By the early afternoon of 29 October 2008, the racing yacht Ericsson 4 had been on world record pace for almost 36 hours. Fourteen tons of Volvo Open 70 in a relentless charge across the South Atlantic, driven by 35 knots of wind pressing on hundreds of square metres of high-technology fabric.

They had first punched through the old mark - 562.96 nautical miles in a day - in the early hours of the morning. The mileage eased briefly after breakfast, but then it clicked relentlessly upwards once again. Now they were closing on a new barrier – 600 miles in a day, sailing at an average 25 knots: that meant 25 nautical miles for each and every one of the 24 hours. This was new territory.

At the wheel just after midday was Stu Bannatyne, the watch captain. He had held the same position aboard the 2001-02 Volvo Ocean Race winner, illbruck. Bannatyne is softly-spoken. At the first meeting, you might think him shy, or aloof. Not at all the kind of a man you imagine flying through freezing southern oceans at maniacal speeds, with the lives of everyone on board in his hands. But the quiet reserve hides iron resolve and a single-minded focus: useful qualities, when the slightest hesitation can spell disaster.

Bannatyne’s first trip away from New Zealand was to the 1989 ISAF World Youth Championships in Canada. It wasn’t so different from home, but there was plenty to distract a curious teenager on his first trip abroad. But none of it had any effect on Bannatyne, who came away with the single-handed title. In doing so he joined a pantheon of sailing luminaries that includes triple Olympic gold medallist, Ben Ainslie, and three time America’s Cup winner, Russell Coutts.

Now Stu Bannatyne was applying all that focus, constantly bracing every nerve and muscle against the elemental battering. The elevated helming position provided a great view, in daylight, but left him exposed to everything that the ocean could hurl at the boat. Protection was afforded by a survival suit, a windsurfing helmet with a full face visor, and he was tethered to a strong line, the jackstay, that runs transversely across the boat by the wheels.

There were just three men on deck with him; two on the sheets, and one at the double-handed winch pedestal, grinding the sails in response to the commands. Those commands were the only words spoken, the howl of wind and waves and the screech of winches allowed for nothing else. This was sailing at the very edge of human endeavour, and they all knew it.

They were sailing the boat at the fastest possible angle to the wind. Now, the wind shifted slightly, forcing them into the waves. Instead of skipping across the back of each one at a steady 26 or 27 knots, Bannatyne was forced to sail down the face, which accelerated them to a speed that would have earned him a fine in an urban area, not to mention the opprobrium of his wife, Amanda.

Then the boat ploughed itself into the back of the wave in front, plunging the foredeck into green water and washing a white wall of boiling foam and spray back down the boat.

If the motion was bad before, now it was impossible. Down below, men were trying to follow the normal routines of any other day – eat, sleep, wash, dress. But this was not a normal day - this might be a day that people would talk about for years to come, the day when Ericsson 4 went through the 600 mile barrier. And then there was a bang.