JACKSONVILLE, Fla. >> In 42 years as a maritime archaeologist, James Delgado has dived to the wreck of the Titanic, descending into the dark ocean for hours inside a nickel-steel sphere. He’s explored ships sunk at Pearl Harbor and during atomic bomb tests at Bikini Atoll. He helped identify the last ship that brought Africans to labor as slaves in America.

He’s dived in Japan on Kublai Khan’s invading Mongol fleet, in the Mediterranean on Venetian and Roman shipwrecks and in the Arctic on doomed exploration and whaling missions. He’s explored Alcatraz Island, Central American temples and an underground Soviet sub base in formerly communist Albania.

On the Titanic he saw passengers’ shoes, still tied in knots, on the sunken bow. On a Roman wreck he saw the dishes and cups sailors used for their last meal.

Delgado’s latest big discovery took place in May in the Pacific Ocean.

He and colleagues at Search Inc. in Jacksonville, Fla., were after the battleship USS Nevada, which, after barely surviving the Japanese attack on Pearl Harbor, was repaired and went on to fight in several landmark battles in World War II. It then became a target in 1946 for Bikini Atoll atomic bomb testing.

Two years later the Navy sank it some 65 miles off Pearl Harbor, though it took more than four days of bombing to get the old ship to the bottom.

It was known to be in an area of 100 square miles, so Delgado, working for Search, called new partner Ocean Infinity, which had a quarantine ship ready to leave Hawaii. He talked to them about “targets of opportunity” to look for, including the Nevada.

So the ship went looking, while Delgado and colleagues watched on screens in Jacksonville.

When the wreck was found, Delgado recognized the hull of the ship, which was upside down, but couldn’t be completely sure it was the Nevada.

Then an underwater robot went into the debris field and found the stern. “The name was scraped off by an anchor chain, but right there was the (ship’s hull) number, 36,” Delgado said. “Yes!”

He said he wanted to find the Nevada as a sign of hope in these troubled times.

“We thought we could find it and that it was important for people to remember, ‘Hey, we’ve been through tough times before,’” he said. “Nevada really came to represent resilience, stubbornness, getting back up and getting into it.”