I could sink an aircraft carrier, if I were allowed aboard with several pounds of explosives and the will to do it. So we should forego the costs of submarines AND carriers, and just arm our soldiers with backpacks full of C-4 or Semtex, right?

A submarine could sink an aircraft carrier, if:

1. it used nuclear munitions to destroy a carrier and its escort group. As I have said, the use of nuclear weapons is highly unlikely by developed nations. The effects and consequences are much too high.

2. it was able to penetrate close enough to initiate a torpedo attack or an SSM attack. There are many problems with this approach. The submarine has to be able to penetrate a multi-layered defense system consisting of SOSUS warning devices, U.S. submarines, carrier-based and land-based ASW aircraft, specific ASW surface ships in the carrier group. After evading or destroying all this, the submarine still must attack and effectively strike a carrier in a manner to cripple or destroy it. This might entail having to perform multiple attacks to destroy so large a target as a carrier, each attack becoming subsequently more challenging than the previous as the submarine has lost both its elements of stealth and surprise. The torpedo or SSM must also, once launched, actually survive and strike the carrier. In the history of the U.S. carrier force, only 3 carriers have been lost to submarines, ever.