Episode 4: The search for history's lost slave ships

National Geographic explorer and Storytelling Fellow Tara Roberts documents Black scuba divers and archaeologists finding the lost wrecks of ships that carried enslaved Africans to the Americas.

Diving With a Purpose lead instructor Kamau Sadiki hovers over and examines part of a wreck in the Florida Keys.
Photograph by Chris Searles

On the bottom of the world’s oceans lie historic treasures—the lost wrecks of ships that carried enslaved people from Africa to the Americas. Only a handful have been identified so far, but National Geographic explorer and Storytelling Fellow Tara Roberts is documenting the efforts of Black scuba divers and archaeologists to find more, hoping to finally bring their stories to light.


TARA ROBERTS: When you dive, it’s a completely different world.

[sound of diving]

AMY BRIGGS (HOST): The first time I ever saw National Geographic explorer and Storytelling Fellow Tara Roberts wasn’t at headquarters. It was on YouTube.

ROBERTS ( in a video recording underwater): And we can see the diameter, what size, and what type of ship this was.

[underwater sounds]

BRIGGS: Last year, Tara was in a Nat Geo video about a group of Black scuba divers called Diving with a Purpose, also called DWP. In this scene, off the coast of the Florida Keys, Tara was getting underwater archaeology training.

Little yellow fish swim past Tara as she floats down toward the seafloor. So what is it she and the other divers looking for? They’re on a mission to help find and document shipwrecks that carried enslaved people across the Atlantic.

ROBERTS: There were approximately 35,000 ships that brought 12.5 million Africans to the Americas. Of those 35,000 ships, approximately 500 to a thousand wrecked. So far, it's a handful—have been found. And of the handful that have been found, even fewer have been properly documented.

BRIGGS: It might have been one of these sunken ships that Tara’s own ancestors sailed on years ago.

ROBERTS: I was talking to my mom, and she's the one in the family who's doing the family tree, and I actually remember seeing my great-grandfather's name and my great- grandmother's name listed on a ledger for a plantation in North Carolina. But that's as far as we can go back. I know nothing else.

BRIGGS: We all want to know where we come from. But people whose ancestors were forced to leave Africa and cross the ocean in slave ships face different challenges when delving into their family histories. Written records can be hard to find, and details are often scarce. But Tara thinks searching for these lost ships can be another way into the story.

What spoke to you about shipwrecks? Why did you choose to focus on that?

ROBERTS: My interest was really in the divers. I just think that there's something extraordinary about Black people saying, I am going to go out and find my own history, and I am going to shape the stories that are told about it.


Every time the divers jump in the water, they dream of finding something new: A new artifact, new information, new insight into the lives of the people on board the ships. But Tara also hopes for something even bigger: a new beginning for the story of Africans in the Americas.

ROBERTS: Like slavery is not the start of our story, but according to the history books, it is.

I’m Amy Briggs, executive editor of National Geographic History magazine, and this is Overheard at National Geographic, a show where we eavesdrop on the wild conversations we have at Nat Geo and follow them to the edges of our big, weird, beautiful world. This week: the quest to find and document the shipwrecks that carried enslaved people from Africa to the Americas, and the Black scuba divers searching for their ancestors’ history at the bottom of the ocean. More after this.

BRIGGS: As a 2020 Nat Geo storytelling fellow, Tara has been following Black scuba divers around the world who are working to locate, identify, and record historical information about these slave ships.

She first learned about Diving with a Purpose during a trip to the National Museum of African-American History and Culture, in Washington, D.C.

ROBERTS: And I ended up on the second floor of the museum. And I saw this picture of Black women in wet suits. They were beautiful Black women, but it was an energy that was beautiful about that picture.

BRIGGS: In the photo, nine Black women in wet suits sit on the front of a dive boat. Some look like instructors, others like students. All look like divers, smiling and confident.

ROBERTS: And that picture really struck me. It made me want to be one of them. And it made me really curious about the work that they were doing.

BRIGGS: When Tara got home, she started looking into them.

ROBERTS: And that's when I discovered this group called Diving with a Purpose, a group of Black scuba divers searching for and helping to document slave shipwrecks.

BRIGGS: She wasn’t just intrigued—she felt drawn to their mission. As a storyteller, Tara didn’t just want to learn about her own ancestry. She saw an opportunity to tell untold stories that have been lost.

