Belic, 62, is a retired Chicago cardiologist who wants to cross the Atlantic Ocean alone in a rowboat as badly as he wants to avoid publicity.

Five weeks after beginning his journey, he has found his way into the Gulf Stream and "he's flying" at a steady 4.2 knots, said oceanographer Jenifer Clark, who has been helping him plot his course.

Belic won't let Clark or his wife, Ellen Stone Belic, divulge his location, both women said Monday.

Clark, who is based in Upper Marlboro, Md., did say that Belic is a lot closer to the United States than his goal of reaching the coast of Portugal.

He wouldn't even tell his boat-builder when he was leaving.

"He wanted no sponsorship, no decals, nobody telling him what to do, nobody telling him what should be on the boat," said Steve Najjar, of Redwood City, Calif. "He also wanted no publicity--he said we can do publicity afterwards. It's really a personal quest."

Ellen Stone Belic, of the Stone Container Corp. family, said her husband has a restless mariner's soul.

"There wasn't much I could say" about his journey, she said Monday. "I said, `Obviously if it's important, you have to do it.' "

"I was married to a doctor, as far as I knew," she added. "This is a new development."

Belic checks in with his family via satellite phone.

So far, he has reported seeing "dolphins, sharks, turtles--a turtle followed him," his wife said. "He's gone swimming off the boat."

He's in good spirits, according to his wife and oceanographer Clark, whom he calls twice weekly for navigational advice. On Sunday, he informed Clark that he had found the Gulf Stream, a warm ocean current that flows north along the East Coast of the United States and then turns toward Europe.

"His morale is always fantastic--whenever he calls, his voice always sounds like he's laughing," Clark said.

He shoved off from Chatham, Mass., on May 11 for what promises to be at least a two-month trip. Clark would have preferred starting from Cape Hatteras, N.C.

"He would have got in the [Gulf] Stream within 20 miles instead of hundreds of miles," she said. "It's just where he decided he wanted to leave from."

A reporter for the Cape Cod Chronicle approached Belic as he prepared to leave. Alan Pollock said Belic "was absolutely crestfallen that he had been discovered."

"We've never had anyone in this situation where it's a secret where he is," said Kenneth F. Crutchlow of the London-based Ocean Rowing Society, which is following Belic's voyage. "He has some notion that he's going to do his own thing."

Belic's red cedar boat, measuring 21 feet long by 5 feet wide, is mostly enclosed to protect him from sun and salt sores, Najjar said. A canopy permits him to look about. The oars stick out of ports on either side of the vessel.

"There are solar panels to recharge the batteries, he's got a full array of electronics for navigation and communication in emergencies," Najjar said.

The boat was built six years ago, and Belic used it to row the length of Lake Michigan without incident, Najjar said.

Belic, who was born in the former Yugoslavia, works out religiously.

"He's a rock," Najjar said.

Halfway through the boat-building project, Belic said he wanted to name the boat "Lun."

He told Najjar it was short for lunatic.