Underwater archaeology researchers on the site of the wreck of the slave ship. (Iziko Museums)

In the final days of 1794, a Portuguese ship taking about 400 slaves from Mozambique to Brazil crashed on the rocks off the coast of Cape Town, South Africa. About half of the slaves died in the rough surf, while the survivors were resold and sent once more to work on Brazil’s sugar plantations.

Now an iron ballast and a wooden pulley block retrieved from the shipwreck of the São José-Paquete de Africa are coming to Washington, where next year they’ll be on view in an exhibition on slavery in the new National Museum of African American History and Culture.

“These will be part of the list of ‘I’ve got to see this,’ ” predicted Lonnie Bunch, the museum’s founding director, who is in South Africa for a formal announcement Monday of the long-term loan of the objects from the Iziko Museums.

The artifacts represent a significant addition to the 33,000-item collection of the newest Smithsonian museum, which is set to open next year on the Mall.

“I’m not attempting to tell a narrative,” Bunch said. “The goal is to create an evocative space, with a few iconic pieces, almost like religious relics.”

Copper fastenings and copper sheathing recovered from the ship wreck. (Iziko Museums)

Created by Congress in 2003, the National Museum of African American History and Culture will open its $540 million facility with 11 exhibitions, including the one on slavery. The museum has already collected important slave-related items, including iron shackles for a child, a bill of sale for a 10-year-old slave boy and a 19th-century slave cabin from Edisto Island, S.C.

Like those pieces, the objects from the São José will personalize the “grand historical story” of slavery, said curator Paul Gardullo.

“We have many items that tell a full and complex story of slavery . . . and the way it shaped our nation and the modern world. This will add to that in a unique way,” Gardullo said.

The iron rods and pulley block are “humble objects,” Gardullo said but, if presented in context, can help visitors make an emotional connection.

“Slave ships cast a large figure in the public imagination,” he said. “We want to get a sense of that reality. These are tangible and authentic pieces of the past, and they hold a tremendous amount of power.”

The agreement between the Iziko and the Smithsonian calls for the objects to be on loan for at least 10 years, Bunch said. “We leave that open because part of this is the research and excavation. There might be objects we don’t know about yet,” he said.

The loan agreement represents a milestone for the Slave Wreck Project, a global effort launched in 2008 to study the slave trade through the discovery and archeological study of ship wrecks. The African American History Museum has been collaborating with five other organizations, including the Iziko Museums and George Washington University, on the project.

“It’s a great collaboration that brings us across the ocean,” Gardullo said. “We’ve created this new model, engaging in these conversations and looking at new ways to do this work.”

The São José shipwreck was first discovered in the 1980s but misidentified as an earlier Dutch vessel. In 2008, researchers with the Slave Wreck Project chose the site as its pilot project and began to explore the underwater location and conduct research in the archives of cities it was thought to have visited.

Since 2010, project researchers have uncovered documents in Portugal that have revealed the ship’s owners, its cargo when it departed from Mozambique and evidence of the sale of a slave by a local sheikh to the ship’s captain.

Officials involved in the project are in Cape Town this week for a series of discussions and workshops about the maritime archaeological effort. They hope that the richly detailed narrative is just the start of their discoveries.

“One of the last areas that can provide us with new knowledge [of the slave trade] is underwater. I wanted to be a part of that process, and the scholarship that can be shaped,” Bunch said. “My hope is this will be a long-term research-driven project and that there will be other wrecks we can identify, and ultimately, I’d like to see over a period of time different artifacts come to the museum.”