Underwater archaeologists are searching the waters off Playa Villa Rica, about 75 kilometers (46.6 miles) north of Veracruz on Mexico’s Gulf coast, for what’s left of conquistador Hernán Cortés’ long-abandoned fleet.

Scouring the seafloor

In 1519, at the very last moment, the Spanish governor of Cuba revoked the charter of an expedition to Mexico after a fierce argument with its leader. But the defiant Cortés set sail with 11 ships and 300 men anyway, and by July, he had worked his way along the Yucatan coast to Veracruz. There, eager to march inland to the Aztec capital of Tenochtitlan, Cortés destroyed 10 of his 11 ships, cutting off his men’s only hope of retreat and leaving them with no option but to head inland.

The expedition ultimately destroyed the Aztec Empire and began the long and often brutal process of colonizing Mexico. Almost no one gave the ships a second thought.

Five hundred years later, underwater archaeologist Roberto E. Junco Sánchez, of Mexico’s National Institute of Archaeology and History (INAH), is giving them that second thought. With a team of colleagues, he’s crisscrossing the waters off Villa Rica with magnetometers and side-scan sonar, looking for Cortés’ abandoned ships. The team is scanning the sea floor for traces of metal that may be the remains of 500-year-old ships’ fittings.

But it turns out a lot of metal is buried beneath the sand off Villa Rica. So far, the team’s survey has turned up between five and six dozen magnetometer targets, any of which could be either Cortés’ ships, a pile of modern junk, or something else entirely.

“Once we have the mag hits, we investigate them using a portable handheld magnetometer, then excavate and look for traces of old metal,” Junco told Ars Technica. If the divers find a shipwreck, they’ll radiocarbon-date samples of the wood to see if it lines up with the dates of Cortés’ expedition. And if there’s enough of the hull left, its design and construction may also yield clues to its origin.

Sixteenth-century high tech

There’s probably not much left of Cortés’ ships after all these centuries on the bottom; tropical waters make short work of wood, canvas, and rope unless they’re well buried. Usually, what's left is the lower section of the hull, protected by seafloor sediment and sometimes the ship’s own ballast stones. Sanchez estimates that about two meters of sediment now cover the wrecks. “It will be interesting to see the state of preservation,” he told Ars.

The state of the wrecked ships may clear up a minor historical debate about how, exactly, Cortés destroyed his fleet. The earliest reports claimed he simply ran them aground, but later historians eventually embraced a more dramatic version of events that featured the conquistador burning his entire fleet.

If found, the scuttled ships could tell archaeologists something about a little-known period of shipbuilding: the cutting-edge 16th-century engineering that paved the way for European colonization, for better or worse. “There are very few early ships located and few 16th-century wrecks known and studied,” Junco told Ars Technica. “These very early ships are the kind of technology that mapped America and the Pacific Islands; they were good vessels to discover and start the process of discovery and colonization.”

The search continues

And Cortés’ ships may not be alone down there.

“There is also the possibility that we might have the fleet of Pánfilo de Narváez, who also, we think, scuttled his ships in the area,” Junco told Ars Technica. Narváez raced to Mexico in 1519 with orders from the Cuban governor to stop Cortés and his mutinous expedition. Despite arriving with a larger force, he failed and lost an eye in the process.

Divers have checked roughly a third of the targets so far, and they’ve found no sign of a shipwreck. But Junco says he’s optimistic. The survey area is relatively small, and they’re looking for the remains of 10 ships clustered together, so it’s less of a needle-in-a-haystack proposition than shipwreck surveys sometimes are. And in 500 years, the INAH team is only the second one to give it a serious try.

“There was an important researcher in the 19th century, Francisco del Paso y Troncoso, who in 1891 put hard-helmet divers in this area to look for the ships,” Junco told Ars Technica. Today’s searchers have the benefit of magnetometers, side-scan sonar, and significantly more advanced dive gear. “Our next move is to keep the mag survey and verify the rest of the anomalies we have,” said Sanchez.