ROBERTS: The slave trade is a global story, like it is Europe. It is Africa. It is the Americas. There is like so much of the world that is in this story. And the world that we have today was created based on that trade. So it is definitely not a Black people's story or Black American story. This is a way of understanding the world and how we got where we are today.

BRIGGS: The scope of the transatlantic slave trade was staggering. The numbers are so big that it can be hard to wrap your mind around them. From the early 16th century through the 19th century, more than 12.5 million African people were forcibly taken across the Atlantic to the Americas, a horrific journey that historians call the Middle Passage.

An estimated 35,000 voyages departed from port cities along the coasts of Africa to bring enslaved labor to the European colonies. Of these, it’s estimated that at least a thousand ships were lost at sea.

And so, geographically, when they’re looking for wrecks, where are people looking? Where are they most likely to be found?

ROBERTS: A lot of these wrecks tend to happen near shore. We know that the ships went around the coast of South Africa to go to the Americas. And it was really the Portuguese and the French that were using Mozambique Island. And those ships for the Portuguese were headed to Brazil. A lot of the ships for the French were headed to the Caribbean. The U.S. Virgin Islands were a stopping point and a point where people disembarked and were shipped or taken elsewhere. But also Cuba, Brazil, like all of these, you know, sort of huge ports where enslaved Africans were brought are the places to look.

BRIGGS: DWP is exploring coastal areas around the world, hoping to find wrecks from the Middle Passage era, and Tara wanted to get involved. The first step? Get in touch with DWP’s founder, Ken Stewart.

KEN STEWART: So Tara contacts me. And the rest is history.

BRIGGS: Ken grew up in the Bronx, and now he lives in Nashville, Tennessee. Tara says he’s kind of a hometown hero.

ROBERTS: Like some people, as they get older, they begin to shut down and they begin to narrow, like the world becomes about sort of the small space that's around them. Ken is always broadening and opening. I want to be like him when I'm in my 70s.

BRIGGS: Ken is retired now, after a 40-year career working in IT. But his real passion has always been scuba diving, which he says is kind of unusual for a kid from the Bronx. In the early 2000s, Ken met an archaeologist in Florida while on a diving trip.

Right off the coast of Miami, in Biscayne National Park, the archaeologist was combing the seafloor—piecing together a high-speed chase from the 1820s. A Spanish ship called the Guerrero was carrying hundreds of enslaved people to Florida. But the British Navy wanted to stop the Guerrero.

STEWART: And the British, so they had, you know, several warships in the Caribbean thereabouts looking for slavers. There's a ship called the NimbleBritish warship called the Nimble spotted the Guerrero in the Caribbean. And the way the story goes approached her. And when they got close to her, she took off. And they chased all night. And they really believe that the Guerrero ran aground in Biscayne National Park after that night chase. Right. There were 561 Africans on board.

BRIGGS: Oh wow.

STEWART: Forty one of them died that night. The rest of the rest of them were either enslaved and sent to Cuba, or some of them were sent back to Liberia over the course of a year or so. We know a lot. We know everything about that ship, except where it is.

BRIGGS: So in 2003, Ken joined the search for the Guerrero. Ken had been on a lot of dives. But this one was different.

STEWART: First time I went, I had tears in my eyes underneath the water. You couldn't tell, but it was a truly emotional experience, because I'm thinking that, you know, my ancestors could be—this could be my great-great-great grandfather's or -grandmother's final resting place, or where they came aboard to the Americas.

BRIGGS: Ken knew that other Black divers would feel the same way. So that same year, he started a new group: Diving with a Purpose. DWP teaches students about conservation and heritage preservation. And it teaches divers how to spot shipwrecks. They aren’t professional archaeologists—but that doesn’t mean they can’t make their own discoveries.

STEWART: If you look at our mission statement, we are committed to telling the stories of the African diaspora and bringing that story alive. Again, a lot of people say, Well, you know, you need to leave it alone. No, no, no, we can't leave it alone. It's part of history. So we've got a long way to go.

BRIGGS: Telling those new stories takes a ton of work. Take the Guerrero. Ken says in order to confirm the identity of a wreck like the Guerrero, archaeologists would need to find certain kinds of artifacts—perhaps items listed in the ship’s manifest like cannon or cargo.

