Currently, it sits on display at the Mel Fisher Maritime Museum in Key West. Many visitors assume that it was simply a cauldron dating back to the 17th century. While the true origin of the object was largely unknown, researchers believe they have finally found the true history of the ancient item—the artifact could potentially be a 17th century diving bell that was tossed into the sea in order to recover treasure from sunken Spanish ships.

It was presumed that the artifact had a rather mundane use—historians believed it was a simple cauldron used to cook fish stew. However, researchers now believe the ancient artifact had an entirely different use during the 17th century.

This revelation would make the object one of the earliest models of a diving apparatus. The primitive diving bells of centuries ago had a surprisingly advanced design. Two researchers have concluded that the copper dome could be what’s left of a 17th century diving bell that was once used by treasure hunters. 

Diving bells would permit divers to work underwater by submerging the heavy bell that contained an air-filled container people would sit inside of. As the chambers lowered down into the water, the divers were able to search through the seas to salvage gold and other precious materials from the ocean.

The object, then presumed to be a cauldron, was located nearly 160 feet (50 meters) below the ocean’s surface. Interestingly enough, the Santa Margarita set out in search of lost treasure, but the copper dome from the galleon is now considered to be treasure in itself.

A maritime archaeologist named Sean Kingsley explained that these “primitive submersibles” were usually submerged into shallow waters. The design of the diving bell allowed the bottom of the device to be open as the middle filled with air, giving divers a pocket of breathable oxygen in between dives.

In the article, Sinclair discussed why they believe that the object is the remains of a “primitive diving bell.” Kingsley revealed that a variety of diving bell designs were produced in the 17th century and the sunken artifact resembles one of them.

Kingsley and Sinclair stated that the object measures 58 inches in diameter and seems to have been built from two copper sheets. The heavy artifact is “studded with copper rivets all the way around.” 

Another interesting point the men made was that there were no “signs of charring or heating” on the object, which would be visible if it were in fact a cooking cauldron. Sinclair said that although the object has been referred to as a “copper cauldron” for years, he has seen many ancient ship cauldrons and none of them “look anything like this.”

When the ship was finally explored by divers in 1980, they stumbled upon other unique objects inside the wreckage. Divers found millions of dollars worth of treasure inside the wrecked galleon, including gold bars, coins, and rock crystals.

Sinclair’s hypothesis would offer an explanation as to why the object was surrounded by numerous “watertight lower panels made of wood and leather.” Some believe that the diving bell was based on a design by Jerónimo de Ayanz in 1606. The Spanish inventor’s design would eventually be used to go pearl diving in Venezuela.

The diving bell theory has gained momentum after further historical research was conducted into the 17th century shipwreck. When the Santa Margarita was originally explored during the 17th century, divers located “350 silver ingots, thousands of gold coins, and eight cannons.”

It would make sense that the copper object is part of an ancient diving bell, making it a rare piece of early underwater technology. The bell would have allowed divers to remain underwater for longer periods of time, retrieving more treasures from the sea.

Kingsley and Sinclair have marveled at the amazing accomplishments of the 17th century such as creating a device that would allow divers to breathe underwater. While technology has made significant advancements as time passed, 17th century scientists created amazing inventions such as the diving bell. “Going into inner space – the depths of the sea – was for a long time one of the great tests of mankind,” Kingsley said.

Whether the object is an ancient cauldron, a diving bell, or something we have yet to realize, the incredible artifact is a part of history. It remains at the Mel Fisher Maritime Museum where it will continue to be viewed by many people.