BANGKOK • In the murky waters of the Strait of Malacca, about 144km south of Phuket, Thailand, four divers discovered a World War II submarine that was scuttled 77 years ago and is now teeming with marine life.

The wreckage, believed to be the USS Grenadier, was found last October by divers Jean Luc Rivoire, Lance Horowitz, Benoit Laborie and Ben Reymenants, the team announced this month.

Over the subsequent six months, the men completed six dives to study and identify the submarine, Mr Horowitz, 36, said last Friday from Phuket.

After measuring parts of the submarine and comparing them with technical drawings from the US National Archives and Records Administration, they felt confident they had located the Grenadier, he said.

"It was as good as we were hoping for, really," Mr Horowitz said of the team's US$110,000 (S$150,000) expedition. "It was a very powerful feeling; it was wonderful."

The Grenadier is more than 91m long and weighs 1,475 tonnes, according to the Naval History and Heritage Command.

The submarine was found sitting upright more than 79m underwater, the divers said in a statement.

Mr Robert Palmer, a sailor who was aboard the Grenadier, wrote in a book titled The Silent Service In World War II that in the early morning of April 22, 1943, crew members fired at a Japanese plane, which dropped a bomb nearby.

All 76 men survived but were picked up by a Japanese armed merchant ship and tortured, Mr Palmer said. Four died in captivity.

The next step is to have the findings verified by the naval history command.

That will likely take a few months, according to Dr Robert Neyland, head of the command's underwater archaeology branch.

"Confirming the identity of any potential discovery, as in the case of USS Grenadier, is a process that is given much weight by the US Navy, as not only does it afford legal protections to the site through the Sunken Military Craft Act, but the act can also provide closure to the families of those sailors lost in the line of duty," he said in an e-mail.

NYTIMES