STEWART: For like, for the Guerrero, we'd be looking for a bell, right, that would say Guerrero on it. But we know the Guerrero was a slaver, so it might not have had a bell on it. We know the Guerrero had a little gold on it. And they know they had some ivory on it. Right. And or anything that would say Guerrero on it..

BRIGGS: DWP’s hoping to wrap up the search for the Guerrero once COVID-19 lifts, and divers can safely get back in the water. So far, the number of confirmed slave shipwrecks can be counted on one hand. Which makes sense because finding them isn’t easy.

STEWART: A lot of people, when they think about archaeology or maritime archaeology, they think of the Titanic, right—a ship that's intact. Right. Most of the ships in saltwater are not intact, especially if they're made out of wood. But when they're made out of wood after years and years and underneath the water, they are actually a scattered debris. What happens is the worms—there are worms that eat the wood over a period of time. And so, believe it or not, a whole ship can be eaten by worms. But what they don't eat are the artifacts, right. They don't eat the artifacts.

BRIGGS: Artifacts can help fill in the picture when historical details are scarce. One shipwreck—the Henrietta Marie—was found in the 1970s and is one of the few to be a confirmed slave ship. The artifacts found there gave archaeologists a kind of blueprint for the sorts of objects that could appear on other slave sites.

STEWART: There was a lot of artifacts that came off the ship—cannons, shackles, a lot of shackles. Right. And a lot of them were small shackles. So we know there were shackles for children.

BRIGGS: In total, more than 7,000 artifacts were recovered—cauldrons for cooking crew meals, glass beads for bartering, and even anchors from the ship itself. But finding underwater artifacts takes an educated eye and a patient hand.

STEWART: When you first do it, you say, what the heck am I looking at? But after your eyes get trained to it, you’ll figure out what the artifacts are. In our code of ethics, we make it very plain that when we do a site, we cannot bring up any artifacts. You can't. In fact, they don’t even want you touching them, right? Everything has to stay in situ. An archaeologist, you know, they believe in obviously leaving any artifacts down. Now they'll bring up an artifact from any slave wreck or anything to be studied and conserved. But basically they believe in leaving everything down tolook at, right. They really wholeheartedly believe that.

RACHEL STEWART (DWP diver): I remember just seeing large pieces, none of which I could identify.

BRIGGS: This is Rachel Stewart—no relation to Ken Stewart. She started out as a DWP student. Now she teaches other students what she’s learned.

R. STEWART: We learn to look for objects or anything in the water that doesn't seem like it's been nature made. So straight lines or perfect circles would be obvious. They mentioned like a boiler being down there, large pieces of wood being there. It wasn’t intact, just large pieces scattered throughout the floor.

BRIGGS: So you’re not seeing some perfect wreck like you see in Scooby-Doo.

R. STEWART: Right, no.

BRIGGS: As a DWP student, Rachel learned the proper techniques to dive on an underwater site and not disturb it. And then she learned how to work alongside maritime archaeologists and record data.

R. STEWART: When we first get to a site, we'll do a swim-through just to get familiar with the site and then we'll go down and place a baseline through the middle of where all the artifacts have been scattered throughout the ocean floor.

BRIGGS: Then Rachel will take measurements called trilaterations.

R. STEWART: And we essentially are just measuring the distance from that point to the baseline at two different spots essentially. So then we'll take the notes after doing the trilaterations, getting all of our distances measured. Then we go back down and draw the objects, and the idea is to get it to scale. We're not drawing to scale underwater. But we have to take every single measurement. So how long is that artifact? How wide is it?

BRIGGS: These measurements then go into creating what’s called a site map, which can then be used as a legal document by conservationists. But there are also the things that can’t be recorded in a data sheet.

R. STEWART: Every time I see it, like I picture what could have happened. I can only imagine the horror and terror that if there is, are enslaved people on the boat, what they may have felt. I just kind of think, what would I have felt if I was stuck on a boat? My ship's about to go. I don't see land in sight. Well, what would I have done?

BRIGGS: Rachel’s now getting her doctorate in environmental engineering. It’s this connection to the past and Ken’s devotion to the future that inspires Rachel and other divers like her.

R. STEWART: He's very inspirational, and you can tell that he really cares about the youth and what they think. And he understands that we are the future. And I think he puts a lot of effort into giving us experiences and carving out paths for us that—so that we can, you know, do better than prior generations.

