Searching for a Slave Ship

Searching for a Slave Ship

Join Dr. Ayana Omilade Flewellen, co-founder of the Society of Black Archaeologists, and Jay V. Haigler, retired electrical engineer, founding board member and lead instructor at Diving With a Purpose, as they go in search of the sunken Spanish slave ship, the Guerrero.


5 - 8


Anthropology, Archaeology, Geography, Human Geography, Physical Geography, Social Studies, U.S. History, World History, Storytelling

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The ocean gently laps against the side of our boat. Our conversations rise and fall in a rhythmic hum as we check our gear one last time. Excitement and eagerness move through us like an electric current. It has taken years of steady research, training, and focus to prepare for this moment—this dive—when we will discover if what lies below us is, in fact, the shipwreck of the slave ship Guerrero.

We’ve asked you to join us on this historic dive. But, before you take that giant leap into the Atlantic Ocean, you may have a few questions that need answering first. Who are we, and how did we get here?

The Guerrero

We are maritime archaeologists and advocates. We are searching for a ship that sank to the sea floor nearly 200 years ago. This ship is unlike many that we see sailing across the ocean today. It, and many others like it, once transported enslaved Africans from the continent of Africa to the New World.

The Guerrero was a Spanish slave ship. Ships like these were often heavily armed. If another ship tried to take its human cargo, it would not be without a fight. The Guerrero carried 14 brass 12-pounder guns and 10 iron 12-pounders. Her crew was 90-men strong. On December 19, 1827, the Guerrero was sailing south toward Cuba in the Florida Straits. In her cargo hold, 561 African captives sat chained together.

The ship was spotted by the HMS Nimble, a British Royal Navy schooner-of-war ship. The Nimble was used for anti-slave patrolling. The British government abolished international slave trading in 1807. The following year, the United States enacted a similar prohibition. Ironically, the HMS Nimble, was a former slave ship under a different name, the Bolivar.

The Nimble was smaller and not as well armed. Despite this, the Nimble fired two warning shots at the slave ship. The Guerrero’s captain, José Gomez, had no intention of being boarded. He tried to outrun the Nimble. What followed was a five-hour chase on the open sea through bad weather and approaching night. As the Nimble caught up and drew closer, the ships engaged in battle.

Early in the battle, the Guerrero appeared to signal surrender, but it was a ruse. The pirated slave ship tried to cut and run again. The Nimble pursued her into shallow water. The Guerrero hit a reef while sailing at speed. The impact tore the hull open and toppled the masts. The Nimble tried to turn away but ran onto the reef as well. Inside the Guerrero, 41 of the confined Africans drowned as the ship sank.

Archaeologists have searched for the site of the sunken Guerrero for many years. Ships like this hold our collective history. In their remains, they tell the stories of what some of our ancestors experienced in the past. And while this history is filled with hardship, it is also a history of perseverance.

The Root of Evil

To explain our search, we need to go back. Way back. We need to explain to you the difference between slavery and the slave trade. Slavery—as it existed long ago and as it still exists in parts of the world today—is evil and immoral.

In ancient times, slavery was what we call a “social construct.” That term refers to the ways in which human behavior was governed within a specific geographic region. There were many ways a person could become enslaved. They could have been born into a family that was already enslaved. They could have been abandoned as a child. Or been a casualty of war. They could have become enslaved because they were in debt. They could even be enslaved as punishment for a crime.

Enslaved people became commodities—something to be bought, sold, and traded. In exchange for money, these people were forced into labor. They could be bought in one place but made to work in another place.

Transportation of enslaved people from one location to another became a critical and essential part of the slave trade. As the demand for forced labor increased, the distance between where people were captured and where they were made to work grew. A system to transport human cargo evolved over time.

It was not enough to move people by foot over land. Slavers thought that was too slow and not far enough. Moving people in horse-drawn carts was also limiting. This perverse human “industry” grew so quickly that slavers needed to move people not just across land but across the ocean, too. Sailing ships became the critical tool for transporting human cargo.

A slave ship is a sailing vessel that carries people from one geographic location to another for the express purpose of delivering them to be used for forced labor. Human beings joined other cargo aboard these ships—sugar, spices, animal hides, raw materials to build with, for example.

Moving human cargo was part of a trading scheme that formed a geographic triangle. Weapons, textiles, and wine were shipped from Europe to Africa. Enslaved people were shipped from Africa to the Americas. Sugar and coffee were shipped from the Americas to Europe.

This shameful part of our global history became known as the transatlantic slave trade. It lasted from the 16th to the 19th century. During this time, as many as 12 million enslaved Africans—men, women, and children—were torn from their homes and families and shipped across the Atlantic Ocean.

