With a sharp blast from 67 explosive charges, three former Navy radio towers the height of 30-story buildings buckled, toppled ever so slowly and crashed to the ground yesterday across the Severn River from Annapolis.

The simultaneous felling of the 300-foot towers marked the beginning in earnest of a $4.2 million project to clear an array of massive antennas and towers from Greenbury Point and turn the 231-acre peninsula into a nature preserve open to the public.

The point has been home to radio spires since World War I, when they beamed messages to Europe. Until recently, the peninsula held 19 antennas and towers, a thicket that long has been a navigational landmark for Chesapeake Bay sailors. All but three of the towers will be removed in coming weeks.

"It's history in the breaking," said John Schorpp, 58, the field's antenna mechanic since 1983. He is not sure whether he will have a job once the demolition is done.

"What you can't win you learn to let go," Schorpp said with a catch in his voice. "It's called progress."

During the Cold War, Greenbury Point was a key communications hub for the nation's nuclear submarine fleet. Its antennas sent low-frequency radio waves capable of penetrating the ocean, allowing vessels to communicate without surfacing.

In recent years, with tight defense budgets and advances in satellite communications, the antenna field's steel and copper technology became outmoded. It was put out of service in 1996.

About three dozen people turned out to watch the destruction of Towers 65, 66 and 67 yesterday. Several observers recalled the antenna field's historic role.

Frank Gentges, 57, of Great Falls, served in the 1960s and 1970s with the Naval Electronic Systems Command, which handled submarine communications from offices in Crystal City. He recalled the urgency the military felt to keep communications flowing.

"We're in the middle of the Cold War. These people . . . they're spending long hours, for instance to upgrade the Goliath antenna"--a 1,200-foot structure at Greenbury Point that will remain in place for a few more weeks.

Contractors had dismantled three 80-foot towers last week. By early next month, weather permitting, they expect to have brought most of the remaining structures down.

The three to be left are known as the Eiffel towers for their resemblance to the Paris landmark. They will remain for at least a year while state and local officials decide whether to adopt them, perhaps for use by police and emergency communications systems. If the governments decline, the Eiffel towers, too, will likely be dismantled.

The Eiffel towers were granted their reprieve after heated community meetings, said state Del. Richard D'Amato (D-Anne Arundel), who wrote federal legislation mandating the tower removal before he retired from a career as a U.S. Senate staffer.

The bill was meant to head off any possibility that the land could be developed, whether to add nine holes to the adjacent Naval Academy Golf Course or after sale to a private developer, D'Amato said.

As word of the plan spread, a vigorous community debate unfolded, D'Amato said. Some residents argued for clearing the point of towers to improve the view, but others said some towers should be preserved for historic and cultural reasons.

Jim Rosenthal, 48, who lives within several hundred yards of the towers, counts himself among the preservationists. "They're sort of the last artifact of that sort of Cold War radio communications," Rosenthal said.

D'Amato called the outcome "win-win" with some chance for tower preservation, the Navy relieved of expensive tower maintenance and the public gaining access to a plot abounding in wildlife, including deer, foxes, herons and ospreys.

"This is a tremendous parcel," D'Amato said.

The blast minutes after 8 a.m. brought laughter and applause from some of the watching naval personnel, radio buffs and golf course greenskeepers.

Workers used slightly more than four pounds of an explosive called RDX, which is far more powerful than dynamite, said Mark Loizeaux, an executive with Controlled Demolition Inc., the Baltimore County company felling the towers.

Next to go, with a tentative demolition date of Saturday: Tower 126, an 800-foot beauty that stands--its bulk balanced upon a single point and held in place by guy wires--on the golf course.

CAPTION: The three towers at Greenbury Point, across the Severn River from Annapolis, are brought down by four pounds of RDX, which is more powerful than dynamite.

CAPTION: "It's history in the breaking," says John Schorpp, the field's antenna mechanic since 1983, who may not have a job after the demolition.