The U.S. Navy was forced, by a "Freedom of Information" lawsuit, to release its data on Chinese submarine operations. The data showed that, while Chinese subs are putting to sea more often (a fact that has generated many headlines about the Chinese naval threat), they are still doing so much less than U.S. subs. In 2007, American subs went to sea for long term operations (this is called "patrols") seven times more often than Chinese boats. But the
55 Chinese subs went out on only six patrols in 2007, versus two in 2006 and none in 2005. Before that, through the 1990s, Chinese subs averaged 1.2 patrols a year. The one Chinese ballistic missile sub (SSBN) has never, in its 25 years of existence, gone out on a patrol.
This is not to say that the Chinese boats don't go out at all, but these are largely day trips, moving off shore into the open water, in order to train and test the equipment. But this is no replacement for the long term (two months or more) tours American boats have been doing since World War II.
While the Chinese are modernizing their submarine force, half their boats are still basically obsolete diesel-electric designs. The U.S. nuclear submarine fleet contains more than half the nuclear boats in service worldwide.
But the major American problem is anti-submarine warfare, because even elderly diesel-electric boats have proved difficult to detect. So the U.S. Navy is rebuilding its anti-submarine capability. That may take a few more years, and the main goal is to keep ahead of Chinese developments. The biggest thing the Americans have going for them is that, while the Chinese are building more subs, they are not training with them. Why is that?
Partly it's a matter of money, partly it's the poorly maintained equipment. But mostly it's fear of embarrassment. Over the last few years, there have been several disastrous accidents involving Chinese subs at sea. These were usually just the day trips for training. Boats broke down, sailors died (in one case, an entire crew). But the Chinese have to go to sea a lot more before they become a serious threat to the United States. If the jump in patrols last year is the start of a trend, then the threat is indeed growing. :