PHUKET, Thailand (AP) _ A Russian man and his teenage son survived for months on rainwater and fish speared with an antenna after a high-seas collision ended their round-the-world voyage and left them adrift on the Indian Ocean.

Six months after leaving South Africa, their tattered boat ran aground Sunday onto the white beaches of this island off Thailand. The voyagers _ gaunt, starving, dehydrated _ were rushed by villagers to a hospital.

The lack of food left Vladimir Medvedev, 44, at just 116 pounds, exactly half his normal weight. His 14-year-old son Maxim fell from 149 pounds to 119.

Speaking through interpreters Friday, the two said their world voyage began 2 1/2 years ago in Khabarovsk, 500 miles north of Vladivostok, and ended when an oil tanker hit their boat in the Indian Ocean. They said the crash occurred as they sailed to Australia, but they aren't sure exactly when or where.

``There was a tremendous crash and everything _ us, equipment, lights _ went flying. We never really got a good look at the ship that hit us, except that it was a huge tanker,'' Medvedev said.

Their rigging sails, radio and compass were damaged. But their hull remained intact.

Their food and fuel quickly ran out. They rigged spars as fishing poles or speared fish them with a TV antenna. The Russians ate their catch raw, washing it down with captured rain water.

They were almost rescued a month ago when an Indonesian fishing boat spotted them. But the boat had no radio and was too small to take them aboard. After leaving the Russians some fish sauce and sandwiches, the Indonesians sailed away.

Medvedev, who's married and also has a daughter, said it was a dream fulfilled to take his son on a world tour in the small sailboat he built over a decade.

For two years they lived sailed _ Japan, Canada, the United States and South Africa. Their last port of call was Cape Town, South Africa, from where they weighed anchor April 27.

Their beached boat has become something of a curiosity for islanders, who have gathered to look it over. Local yacht club members are setting up a bank account for the Russians and soliciting money and spare parts to get the vessel seaworthy again.

``We're always ready to help other yachties out,'' said Horst Lakits, the club's commander.

The Medvedevs say they're determined to put to sea again, though doctors warn their recovery from malnutrition will take several weeks.

Maxim appeared undaunted, giving a huge smile to a visitor. Asked why, he replied: ``I spoke to my mother today.''