Rival treasure hunters were on their heels, so the boat's crew had to move quickly.

On the back deck , they cobbled together an underwater vehicle as they frantically searched for the U.S. Mail Steamship Central America, a side-wheeled paddleboat that sank in 1857. After years of tropical storms and mechanical setbacks, they found the ship resting on the bottom of the Atlantic Ocean.

Inside its watery grave: three tons of gold coins, bars and nuggets.

It was nearly 16 years ago that Alan Scott and other Seattle area engineers discovered one of the most lucrative treasures in American maritime history.

But they're still waiting for their share of the gold.

Ten members of the original group have a little more than a year left before the statute of limitations to file a claim for their share runs out, so they've hired a lawyer to get the gold from the man who coordinated the effort.

Scott, who won't take part in the claim, stands to gain tens of thousands of dollars if the group succeeds.

For him, though, the adventure of it all -- and a longing to go back there -- is the thing.

"This was a unique opportunity for an engineer to play a little part in history," he said.

Accounts from news clippings, history books and journals characterize the ship's sinking on Sept. 12, 1857, as one of the worst peacetime marine disasters in U.S. history.

Historians compare it to the Titanic disaster and speculate the loss may have caused a national gold shortage and sparked a financial-market crash. Until then, the Central America was just another nondescript paddleboat taking California miners to New York to sell their gold.

After a brief stop in Cuba, the ship resumed course until a hurricane developed off the southeast coast of South Carolina. The crew discovered a leak in the ship, and sea water eventually extinguished the coal furnaces as the Central America surrendered to 35-foot waves.

By evening, the ship plunged stern-first into the Atlantic Ocean, dragging with it 425 men in the undertow. Sinking with the dead were tons of California gold.

For about 130 years, the Central America sat on the ocean floor, about 11/2 miles below the surface, until Tommy Thompson, a Columbus, Ohio-based marine engineer, coordinated an effort to recover the fortune in the mid-1980s.

Thompson hired Tim McGinnis and a Seattle marine engineering company to pull together a survey crew and develop a plan to find the Central America. Historians and scientists were able to narrow the search for the wreck's resting place.

Because of mounting interest from other treasure hunters, the survey crew -- made up of 10 Seattle area engineers, electricians and technicians -- had to sign an agreement not to mention the details of the search. In exchange, each was promised in writing a salary and a fraction of the gold once it was found, crew members said.

In May 1986, the crew towed a sonar device -- a system that reflects sound waves to find objects underwater -- through the Atlantic to map the ocean floor and to find possible wreck sites.

The next year, Scott got a call from Thompson to return to the target sites with a new remote-control vehicle. A new team hurried out to the site, competing with other treasure hunters.

There wasn't enough time to build the vehicle, dubbed Nemo, on land. So the team built it on the back deck of the vessel, using aluminum framing, high-intensity video cameras and other electronic equipment.

"It looked like an open-frame erector set," Scott said.

By the end of the three-month tour, the team discovered a target site with several telltale signs of the Central America: pre-Civil-War-era artifacts, splintered wood and traces of coal.

After months of technical problems, the team decided to test Nemo and its video equipment far from the target site to keep rival gold seekers off its trail. But as the ship towed Nemo just above the site's ocean floor on Sept. 12, 1988 -- exactly 131 years after the sinking -- video cameras caught glimpses of objects that appeared to be timbers and pieces of a shipwreck.

Nemo was pulled higher by a mechanical crane so video cameras could get a better look. Scott remembers seeing a curved image.

"All of a sudden everyone started screaming, because that was the side wheel ," said Scott, his voice raised with excitement.

The team confirmed it had found the ship weeks later after discovering its bell.

"That was the identifying factor," Scott said. "The . . . paddlewheel was a hopeful sign that we found the Central America. But it was really when we found the ship's bell that we knew we had the Central America for sure."

When the water cleared, "a garden of gold" littered the ocean floor, Scott said. Heaps of bars were stacked on fallen beams of disintegrated wood. Mounds of gold dust had clumped together, and thousands of gold coins lay about.

The crew spent the next two weeks taking photographs and shooting videotape.

"It was a dream come true to find gold lying on the boat and being able to, for historical purposes, document it as best we could," Scott said.

When the team returned to shore in Norfolk, Va., in 1989, it was greeted by a welcoming committee and a 21-cannon salute.

"Everyone was hooting and hollering, and I turned every color of the rainbow," Scott recalled, "and I was thinking, 'What in the world is happening?' "

After docking, U.S. marshals boarded the ship and took custody of the gold, a customary procedure under maritime law.

Scott and about two dozen crew members carried boxes of treasure to waiting Brinks trucks past marshals clutching machine guns, reporters and television cameras.

Thompson, the coordinator of the mission, then spent years battling insurance companies who sued for a portion of the gold. Federal judges agreed in 1995 to give 92 percent to Thompson and 8 percent to the companies that paid claims on the shipwreck.

A federal court decision said Thompson never had to publicly release a list of all the gold bars, coins and nuggets his group had. According to press accounts, he sold his portion for an undisclosed amount to a California sports agent, who then resold it for about $100 million in December 1999.

But the survey crew still waits for its promised share. Crew members said they were promised a collective 2 percent of the value of the gold in exchange for signing the agreement not to mention details of the search.

The crew got together and hired a lawyer in New York, who negotiated with Thompson over many years. Now there's a little more than a year before the Ohio statute of limitations runs out to file a claim.

"The real story is what happened to the gold," said Mike Williamson, a Seattle resident who heads the crew's effort to get the gold.

"None of the investors have been paid a cent. None of the percentage people [the survey team] have been paid anything. We can't even get a hold of the inventory of the gold that has been sold."

Repeated attempts to contact Thompson for this story were unsuccessful.

For his part, McGinnis has collected everything he could about the U.S. Central America since the recovery began. There are 17-year-old records and folded handwritten notes about the sunken ship organized in a pile of manila folders he keeps in his home.

"It's something to pass on to my kids," he said. "It was something neat that their dad did."

As for his share of the gold, McGinnis is hopeful.

"Whether I am optimistic, it's harder to say. The gold is just really this bonus. I am not going to lose any sleep over it," he said. "It was a fun project to get involved in. With three tons of gold on the seafloor, it doesn't get much funner than that."

Scott said gold was never his incentive to spend six years working with Thompson.

Rather, Scott hopes to return to the wreck site one day and continue exploring the area.

Besides gold, the team found suitcases filled with clothes, jewelry, newspapers and other items historians would treasure, as well as several new species of sea life.

"It was never important to me," Scott said of the gold.

Alan Scott says a "garden of gold" littered the ocean floor when salvagers found the wreck of the steamship Central America, which sank in 1857. Scott has yet to receive his share of the loot.Tim McGinnis says he enjoyed searching for the Central America, pictured in the book he holds.Treasure hunters found more than three tons of gold bars, coins and nuggets.