Three American adventurers aboard the Double Eagle II passed over the Irish coastline at 20,000 feet last night, finally achieving man's century-old dream of soaring across the Atlantic under a balloon.

"We are on top of the world," radioed 43-year-old Max Anderson as he and fellow ballonists Ben Abruzzo, 47, and Larry Newman, 31, all of Albuquerque, N.M., passed over the tiny Irish port of Louisburgh, County Mayo.

"All three of us are jubilant. We almost jumped out of our skins when we reached the Irish Coast," Anderson told radio operator Jim Hearne at the Bally Green radio station.

Hearne said the balloonists, who lifted off from Presque Isle, Maine, last Friday, were in good shape and hoped to "follow in the footstops of Lindbergh and fly direct to Paris."

Their present course, however, was expected to take them over England early today, and Hearne said the three adventurers planned to decide where to land "when they got over the United Kingdom and see if the wind is still behind them."

Wherever the Double Eagle II finally lands, the adventurers were carrying a bottle of champange to share with whomever greets them when they finally touch down.

In reaching Ireland, the three Americans succeeded where 17 previous recorded attempts to cross the Atlantic by balloon had failed. At least seven balloonists have died trying since the first attempt was made in 1859.

Only two weeks ago, two Britons came the closest of any previous attempts to succeeding. They had drifted almost to within sight of the English coast when the wind shifted, ultimately forcing them to ditch their crippled craft 110 miles out.

A Shannon air traffic controller said last night that the Double Eagle II, at its present speed of between 40 and 45 knots, would leave Ireland via Wexford in the early hours today, heading toward Wales. He said the men were not maintaining constant radio contact.

"They are worried because their batteries are getting low," he said.

Earlier yesterday, the three men had set a new endurance record for unpowered balloon flight, passing the old mark of 107 1/2 hours established during an attempted Atlantic crossing in 1976.

Things were going so well aboard the Double Eagle II, flight spokesman David McClure reported at Bedford, Mass, that the three men were thinking of keeping on floating over Europe to see how far they could get.

While Ireland is considered European soil, the three men had indicated earlier that they would like to land on the European mailand.

During their Atlantic voyage, the three adventurers dined on hot dogs canned sardines and instant mixes.

The balloon encountered showers over the North Atlantic Tuesday, and at one point yesterday, the balloonists told their gound control team that the temperature outside their 11-story-high craft was only three degrees above zero Fahrenheit.

The balloonists, however, had a portable heater in their gondola, and also were clad in thermal underwear purchased for the trip.

For two of the three travelers, the current crossing was their second attempt to make it across the Atlantic.

Abruzzo and Anderson last year traveled 2,950 miles in 66 hours aboard the Double Eagle I before they were forced to ditch short of their goal.

The familites of the balloonists arrived in London yesterday hoping for an early rendezvous with the three men.

Abruzzo, married with four children, is in real estate and other businesses. He is a veteran pilot and ballonist. Anderson, who also is married and has four children, is a long-time pilot and ballonist who heads a uranium and copper mining company. Newman, who was married five months ago, is a hang glider manufacturer and a former airline pilot.

Of the previous 17 attempts to across the Atlantic, 16 went east and two headed west from Europe. Three never got off the ground, four traveled less than 200 miles. Only three managed to stay in the air for more than 2000 miles.