It might well have remained a footnote to Cold War history were it not for the man on the boat and his one question: Is it a danger?

As a child growing up near Savannah, Derek Duke, 58, heard the story: A pilot was forced to jettison a hydrogen bomb near Tybee, one of city’s barrier islands, after a midair collision.

But it wasn’t until 1998, when he stumbled onto some old news stories about the “Tybee Bomb” while surfing the Web, that Duke became intrigued by it.

He searched the Internet and local newspaper archives. He read the limited information available about the bomb. Many details, including the amount of uranium it contained, remain classified.

By 1999, he began contacting others who might know something about the case. He talked to people who lived in the area. He wrote letters requesting unclassified documents.

Duke then looked up the pilot.

Howard Richardson was surprised by the telephone call from Duke. Richardson shared his story.

It was Feb. 5, 1958, and he was a major at the controls of a B-47 bomber, one of a dozen from the 19th Bombardment Wing taking off on a training mission from Homestead Air Force Base in Florida.

At the time, crews in training routinely carried transportation-configured nuclear bombs, with the detonation capsules removed to prevent a nuclear explosion, the Air Force said. It gave the crews the opportunity to practice, said Billy Mullins, associate director of the Air Force Nuclear Weapons and Counterproliferation Agency.

The mission was to simulate dropping a bomb on a city in the Soviet Union and to evade Air Force fighters sent up to simulate Russian interceptors.

Over Reston, Va., which unknowingly was playing the role of the Soviet city, Richardson’s navigator lined up the target on the radar screen and punched the launch button. The button activated a transmitter that recorded how close the crew came to hitting the target.

Richardson then turned south toward home through a screen of “enemy” fighters. When he and his two-man crew crossed into North Carolina at more than 37,000 feet, they were back in friendly skies.

But that’s when the B-47 collided in midair with one of the “enemy” fighters.

Struggling to keep the bomber under control, Richardson headed for Hunter Army Airfield in Savannah. But the tower operator told the crew the runway was under construction.

“I thought that if we landed short, the plane would catch the front of the runway and the bomb would shoot through the plane like a bullet through a gun barrel,” Richardson said.

So, on that clear, moonlit night, Richardson turned the B-47 toward sea and dropped the bomb in the ocean before landing.

‘Something is just not right’

Navy divers searched the waters near Tybee Island for nearly 10 weeks. The weather was bad, the water cold, the visibility poor. On April 16, 1958, the military declared the bomb “irretrievably lost.” No. 47782 became one of 11 “Broken Arrows,” nuclear bombs lost during air or sea mishaps, according to U.S. military records.

Four months after Richardson’s accident, the Atomic Energy Commission changed its policy, banning the use of nuclear bombs during training.

As Duke was learning this, he turned up a copy of the receipt Richardson had signed. Written near the top was the word “simulated.” That, according to the Air Force, meant the bomb did not have a detonation capsule. Without it, there was no risk of a nuclear explosion.

That might have been the end of the story if not for another document Duke soon acquired.

This one was a letter, written in 1966 to the chairman of the Joint Committee on Atomic Energy, recounting the testimony of Assistant Defense Secretary Jack Howard before a 1966 congressional committee.

Howard, the letter says, testified that there were four complete nuclear weapons, including detonation capsules, that were missing or lost. Among them: the bomb dropped off Savannah.

Decades later, Howard recanted his testimony after Duke gave the letter to the media and elected officials.

That’s when Duke’s intrigue turned to determination.

“Until that point, I bought the military’s story,” he said. “But not now. Something is just not right.”

Tainted motives?

He began studying topography maps, tidal charts and weather patterns. But Duke knew he needed help navigating the waterways. In Harris Parker, 64, a treasure hunter and movie consultant, he found an expert and a partner.

Together, Duke and Parker spent hours trolling Wassaw Sound, dragging Geiger counters behind their boat and bringing up sand to test. Mapping every inch of their effort, they identified what they believe is a plume of radiation, although the readings are only slightly higher than the sea’s natural radiation level.

But the plume wasn’t near Tybee Island. Rather, it was just off Wassaw Island, about 20 miles from Savannah. Perhaps, Duke says, the bomber crew had mistaken one landmark — an old World War II bunker — for another near Savannah when it dropped the bomb.

In August 2000, Duke gave the Howard letter to U.S. Rep. Jack Kingston, a Savannah Republican. Kingston, in turn, asked the Air Force to investigate whether a live nuclear bomb might be lurking off the Georgia coast.

On April 12, 2001, the Air Force Nuclear Weapons and Counterproliferation Agency reported the bomb was likely buried 5 to 15 feet below the ocean floor. There is “no current or future possibility of a nuclear explosion,” the report said. And if left undisturbed, the conventional explosives in the bomb posed no hazard.

Nonetheless, after the Sept. 11, 2001, terrorist attacks, some folks in Savannah began to worry. A town-hall meeting was called to discuss the bomb and the Air Force findings.

“If we’re so worried about terrorists getting ahold of nuclear weapons, why aren’t we doing anything about this?” Duke says. “Right down there, somewhere, is the material to make a dirty bomb.”

So Duke, Parker and a handful of others formed a company to look for the bomb and submitted a bid to the government to locate it. The bid — $900,000-plus — was denied.

Parker, meanwhile, co-wrote a movie script, titled “The Tybee Bomb,” a Tom Clancy-esque mystery. But the script, along with the creation of the company, led some to wonder about their motives.

At home in Jackson, Miss., Richardson eases onto a couch.

Richardson, 82, is a big man with a gentle heart. He doesn’t like to speak ill of anyone, but …

“Derek Duke just doesn’t know what he’s talking about. I keep telling him he’s wrong,” he said. “The paper says no capsule on board. I think I know what I signed for.”

He has come to believe Duke and Parker are motivated more by money than by virtue. He points to the government bid and the movie script. “They are scaring those people in Savannah for no good reason,” he said.

Back on the Boston Whaler, Parker and Duke check the onboard Global Positioning System gear as they motor toward where they believe the bomb rests.

Their efforts are at a standstill. They don’t have the hundreds of thousands of dollars needed to take the search underwater. They don’t have the backing of the military, the government or local elected officials.

Parker stops the boat a few hundred yards from the soft, fine sand of Wassaw Island and turns off the engine.

It’s quiet, except for the occasional bird or a dolphin breaking the surface.

“It’s down there,” Duke says. “Somewhere.”