Since narrowly avoiding disaster in the Big Boat Challenge two weeks ago, skipper David Witt said his crew was primed to challenge Wild Oats XI for line honours following a "perfect" weather forecast.

Scallywag's race was almost over before it began when a poorly positioned NSW Roads and Maritime boat, supposed to be patrolling traffic on Sydney Harbour during the Big Boat Challenge, came within centimetres of tearing a hole in Scallywag's imposing hull.

Witt miraculously kept his boat safe when a collision looked inevitable, and last year's Sydney to Hobart runners-up avoided catastrophe.

Now he and new owner Seng Huang Lee, who bought the boat formerly known as Ragamuffin 100 from Syd Fischer, have turned their attention towards Boxing Day where the fleet will be greeted by a gusty northeasterly wind before a southerly change blows in around midnight.

"If I had to design one [a weather forecast], I'd write that," Witt said.

"It's one that's going to put the race record in serious jeopardy. It'll be a good race this one, it won't be like last year's.

"That [the start] will be quick and then the [southerly] change, but the change seems to be getting smaller and smaller now.

"History tells you Oats are going to win right. I don't think CQS can, I think they'll get dropped off the back pretty quick and I think the light air won't help [Perpetual] Loyal, they were looking really good three days ago. I think it's us or Oats."

Perpetual Loyal's chances took a significant hit on Saturday morning when the updated weather forecast came through suggesting the southerly change would no longer be as strong as initially forecast.

It's a big blow for the imposing hundred-footer which does its best work sailing upwind, although Perpetual Loyal remains a serious contender having ditched its celebrity crew and replaced it with several of the sailors who helped Comanche to line honours in last year's race.

Rudder damage forced the yacht out of contention last year and in 2014 it was an unidentified object in the water ruining the race for owner/skipper Anthony Bell.

That makes it three years since Perpetual Loyal finished runner-up to Wild Oats XI, and Bell admits he still has nightmares over the boat's recent run of misfortune.

"It's haunting my dreams right now – the failure, the turnaround just breaks your heart," Bell said.

"The catchcry we've been going with is to win a Sydney to Hobart, you've got to get to Hobart, so we're thinking strongly about that.

"Our biggest aim is not to have a team meeting at the Watson's Bay Hotel on the 27th this year.

"We liked the forecast a couple of days ago. For us, we need a bit of luck and we've certainly had our fair share of bad luck so we'll be saying our Hail Marys on Christmas day."

Should the forecast remain as is, Wild Oats XI is widely tipped to break her Sydney to Hobart race record set four years ago in a time of one day, 18 hours, 23 minutes and 12 seconds.

A rapid southerly change forced skipper Mark Richards to retire his boat last year when its mainsail was ripped in half, but the weather is predicted to be nowhere near as brutal this time around.

Despite the ideal forecast, Richards remained coy on whether or not his boat was on the verge of smashing its own benchmark.

"I don't even think about the record, mother nature waves her magic wand and you're just in the conditions," Richards said.

"We've got four very good boats. We don't know the history of CQS yet, she doesn't have any, she's put herself on the radar with radical design and what have you.

"Scallywag's done a lot of yachting this year, a lot of sailing. They're sailing that boat a lot better, the team looks better, the build looks better, they've got good sails, it's a very different animal to what we've raced against in the last Hobart.

"With Anthony [on] Loyal, it's a great team, they've got a fair bit more talent on board this year."