An accident in the South China Sea involving a nuclear-powered American submarine was caused by an uncharted, natural underwater feature, the U.S. Navy has concluded after a month-long investigation.
In a statement issued late Monday, the U.S. 7th Fleet said its investigation into the Oct. 2 collision determined that the USS Connecticut "grounded on an uncharted seamount while operating in international waters in the Indo-Pacific region." A seamount is a mountain under the sea.
The investigation has been submitted to the commander of the U.S. 7th Fleet, Vice Adm. Karl Thomas, for review and endorsement, as well as to decide whether further accountability actions are needed, the three-sentence statement said.
The U.S. military initially reported, five days after the collision, that the submarine struck an unknown object while operating in the South China Sea. Eleven sailors were reportedly hurt, but none with life-threatening injuries. The sub is undergoing repairs at the Guam Naval Base.
China, which accused the U.S. Navy of covering up the incident, on Tuesday called for the U.S. to explain in detail what happened.
Foreign Ministry Spokesperson Wang Wenbin said the U.S. side had not clarified the “intended navigation” of the sub, whether the incident happened in the waters of another country or whether it caused nuclear leakage or damage to the marine environment.
"This fully exposes the opacity and irresponsibility of the U.S. side," Wang was quoted as saying by state-run Xinhua news agency.
The U.S. has denied any cover-up.
Alexander Neill, a defense and security consultant based in Singapore, told RFA that in his opinion the explanation seemed genuine.
“I don't think the U.S. Navy would attempt to cover up or distort the truth about the nature of the accident. They know that eventually it would leak over time,” Neill said.
Experts say a large area of the disputed Spratly islands in the South China Sea are listed on nautical charts as so-called “dangerous ground” - a poorly surveyed and extremely challenging area to navigate. The deep waters are studded with seamounts.
“The USS Connecticut is one of the fastest subs in the fleet. It has the most sophisticated sonar and tracking technologies to scan what is all around the sub, but sea conditions under the surface are a bit like flying at altitude - undersea weather if you like – with turbulence, currents, changes in salinity and temperature,” the Singapore-based analyst explained.
“This might mean the sub travelling at speed might suddenly descend while the seabed is not fixed and the topography can change,” he added.
Accountability action
In 2005, another submarine - the USS San Francisco - struck a seamount near Guam at full speed, killing one sailor and injuring 24 others.
Andrew Korybko, a Moscow-based American political analyst who has been critical of the U.S. foreign policy in Asia, said: “Questions naturally arise about the U.S. Navy's professionalism and whether they should continue operating nuclear-powered submarines in foreign waters lest they risk another collision that might lead to an ecological catastrophe in the worst-case scenario.”
“This is very embarrassing because it was avoidable, " Korybko added.
In its initial statement on Oct. 7, five days after the collision, the U.S. Pacific Fleet reported that the submarine was in “a safe and stable condition” and its “nuclear propulsion plant and spaces were not affected” and remained fully operational.
According to Neill, the incident has been under investigation to establish whether it was a true accident or avoidable.
“In most cases of avoidable incidents the commander of the vessel is relieved of duty and mostly this is the end of their naval career,” he said.
“The best narrative for China is to accuse the U.S. of irresponsible and unprofessional behavior, also throw in the nuclear threat - which is also their narrative on AUKUS,” Neill added, referring to an Australia-U.K.-U.S. security pact announced in September.
China has been strongly critical of AUKUS which would help Australia develop nuclear submarines and is seen as a pushback against China’s growing military presence in the Indo-Pacific.
The South China Sea has become a flashpoint of tensions between the U.S. and China and a potential conflict zone between the two powers. Observers say Beijing has been expanding its underwater warfare capabilities including a submarine fleet that is currently inferior to the U.S. but developing rapidly.
The U.S. Defense Department's latest report on Chinese military power, published in September 2020, said that China puts high priority on submarine development.
The report said the Chinese Navy “will likely maintain between 65 and 70 submarines through the 2020s, replacing older units with more capable units on a near one-to-one basis."
Currently China operates four nuclear-powered ballistic missile submarines, six nuclear-powered attack submarines, and 50 diesel-powered attack submarines, according to the report.
The U.S. Navy reportedly has around 70 submarines, all nuclear-powered.