Negotiating a wind change off the Tasmanian coast was all that stood in the way of super maxi Wild Oats XI smashing its own Sydney to Hobart race record late on Thursday evening.

Powered by perfect 15-30-knot northerly winds, the Mark Richards-skippered boat was 45 nautical miles ahead of its position at the same time in 2005, when it finished the race in a record one day 18 hours, 40 minutes and 10 seconds.

The Wild Oats team was forecasting a finish up to an hour inside the record, which would have the boat arriving at Constitution Dock any time from 6.40am (AEDT) on Friday.

It would need to arrive within nine seconds of the clock hitting 7.40am to claim the record.

The five-time winner was almost certain to add line honours to a new record, while the overall victory on handicap also remained a possibility.

Wild Oats had increased its lead over 2011 line honours victor Ragamuffin Loyal by 56 nautical miles with third maxi Lahana another 40 miles behind.

On handicap, Oats was ahead of Jazz, last year's winner Loki and Black Jack, which led at stages on Thursday.

Wild Oats tactician Iain Murray said the focus was on avoiding mishap after the boat narrowly avoided damage when it hit a log on night one.

"Everyone's tired, the boat's going fast," he told reporters from the boat.

"We've just learnt to be very careful with this boat because things can happen so badly very quickly.

"Everyone's got to watch each other and look out for their buddies and we'll just try to keep it simple."

Asked if the record was a priority, he said: "I think we'll just try to get there in one piece.

"We're sailing along doing 23, 24 knots in a bit of a confused sea so our concentration needs to be on getting to Tasman (Island) right now."

Complicating matters was the forecast of westerly winds, expected to hit the fleet between 9-11pm on Thursday night.

Murray said those winds and a predicted southwesterly when the leader turned into the River Derwent could still be favourable.

"Obviously it's always a tricky place," he said.

"We're just positioning ourselves ... for the breeze to go left and then be ready to get headsails up and start back on a wind.

"We should have pretty good southwesterly breeze so we should have a reasonably quick trip down the Derwent."

In a rare event for the race, none of the 76-strong fleet had yet retired.

Meanwhile, Ragamuffin could face a time penalty after jumping the start on Sydney Harbour on Wednesday.

The matter has been referred to the race's international jury following an apparent failure to notify the boat's skipper of his infringement within a five-minute limit.

It is likely to be held in Hobart after Ragamuffin's arrival.