Chinese Submarine sneaks into Navy excercise.

This is a picture of a Song class submarine, the same one that popped up during a U.S. Navy exercise with the Kitty Hawk Battle Group.


I heard this on the radio and it is messed up in my opinion. We know the Chinese are rapidly building up a "Blue Water" fleet. They are acquiring subs and sub technology from Russia. They are also buying old Russian Carriers and building two carriers from scratch.
The question is, when are we going to start building more subs or upgrading old ones? I know the life of a sub is around 20 years. About the life of their reactor(s).
We know China is a growing threat, what are we going to do about it? Maybe we should change our naval doctrine and build more subs.
Anyone on the blog who was in the Navy has any comments?