Reason why US submarine collided with 'object' in the East Sea
The seabed in the South China Sea is complex, so even small mistakes can have big consequences.
USS Connecticut is believed to be thesubmarineThe USS Connecticut is the most advanced submarine in the US fleet. It cost $3 billion, moved at high speed and was equipped with the latest electronic equipment. Despite its sophisticated technology, the ship still had an accident when it hit an underwater mountain in the South China Sea on October 2. The USS Connecticut is currently stationed at a US naval base on the Pacific island of Guam for repairs after the incident.
Limited visibility
The US Navy on November 4 provided some clues about the cause of this incident and fired some people involved in the incident. The commanding officer of the nuclear submarine USS Connecticut, Mr. Cameron Aljilani, along with the executive officer - Lieutenant Colonel Patrick Cashin and Boat Commander Cory Rodgers were relieved of their duties. Speaking when announcing this decision, Vice Admiral Karl Thomas - commander of the US Navy's 7th Fleet said: "If the submarine commanders had made good judgment, made careful decisions and followed the required procedures in planning the navigation, closely following the work of the operation team and managing risks, the incident could have been avoided."
The underwater environment is complex and even small mistakes can have big consequences. “You don’t have any windows and you can’t see out,” said Bryan Clark, who has 25 years of experience working with submarines. “You’re moving in the dark without a clear view of what’s going on in front of you.” The USS Connecticut’s mission on October 2 was made even more difficult by the shallow depths of the complex terrain in the South China Sea.
“Submarines are hard to operate,” said Thomas Shugart, a senior fellow at the Center for a New American Security who spent more than 11 years working on U.S. submarines. “Things don’t always go your way.”
According to this expert, surface ships or submarines diving at the depths where periscopes can operate can receive information from global positioning systems to provide sailors with accurate locations. But when diving deeper, the GPS system is not available, submarines must use compasses and maps of the seabed.
Seafloor maps are compiled by sending surface ships over an area and probing the bottom with sound waves—a method called multibeam sonar. However, this process is expensive and time-consuming. Currently, 80% of the Earth’s seafloor has not been mapped.
Complex seabed topography
Speaking to CNN, Mr. David Sandwell, professor of geophysics at the Scripps Institution of Oceanography in California, USA, said that in the East Sea alone, about 50% of the seabed has not been mapped.
The South China Sea is a busy shipping route, accounting for one-third of the world’s shipping traffic. It is also where China is accelerating the construction and reclamation of illegal artificial islands. “Therefore, it is not surprising that a submarine would hit an object,” said David Sandwell. Although the US Navy has not officially announced the location where the USS Connecticut hit the seamount, using satellite measurements of the Earth’s magnetic field and combined with the results of the South China Sea survey, Mr. Sandwell was able to identify 27 locations where the Connecticut may have hit the seamount. These locations are not on the US Navy’s maps.
The US Navy says the Seawolf-class submarines can dive to a maximum depth of 800 feet, but some experts believe they can dive twice that deep. Submarines have sonar, but using it makes them invisible. When sonar is active, it sends out a pulse of sound, commonly called a “ping,” and then tracks the reflected signal from underwater obstacles.
“Using sonar is the only way to see the seabed, but it makes more sound than is necessary. To get an accurate image they have to sound about every 20 seconds, which is a lot of noise,” said David Sandwell.
And even if the terrain below is visible, obstacles are hard to spot. “The surface of the moon is basically better mapped than the ocean floor,” he said.
Gregory B. Poling - Director of the Southeast Asia Program and the Asia Maritime Transparency Initiative (AMTI) of the Center for Strategic and International Studies (CSIS) commented that: "The East Sea is not only a hot spot in the competition between the US and China. This place also causes concern because of its complex terrain." According to this expert, some areas in the East Sea have been marked as dangerous areas on maps for centuries.
Mr. Clark added that some areas of the sea are only 150m or more than 180m deep, so the submarine must pass through a narrow strip to keep its distance from the seabed and away from the surface to avoid detection.
“You can’t dive too deep to avoid hitting an undetected object on the seabed, but you also have to stay far enough away from the surface to avoid enemy detection equipment. To be able to operate safely, you need to have accurate maps,” the expert noted, noting that the US Navy’s seabed maps in the South China Sea may not be as accurate as those in other seas.
The USS Connecticut is not the only submarine to hit a seamount while diving deep under the sea. On January 8, 2005, the USS San Francisco, a US Los Angeles-class attack submarine, crashed into a seamount about 563 km south of Guam, killing one sailor and injuring 97 others./.