Unidentified object off the American coast: a seventeenth-century submarine?

For centuries, an unknown disk-shaped object found off the coast of Florida was assumed to be a 17th-century cauldron. And now, it appears that experts may have finally discovered its true nature. Could this artifact be a 17th-century diving bell, ingeniously used in the perilous quest to rescue treasure from a sunken Spanish galleon?

The mysterious copper object was originally discovered off the coast of Florida in 1980 near a wrecked Spanish galleon, and is believed to have been a cauldron for making fish stew at sea. But now, two researchers have suggested that the copper dome represents the remains of a primitive diving bell dating back to the 17th century and used by treasure hunters.

If this object was not a cauldron, it was likely part of an early diving bell, making it one of the earliest known examples of diving devices ever found.

Discovery of a mysterious copper object off the coast of Florida. ( Mel Fisher Maritime Museum )

Cauldron or diving bell? Reinterpretation of the unidentified metal object in Florida

Deep sea divers discovered the copper dome in 1980 near the Santa Margarita, a wrecked Spanish ship that sank in 1622 in the Straits of Florida, about 65 km west of Key West. The object was recovered at a depth of about 50 meters (160 ft), and was initially supposed to be a large cooking cauldron.

It is now on display at the Mel Fisher Museum in Sebastian, Florida, and two marine archaeologists now suggest that the object was actually the top of a 17th-century diving bell that was used to salvage treasure from the sinking ship.

Sean Kingsley, marine archaeologist and magazine editor Wreckwatch Magazine Tell live science That these primitive submarines were deployed most often in shallow waters. He added that as the bottom of the device opens, it fills with air, providing divers with a breathable bubble of air at depth.

Illustration of Halley’s diving bell, designed by Edmund Halley in 1690. (Welcome Pictures/ CCP 4.0 )

The old diving bell doesn’t look like a cauldron!

In the latest version of Wreckwatch Magazine Sean Kingsley and marine archaeologist Jim Sinclair, who was a member of the recovery team, explained why they thought the piece was a “primitive diving bell”. Kingsley said many of the designs for diving bells were produced in the 17th century. One of the most famous is the design of the English scientist Edmund Halley, the discoverer of Halley’s comet, in 1690.

According to Sinclair and Kingsley, the object is 147 cm (58 in) in diameter, and appears to have been made of two copper plates. With a heavy rim, studded with brass rivets all the way around, the researchers said it’s “very substantial for cooking” and that “there are no signs of charring or heating.” Sinclair said live science that although it had been called a “copper cauldron” in the past, he had seen quite a few ship’s boilers and none of them “looked like this”.

Besides a mysterious cauldron-shaped diving bell that was discovered near the Santa Margherita treasure ship, divers found an inscribed gold plate from the wreck in 1980. (Don Kincaid)

Pearl diving device of the initial type?

The treasure ship Santa Margarita sank in 1622 during a hurricane in the Straits of Florida, with the loss of all 142 crew members. When the ship was explored in 1980, divers found a metal object alongside iron ingots, which may have anchored the device to the sea floor. The wreck of the Santa Margherita has since yielded millions of dollars in treasure, including gold bars and coins and a religious reliquary of gold and rock crystal.

The dome-shaped object is probably “the upper part of a diving bell described by rescuer Francisco Nunez Milian in 1625,” Sinclair said. This would explain why the device is surrounded by several waterproof bottom panels made of wood and leather. It is believed that the diving bell was inspired by a design by Spanish inventor Jeronimo de Ayanes in 1606, which was later used for pearl diving in Venezuela.

The researchers believe that the diving bell may have been carried by three divers, and that it may have been connected to a surface support vehicle with an air hose. The “diving bell” hypothesis gained further support from the fact that when Melian discovered the shipwreck in the 17th century, his divers recovered “350 silver ingots, thousands of gold coins, and eight cannons”. This large amount strongly indicates that a diving bell was used in the process.

Top image: The mysterious copper “cauldron” is now believed to be a 17th-century diving bell. Source: Melvin Fisher Abt

Written by Ashley Coe