed her."
His image, standing 50ft high, still lines the walls of the old port. He might be able to walk unrecognised around his home town of Southampton, but one banner – "You do. We Dream" – testified to his rock-star status here.
He knows the crowds turn out because they wonder if they will see him alive again. However, out in the open sea, once the chaos of the start was behind him, he was in his element. "This is the special time" he said. "Now it is just me, and the boat."