BRIGGS: And Ken’s not done.

K. STEWART: I'm going to dig in. You know, my tenure here on Earth is—I’m not gonna be here a lot longer. Right. And so I want to help. Right. I think our young people need us. Right. And we're getting ready to hand this planet off to them. And my generation has almost already thoroughly destroyed it. Right. It's on its way down. And if we don't teach the next generation how to save this planet, it will be no planet. So I think if young people knew more of the history, you know, would they be inclined to be a better person? I don't know. But, you know, I think the first step is to be taught.

BRIGGS: More after this.

BRIGGS: When we last checked in with Tara, she was hitting the road.

ROBERTS (in her car): All right, it is Monday morning around 5 a.m., and I just backed out of the garage and I am headed to Mobile, Alabama.

BRIGGS: Tara’s headed to see the Clotilda, the most recent confirmed slave shipwreck, that was discovered in 2019. It’s part of her yearlong Nat Geo storytelling fellowship.

She’s going to follow the divers, historians, and archaeologists around the world who are studying slave ships and document it as part of a narrative podcast series.

ROBERTS: So we're going to spend an entire season going deep and letting people hear from the divers themselves, hear from the archeologists themselves, and hear from the historians. Those communities include Mozambique, South Africa, Senegal, Costa Rica, St. Croix, and the U.S. And I think it’ll be very cool.

BRIGGS: Tara hopes to reveal more dimensions to the history of slavery and chart new beginnings to the story.

ROBERTS: I was thinking the other day about how many stories and how much work was done or devoted to documenting the Titanic. Like there's so many stories about the Titanic. And it is— it's a great story. Like it's a tragic story. It's a moving story. So how does this story get that kind of weight, where then resources are dedicated to it...

It feels, Amy, like there's this really interesting moment in time right now, where things that have been hidden in the shadows are coming out—like people are seeing things that they hadn't seen before.

BRIGGS: Tara says there has to be a will to find this history. And a will to look at the story differently. And maybe, at the end of it all, there will be a new beginning to the story of Africans in the Americas. More after the break.

Tara will be posting updates about her travels on Instagram and Facebook. You can find those @storiesfromthedepths.

If you’d like to see photos of DWP divers–including the one that Tara saw at the National Museum of African American History and Culture–you can find a link in our show notes.

You can also find out more about the African Americans who are excavating the stories of their ancestors, including Matilda McCrear, who is widely thought to be the last slave ship survivor. She was just two years old when she arrived in Mobile, Alabama, in 1860.

And for subscribers, check out National Geographic Magazine’s cover story about the Clotilda, the most recent slave ship to be discovered. It tells the story of how the ship illegally smuggled 110 West Africans into the United States on the eve of the Civil War.

We also have a National Geographic History magazine article about 1619, when the first enslaved Africans arrived in colonial North America.

That’s in the show notes, right there in your podcast app.


Overheard at National Geographic is produced by Laura Sim, Jacob Pinter, and Brian Gutierrez.

Our senior editor is Eli Chen.

Executive producer of audio is Davar Ardalan, who also edited this episode.

Our fact-checker is Michelle Harris.

Hansdale Hsu composed our theme music and engineers our episodes.

This podcast is a production of National Geographic Partners.

Whitney Johnson is the director of visuals and immersive experiences.

Susan Goldberg is National Geographic’s editorial director.

And I’m your host, Amy Briggs. See you next time.


The National Geographic Society, committed to illuminating and protecting the wonder of our world, funds the work of National Geographic Explorer Tara Roberts and National Geographic Explorer and Photographer Ruddy Roye.

Want more?

Follow Tara’s journey around the world on Instagram. And here’s the photo that Tara Roberts saw at the National Museum of African American History and Culture that inspired her to learn to scuba dive. Read about the last slave ship survivor, Matilda McCrear, and what her descendants make of her legacy. Tag along on a scuba mission with DWP divers in this video produced by National Geographic.

And for paid subscribers:

Read a History magazine article about the Clotilda, the ship that illegally smuggled 110 West Africans into the United States on the eve of the Civil War. We have another History magazine article about 1619, when the first enslaved Africans arrived in colonial North America.

The National Geographic Society is committed to illuminating and protecting the wonder of our world. Learn more about the Society’s support of its Explorers.