Supermaxi Wild Oats XI won its eighth line honours in the Sydney to Hobart race on Sunday, officials said, to become the most successful yacht in the history of the competition.

The Mark Richards-skippered 100-footer crossed the finish line ahead of American newcomer Comanche in the gruelling 628 nautical mile (1,163 kilometre) race down the east coast of southern Australia, organisers the Cruising Yacht Club of Australia said.

The nine-year-old yacht crossed the line after two days, two hours, three minutes and 26 seconds at 3.03pm (0403 GMT), while Comanche finished in two days, two hours, 52 minutes and 44 seconds.

"It was our toughest race. To have a boat (Comanche) so close is always difficult, especially when they are going faster than you," Richards told reporters in Hobart after the yacht crossed the line at Battery Point.

"We managed to pull it off and I just said to the guys, we have just got to hang in there, hang tough, minimise the losses and wait for the first opportunity we could to attack and we did and it paid off."

Wild Oats XI, one of five supermaxis -- the biggest and fastest yachts -- in this year's race was also first across the line every year from 2005 to 2008 and in 2010, 2012 and 2013.

It surpassed the record of Morna/Kurrewa IV, which won seven line honours titles in the 1950s and in 1960.

But choppy seas during the race meant the leaders were unable to challenge the race record set by Wild Oats XI in 2012 of one day, 18 hours, 23 minutes and 12 seconds.

The brand-new, cutting-edge Comanche, owned by American technology entrepreneur Jim Clark, had a stellar start when it flew out of Sydney Harbour at the start on Friday, followed closely by Wild Oats XI.

But as the boats turned south they encountered choppy seas, prompting the fleet to spread out as they tried to avoid the worst of the weather.

By morning the winds had eased, giving an advantage to the slim-line Wild Oats XI, owned by billionaire Bob Oatley, which broke away from the wider-bodied Comanche on Saturday afternoon.

- 'Exciting moment' -

Wild Oats XI extended its lead on the second night, taking advantage of a high-pressure ridge in the Bass Strait, although Comanche narrowed the gap to 10 nautical miles at Tasman Island on Sunday.

"It all went really, really well. To win a Hobart is such a great honour, but to win an eighth one, it's just wonderful," Richards said.

"The opportunity to rewrite a bit of sailing history doesn't happen every day of the week, that's for sure. Just a very exciting moment."

Oatley said his yacht would "definitely be back next year", adding: "It's a miracle... she is the best boat in the world, she's proved that."

Clark said he was not sure if Comanche would be back to race next year, but praised Wild Oats XI and its crew.

"Wild Oats and Mark Richards ran one hell of a race and it's a really excellent boat," he said.

The Sydney to Hobart was Comanche's first major ocean race, with accomplished American skipper Ken Read admitting before the start that the yacht -- which is broader than its class rivals and has a towering 150-foot mast set further back than most -- was not perfect for the competition.

Perpetual Loyal, another supermaxi, was the most high-profile retirement after withdrawing with hull damage, while Brindabella, a former line honours winner, also pulled out after it started taking on excess water due to damage to rudder bearings.

The 70th Sydney to Hobart bluewater classic drew its biggest fleet since 1994 of 117 yachts.

Source: AFP