This Friday, a documentary, Alone Against The Tasman, tracing Quincey’s epic journey, chronicling his struggles against the elements and, just as gruellingly, against his own emotions, will be broadcast in the UK. The opening scenes show Quincey at one of his lowest points, on the verge of surrender, after his small boat had been rolled three times in ferocious midnight surf.

“I thought it was over. It was dark and there was too much of a storm,” he says. “I thought I’d lost all my oars and that the boat was partially cracked. It was terrifying.”

Upon reflection, though, Quincey, now 27, insists emerging from his trial by fire – or by water, at least – was the turning point that fortified him. Among the messages of concern and support received the next day, one in particular rebooted Quincey’s approach.

“One guy sent me a message saying, ‘Heard you got rolled three times – you lucky bastard’,” he recalls. “And that caused a bit of a shift for me. It changed my attitude – if I can survive that, I can survive anything – and it just adds to the experience I had. It was a pretty crazy time, definitely a good challenge and a good adventure.”

Quincey made the crossing in a modified surf-boat, 7.3m-long and 1.8m-wide, with room to row and a cramped cabin where he slept and stored his food. He can relive the tough times at sea, having overcome them and looking back through the prism of triumph but the documentary shows that, for much of the 54 days, Quincey was a broken man.

“The rowing was OK but the loneliness and the boredom were rough. The psychological part of it was horrific,” he says, recalling the effort required simply to keep going. “The hardest part was just the monotony, the repetition. You wake up and you know straight away that you’ll be rowing for 15 hours that day. When the weather’s bad, that’s pretty tough. You never have an easy day – there’s never a break. You have to be on your guard the whole time. You’re always stressed out.”

Every day, Quincey considered quitting. Every day, he sat at his oars and felt he couldn’t continue, often breaking down before having to build himself up again. It was, he says, a miserable experience.

“I probably gave up a few times. I threw down my oars and decided I’d had enough. But what do you do? You’re out there anyway and it’ll take five days for someone to come and get you and by that time you could be another few hundred miles closer to New Zealand. So the logical solution was always to keep going, but there was a constant debate in my head.

“At about 10am every day, by the time I’d rowed for about two hours, so at pretty much the same time every day, I would start to feel really rubbish. I didn’t want to be there and would get upset about the smallest things. I’d pick up the oars and last about 20 minutes and just feel completely broken, completely depressed, but you had to push through. I’d row again for another 30 minutes and realise I was making progress. But it was a real rollercoaster.”

Aside from the emotional toll extracted by his journey, Quincey was acutely aware of the fate of the last man who attempted the crossing – in 2007, Australian Andrew McAuley disappeared while within sight of New Zealand. His kayak sunk at sea and he is presumed dead. This sobering reality was never far from Quincey’s mind – that the last bloke who tried to cross the Tasman on his own didn’t make it back to dry land.

“It was a reminder every day – it doesn’t matter how close you get, you can still just disappear,” he says. “I was very conscious of the fact that I could die any second I was out there but I had strategies to guard against that, so I learned some lessons from his expedition. I was always aware of it, so stuck to certain rules and routines.”

Despite being exhausted and depressed, and unravelling quickly, Quincey was forced to steel himself further in the final days of his trip, when it became clear that, if he didn’t accelerate, the current would carry him north so rapidly that he would overshoot New Zealand completely, condemning him to an extra 10 days at sea. It meant Quincey had to row non-stop, through the night, getting by on only snatches of sleep while hunched at his oars.

“You don’t know where the waves are coming from – you can’t see anything. You get hit on the side and the boat partially rolls – it’s rubbish,” he says.

“It was a real race against time because I knew that I was losing 10 miles north for every mile I was rowing towards land. I was running out of water, so that was a big factor and I just got by on No-Doz and as much coffee as I could drink. It was do or die. I’d had enough.”

Eventually, though, Quincey made it in one piece, landing at Ninety Mile Beach, near Kaitaia on New Zealand’s North Island, where he was greeted by a throng of supporters.

Quincey, originally from Auckland, now lives in London, working as a motivational speaker, but plans to get behind the oars again, although he’ll make sure he has some company for any future expeditions.

“I’m looking at taking a four-man crew around the world – that would be over three years with stop-offs along the way – and I’ll be rowing the Caribbean Sea in March,” he says. “It’ll be great to do it with a crew, although there are some different challenges, managing the personalities, but it’s just shit being out there by yourself.”

Alone Against The Tasman will be broadcast on Friday, December 9 at 8pm on Eden (Sky 532, Virgin 208). Follow Shaun Quincey on Twitter: @tasmanrower