What lies beneath: Captain Morgan's final adventure

His name is written into the lore of piracy – and rum. Now a salvage team's coup is bringing the details to the surface

Someone certainly wasn't paying attention, and – who knows? – maybe the look-out boys had been hitting the rum on a fateful night in 1671 when the good ship Satisfaction hit a reef off the coast of Panama, sinking with the loss of its entire crew.

The flagship of Admiral Sir Henry Morgan's fleet, which was travelling to the mouth of the Chagres River to capture the Castillo de San Lorenzo from the Spanish, was one of five vessels that disappeared in choppy seas. It sank to the ocean floor, where it lay for the next 340 years being slowly covered by sand and mud.

By the time a team of divers and archaeologists led by Texas State University chanced upon the wreck earlier this year, just two inches of Satisfaction's hull were still visible. After months of digging, they uncovered roughly 50 feet of her starboard side, along with several wooden chests, encrusted with coral.

The find was announced this week by Frederick "Fritz" Hanselmann, the leader of the research team, who said it had been like chancing upon a "needle in a haystack". Mr Hanselmann hopes the Satisfaction will help to shed light on an inglorious chapter in British adventurism. In March, Mr Hanselmann's team unearthed six cannon from Morgan's fleet near the mouth of the Panama Canal. But the team is yet to discover treasure.

"For us, the real treasure is the shipwrecks themselves, which can give us the ability to accurately tell the story of a legendary historical figure like Captain Henry Morgan," Mr Hanselmann said. "Discoveries of this nature allow us to study these artefacts and teach others what life was like for these famous privateers more than 300 years ago."

Morgan, a mercenary and (some would say) pirate from Monmouthshire, in South Wales, was employed by the Crown to protect trade routes from the Caribbean. After finding that an advance party of his own men had already captured the Castillo de San Lorenzo, he continued up the Chagres towards Panama City, which he promptly destroyed.

That attack violated a peace treaty between England and Spain, meaning that Morgan was arrested. He successfully pleaded ignorance of the treaty, was acquitted and then knighted by Charles II, and subsequently went to Jamaica, where he became lieutenant governor.

Morgan, who died in 1688, remains a legendary figure thanks in part to the brand of cheap rum named after him. And there is at least a whiff of a PR stunt about the fact that Mr Hanselmann's latest expedition was part-funded by that drinks company, which issued a press release yesterday describing the sponsorship deal as "a natural fit".

The corporatisation of the salvage industry is nothing new, though. In recent years, there has been a huge rise in the number of shipwrecks being unearthed by privately funded marine archaeologists, using cutting-edge undersea exploration technology, such as sonar, magnetometers, and remotely operated submersible robots.

Unlike Mr Hanselmann's non-profit operation, the vast majority of today's undersea explorers are commercial enterprises which operate in great secrecy, leading to fears that valuable historical sites are being plundered. The UN estimates that 3 million shipwrecks litter the ocean floor, and the value of their sunken cargo runs to tens of billions of pounds. Under the 1989 International Convention on Salvage, wrecks in international waters are there for the taking, provided they are not sovereign vessels. Interpreting that law can be complicated. A US company called Odyssey Marine Exploration is locked in a legal dispute with the Spanish government over the discovery of 500,000 gold and silver coins, weighing 17 tons, near Portugal. Spain insists the haul, worth some $500m (£310m), was from the Nuestra Senora de las Mercedes, a frigate sunk by the Royal Navy in 1804. Odyssey insists otherwise.

Such firms insist that, in the absence of government funding, private salvage is the only way to uncover and preserve important artefacts. Odyssey has in the past struck deals with the British government to share profits and preserve important pieces from three UK vessels it discovered: HMS Sussex; RMS Laconia; and HMS Victory, the predecessor to Nelson's flagship, which was found some 60 miles off Alderney in May 2008. Odyssey has also worked with US museums to allow the public to see the remains of ships such as the SS Republic, a steamship from Baltimore which sank in a hurricane in 1865.

The Satisfaction, along with any other remnants of Captain Morgan's fleet that Mr Hanselmann discovers, will end up informing the public. Mr Hanselmann said yesterday all his finds will be donated to Panama's National Institute of Culture.

Famous shipwrecks

The Mary Rose King Henry VIII's flagship vessel was raised to the surface in 1982, after 437 years at the bottom of the Solent. More than 10,000 artefacts from the ship's last voyage (to meet the French in battle in 1510) were recovered. The ship is on display in Portsmouth Historic Dockyard.

The Titanic An American-French expedition rediscovered The Titanic in 1985, 73 years after the infamous liner hit an iceberg and sank on 15 April 1912, killing 1,503 passengers and crew. Experts believe it would be impossible to raise the wreck from its resting place 2.5 miles (4 km) below the surface of the Atlantic Ocean.

Bismarck The 45,000-ton battleship was once the German Navy's pride and joy during the Second World War, before it was sunk by British torpedoes in 1941 along with 2,900 crew members. Now, its remains lie around 600 miles west of Brest, on the French coast, at a depth of almost 4,790 metres (15,700 feet).