Wild Oats XI skipper Mark Richards could only marvel at his new rival's sizzling start.
"She's smoking. Look at that thing go!" Richards exclaimed.
Comanche, contesting her first major race, increased her lead to 38 seconds by the second mark and appeared to be extending her advantage after that.
The fleet of 117 yachts set out under southeasterly breezes of around 15 knots and was followed by a vast spectator fleet on a sunny afternoon.
Since Comanche arrived on November 30, she has been parked just a few metres away from Wild Oats XI at Sydney's Woolwich Dock. They were also hard to separate in the minutes counting down to the start, as they shadowed each other like boxers sizing up their opponent. Then the starting cannon went and Comanche quickly put clear air on their rivals.
The fleet left from three different starting lines and there were no reports of any boats breaking early.
The competitors were expected to encounter freshening southerlies of up to 30 knots late last night.
Remarkable Sydney to Hobart stalwart Syd Fischer also racked up records early on, adding two individual race records to his already impressive sailing portfolio.
The skipper and owner of supermaxi Ragamuffin 100, 87-year-old Fischer is now the oldest skipper and oldest sailor of any rank to contest the race.
He previously shared both marks with John Walker.
Fischer is making his 46th appearance in the race, but he doesn't hold the record in that category.
That belongs to Tony Cable, who is logging up start No49 this year, meaning in 2015 he could become the first sailor in the race to reach the half century mark.
"I don't get too overwhelmed about that, guys mention it, but it's froth and bubble," said Cable, who will be aboard the 52-footer Duende this year.
Every one of Cable's starts since his debut in 1961 has been on somebody else's boat.
"One thing I reflect on is that when I started in 1961, I was one of the youngest and now I've outlived them all," Cable said.
Renowned navigator Adrienne Cahalan this year extends to 23 the race record for most appearances by a female.
Cahalan, who has enjoyed line honours success in the past aboard Wild Oats XI, is heading south this year on the 60-foot Ichi Ban.
Another record to be extended this year is Bacardi's race-leading tally of most starts by a boat.
The 44-foot yacht, which was built in 1978, is making her 29th passage to Hobart.
- AAP
