On a pre-dawn Friday morning in June 1942, the Japanese cargo ship Burma Maru was traveling at a leisurely 9 knots in the Gulf of Thailand when a torpedo rocked its bow. A second shot followed 15 seconds later.
Twelve minutes after that, sailors from the USS Swordfish submarine watched as the ocean swallowed the 117-meter steamer.
For the next half-century, it’s likely no humans laid eyes on the Burma Maru as it rusted 68 meters beneath the surface, about 111 km off the coast of Koh Rong, Cambodia’s second-largest island.
That all changed last week, when a team of divers based in Cambodia and Thailand located the shipwreck—possibly the largest of its kind in Cambodian waters.
“Basically, in the war reports, there’s only one very interesting shipwreck and that’s the one we found,” said Dennis Funke, the 32-year-old German owner of The Dive Shop Cambodia in Sihanoukville.
Mr. Funke has spent the past few years doggedly combing through World War II-era U.S. Navy ship histories for nearby scuttled boats and asking local fishermen where their nets hit snags.
The USS Swordfish’s patrol report caught his eyes. The nearly 1,500 ton submarine had made history with its December 1941 takedown of a Japanese vessel, an attack that marked the first U.S. submarine to sink a Japanese ship in World War II.
Mr. Funke was intrigued. The coordinates of the Swordfish’s attack on the Burma Maru put it within striking distance and lined up with the accounts of local fishermen. And so began a search that Mr. Funke likened to finding “a needle in a hay bale.”
In the end, however, with some help from a sonar radar system, the team found success on its first dive. The evidence was unmistakable: an old porthole, a telegraph, an 8-meter large brass propeller and a build that matched records of the Burma Maru, according to Mikko Paasi, the Finnish owner of Koh Tao Tec Divers and one of six divers who submerged last week.
“It is the passion to solve a little puzzle of history, because nobody knows where these ships are,” Mr. Paasi said.
There is little documentation of the Burma Maru, its crew or its cargo, aside from the faded few sentences in the Swordfish’s log and regular appearances in Lloyd’s Register, an annual inventory of vessels. The 1942 to 1943 entry in Lloyd’s inventory said it was owned by “Nanyo Kaiun K.K.” and had been built in 1917 in Kobe, Japan.
“The Japanese were very hush-hush about their boats,” Mr. Paasi said.
It’s also unclear if any of the crew survived, though it seems unlikely.
“The shipwreck is basically a war grave,” Mr. Funke said on Tuesday, though the first dive did not reveal any human remains.
For its part, the USS Swordfish and its crew of 89 likely met a similar fate in January 1945, when the ship stopped responding to messages off the coast of Japan.
Henri Locard, a French historian who has extensively studied Cambodian history of the era, said the Japanese troops who occupied French Indochina during the period used the region as a base from which to attack U.S. allies.
Cambodia lacked any major ports, while “Saigon was the only port of call for the Japanese Navy” in occupied Indochina, according to Mr. Locard, who speculated that the Burma Maru might have been heading to or from the city laden with food, weapons and other war wares.
Mr. Funke fears that the ship—whatever its contents —might soon attract enterprising looters. In Malaysian waters, scuttled ships have been sold to Chinese companies for scrap.
While other Cambodian wrecks have been picked over by amateur divers, Mr. Funke said this site is “simply too deep and too dangerous for locals to go.”
He wants to preserve the ship as an intact historical site and plans to eventually lead commercial tours for advanced divers to the site, hoping to “boost my own company and Cambodia tourism in general.”
“I want to be very careful these coordinates don’t get into the wrong hands,” he said.
For now, though, Mr. Funke and his five friends are diving just for kicks.
“My passion is scuba diving,” Mr. Funke said. “I made my passion my work.”