US submarine makes quiet, yet deliberate visit to Japan
KEN MORIYASU, Nikkei staff writer
YOKOSUKA, Japan -- Port visits by nuclear-powered submarines are never announced beforehand. Neither is the duration of the stay or the planned date of departure. They just quietly surface without warning, as the U.S. Navy's Ohio-class guided-missile submarine (SSGN) USS Michigan did this week here in Yokosuka, home to the U.S. Navy's 7th Fleet.
Once these submarines submerge, they are nearly impossible to track. "We make our own fresh water, we make our own oxygen. The only thing that limits our sustainability is food," the ship's commanding officer, Captain Joe Turk, told reporters Friday on a rare media tour of the ship. "We carry 90 to 100 days' worth of food."
The port call this time is for replenishment of stores and a short rest for the crew. Yet the visit, while quiet, is a deliberate one, experts say, and is intended to send a clear message.
"The guided-missile submarine is America's most capable asset to counter China's anti-access/area-denial strategy," said Tetsuo Kotani, chief researcher at the Japan Institute of International Affairs, a think tank. China's military doctrine of denying other militaries access to the South China Sea is supported by submarines plus air-launched cruise missiles, and is believed to be a serious threat to American surface ships, including aircraft carriers.
"The guided-missile submarine, on the contrary, can slip beneath such measures and get close to China's shores. China, at this moment, does not have the sonar capability to detect U.S. submarines," Kotani said.
The 170-meter Michigan carries 154 cruise missiles, which can be launched to, for example, destroy enemy runways to prevent aircraft from taking off.
Initially, all 18 Ohio-class subs were strategic ballistic missile submarines (SSBN), carrying submarine-launched ballistic missiles with nuclear warheads. Along with strategic bombers and intercontinental ballistic missiles (ICBMs), they form the triad of the U.S. military's nuclear deterrence.
In the mid-2000s, the Navy converted the oldest four of the 18 Ohios, including the Michigan, to conventional weapon submarines. The 2.2-meter-diameter missile tubes that once held strategic Trident missiles were modified to contain clusters of seven Tomahawk cruise missiles.
The SSBNs are the most lethal ships in the U.S. submarine fleet, but they cannot make port calls in foreign countries due to the nuclear payload they carry, and so are limited in their areas of activity. The converted Michigan has more mobility.
Prior to arriving in Yokosuka, the Michigan made a friendly visit to Busan, South Korea. Despite the tranquil port entry, the message, once again, was loud and clear.
"The U.S.'s heinous intentions, to use the Michigan to launch a preemptive nuclear strike against our republic, has been exposed," the North Korean official newspaper Rodong Sinmun blasted in a commentary. Although technically the Tomahawk cruise missiles inside the Michigan can carry nuclear warheads, the U.S. Navy has moved away from mounting nuclear warheads on tactical missiles.
Michigan left its home port of Bangor, Washington, in November 2013, and has been deployed to the Western Pacific for nearly two years. The ship has two sets of crew, each with 165 sailors -- the Blue crew and the Gold crew -- who rotate every few months to keep the submarine manned.
During that two-to-three month rotation, the crew has no days off. The sailors stand an eight-hour watch, after which they study or receive training to augment their skills. "A day off is when we only have the eight-hour watch," Captain Turk joked. But not many complain. There is little else to do, since, after all, there is no TV, telephone or Internet deep underwater.