James Delgado started in archaeology anticipating a career with his feet firmly on dry land. What changed his mind was an old whaling ship under San Francisco's financial district, six blocks from the ocean.

“In 1978, my employers, the US National Park Service, asked me to excavate it,” Dr Delgado said.

Instead of whaling hooks, ancient bottles of champagne were pulled from the depths and Dr Delgado discovered the Niantic's long history.

First a Nantucket whaling ship, then a California Gold Rush ship, she then became a fancy inland hotel rebuilt several times after city fires. “After that I was hooked,” said the 60-year-old. “I knew shipwrecks were what I wanted to do with my life.”

Forty years later, he's hosted the television show Sea Hunters and worked for the US National Oceanic and Atmospheric Administration. He's currently with one of the world's largest archaeology companies, Search Inc.

Although much of his deep-sea work involves remote operated vehicles, Dr Delgado insists there's nothing like plunging into the ocean on a wreck dive.

“It's like passing from one world into another,” he said. “You're free to explore and slowly fly through these sites. And you are seeing something not very many other people get a chance to see.”

It's that experience that led the Bermuda Underwater Exploration Institute and the Bermuda National Museum to bring him here for a public talk on archaeology and technology tonight.

“Bermuda, in particular, has many wrecks representing the greatest collection of ships we know of from the last 500 years,” said Dr Delgado, who helped anthropologist Philippe Rouja excavate the US Civil War blockade runner The Mary Celestia, a paddle wheel steamer, in 2011.

On previous visits he'd dived The Mary Celestia, not knowing treasure lay beneath a bank of sand at its bow. When it sank on September 13, 1864 it was supposed to be carrying military supplies, “bullets, boots and bacon” to troops in the Confederate States of America.

Instead, researchers were surprised to find perfume and the form for a lady's shoe in a storage locker found under the sand.

“These were probably put there by the crew, and were intended for family members in the United States who were living behind the blockade,” he said.

Last August, eight former crew members of the USS Bugara were able to watch via satellite feed as Dr Delgado and a team explored the submarine, sunk accidentally off Washington State in 1971.

The men were able to share their observations with the archaeologists working on the exploration.

It's one example Dr Delgado gives of how technology has made underwater archaeology “a lot more immediate for others”.

What's most exciting to him is that so much of the world's oceans are still unexplored.

“It really is the final frontier,” he said.

He admitted that diving shipwrecks, particularly in deep water, can be dangerous.

While exploring a Gold Rush ship on California's Sacramento River, he was almost killed by a floating tree.

“In 40ft of water I got tangled in its branches and was carried some distance,” he said. “Luckily, I was able to untangle myself.”

The biggest threat was sharks while examining once radioactive ships off Bikini Atoll in the Pacific.

“The ships aren't radioactive any more,” he said. “With the sharks, you just have to remember that it's their territory and be respectful. Another danger is the ships themselves. You don't want the corroded metal to fall in on you.”

Shipwreck diving can also be quite emotional as many wreck sites are graveyards.

He found this to be especially true when he worked on the Titanic in August 2010. The Noaa project involved mapping the wreck site.

“When you drop to a wreck like Titanic, that is essentially frozen in time, it is easy to be drawn into what the ship represents,” he said. “It is a cemetery and a museum. It is a site that means something to a great many people.”

When he looks at any wreck, he's often struck by how much it speaks to the human experience.

Hear James Delgado speak tonight at the BUEI at 7.30pm. Tickets, $20 for members, $25 for non-members and $10 for students, are available on www.ptix.bm, 294-0204 or in the BUEI gift shop or more information visit www.buei.bm. Watch Dr Delgado talk about his career on www.royalgazette.com