By Mia Womersley and Juris Abramenko

ABOARD THE RESPONDER Oct 28 (Reuters) - Migrants broke into song and dance or clapped their hands with delight on Thursday as they were brought to Italy on a search and rescue ship after their rubber boats capsized at sea.

The Responder, a vessel run by the Migrant Offshore Aid station, carried 347 people from Syria, Libya, Ghana, Nigeria, Niger, Togo, Pakistan and Morocco to mainland Italy on Thursday.

Among the migrants it rescued from flimsy boats was Juliet, 24, who said she had fled Nigeria because of the turmoil wreaked by Islamist militant group Boko Haram.

"We don't even know the sea is big like this," Juliet said.

"Before you know, the boat start capsizing. Everybody's shouting, everybody's crying, people are dying. Oh my God. I can't forget that moment."

Juliet said she had spent three months in the Sahara and another in Libya before attempting to cross the Mediterranean. She said she hoped to go back to school and become a doctor.

Since the European Union-Turkey deal in March to close down boat crossings to Greece, the Libya-to-Italy route has become the main one for migrants trying to reach Europe.

Smugglers' ill-equipped and overcrowded vessels often break down or sink.

More than 3,900 people have drowned on their way to Europe this year, the International Organization for Migration estimates, already more than the total for 2015.

On Tuesday, aid group Doctors Without Borders found 25 bodies submerged in water and fuel at the bottom of a boat off Libya. (Writing by Patrick Johnston; editing by Andrew Roche)