Everything is on the line for Sydney to Hobart favourite Andoo Comanche.
Skippered by John Winning Jr, the supermaxi yacht is out to defend her line honours title and break her own race record.
But a thunderstorm is forming, bringing with it erratic wind, hail and rain to test the fleet which includes three fellow 100-footers.
But Winning likes his chances.
"For us, it's really our swan song. We want to go out on a high," he said on Tuesday.
"We've got nothing to prove but everything to lose. We put ourselves in this position of being favourites.
"We've won all the races that we've had (navigator) Justin Shaffer on board and we really back his decision-making.
"The rest will be up to the wind."
With the wind behind her sails in 2022, Comanche stormed home in one day, 11 hours, 56 minutes and 48 seconds - the second fastest time for any line honours victor in Hobart history.
Winning and his crew are bent on beating the fastest-ever time of one day, nine hours, 15 minutes and 24 seconds - set by Comanche in 2017.
"I would say it's a little more than a glimmer of hope," he said.
"My navigator - I looked at him and he's looking at the wind, and he said, 'if we sail really well or whichever of the 100-footers in front sails really well, the breeze will deliver about a 10 to 20 per cent chance of things going and falling into place'.
"But we'd have to get down to Tasmania and up the Derwent in the easterly before that dies. If that's gone by the time we get there, it won't be possible."
Sailing master Iain Murray is predicting Comanche and her crew will clear the Boxing Day storm and enjoy at least some daylight on their 628-nautical-mile trip to Constitution Dock.
"We don't like thunderstorms," he said.
"You don't want to get caught with too many sails up and you certainly want to be able to react.
"Luckily, we're probably going to clear Sydney and most of the storms in daylight so you will have sort of some chance of seeing what's coming."
