A boat made of thousands of plastic bottles sailed into Sydney Harbour on Monday and completed a four-month trans-Pacific voyage to show the benefits of recycling.

This 60-foot-long ship made of12,500 plastic bottles was welcomed by hundreds of supporters because it just finished the journey of15,000 kilometers.

"This is a great adventure." The leader of this trip, David Roth Child from a famous British bank family, said, "We are very happy to be here."

"Pratiki" was named after the voyage of the Kon-Tiki raft set off from San Francisco by Norwegian explorer Thor heyerdahl in March 1947.

The ship, with six crew members, crossed the North Pacific Ocean, stopped in the Lane Islands, Western Samoa and New Caledonia, and then left Australia.

Platiki relies on renewable energy and gets power from sunlight and wind. They can keep in touch with supporters through websites and blogs, or use social networking sites such as Twitter.

Captain Joe royle once said that the sailboat Pratiki was "completely different" from the sailboat they used to sail, but "in our hearts, there is no doubt that she came here."

Rothschild said that he came up with the idea of this trip after reading the UN report in 2006, which claimed that pollution, especially plastic waste, was a serious threat to the world's oceans.

At the same time, he said that when the impact of sailing exceeded his expectations, they also faced serious problems in sailing.