Ever since Ben Benson first dived into the cold waters of the Atlantic Ocean when he was an 11-year-old living on Cape Cod, Mass., he has had visions of becoming a latter-day Lloyd Bridges, exploring for sunken treasure.

Now, nearly three decades and 5,000 dives later, Benson believes his company, Sea Hunt Inc. -- named for Bridges' old television show -- has discovered the wreckage of two Spanish galleons, the Juno and the La Galga, just off the Virginia coast here that could hold millions of dollars in coins and other precious artifacts.

But where Bridges had to battle only sharks and tangled dive lines, Benson is enmeshed with the governments of two countries, his own and Spain's, which are trying to prevent him from disturbing the submerged vessels.

Benson, a millionaire land developer who retired before age 40 to chase his dream, has a contract to share any artifacts he recovers with the State of Virginia, which contends that the federal Abandoned Shipwreck Act of 1987 gives states ownership of submerged lands within two miles of their shores.

The federal government, however, argues that a 1902 treaty gave Spain control over its sunken ships, regardless of their location.

"These are clearly state waters," said Robert W. Grabb, of the Virginia Marine Resources Commission, which along with the Army Corps of Engineers granted Benson permits to search two six-square-mile sites just off the coast here in March 1997.

The agreement, also approved by the Virginia Department of Historic Resources, gives the state a 25 percent stake in any recovered treasure, and first pick of whatever historical artifacts Benson's crew finds.

Chris Watney, a spokesman for the Justice Department, said Spain doesn't want the ships disturbed because they are the final resting place for hundreds of its citizens.

Benson points out that Spain made no such claim in 1985, when salvager Mel Fisher recovered $538 million worth of coins and artifacts from another sunken Spanish ship, the Nuestra Sen~ora de Atocha, off the Florida Keys.

Steven Anthony, of the Maritime Archeology and Historical Society, compares Benson and other treasure hunters to adventurers who desecrated Egyptian pyramids in searches for gold.

"Once this stuff is sold at a Christie's auction, it will be lost forever," said Anthony, a Bethesda lawyer and scuba diver.

"This comes down to an ideological debate," conceded Benson, who halted his explorations last month while a federal court decides the outcome of his case.

Benson employs off-the-shelf high-technology instruments in his searches, along with software he developed to help him use sonar to find items buried deep in mud. He came to the region in 1995 to test his equipment before heading on to the Caribbean to search for sunken treasure.

But he stayed after seeing a 13-foot anchor, which was attached to a battered pewter plate inscribed with a word that seemed to be "Jane" or "Jolle" or "Juno," on display in a Chincoteague treasure shop.

They were found in 1989 by a local resident fishing a quarter-mile from the Assateague Island lighthouse, just north of Chincoteague.

Until the federal intervention forced him to stop, Benson had recovered an eight-bit Spanish coin (dated 1789), a dinner plate and two anchors, all of which had been embedded in wood and mud. He also had used sonar to obtain an image of what looked like a ship's bow buried in a sandbar.

Benson won't put a price tag on what may lay on the ocean bottom here, but another salvager, who believes the Juno went down 40 miles offshore, estimates that the ship's treasure is worth $500 million.

Benson played down the potential value of Juno's cargo but acknowledged that "anyway you slice it, it's a lot."

Benson's attorney, Anthony F. Troy, of Richmond, said, "It is inconceivable that our Justice Department would side with a foreign government against the legitimate interests of the Commonwealth of Virginia."

Virginia Gov. James S. Gilmore III (R) wrote Spain's ambassador to the United States, Antonio de Oyarzabal, that "Spain's interest in the wrecks seems premature," because not enough artifacts have been recovered to link the wreckage to the Juno and La Galga.

De Oyarzabal promised Gilmore that his country "will consider any initiatives that guarantee proper respect for the dead, have archaeological value, and will promote a better knowledge of our common history."

