http://www.boston.com/dailyglobe2/124/nation/Cause_of_submarine_disaster_is_mystery+.shtmlCause of submarine disaster is mystery
By Indira A.R. Lakshmanan, Globe Staff, 5/4/2003
BEIJING -- When submarine No. 361 descended on a training mission two weeks ago, a malfunctioning diesel engine may have sucked the oxygen out of the hull, claiming the lives of all 70 crewmen within two minutes, a senior Chinese Navy official said yesterday.
All the victims were found at their posts, and there were no signs of struggle, suggesting that death came upon the men quickly, according to the official, who spoke on condition of anonymity.
The Chinese military publicly attributed the tragedy to ''mechanical failure,'' giving no further explanation in a brief announcement Friday night. But Western naval specialists familiar with diesel-powered submarines said the official's account was plausible.
According to the navy official, the submarine had charged its batteries from its diesel engine at the surface in preparation for descent. Diesel power is switched off in preparation for descent because diesel requires oxygen to burn, the specialists said.
In this case, mechanical failure is believed to have caused the diesel power to continue running, depriving the hull of its oxygen and suffocating the crew, the official said.
''That is very plausible, and I'm inclined to believe that's what happened,'' said retired admiral Lloyd ''Joe'' Vasey, who served 36 years in the US Navy, including a dozen aboard diesel-powered submarines.
In a telephone interview from Honolulu, where he founded the Pacific Forum with the Center for Strategic and International Studies, Vasey said that ''the first thing you do when you dive is you shut off the diesel because it sucks up a lot of air, switch to battery power, and close the hatch. People don't forget to shut it down,'' he said of the diesel engine, which in Ming class submarines is easily shut off.
Mechanical failure of the engine, air induction valve in the engine room, secondary air ducts, or a gasket are possible explanations, he said.
''But it's possible we may never know the cause,'' Vasey said.
The accident occurred during a training mission on April 16, the official said, but was not discovered by the navy until 10 days later, when the submarine crew did not contact their base as expected. The crew had been under instructions to maintain radio silence during training to practice disguising their location from detection by enemy intelligence.
Ming class submarines can go 60 days without resupply, according to Jane's Defence Weekly.
The crew had been training in the Neichangshan Islands off the coast of northeastern Shandong and Liaoning provinces.
It is rare for China to release any news of military accidents, making the announcement, even if belated, striking. In the 1980s, a destroyer is believed to have exploded near the southern island of Hainan, killing about 100 crew members in what is thought to be the nation's worst naval accident in the last 50 years. That incident was never officially reported.
Western analysts said the disclosure suggests that President Hu Jintao's pledge to promote openness in government and media could be genuine. Smarting from global criticism over its coverup of severe acute respiratory syndrome, China might be more inclined to release bad news now rather than have it leaked by an insider, analysts said. An indignant military doctor publicized the hidden cases of SARS in hospitals.
The No. 361 submarine was built in 1995, making it one of the newer of the Ming class that China produced from 1971 to 1996. Intended for patrols and coastal defense, it is copied from the decades-old Soviet Romeo class, which was based on a German U-boat produced in 1944.
The Ming class is considered obsolete by the Federation of American Scientists, but Vasey said he did not see any reason for China to retire its fleet of Ming class submarines, now estimated at 13, because ''accidents can happen to any subs.''
But James Clay Moltz, a research professor at Monterey Institute of International Studies in California, said the Ming class has had problems before. One of the earliest produced was scrapped because of a fire.
In a telephone interview, Moltz said that No. 361 was the only Ming class submarine built at Hudong Shipyard, suggesting there may have been some engineering differences in this boat that contributed to the malfunction.
The Ming class submarines are 249 feet long and 25 feet wide, able to submerge to 984 feet and travel at 18 knots underwater. They are equipped with eight torpedo tubes for 16 torpedoes or 32 mines, Chinese military sources say. They usually hold nine officers and 46 sailors, suggesting that other technicians or staff officers were aboard for this exercise.
The accident highlights vulnerability in China's aging fleet of domestic and Russian submarines, estimated to number around 90. Submarines are tactically useful for China, especially to enforce its claim on the island of Taiwan, because they are difficult to detect, and unseen submarines are a powerful deterrent to any enemy.
