A 16-year-old Australian girl who spent seven months at sea in her pink yacht sailed across the finish line of her round-the-world journey today, becoming the youngest sailor to circle the globe solo, non-stop and unassisted.

Thousands of spectators erupted into cheers as Jessica Watson sailed into Sydney Harbour, the finale to an epic adventure in which she battled 40ft waves, homesickness and critics who said she'd never make it home alive.

"She said she'd sail around the world, and she has," a tearful Julie Watson said as she watched her grinning daughter cruise past the finish line from a nearby boat. "She's home."

Watson docked at Sydney's iconic Opera House. The teenager burst into tears and gasped in relief as she stepped off the yacht and into the arms of her parents, whose decision to let their daughter attempt the feat was called an act of insanity by critics.

She hung on to her father and brother as she walked slowly and tentatively along a pink carpet rolled out in her honour - her first steps on land in 210 days.

"People don't think you're capable of these things - they don't realize what young people, what 16-year-olds and girls are capable of," Watson told the raucous crowd. Many onlookers wore pink clothes and waved pink flags in honour of her 34ft yacht, Ella's Pink Lady. "It's amazing when you take away those expectations what you can do."

Watson, from Buderim, north of Brisbane in Queensland state, sailed out of Sydney on October 18 despite protests by critics that she was too immature and inexperienced for the treacherous journey. Her parents maintained that she was well-prepared and noted she has been sailing since the age of eight.

"I don't think any of us would ever doubt Jessica Watson again," said New South Wales state Premier Kristina Keneally, who greeted Watson at the Opera House.

Watson's journey took her northeast through the South Pacific and across the equator, south to Cape Horn at the tip of South America, across the Atlantic Ocean to South Africa, through the Indian Ocean and around southern Australia.

Australian Jesse Martin holds the current record for the youngest person to sail around the world solo, non-stop and unassisted, after he completed the journey in 1999 at the age of 18.

Martin boarded Watson's boat to take over during her cruise toward the Opera House, so she could relax and wave to fans.

She was also joined on board by Britain's Mike Perham, who completed a solo circumnavigation at the age of 17 in 2009, though technical problems forced him to stop for assistance.

Watson's feat, however, will not be considered an official world record, because the World Speed Sailing Record Council discontinued its "youngest" category.

And though she sailed nearly 23,000 nautical miles, some sailing enthusiasts have also argued that Watson didn't travel far enough north of the equator for her journey to count as a true round-the-world sail as defined by the record council's rules.

Watson's managers have dismissed those claims and argued she didn't need to adhere to the council's rules anyway, since they wouldn't be recognising her voyage.

The route took Watson through some of the world's most treacherous waters, and she battled through monstrous storms, suffering seven knockdowns.

But her journey was also peppered with moments of beauty. On her blog, she described stunning sunrises over glassy seas, the excitement of spotting a blue whale and the dazzling, eerie sight of a shooting star racing across the night sky above her boat.

She also had fun, chatting about boys and fashion with "Silly", a little brown seabird that landed on her yacht and hung around for awhile.

She sang at the top of her lungs with no audience to critique her and indulged her sweet tooth with chocolate cupcakes she baked in her tiny kitchen. A video she shot shows her giggling while dumping a ceremonial bucket of saltwater over her head after crossing the equator.

Prime Minister Kevin Rudd greeted Watson at the Opera House with a grin and a hug, dubbing her "Australia's newest hero" - a description Watson dismissed.

"I'm actually going to disagree with the Prime Minister," she said, as the crowd laughed. "I don't consider myself a hero. I'm an ordinary girl who believed in her dream."

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