Not all ships completed their journeys. We know lives were lost on the Guerrero. The lives of the people who survived were changed forever.

Its Lasting Effect

The institution of slavery is the foundation of our global economy. Many nations, like the United States, prospered under its evils. Even the U.S. Constitution, America’s governing document, originally protected the slave industry. Slavery was not abolished until the ratification of the 13th Amendment in 1865.

Yet that was not the end of disparity for people of African descent. New laws were created as tools to continue to marginalize African Americans. “Jim Crow” laws were a collection of state and local statutes that legalized racial segregation. These laws—active from the post-Civil War era until around 1968—were meant to marginalize African Americans by denying them the right to vote, hold jobs, buy homes, get an education or other opportunities. Those who attempted to defy Jim Crow laws often faced arrest, fines, jail sentences, violence, and even death.

The Jim Crow era led to the 1960’s Civil Rights movement, which in turn has led to the current Black Lives Matter movement.

Why the Past Matters

The English playwright William Shakespeare wrote: “What’s past is prologue.” It’s a statement we divers think about often. It means that understanding history—the past—helps explain the present to us. It can also be a precursor to our future. We want to understand, amplify, and honor our past so we can make a better future for everyone.

You have to remember that sailing ships were the first instrument used to scale the slave trade and create the first global economy. And as such, slave ships became the origin point for African American oppression in the United States.

The work we do now to locate and identify sunken slave ships is an integral part of the narrative of institutional slavery. Searching, documenting, and telling the stories of these ships and the people captured aboard brings awareness and helps our discussions of race relations not just in the United States but throughout the world.

The Smithsonian Institution’s National Museum of African American History and Culture created a research center called the Center of the Study of Global Slavery. In it, the Slave Wrecks Project (SWP) came into being. It’s an international network of institutions that investigates enduring legacies of the African slave trade.

Organizations like our group, Diving With a Purpose (DWP), partner with SWP to execute the project’s mission. George Washington University, the U.S. National Park Service, and IZIKO Museums of South Africa are also a part of SWP’s global collaborative.

Finding a Slave Shipwreck

The Transatlantic Slave Trade Database documents more than 35,000 voyages of slave ships from 1500 to 1880. At least 1,000 of those vessels were shipwrecked. Only a handful have been positively identified. How do we know where to look?

The search to find the Guerrero began with archival research conducted by a Florida-based historian and author Gail Swanson. Swanson combed through documents, oral histories, and records of the ship-wrecking event. She scoured newspaper accounts, government records, and ship manifests.

Swanson also checked insurance records and financial transactions from banks. These can also be surprising resources for slave ships. Here’s why. The slave trade became so lucrative that captured humans were insured to mitigate financial loss to the owner. If a slave ship was lost due to a wrecking event, it was common for an insurance claim to be filed with the company that issued the policy.

During the process of administering the claim, an investigation was often conducted. Some investigations prompted legal proceedings to resolve disputes and claims. Any legal activity produced voluminous records, such as sworn testimony, captain’s logs, and court transcripts.

Based upon Swanson’s work and further work by Dr. Corey Malcom and National Oceanic and Atmospheric Administration (NOAA) maritime archaeologists, we began to narrow down where the ship might have been lost.

Narrowing the Search

Based on the archival research, we believed that the Guerrero could be resting in one of two major areas. Both areas are in marine protected areas. The first is protected by the National Park Service (NPS). The other is protected by the National Oceanic and Atmospheric Administration (NOAA).

Both locations measure several square miles. That’s too great an area to be checked by divers. So, we used remote sensing equipment connected to a motorized boat to survey them.

At each potential site, we were hoping to identify magnetic disturbances along the ocean floor of Earth’s natural electro-magnetic field. These disturbances are called “anomalies.” An anomaly could be an item from the shipwreck. We were looking for items typically found on slave ships: iron shackles, cannons, or cannon balls.

We investigated 410 anomalies within the NPS search area and more than 100 anomalies in the NOAA search area. Yet, finding an artifact isn’t enough. The artifact had to be tied to the right time period.To help identify a site specific to the Guerrero, it had to be a certain kind of artifact.

One site we investigated had cannon balls that weighed approximately 5.4 kilograms (12 pounds). The historical record specifies that the Guerrero carried 12-pound cannon balls.

We kept searching. At one of the sites, we discovered iron pins, bar shots, ring bolts, and a thimble. Copper sheathing, spikes, tacks, and other items were also found.

A signature item kept on slave ships were ballast stones. Ballast stones are used to keep ships weighted down to help stabilize the vessel as they move across seas. In slave ships, these stones were used to counter-balance the weight of their human cargo.