Benson also wrote to de Oyarzabal, pleading that he is not "a greedy treasure hunter." Otherwise, he said, he would not have spent two years and $1 million "studying ships that haven't been proved to even have treasure on them" or visiting the Spanish home towns of some members of Juno's crew. Benson said he "even tried to find the cemetery {in Cadiz} where one of the seven survivors {rescued by an American ship} was buried in 1825."

Benson said that "in our exhaustive research, we have not found any manifest or document to support the idea that the Juno carried a huge treasure," a theory that is consistent with Spain's belief that Juno's cargo was transferred to another ship before it sank in an 1802 storm, taking the lives of 413 sailors, soldiers and their families.

The real heritage of the Galga, which disappeared in a hurricane in 1750, may be the famed wild ponies that roam Assateague Island and are prodded to swim to the mainland the last week in July as the highlight of an annual festival.

A native of Baltimore, Benson was a lackluster student who dropped out of school in the ninth grade and ran away from home by stealing the family's Oldsmobile 98. That ended his relationship with his family.

He drove to rural Machias, Maine, where partly thanks to his size (6-foot-4) he was able to lie about his age, rent a motel room and apply for a credit card, Benson said.

He got a real estate license and bought 100 acres of forlorn land near the rocky coast for $10,000, which he financed with a $99 down payment with the credit card. He then advertised the land as five-acre hunting and fishing lots, which he sold for $1,000 to $2,000 each, Benson said.

With a tidy profit in his pocket, he went to Key West, Fla., where he bided his time until his 17th birthday, when he joined the Navy submarine corps, Benson said.

Benson's hopes for a Navy career vanished, however, when he developed an allergy. He quit and moved to New Hampshire, where, again using his credit card, he made a $3,000 down payment on a logging truck and grew the business to 12 logging trucks and an oil tanker to fuel them.

Working day and night took its toll, though, and Benson gained 80 pounds in the first of what became a pattern of his weight ballooning under the stress of business.

At age 23, he sold the trucks for an $80,000 profit and bought a sailboat. For the next two years, he sailed the Atlantic Coast between Boston and Fort Lauderdale, Fla., perfecting his scuba-diving skills and working out at health clubs to keep his weight under control.

While hanging out at a marina in Fort Lauderdale, he met a young woman from Virginia, Elizabeth Hall, whose grandfather was a developer on Virginia's sparsely populated Eastern Shore. They married in 1984 and settled in Accomac, where Benson returned to working as a land developer.

The deal that made early retirement a reality for Benson, now 39, came in 1991 when he and a partner bought 340,000 acres on Michigan's Upper Peninsula in a $25 million deal. Benson on his own bought an additional 100,000 acres in the region and was working toward acquiring 1 million acres when he had the first of two heart attacks. He reacted to those jolts by selling his stakes in Michigan timberland for a $10 million profit.

He and his wife then set off on an around-the-world cruise on a 65-foot Hatteras yacht he bought in San Diego. With a crew hired in California, they sailed the $1 million yacht through the Panama Canal and up the Atlantic Coast to Provincetown, Mass., where they tied up next to a shipwreck museum.

It was there that Benson got the idea that now engulfs him.

Benson is so confident that the story of the Juno is compelling -- "better than the Titanic," he said -- that he has advertised in two entertainment industry newspapers, Variety and the Hollywood Reporter, seeking a company to tell his story.

But first he may have to deal with MGM, the studio behind the old "Sea Hunt" television show. It wants to talk with him about the name of his company. Sunken Treasure? Millionaire developer Ben Benson believes he has discovered the wreckage of two Spanish galleons -- the La Galga, which sank in 1750 and the Juno, which sank in 1802. The ships are thought to have coins and artifacts worth millions of dollars. CAPTION: Diver Tom Birch, assisted by Wes Speigel, plunges into the Atlantic with metal detector in hand to search for anything out of the ordinary. CAPTION: A silver coin and some straight pins were among the items retrieved by the divers.