During the Middle Passage more than a 1,000 slave ships sank on the way from Africa to the Americas, drowning an estimated 1.8 million people, most of them Africans. Less than 20 of those sunken slave ships have ever been explored and documented.

American Tara Roberts is part of Diving with a Purpose, a Black-led group aiming to improve those figures. They explore and document slave ship wrecks and educate the public about them.

Ms Roberts, a writer, podcaster and National Geographic Explorer in Residence, will be in Bermuda this month to talk about her work with DWP.

She first saw a photograph of DWP divers at the Smithsonian Museum in Washington, and was immediately intrigued.

“They looked like me,” she told The Royal Gazette. “I had never seen a group of Black scuba divers before.”

She explained that there is a myth in America that Black people do not swim.

This was spurned on by an historic lack of access to swimming pools due to segregation, and a disproportionate number of drownings in Black communities.

“Some psychologists have theorised that the Middle Passage may have left some subconscious fears of the water,” she said. “Scuba diving is also very expensive and you need training and a lot of equipment to participate.”

Telling herself she just wanted to learn how to scuba dive, Ms Roberts reached out to DWP.

When she met the group and learnt more about their work her ambition quickly morphed into helping them. She was working in the non-profit world after being a magazine editor for several years.

Missing storytelling, she quit her job.

She now dives, and uses her narrative powers to tell the story of the shipwrecks and the group itself.

She has worked on seven vessels including the Henrietta Marie off of Key West Florida, the last ship to bring slaves to the United States, the Clotilda in Alabama, and two Danish wrecks, Christianus Quintus and Fredericus Quartus, that were deliberately sunk off of Costa Rica.

“Some of them I could not dive,” she said. “For example, you had to be a technical diver to dive the Clotilda, because of its location. Another was off of South Africa and was just too rough to dive.”

The wrecks near Costa Rica were the most memorable for her, mainly because of the story surrounding them.

“On those wrecks the captive Africans did not die and were set free on shore,” Ms Roberts said. “They became a part of Costa Rican culture. To dive on that site was really incredible because it was about a story that is ongoing.”

Many of the divers on the project were Costa Ricans between the ages of 14 and 21, some of them possible descendants of the people from the wrecks.

“These ships were not initially headed to Costa Rica,” Ms Roberts said. “They became lost on the way from Africa several times, due to an inexperienced captain.

“The crew mutinied. They took all the money and goods that had been traded for. They set the Africans free and burnt the ships until they sank.”

On the wrecks shackles and other evidence of slavery can often be found, but also African beads.

Human remains are difficult to find so many centuries later.

When the wooden ships sank they often broke apart, scattering their contents across the seabed. Much of the ship content was eventually engulfed in coral.

“Finding human remains is the next part of DWP’s mission,” she said.

One indication of a slave ship are finds of ballast stones — bricks, gravel and heavy debris.

This was often placed in the hold to counter the weight of people.

Slave ship exploration does not start in the ocean but in archives and libraries, Ms Roberts said.

“There are lots of records about these ships,” she said. “Records were kept of how many pounds of this and how many gallons of that they were carrying, and how many passengers were on board.

“As divers find artefacts in these areas, they see if it corresponds to the records.”

Divers feel a variety of different emotions while exploring these wrecks.

“Some people feel sad,” she said. “It impacts people in different ways, For me, this is profoundly joyful work. I am not happy about the history behind it, but I feel deeply proud of being able to tell stories of all of these ancestors.”

Out of the many people lost on the way to enslavement in the Americas, few were grieved for or honoured, she said.

“When you see some of the artefacts such as shackles, it does impact me to reflect on how they were used,” she said. “However, the bigger feeling is a sense of urgency to tell these stories.”

Her hope is that people come away from her talk wanting to learn more. “There is so much history to learn,” she said.

Ms Roberts has written a memoir about her experiences: Written in the Waters: A Memoir of History, Home and Belonging, released in March. She also has a National Geographic podcast Into the Depths.

• Tara Roberts will speak on September 19 at the Bermuda College in North Hall, Room G301. Doors open at 6pm and the event starts at 7pm.General admissions is $35 per person. Premium admission is $80 and includes a private cocktail reception and reserved seating. Tickets are available at www.gpass.com