LONDON, JULY 3 -- The first Atlantic crossing by a hot-air balloon nearly ended in tragedy today as the craft descended from 27,000 feet to scrape along the ground in Northern Ireland, then reascended to head toward the Scottish coast before slamming into the Irish Sea.

British millionaire Richard Branson, 36, and his Swedish crewmate, Per Lindstrand, were forced to jump into the water from the capsule hanging from the 21-story balloon. They were pulled to safety by air-sea rescue teams that were standing by in response to their emergency radio call.

Speaking tonight to reporters gathered at a hospital in Kilmarnock, in southwest Scotland, Branson said, "I'm lucky to be alive." With his girlfriend and two children by his side, Branson said he had promised his family he would never again attempt such a dangerous adventure.

In an interview with the British Broadcasting Corp., Branson described the flight's nearly fatal ending, in which an attempt to land on a Northern Ireland beach led to the balloon capsule being pulled into the sea and starting to fill with water.

Branson said he and Lindstrand climbed onto the capsule's roof, and the balloon began rising again. He said Lindstrand jumped into the water from about 60 feet, while he decided to stay aboard until the balloon hit the water again off the Scottish coast.

The balloon, called the Virgin Atlantic Flyer, after Branson's Virgin record company and airline, ended up near the Firth of Clyde in the North Channel of the Irish Sea. But Branson's ground team said the brief touchdown in Northern Ireland constituted an official landing, completing the record crossing from Maine.

Like his previous adventures, Branson's trip was part publicity stunt, part personal adventure. Two years ago, his attempt to beat the transatlantic sea crossing record ended three miles off the British coast when his specially designed powerboat struck floating debris and abruptly sank. With a new boat, he tried again and succeeded last year.

The balloon adventure started with an idea by Lindstrand and Branson's money. The Flyer took off before dawn yesterday from Maine's Sugarloaf Mountain after several weather delays. Two of the propane fuel tanks caught in a rope and smashed to the ground on takeoff, but favorable winds and fair skies sent the balloonists floating eastward at up to 140 miles an hour.

By yesterday afternoon, they already had broken the previous hot-air balloon distance record of 913 miles, and what had been planned as a three- to four-day trip appeared to have been cut in half.

It remained unclear why the craft had touched ground in the far northern corner of Northern Ireland. At about 5 p.m. (noon EDT) it scraped along a peat bog near the town of Limavady, dropping a few more fuel tanks before taking off.

Branson, in an interview with BBC television tonight, explained what happened next.

"It wasn't initially an emergency," he said. "We . . . thought a basic way of landing would be on a beach rather than on land." As they lost altitude and hit the water, "we pressed the button which fires the explosive bolts which release the balloon from the capsule, and it didn't work.

"The next thing, we found ourselves being hurtled through the water . . . at tremendous speed . . . with water coming into the capsule. We climbed out onto the roof, and the capsule started rising" up into the air again. "Per threw himself off at about 60 feet," Branson said. "I decided to stay with the capsule.

"The capsule then floated on upwards. I put on an oxygen mask and got myself ready for parachuting, which I didn't fancy because it was mist below and obviously heavy seas. In the end, I decided to stay with the capsule through a similar sort of approach to the sea, and this time, be ready to throw myself off just as it hit the sea."

Commander Tim Barton of the British naval frigate Argonaut, which led the rescue operation, said, "We saw the balloon coming down, then it rose dramatically and lifted into the clouds." When it descended again, "as it hit the water, Mr. Branson jumped out" and was rescued by helicopter and brought aboard the Argonaut.

"He was considerably shaken and suffering from hypothermia," Barton said. After "a considerable amount of confusion," Branson managed to convey to them that his crewmate, Lindstrand, was still in the water.

"He spent two and a half hours swimming, without a life raft" in the cold water, Branson said of Lindstrand. "He got picked up just in time, I would say."

Asked if he had panicked, Branson said no. "But I thought it was very likely that I would die," he said. "I was extremely shocked, mainly because I thought Per had had it."

"I'm not hurt," Branson said. "It's just wonderful to be alive. It's lovely to be back down from it all again. It's been quite a long 48 hours, with different exhilaration. We had the most fantastic crossing."