NOAA’s search area, within the Florida Keys National Marine Sanctuary, seems to have a lot of promise. The wreck site in this area has a cologne bottle from the early 1800s, bone china, lead shot, blue-edged earthenware, metal rigging, copper fasteners, and wooden plank fragments that have characteristics of the type of material that was used to build the Guerrero.

Now, here we are. We plan our dives for the next day. It’s hard not to think about what we might find. It’s also hard not to think about what the 561 captured people were thinking the night the ship sank…the terror that they felt as an epic gun battle waged above them, and there was nothing they could do.

Gearing Up

Everyone falls quiet as we make our way to the site. Each of us is focused on the specific tasks we have been assigned. You’ve been training with us, so you’re familiar with the survey equipment. Your wetsuit will help keep your body warm as we dive down to search for what might be the Guerrero.

We never enter the water before our pre-dive safety check for ourselves and our dive buddy. We’ve already checked our Buoyancy Control Device (BCD) vests. These vests help us maintain buoyancy—our ability to float—while underwater.

We check our lead weights. Without them, we will not be able to descend to the wreck. The ocean’s salt water will not allow us to sink without these additional weights.

Our releases on our BCDs are checked. These releases keep our air tanks from falling off as well as keep the BCDs on our bodies.

We check the gauge on our regulators to make sure that we have a full tank of air in our tanks and make sure our regulators are properly connected to the air tanks. This will ensure that we can take nice deep breaths underwater. We don’t forget our mask and fins, so we can see clearly and be able to move smoothly through the water. We’re each equipped with the tools we’ll need to help us with our underwater archaeological work.

We have to be careful as we descend and work on the wreck site. We don’t want to go crashing into the shipwreck! We need to be able to hover above it and any artifacts that we come upon. Remember, a shipwreck is an artifact. As archaeologists, we gain a lot of information by documenting what we observe.

The Dive

We make our giant stride into the water. Dive buddies meet on the ocean surface, then they start their descent. The water envelops you like a warm blanket.

On your way down, you swim through a cloud of life: yellow-tail snapper, sergeant major, blue tang, and parrot fish. They don’t notice you. They are focused on eating. If you listen carefully, you can hear high-pitched sounds, like a thousand raindrops hitting hard on a windowpane. This is the sound of the fish feeding on corals.

Typically, a baseline is established by the principal investigator and other divers prior to the rest of the dive team descending on the wreck site. A baseline will be laid down the middle of the wreck site. The baseline provides the main reference for all artifact location measurements. A baseline consists of two datum points located at the ends of the wreck site connected by baseline rope with measurement clips or a tape measure.

You and your dive buddy arrive at your assigned section of the baseline. As a team, you begin the focused work of measuring and documenting items of interest or potential artifacts of the shipwreck.

You take out your Number 2 pencil, clip board, mylar paper, tape measure, and ruler. As archaeologists and archaeology advocates, our work here is like the work of a crime scene investigator. If what you see can be verified as the remains of the Guerrero, you will be investigating part of one of the greatest global crimes in the history of mankind, slavery.

Time moves quickly as you are engrossed in your work. The gauge of your scuba regulator indicates that you’ve been working for 90 minutes. It is time to end the dive. So, you and your buddy gather your data sheets and measuring equipment, then head toward the surface. As your hand breaks the water, you pass your data and equipment to the dive master on the boat. This is the first of many dives we will make at this site as we seek to verify this ship’s identity.

For us, we already think of this place as hallowed ground. The archival record indicates that 41 souls were lost here. The search for the Guerrero is an effort to honor these lives as well as the lives of the other enslaved people who survived the shipwreck but who endured so many hardships afterward.

The words of abolitionist Frederick Douglass come to mind. In an 1889 speech called “The Nation’s Problem,” he said:

Our past was slavery. We cannot recur to it with any sense of complacency or composure. The history of it is a record of stripes, a revelation of agony. It is written in characters of blood. Its breath is a sigh, its voice a groan, and we turn from it with a shudder. The duty of today is to meet the questions that confront us with intelligence and courage.

These words are why we Dive With a Purpose.


Approximately 1,200 anomalies have been identified in the marine protected area managed by NPS and 100 anomalies have been identified in NOAA’s protected area. Nearly all of the anomalies in NOAA’s area have been investigated. There are 790 anomalies within the national park yet to be investigated as a part of determining the likely wreck site of the Guerrero. So, the work continues to locate the sacred ground where 41 souls were lost, the remnants of a ship where 399 human beings were carried to Cuba and sold into bondage, and 91 survivors returned to their homeland. The search for the Guerrero continues. Come join us!

Media Credits

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Tyson Brown, National Geographic Society
National Geographic Society
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Gina Borgia, National Geographic Society
Program Specialists
Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Specialist, Content Production
Clint Parks
André Gabrielli, National Geographic Society
Last Updated

October 19, 2023

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