Students and crew rescued from the sinking of a Canadian-owned tall ship in the South Atlantic were back on solid land Saturday after spending up to 40 hours in life rafts after their ship capsized.

The first of 64 people on board the three-masted SV Concordia were ferried into Rio de Janeiro aboard Brazilian Navy and merchant vessels, exhausted but relieved after their long ordeal.

Wearing navy caps and borrowed clothing, 12 of those rescued held an emotional news conference in Rio. The rest were to arrive later in the afternoon on two merchant vessels.

CTV producer Ana Pereira said survivors indicated that the ship went down very quickly, slipping beneath the waves in only "a few minutes."

The ship's captain said that his vessel sank Wednesday afternoon -- a day earlier than previously reported – after being flipped on its side by a powerful gust of wind. He and his passengers and crew were rescued by merchant ships early Friday.

Capt. William Curry told reporters he was below deck when the ship suddenly keeled, banking over at a sharp angle in the strong wind. Curry said that was normal, but when the vessel immediately went over a second time, he knew the vessel was in great danger.

The captain blamed the wreck on a "microburst," a sudden, vertical downdraft that struck the entire surface area of the Concordia's sails as it was angled over to one side. Within seconds, the boat went from sailing upright to lying on its side and beginning to sink.

Thirty minutes later it was completely underwater, Curry said.

"The boat started keeling a lot," said 16-year-old passenger Lauren Unsworth, a Dutch-Canadian who lives in Amsterdam. "It came back up, keeled again, was basically lying on its side and all the windows began to break. That's when we knew it was time to flee."

Curry said that they abandoned ship and took to their life rafts in high winds and heavy seas, spending more than a day adrift in the Atlantic before spotting their rescuers.

"We had been in the life raft for about 30 hours when we saw a search plane for the first time," Unsworth added. "That's when we knew we were not alone and that help was on the way."

Toronto-native Keaton Farwell said her biggest fear was that no one was aware the group needed to be rescued.

"We thought our signal had failed and nobody knew and it could be weeks before we were saved," she told a news conference. "The worst life-and-death thoughts were going through our heads, and everybody was panicking."

The navy said the distress signal was picked up about 5 p.m. Thursday, and an air force plane later spotted life rafts in the ocean about 500 kilometres from Rio.

Students on five-month voyage

The three-masted SV Concordia was on a five-month voyage that allows students in grades 11 and 12 and the first year of college to study while sailing around the world.

Parents of the 48 young people on board were overwhelmed with relief.

Doris Smith, of Kelowna, B.C., said her 19-year-old daughter Sarah had boarded the ship only two weeks earlier, after earning the last open spot on the shipboard school program.

"I had been following their progress on GPS and everything was going fine: the weather was warm, it was sunny and Sarah was having a great time," Smith told in telephone interview early Saturday morning. "Then I got a call at 9 p.m. [Thursday] from the school and I could tell by his voice that something was wrong."

"He said the ship's emergency beacon had gone off, they couldn't contact the ship and that was all they knew ... I didn't get the call saying that everyone was safe until about 3 a.m. so that was a pretty tense few hours. I was pretty relieved."

Smith said she was looking forward to talking to her daughter once she lands in Rio. "This will be like surviving the Titanic for her – she'll have quite the story I imagine," she said. "But it was a happy ending thankfully – everyone got through this okay."

Ruth McArthur, 23, of Brampton, Ont., was teaching a biology class on board the Concordia when it became apparent that the ship was in trouble.

Reached aboard the Philippine-flagged Hokuetsu Delight, McArthur told The Canadian Press that her students quickly dressed in immersion suits and were able to get into life rafts as the ship rolled onto its side.

"It was pretty intense, but the students and the whole crew were very focused and they all did an excellent job by helping and supporting each other," said McArthur. "Instinctively the students and the crew knew what to do . . . and I think that's one of the reasons we were all able to get out of there safely."

McArthur said it the life rafts moved away from the ship and "we were able to watch it go down."

"We then organized ourselves and made sure we had watches and water," she said. "We collected rain water as the rain fell around us and just prepared for a long stay in the life raft."

A Brazilian Air Force plane later spotted life rafts in the ocean and a navy ship and nearby merchant vessels moved in to aid in the rescue.

"This was only my 15th day at sea. It was definitely a shocker," said a tearful Katherine Irwin, 16, of Calgary. "At first I was, like, I'm never going back into the ocean. But after thinking about the friendships I made in the raft, I definitely would do it again."

The first 12 crew and students came into port aboard a Brazilian Navy frigate. The rest were heading into Rio aboard slower merchant vessels and were expected to arrive later Saturday afternoon.

The Concordia was five days out from Montevideo, Uruguay when it sank.

The federal Transportation Safety Board says it will assist in an investigation to be led by the ship's flag state country, Barbados.

The Concordia is owned by West Island College International with offices in Lunenburg, N.S. Forty-two of those onboard were identified as Canadians, mostly high school and university students, said Kate Knight, head of West Island College International of Lunenburg, which operates the Class Afloat program.

Prime Minister Stephen Harper issued a statement thanking the Brazilian Navy and the merchant ships "for their swift and heroic response."

But the president and CEO of West Island College International said a British maritime agency would probe why it took so much time for authorities to detect the emergency beacon.

"I'm concerned, I'm concerned," Nigel McCarthy told The Associated Press. "Obviously we don't know the reality of what's happened at every stage of this process, and we're just thankful to the Brazilian navy for having gone and got them."

The ship had visited Europe and Africa since leaving Canada in September, and it had just begun a five-month semester program on leaving Recife in northeast Brazil on Feb. 8.

West Island College International's website says the 57.5-metre-long Concordia was built in 1992 and "meets all of the international requirements for safety." It carries up to 66 passengers and crew and also can operate under motor power.

The site lists tuition for the sailing program at $42,500 a year.

With files from The Associated Press