Divers in Sweden Find Shipwreck in Baltic Sea. Credit — The Swedish National Maritime Museum via Storyful

Divers in Sweden Find Shipwreck in Baltic Sea. Credit — The Swedish National Maritime Museum via Storyful

THE worth of a wrecked galleon dubbed the “holy grail of shipwrecks” has been revealed, and it could be more than $22 billion.

Known as the San Jose, the Spanish galleon was sunk by the British Navy more than 300 years ago while carrying a wealth of gold, silver and emeralds.

Those riches are now worth as much as $17 billion ($A22 billion) by modern standards, but treasure hunters hoping to get a piece of the booty will be sorely disappointed.

The location of the wreck remains a state secret, but it’s known to be at the bottom of the Carribean Sea off the coast of Colombia.

The 62-gun, three-masted galleon was found three years ago in more than 600 metres of water with the help of an autonomous vehicle operated by the Woods Hole Oceanographic Institution (WHOI)

But agencies involved in the discovery only recently gave researchers permission to release the findings to the public.

For centuries its location was known as the “holy grail of shipwrecks,” and long considered one of history’s greatest maritime mysteries.

“We’ve been holding this under wraps out of respect for the Colombian government,” WHOI’s vice president for marine facilities and operations Rob Munier said.

The Massachusetts-based WHOI was invited to join the search because of its recognised expertise in deep water exploration.

The institute’s autonomous underwater vehicle, REMUS 6000, helped find the wreckage of Air France Flight 447 in 2011, which crashed in 2009 several hundred miles off the coast of Brazil. It was REMUS 6000 that in November 2015 took some side sonar images that found the San Jose.

The vehicle descended to nine metres above the wreck to take several photographs, including some of the distinctive dolphin engravings on the San Jose’s cannons, a key piece of visual evidence.

“The wreck was partially sediment-covered, but with the camera images from the lower altitude missions, we were able to see new details in the wreckage and the resolution was good enough to make out the decorative carving on the cannons,” WHOI engineer and expedition leader Mike Purcell said.

The treasure has been the subject of legal battles between several nations as well as private companies.

Several weeks ago, UNESCO, the United Nations cultural agency, called on Colombia not to commercially exploit the wreck, whose exact location remains a state secret.

WHAT HAPPENED TO THE SAN JOSE?

THE 64-gun San Jose was sunk off the coast of the Colombian port city of Cartagena in 1708 during 90 minutes of heavy fighting with the British Navy.

It was part of a fleet carrying jewels, precious metals and 11 million gold and silver coins from Spain’s South American colonies.

The cargo was destined to help Spain’s King Philip V fund his war against Britain. But the British weren’t the only ones with their eyes on the galleons.

Frequent voyages by Spanish treasure ships had led to a golden age of piracy — with raiders sinking more than 1000 Spanish ships off the coast of Colombia during three centuries of colonial rule.

The San José’s 600-strong crew knew the voyage would be fraught with danger. But they were barely 16 miles (25kms) out when they were tracked down by English Commodore Charles Wager, in command of four British ships including HMS Expedition.

Wager’s plan was to seize the San Jose, the largest ship in the fleet. But before it could be boarded, something went terribly wrong and the San Jose blew up.

Writing in his log, Wager described an explosion so intense that he could feel the heat from his own ship.

He wrote: “I believe the ship’s side blew out, for she caused a sea that came in our ports. She immediately sank with all her riches.”

Australian Ship Found 74 Years After Sinking in Japanese Airstrikes. Credit — CSIRO Marine National Facility via Storyful Australian Ship Found 74 Years After Sinking in Japanese Airstrikes. Credit — CSIRO Marine National Facility via Storyful

Parts of this story originally appeared in The Sun and are republished with permission.