A handy northerly pushed their small yacht jauntily along on day one. But just off the coast of Eden, the clouds came in and the team of university students, with an average age of 21, readied themselves.

''We knew it was going to be rough, and we got it,'' Lewin said.

For a day and a half, the rookies steered their boat through an irate sea, mounting house-sized waves as winds threatened to shred their sails.

By race end, almost half the 116 starters had pulled out including the star supermaxi Skandia, which capsized in the Tasman Sea.

But Lewin's team would glide down the Derwent River to become the youngest crew to attempt, let alone finish, one of the world's toughest yacht races.

''I almost literally felt this weight lift off my shoulders. It was a sense of mission accomplished,'' Lewin said.

Not quite. Seven years on and Lewin is back for his fifth tilt - this time, against a competitor of his own making.

The 28-year-old has spent the past three months training round-the-world sailor Jessica Watson and her crew who, with an average age of 19, are poised to snatch their coach's record.

Lewin will not cut his young charge any slack.

''There won't be any relaxing on our side. Myself and nine others are very keen to win,'' Lewin said.

''We'll be doing everything we can to make sure Jess does well - but finishes just behind us.''

The Melburnian has taken time off from his job as a technology consultant to aid Watson's bid.

He lent the 18-year-old his boat, another Challenge, and hired an identical vessel, dubbed Deloitte As One, to sail against her in the competitive Sydney 38 class.

Watson said if nothing else, racing against her mentor was ''an incredible motivation''.

''We are so determined to beat our coach.

''All he has to say is, 'We're coming up behind you, put a bit more speed on'. What are you going to do?'' she said.

Watson's evolution from long-distance stayer to sprinter has required more than just new technical prowess.

''Sailing is one thing, but what I found most invaluable is how to run a team and work together,'' she said.

''When you're out at sea and the waves are crashing over you and you haven't slept for three days … one bit of communication can be critical.''

Lewin said coaxing the best from the teams would be the key to conquering the 628 capricious nautical miles to Hobart.

''You want people who, even if they are tired and wet and hungry, will turn around and make that effort to improve the performance of the boat, rather than just sit there and get through it,'' he said.

''It's not a relaxing, pleasant thing to do. But that's the point.''